Sample records for heat exchanger surface

  1. Corrosive resistant heat exchanger

    DOE Patents [OSTI]

    Richlen, Scott L. (Annandale, VA)

    1989-01-01T23:59:59.000Z

    A corrosive and errosive resistant heat exchanger which recovers heat from a contaminated heat stream. The heat exchanger utilizes a boundary layer of innocuous gas, which is continuously replenished, to protect the heat exchanger surface from the hot contaminated gas. The innocuous gas is conveyed through ducts or perforations in the heat exchanger wall. Heat from the heat stream is transferred by radiation to the heat exchanger wall. Heat is removed from the outer heat exchanger wall by a heat recovery medium.

  2. Sea surface exchanges of momentum, heat, and freshwater determined by satellite remote sensing

    E-Print Network [OSTI]

    Yu, Lisan

    1 Sea surface exchanges of momentum, heat, and freshwater determined by satellite remote sensing Freshwater flux Latent heat flux Longwave radiation Satellite remote sensing Sea surface flux estimation Sensible heat flux Shortwave radiation Surface wind fields 2 #12;Sea surface exchanges of momentum, heat

  3. A theory for heat exchangers with liquid-desiccant-wetted surfaces

    SciTech Connect (OSTI)

    Otterbein, R.T. [Otterbein Engineering, Phoenix, AZ (United States)

    1995-08-01T23:59:59.000Z

    The following theory extends the wet surface model of Maclaine-cross and Banks (1981) to include heat exchangers that heat or cool moist air with liquid-desiccant-wetted surfaces. The theory uses a wall boundary condition that forces the moist air to be at an arbitrary relative humidity that is less than totally saturated. The theory defines a new temperature scale (brine-bulb temperature) for which the wet-bulb temperature is a special case. Brine-bulb heat capacitance and heat transfer coefficient are defined. By using an analogy to the dry surface heat exchanger theory, the performance of these heat exchangers can then be estimated from the performance of geometrically identical heat exchangers with a dry surface. Charts to utilize the theory at various elevations are shown.

  4. A corrosive resistant heat exchanger

    DOE Patents [OSTI]

    Richlen, S.L.

    1987-08-10T23:59:59.000Z

    A corrosive and erosive resistant heat exchanger which recovers heat from a contaminated heat stream. The heat exchanger utilizes a boundary layer of innocuous gas, which is continuously replenished, to protect the heat exchanger surface from the hot contaminated gas. The innocuous gas is pumped through ducts or perforations in the heat exchanger wall. Heat from the heat stream is transferred by radiation to the heat exchanger wall. Heat is removed from the outer heat exchanger wall by a heat recovery medium. 3 figs., 3 tabs.

  5. Heat and mass exchanger

    DOE Patents [OSTI]

    Lowenstein, Andrew (Princeton, NJ); Sibilia, Marc J. (Princeton, NJ); Miller, Jeffrey A. (Hopewell, NJ); Tonon, Thomas (Princeton, NJ)

    2007-09-18T23:59:59.000Z

    A mass and heat exchanger includes at least one first substrate with a surface for supporting a continuous flow of a liquid thereon that either absorbs, desorbs, evaporates or condenses one or more gaseous species from or to a surrounding gas; and at least one second substrate operatively associated with the first substrate. The second substrate includes a surface for supporting the continuous flow of the liquid thereon and is adapted to carry a heat exchange fluid therethrough, wherein heat transfer occurs between the liquid and the heat exchange fluid.

  6. Heat and mass exchanger

    DOE Patents [OSTI]

    Lowenstein, Andrew (Princeton, NJ); Sibilia, Marc J. (Princeton, NJ); Miller, Jeffrey A. (Hopewell, NJ); Tonon, Thomas (Princeton, NJ)

    2011-06-28T23:59:59.000Z

    A mass and heat exchanger includes at least one first substrate with a surface for supporting a continuous flow of a liquid thereon that either absorbs, desorbs, evaporates or condenses one or more gaseous species from or to a surrounding gas; and at least one second substrate operatively associated with the first substrate. The second substrate includes a surface for supporting the continuous flow of the liquid thereon and is adapted to carry a heat exchange fluid therethrough, wherein heat transfer occurs between the liquid and the heat exchange fluid.

  7. Optimization of Heat Exchangers

    SciTech Connect (OSTI)

    Ivan Catton

    2010-10-01T23:59:59.000Z

    The objective of this research is to develop tools to design and optimize heat exchangers (HE) and compact heat exchangers (CHE) for intermediate loop heat transport systems found in the very high temperature reator (VHTR) and other Generation IV designs by addressing heat transfer surface augmentation and conjugate modeling. To optimize heat exchanger, a fast running model must be created that will allow for multiple designs to be compared quickly. To model a heat exchanger, volume averaging theory, VAT, is used. VAT allows for the conservation of mass, momentum and energy to be solved for point by point in a 3 dimensional computer model of a heat exchanger. The end product of this project is a computer code that can predict an optimal configuration for a heat exchanger given only a few constraints (input fluids, size, cost, etc.). As VAT computer code can be used to model characteristics )pumping power, temperatures, and cost) of heat exchangers more quickly than traditional CFD or experiment, optimization of every geometric parameter simultaneously can be made. Using design of experiment, DOE and genetric algorithms, GE, to optimize the results of the computer code will improve heat exchanger disign.

  8. Segmented heat exchanger

    DOE Patents [OSTI]

    Baldwin, Darryl Dean (Lafayette, IN); Willi, Martin Leo (Dunlap, IL); Fiveland, Scott Byron (Metamara, IL); Timmons, Kristine Ann (Chillicothe, IL)

    2010-12-14T23:59:59.000Z

    A segmented heat exchanger system for transferring heat energy from an exhaust fluid to a working fluid. The heat exchanger system may include a first heat exchanger for receiving incoming working fluid and the exhaust fluid. The working fluid and exhaust fluid may travel through at least a portion of the first heat exchanger in a parallel flow configuration. In addition, the heat exchanger system may include a second heat exchanger for receiving working fluid from the first heat exchanger and exhaust fluid from a third heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the second heat exchanger in a counter flow configuration. Furthermore, the heat exchanger system may include a third heat exchanger for receiving working fluid from the second heat exchanger and exhaust fluid from the first heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the third heat exchanger in a parallel flow configuration.

  9. Optimization of Heat Exchanger Cleaningá

    E-Print Network [OSTI]

    Siegell, J. H.

    1986-01-01T23:59:59.000Z

    The performance of heat integration systems is quantified in terms of the amount of heat that is recovered. This decreases with time due to increased fouling of the heat exchange surface. Using the "Total Fouling Related Expenses (TFRE)" approach...

  10. Value pricing of surface coatings for mitigating heat exchanger fouling

    E-Print Network [OSTI]

    Wilson, D.I.; Gomes da Cruz, L.; Ishiyama, E.M.; Boxler, C.; Augustin, W.; Scholl, S.

    2014-05-19T23:59:59.000Z

    crystallisation fouling; (b) fluorocarbon-based coatings which offer antifouling performance but can reduce heat transfer, for crystallisation fouling; and (c) fluorocarbon-based coatings in a dairy pasteuriser application. A novel strategy, of replacing stainless...

  11. Woven heat exchanger

    DOE Patents [OSTI]

    Piscitella, R.R.

    1984-07-16T23:59:59.000Z

    This invention relates to a heat exchanger for waste heat recovery from high temperature industrial exhaust streams. In a woven ceramic heat exchanger using the basic tube-in-shell design, each heat exchanger consisting of tube sheets and tube, is woven separately. Individual heat exchangers are assembled in cross-flow configuration. Each heat exchanger is woven from high temperature ceramic fiber, the warp is continuous from tube to tube sheet providing a smooth transition and unitized construction.

  12. Active microchannel heat exchanger

    DOE Patents [OSTI]

    Tonkovich, Anna Lee Y. (Pasco, WA) [Pasco, WA; Roberts, Gary L. (West Richland, WA) [West Richland, WA; Call, Charles J. (Pasco, WA) [Pasco, WA; Wegeng, Robert S. (Richland, WA) [Richland, WA; Wang, Yong (Richland, WA) [Richland, WA

    2001-01-01T23:59:59.000Z

    The present invention is an active microchannel heat exchanger with an active heat source and with microchannel architecture. The microchannel heat exchanger has (a) an exothermic reaction chamber; (b) an exhaust chamber; and (c) a heat exchanger chamber in thermal contact with the exhaust chamber, wherein (d) heat from the exothermic reaction chamber is convected by an exothermic reaction exhaust through the exhaust chamber and by conduction through a containment wall to the working fluid in the heat exchanger chamber thereby raising a temperature of the working fluid. The invention is particularly useful as a liquid fuel vaporizer and/or a steam generator for fuel cell power systems, and as a heat source for sustaining endothermic chemical reactions and initiating exothermic reactions.

  13. Thermoelectric heat exchange element

    DOE Patents [OSTI]

    Callas, James J. (Peoria, IL); Taher, Mahmoud A. (Peoria, IL)

    2007-08-14T23:59:59.000Z

    A thermoelectric heat exchange module includes a first substrate including a heat receptive side and a heat donative side and a series of undulatory pleats. The module may also include a thermoelectric material layer having a ZT value of 1.0 or more disposed on at least one of the heat receptive side and the heat donative side, and an electrical contact may be in electrical communication with the thermoelectric material layer.

  14. Radial flow heat exchanger

    DOE Patents [OSTI]

    Valenzuela, Javier (Hanover, NH)

    2001-01-01T23:59:59.000Z

    A radial flow heat exchanger (20) having a plurality of first passages (24) for transporting a first fluid (25) and a plurality of second passages (26) for transporting a second fluid (27). The first and second passages are arranged in stacked, alternating relationship, are separated from one another by relatively thin plates (30) and (32), and surround a central axis (22). The thickness of the first and second passages are selected so that the first and second fluids, respectively, are transported with laminar flow through the passages. To enhance thermal energy transfer between first and second passages, the latter are arranged so each first passage is in thermal communication with an associated second passage along substantially its entire length, and vice versa with respect to the second passages. The heat exchangers may be stacked to achieve a modular heat exchange assembly (300). Certain heat exchangers in the assembly may be designed slightly differently than other heat exchangers to address changes in fluid properties during transport through the heat exchanger, so as to enhance overall thermal effectiveness of the assembly.

  15. Proceedings: Heat exchanger workshop

    SciTech Connect (OSTI)

    Not Available

    1987-07-01T23:59:59.000Z

    Heat transfer processes are of controlling importance in the operation of a thermal power plant. Heat exchangers are major cost items and are an important source of problems causing poor power plant availability and performance. A workshop to examine the improvements that can be made to heat exchangers was sponsored by the Electric Power Research Institute (EPRI) on June 10-11, 1986, in Palo Alto, California. This workshop was attended by 25 engineers and scientists representing EPRI-member utilities and EPRI consultants. A forum was provided for discussions related to the design, operation and maintenance of utility heat transfer equipment. The specific objectives were to identify research directions that could significantly improve heat exchanger performance, reliability and life cycle economics. Since there is a great diversity of utility heat transfer equipment in use, this workshop addressed two equipment categories: Boiler Feedwater Heaters (FWH) and Heat Recovery Steam Generators (HRSG). The workshop was divided into the following panel sessions: functional design, mechanical design, operation, suggested research topics, and prioritization. Each panel session began with short presentations by experts on the subject and followed by discussions by the attendees. This report documents the proceedings of the workshop and contains recommendations of potentially valuable areas of research and development. 4 figs.

  16. NGNP Process Heat Utilization: Liquid Metal Phase Change Heat Exchanger

    SciTech Connect (OSTI)

    Piyush Sabharwall; Mike Patterson; Vivek Utgikar; Fred Gunnerson

    2008-09-01T23:59:59.000Z

    One key long-standing issue that must be overcome to fully realize the successful growth of nuclear power is to determine other benefits of nuclear energy apart from meeting the electricity demands. The Next Generation Nuclear Plant (NGNP) will most likely be producing electricity and heat for the production of hydrogen and/or oil retrieval from oil sands and oil shale to help in our national pursuit of energy independence. For nuclear process heat to be utilized, intermediate heat exchange is required to transfer heat from the NGNP to the hydrogen plant or oil recovery field in the most efficient way possible. Development of nuclear reactor - process heat technology has intensified the interest in liquid metals as heat transfer media because of their ideal transport properties. Liquid metal heat exchangers are not new in practical applications. An important rational for considering liquid metals is the potential convective heat transfer is among the highest known. Thus explains the interest in liquid metals as coolant for intermediate heat exchange from NGNP. For process heat it is desired that, intermediate heat exchangers (IHX) transfer heat from the NGNP in the most efficient way possible. The production of electric power at higher efficiency via the Brayton Cycle, and hydrogen production, requires both heat at higher temperatures and high effectiveness compact heat exchangers to transfer heat to either the power or process cycle. Compact heat exchangers maximize the heat transfer surface area per volume of heat exchanger; this has the benefit of reducing heat exchanger size and heat losses. High temperature IHX design requirements are governed in part by the allowable temperature drop between the outlet and inlet of the NGNP. In order to improve the characteristics of heat transfer, liquid metal phase change heat exchangers may be more effective and efficient. This paper explores the overall heat transfer characteristics and pressure drop of the phase change heat exchanger with Na as the heat exchanger coolant. In order to design a very efficient and effective heat exchanger one must optimize the design such that we have a high heat transfer and a lower pressure drop, but there is always a trade-off between them. Based on NGNP operational parameters, a heat exchanger analysis with the sodium phase change will be presented to show that the heat exchanger has the potential for highly effective heat transfer, within a small volume at reasonable cost.

  17. Heat exchanger for power generation equipment

    DOE Patents [OSTI]

    Nirmalan, Nirm Velumylm; Bowman, Michael John

    2005-06-14T23:59:59.000Z

    A heat exchanger for a turbine is provided wherein the heat exchanger comprises a heat transfer cell comprising a sheet of material having two opposed ends and two opposed sides. In addition, a plurality of concavities are disposed on a surface portion of the sheet of material so as to cause hydrodynamic interactions and affect a heat transfer rate of the turbine between a fluid and the concavities when the fluid is disposed over the concavities.

  18. DHE (downhole heat exchangers). [Downhole Heat Exchangers (DHE)

    SciTech Connect (OSTI)

    Culver, G.

    1990-11-01T23:59:59.000Z

    The use of downhole heat exchangers (DHE) for residential or commercial space and domestic water heating and other applications has several desirable features. Systems are nearly or completely passive -- that is, no or very little geothermal water or steam is produced from the well either reducing or completely eliminating surface environmental concerns and the need for disposal systems or injection wells. Initial cost of pumps and installation are eliminated or reduced along with pumping power costs and maintenance costs associated with pumping often corrosive geothermal fluids. Many residential and small commercial systems do not require circulating pumps because the density difference in the incoming and outgoing sides of the loop are sufficient to overcome circulating friction losses in the entire system. The major disadvantage of DHEs is their dependence on natural heat flow. In areas where geological conditions provide high permeability and a natural hydraulic gradient, DHEs can provide a substantial quantity of heat. A single 500-ft (152 m) well in Klamath Falls, Oregon, supplies over one megawatt thermal and output is apparently limited by the surface area of pipe that can be installed in the well bore. In contrast, DHEs used in conjunction with heat pumps may supply less than 8 KW from a well of similar depth. Here output is limited by conductive heat flow with perhaps a small contribution from convection near the well bore. The highest capacity DHE reported to date, in Turkey, supplies 6 MW thermal from an 820-ft (250 m) well. There were two main goals for this project. The first was to gather, disseminate and exchange internationally information on DHES. The second was to perform experiments that would provide insight into well bore/aquifer interaction and thereby provide more information on which to base DHE designs. 27 refs., 31 figs., 3 tabs.

  19. Heat exchanger with transpired, highly porous fins

    DOE Patents [OSTI]

    Kutscher, Charles F. (Golden, CO); Gawlik, Keith (Boulder, CO)

    2002-01-01T23:59:59.000Z

    The heat exchanger includes a fin and tube assembly with increased heat transfer surface area positioned within a hollow chamber of a housing to provide effective heat transfer between a gas flowing within the hollow chamber and a fluid flowing in the fin and tube assembly. A fan is included to force a gas, such as air, to flow through the hollow chamber and through the fin and tube assembly. The fin and tube assembly comprises fluid conduits to direct the fluid through the heat exchanger, to prevent mixing with the gas, and to provide a heat transfer surface or pathway between the fluid and the gas. A heat transfer element is provided in the fin and tube assembly to provide extended heat transfer surfaces for the fluid conduits. The heat transfer element is corrugated to form fins between alternating ridges and grooves that define flow channels for directing the gas flow. The fins are fabricated from a thin, heat conductive material containing numerous orifices or pores for transpiring the gas out of the flow channel. The grooves are closed or only partially open so that all or substantially all of the gas is transpired through the fins so that heat is exchanged on the front and back surfaces of the fins and also within the interior of the orifices, thereby significantly increasing the available the heat transfer surface of the heat exchanger. The transpired fins also increase heat transfer effectiveness of the heat exchanger by increasing the heat transfer coefficient by disrupting boundary layer development on the fins and by establishing other beneficial gas flow patterns, all at desirable pressure drops.

  20. Heat exchange assembly

    DOE Patents [OSTI]

    Lowenstein, Andrew; Sibilia, Marc; Miller, Jeffrey; Tonon, Thomas S.

    2004-06-08T23:59:59.000Z

    A heat exchange assembly comprises a plurality of plates disposed in a spaced-apart arrangement, each of the plurality of plates includes a plurality of passages extending internally from a first end to a second end for directing flow of a heat transfer fluid in a first plane, a plurality of first end-piece members equaling the number of plates and a plurality of second end-piece members also equaling the number of plates, each of the first and second end-piece members including a recessed region adapted to fluidly connect and couple with the first and second ends of the plate, respectively, and further adapted to be affixed to respective adjacent first and second end-piece members in a stacked formation, and each of the first and second end-piece members further including at least one cavity for enabling entry of the heat transfer fluid into the plate, exit of the heat transfer fluid from the plate, or 180.degree. turning of the fluid within the plate to create a serpentine-like fluid flow path between points of entry and exit of the fluid, and at least two fluid conduits extending through the stacked plurality of first and second end-piece members for providing first fluid connections between the parallel fluid entry points of adjacent plates and a fluid supply inlet, and second fluid connections between the parallel fluid exit points of adjacent plates and a fluid discharge outlet so that the heat transfer fluid travels in parallel paths through each respective plate.

  1. Comparative analysis of compact heat exchangers for application as the intermediate heat exchanger for advanced nuclear reactors

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bartel, N.; Chen, M.; Utgikar, V. P.; Sun, X.; Kim, I. H.; Christensen, R.; Sabharwall, P.

    2015-07-01T23:59:59.000Z

    A comparative evaluation of alternative compact heat exchanger designs for use as the intermediate heat exchanger in advanced nuclear reactor systems is presented in this article. Candidate heat exchangers investigated included the Printed circuit heat exchanger (PCHE) and offset strip-fin heat exchanger (OSFHE). Both these heat exchangers offer high surface area to volume ratio (a measure of compactness [m2/m3]), high thermal effectiveness, and overall low pressure drop. Heliumľhelium heat exchanger designs for different heat exchanger types were developed for a 600 MW thermal advanced nuclear reactor. The wavy channel PCHE with a 15░ pitch angle was found to offer optimummoreá╗combination of heat transfer coefficient, compactness and pressure drop as compared to other alternatives. The principles of the comparative analysis presented here will be useful for heat exchanger evaluations in other applications as well.źáless

  2. High Temperature Heat Exchanger Project

    SciTech Connect (OSTI)

    Anthony E. Hechanova, Ph.D.

    2008-09-30T23:59:59.000Z

    The UNLV Research Foundation assembled a research consortium for high temperature heat exchanger design and materials compatibility and performance comprised of university and private industry partners under the auspices of the US DOE-NE Nuclear Hydrogen Initiative in October 2003. The objectives of the consortium were to conduct investigations of candidate materials for high temperature heat exchanger componets in hydrogen production processes and design and perform prototypical testing of heat exchangers. The initial research of the consortium focused on the intermediate heat exchanger (located between the nuclear reactor and hydrogen production plan) and the components for the hydrogen iodine decomposition process and sulfuric acid decomposition process. These heat exchanger components were deemed the most challenging from a materials performance and compatibility perspective

  3. Ceramic heat exchanger

    DOE Patents [OSTI]

    LaHaye, P.G.; Rahman, F.H.; Lebeau, T.P.; Severin, B.K.

    1998-06-16T23:59:59.000Z

    A tube containment system is disclosed. The tube containment system does not significantly reduce heat transfer through the tube wall. The contained tube is internally pressurized, and is formed from a ceramic material having high strength, high thermal conductivity, and good thermal shock resistance. The tube containment system includes at least one ceramic fiber braid material disposed about the internally pressurized tube. The material is disposed about the tube in a predetermined axial spacing arrangement. The ceramic fiber braid is present in an amount sufficient to contain the tube if the tube becomes fractured. The tube containment system can also include a plurality of ceramic ring-shaped structures, in contact with the outer surface of the tube, and positioned between the tube and the ceramic fiber braid material, and/or at least one transducer positioned within tube for reducing the internal volume and, therefore, the energy of any shrapnel resulting from a tube fracture. 6 figs.

  4. Heat exchanger using graphite foam

    DOE Patents [OSTI]

    Campagna, Michael Joseph; Callas, James John

    2012-09-25T23:59:59.000Z

    A heat exchanger is disclosed. The heat exchanger may have an inlet configured to receive a first fluid and an outlet configured to discharge the first fluid. The heat exchanger may further have at least one passageway configured to conduct the first fluid from the inlet to the outlet. The at least one passageway may be composed of a graphite foam and a layer of graphite material on the exterior of the graphite foam. The layer of graphite material may form at least a partial barrier between the first fluid and a second fluid external to the at least one passageway.

  5. Heat exchanger with ceramic elements

    DOE Patents [OSTI]

    Corey, John A. (North Troy, NY)

    1986-01-01T23:59:59.000Z

    An annular heat exchanger assembly includes a plurality of low thermal growth ceramic heat exchange members with inlet and exit flow ports on distinct faces. A mounting member locates each ceramic member in a near-annular array and seals the flow ports on the distinct faces into the separate flow paths of the heat exchanger. The mounting member adjusts for the temperature gradient in the assembly and the different coefficients of thermal expansion of the members of the assembly during all operating temperatures.

  6. Designing Flexible Heat Exchanger Networks

    E-Print Network [OSTI]

    Gautam, R.; Chen, H. S.; Wareck, J. S.

    Procedures and methods used for designing flexible heat exchanger networks are described. The general approach consists of defining the flexibility problem as a set of cases. Pinch Technology is then used to develop an initial network design...

  7. DESIGN OF A COMPACT HEAT EXCHANGER FOR HEAT RECUPERATION FROM A HIGH TEMPERATURE ELECTROLYSIS SYSTEM

    SciTech Connect (OSTI)

    G. K. Housley; J.E. O'Brien; G.L. Hawkes

    2008-11-01T23:59:59.000Z

    Design details of a compact heat exchanger and supporting hardware for heat recuperation in a high-temperature electrolysis application are presented. The recuperative heat exchanger uses a vacuum-brazed plate-fin design and operates between 300 and 800░C. It includes corrugated inserts for enhancement of heat transfer coefficients and extended heat transfer surface area. Two recuperative heat exchangers are required per each four-stack electrolysis module. The heat exchangers are mated to a base manifold unit that distributes the inlet and outlet flows to and from the four electrolysis stacks. Results of heat exchanger design calculations and assembly details are also presented.

  8. Temperature profile of the infrared image Heat exchange between

    E-Print Network [OSTI]

    Jaehne, Bernd

    T Temperature profile of the infrared image Heat exchange between atmosphere and ocean References coefficient of heat in water determine the heat transfer velocity: *t Infrared images of the water surface: a-Karls-Universit├Ąt Heidelberg www.uni-heidelberg.de Active controlled flux technique (ACFT) Continuous heat flux Periodic heat

  9. THERMOSIPHON WATER HEATERS WITH HEAT EXCHANGERS

    E-Print Network [OSTI]

    Mertol, Atila

    2012-01-01T23:59:59.000Z

    The Performance of Solar Water Heater With Natural Ci rcul2-6, 1980 THERMOSIPHON WATER HEATERS WITH HEAT EXCHANGERSJune 1980 THERMOSIPHON WATER HEATERS WITH HEAT EXCHANGERS*

  10. Low-Cost Microchannel Heat Exchanger

    Energy Savers [EERE]

    process Produce prototype heat exchangers for electronics cooling and high pressure waste heat recovery power system applications Test integrity and confirm high...

  11. Synergistic diffuser/heat-exchanger design

    E-Print Network [OSTI]

    Lazzara, David S. (David Sergio), 1980-

    2004-01-01T23:59:59.000Z

    The theoretical and numerical evaluation of synergistic diffusing heat-exchanger design is presented. Motivation for this development is based on current diffuser and heat-exchange technologies in cogeneration plants, which ...

  12. Heat Exchanger Fouling- Prediction, Measurement and Mitigationá

    E-Print Network [OSTI]

    Peterson, G. R.

    1989-01-01T23:59:59.000Z

    The U. S. Department of Energy (DOE), Office of Industrial Programs (OIP) sponsors the development of innovative heat exchange systems. Fouling is a major and persistent cost associated with most industrial heat exchangers and nationally wastes...

  13. Heat transfer in the plate heat exchanger of an ammonia-synthesis column

    SciTech Connect (OSTI)

    Obolentsev, Y.G.; Chus', M.S.; Norobchanskii, O.A.; Teplitshi, Y.S.; Tovazhnyanskii, L.L.

    1983-01-01T23:59:59.000Z

    The planning and construction of high-capacity synthetic ammonia plants requires the development and fabrication of unique, high unit-power equipment with high technical and economic characteristics. In foreign and domestic practice, tubular heat exchangers with relatively low heat-transfer coefficients are used. Plate heat exchangers are a promising alternative. They are compact and have a high heat energy efficiency and a relatively small metal content. To make an experimental check of the operating capability of a plate heat exchanger under ammonia production conditions, a welded plate heat exchanger was designed for an ammonia synthesis column 800mm in diameter. On prolonged testing (four years), the device provided an autothermal operating mode in the column and the heat transfer coefficient was practically constant for fixed space velocities. Consequently, the heat exchange surface was not contaminated significantly with catalyst dust, confirmed by visual observation of the heat exchanger after disassembly.

  14. Progress Report for Diffusion Welding of the NGNP Process Application Heat Exchangers

    SciTech Connect (OSTI)

    R.E. Mizia; D.E. Clark; M.V. Glazoff; T.E. Lister; T.L. Trowbridge

    2011-04-01T23:59:59.000Z

    The NGNP Project is currently investigating the use of metallic, diffusion welded, compact heat exchangers to transfer heat from the primary (reactor side) heat transport system to the secondary heat transport system. The intermediate heat exchanger will transfer this heat to downstream applications such as hydrogen production, process heat, and electricity generation. The channeled plates that make up the heat transfer surfaces of the intermediate heat exchanger will have to be assembled into an array by diffusion welding.

  15. IMPLEMENTING GROUND SOURCE HEAT PUMP AND GROUND LOOP HEAT EXCHANGER

    E-Print Network [OSTI]

    IMPLEMENTING GROUND SOURCE HEAT PUMP AND GROUND LOOP HEAT EXCHANGER MODELS IN THE ENERGYPLUS #12;ii IMPLEMENTING GROUND SOURCE HEAT PUMP AND GROUND LOOP HEAT EXCHANGER MODELS IN THE ENERGYPLUS............................................................... 2 1.3. Overview of the Parameter Estimation Water-to-Water Heat Pump Model ........... 5 1

  16. Sandia Energy - Heat Exchanger Development

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Scienceand RequirementsCoatingsUltra-High-Voltage SiliconEnergyFailureGlobalHeat Exchanger

  17. Testing and analysis of immersed heat exchangers

    SciTech Connect (OSTI)

    Farrington, R.B.; Bingham, C.E.

    1986-08-01T23:59:59.000Z

    The objectives were to determine the performance of four immersed, ''supply-side'' heat exchangers used in solar domestic-hot-water systems; to examine the effects of flow rate, temperature difference, and coil configuration on performance; and to develop a simple model to predict the performance of immersed heat exchangers. We tested four immersed heat exchangers: a smooth coil, a finned spiral, a single-wall bayonet, and a double-wall bayonet. We developed two analyticl models and a simple finite difference model. We experimentally verified that the performance of these heat exchangers depends on the flow rate through them; we also showed that the temperature difference between the heat exchanger's inlet and the storage tank can strongly affect a heat exchanger's performance. We also compared the effects of the heat exchanger's configuration and correlated Nusselt and Rayleigh numbers for each heat exchanger tested. The smooth coil had a higher effectiveness than the others, while the double-wall bayonet had a very low effectiveness. We still do not know the long-term effectiveness of heat exchangers regarding scale accumulation, nor do we know the effects of very low flow rates on a heat exchanger's performance.

  18. A Thermoelectric Generator with an Intermediate Heat Exchanger...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    A Thermoelectric Generator with an Intermediate Heat Exchanger for Automotive Waste Heat Recovery System A Thermoelectric Generator with an Intermediate Heat Exchanger for...

  19. Microchannel crossflow fluid heat exchanger and method for its fabrication

    DOE Patents [OSTI]

    Swift, G.W.; Migliori, A.; Wheatley, J.C.

    1982-08-31T23:59:59.000Z

    A microchannel crossflow fluid heat exchanger and a method for its fabrication are disclosed. The heat exchanger is formed from a stack of thin metal sheets which are bonded together. The stack consists of alternating slotted and unslotted sheets. Each of the slotted sheets includes multiple parallel slots which form fluid flow channels when sandwiched between the unslotted sheets. Successive slotted sheets in the stack are rotated ninety degrees with respect to one another so as to form two sets of orthogonally extending fluid flow channels which are arranged in a crossflow configuration. The heat exchanger has a high surface to volume ratio, a small dead volume, a high heat transfer coefficient, and is suitable for use with fluids under high pressures. The heat exchanger has particular application in a Stirling engine that utilizes a liquid as the working substance.

  20. Microchannel crossflow fluid heat exchanger and method for its fabrication

    DOE Patents [OSTI]

    Swift, G.W.; Migliori, A.; Wheatley, J.C.

    1985-05-14T23:59:59.000Z

    A microchannel crossflow fluid heat exchanger and a method for its fabrication are disclosed. The heat exchanger is formed from a stack of thin metal sheets which are bonded together. The stack consists of alternating slotted and unslotted sheets. Each of the slotted sheets includes multiple parallel slots which form fluid flow channels when sandwiched between the unslotted sheets. Successive slotted sheets in the stack are rotated ninety degrees with respect to one another so as to form two sets of orthogonally extending fluid flow channels which are arranged in a crossflow configuration. The heat exchanger has a high surface to volume ratio, a small dead volume, a high heat transfer coefficient, and is suitable for use with fluids under high pressures. The heat exchanger has particular application in a Stirling engine that utilizes a liquid as the working substance. 9 figs.

  1. Microchannel crossflow fluid heat exchanger and method for its fabrication

    DOE Patents [OSTI]

    Swift, Gregory W. (Los Alamos, NM); Migliori, Albert (Santa Fe, NM); Wheatley, John C. (Los Alamos, NM)

    1985-01-01T23:59:59.000Z

    A microchannel crossflow fluid heat exchanger and a method for its fabrication are disclosed. The heat exchanger is formed from a stack of thin metal sheets which are bonded together. The stack consists of alternating slotted and unslotted sheets. Each of the slotted sheets includes multiple parallel slots which form fluid flow channels when sandwiched between the unslotted sheets. Successive slotted sheets in the stack are rotated ninety degrees with respect to one another so as to form two sets of orthogonally extending fluid flow channels which are arranged in a crossflow configuration. The heat exchanger has a high surface to volume ratio, a small dead volume, a high heat transfer coefficient, and is suitable for use with fluids under high pressures. The heat exchanger has particular application in a Stirling engine that utilizes a liquid as the working substance.

  2. Modeling of Heat Transfer in Geothermal Heat Exchangersá

    E-Print Network [OSTI]

    Cui, P.; Man, Y.; Fang, Z.

    2006-01-01T23:59:59.000Z

    Ground-coupled heat pump (GCHP) systems have been gaining increasing popularity for space conditioning in residential and commercial buildings. The geothermal heat exchanger (GHE) is devised for extraction or injection of thermal energy from...

  3. Heat exchanger device and method for heat removal or transfer

    DOE Patents [OSTI]

    Koplow, Jeffrey P

    2013-12-10T23:59:59.000Z

    Systems and methods for a forced-convection heat exchanger are provided. In one embodiment, heat is transferred to or from a thermal load in thermal contact with a heat conducting structure, across a narrow air gap, to a rotating heat transfer structure immersed in a surrounding medium such as air.

  4. Heat exchanger device and method for heat removal or transfer

    DOE Patents [OSTI]

    Koplow, Jeffrey P. (San Ramon, CA)

    2012-07-24T23:59:59.000Z

    Systems and methods for a forced-convection heat exchanger are provided. In one embodiment, heat is transferred to or from a thermal load in thermal contact with a heat conducting structure, across a narrow air gap, to a rotating heat transfer structure immersed in a surrounding medium such as air.

  5. Heat Exchanger Technologies for Distillation Columns

    E-Print Network [OSTI]

    Polley, G. T.

    Heat Exchanger Technologies for Distillation Columns G.T.Polley Pinchtechnology.com In this paper we look at the challenges that improvements in energy efficiency of distillation systems presents the heat exchanger designer. We examine... condensate sub-cooling. So, if this condensate subsequently requires re-heating both energy and capital have been wasted. If the condensate forms a feed to another distillation column it results in increased energy consumption if that separation...

  6. Research on thermophoretic and inertial aspects of ash particle deposition on heat exchanger surfaces in coal-fired equipment

    SciTech Connect (OSTI)

    Rosner, D.E.

    1989-03-01T23:59:59.000Z

    Little is yet known (theoretically or experimentally) about the simultaneous effects of particle inertia, particle thermophoresis and high mass loading on the important engineering problem of predicting deposition rates from flowing dusty'' gases. For this reason, we investigate the motion of particles present at nonnegligible mass loading in a flowing nonisothermal gaseous medium and their deposition on strongly cooled or heated solid objects by examining the instructive case of steady axisymmetric dusty gas'' flow between two infinite disks: an inlet (porous) disk and the impermeable target'' disk -- a flow not unlike that encountered in recent seeded-flame experiments. Since this stagnation flow/geometry admits interesting self-similar solutions at all Reynolds numbers, we are able to predict laminar flow mass-, momentum- and energy-transfer rate coefficients over a wide range of particle mass loadings, dimensionless particle relaxation times (Stokes numbers), dimensionless thermophoretic diffusivities, and gas Reynolds numbers. As a by-product, we illustrate the accuracy and possible improvement of our previous diffusion model'' for tightly coupled dusty gas systems. Moreover, we report new results illustrating the dependence of the important critical'' Stokes number (for incipient particle impaction) on particle mass loading and wall/gas temperature ratio for dust-laden gas motion towards overheated'' solid surfaces. The present formulation and insulating transport coefficients should not only be useful in explaining/predicting recent deposition rate trends in seeded'' flame experiments, but also highly mass-loaded systems of technological interest.

  7. Heat Exchanger Support Bracket Design Calculations

    SciTech Connect (OSTI)

    Rucinski, Russ; /Fermilab

    1995-01-12T23:59:59.000Z

    This engineering note documents the design of the heat exchanger support brackets. The heat exchanger is roughly 40 feet long, 22 inches in diameter and weighs 6750 pounds. It will be mounted on two identical support brackets that are anchored to a concrete wall. The design calculations were done for one bracket supporting the full weight of the heat exchanger, rounded up to 6800 pounds. The design follows the American Institute of Steel Construction (AISC) Manual of steel construction, Eighth edition. All calculated stresses and loads on welds were below allowables.

  8. Supercritical Carbon Dioxide Turbo-Expander and Heat Exchangers...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Supercritical Carbon Dioxide Turbo-Expander and Heat Exchangers Supercritical Carbon Dioxide Turbo-Expander and Heat Exchangers This fact sheet describes a supercritical carbon...

  9. 4. Heat exchangers; Steam, steam processes

    E-Print Network [OSTI]

    Zevenhoven, Ron

    pictures: KJ05 Temperature distributions of fluid in (a) counterflow, (b) parallel flow, and (c) 1 shell pass and 2 tubes passes. #12;7/74 Heat exchangers: Geometries /3 Temperature distribution in a counter

  10. A fundamentally new approach to air-cooled heat exchangers.

    SciTech Connect (OSTI)

    Koplow, Jeffrey P.

    2010-01-01T23:59:59.000Z

    We describe breakthrough results obtained in a feasibility study of a fundamentally new architecture for air-cooled heat exchangers. A longstanding but largely unrealized opportunity in energy efficiency concerns the performance of air-cooled heat exchangers used in air conditioners, heat pumps, and refrigeration equipment. In the case of residential air conditioners, for example, the typical performance of the air cooled heat exchangers used for condensers and evaporators is at best marginal from the standpoint the of achieving maximum the possible coefficient of performance (COP). If by some means it were possible to reduce the thermal resistance of these heat exchangers to a negligible level, a typical energy savings of order 30% could be immediately realized. It has long been known that a several-fold increase in heat exchanger size, in conjunction with the use of much higher volumetric flow rates, provides a straight-forward path to this goal but is not practical from the standpoint of real world applications. The tension in the market place between the need for energy efficiency and logistical considerations such as equipment size, cost and operating noise has resulted in a compromise that is far from ideal. This is the reason that a typical residential air conditioner exhibits significant sensitivity to reductions in fan speed and/or fouling of the heat exchanger surface. The prevailing wisdom is that little can be done to improve this situation; the 'fan-plus-finned-heat-sink' heat exchanger architecture used throughout the energy sector represents an extremely mature technology for which there is little opportunity for further optimization. But the fact remains that conventional fan-plus-finned-heat-sink technology simply doesn't work that well. Their primary physical limitation to performance (i.e. low thermal resistance) is the boundary layer of motionless air that adheres to and envelops all surfaces of the heat exchanger. Within this boundary layer region, diffusive transport is the dominant mechanism for heat transfer. The resulting thermal bottleneck largely determines the thermal resistance of the heat exchanger. No one has yet devised a practical solution to the boundary layer problem. Another longstanding problem is inevitable fouling of the heat exchanger surface over time by particulate matter and other airborne contaminants. This problem is especially important in residential air conditioner systems where often little or no preventative maintenance is practiced. The heat sink fouling problem also remains unsolved. The third major problem (alluded to earlier) concerns inadequate airflow to heat exchanger resulting from restrictions on fan noise. The air-cooled heat exchanger described here solves all of the above three problems simultaneously. The 'Air Bearing Heat Exchanger' provides a several-fold reduction in boundary layer thickness, intrinsic immunity to heat sink fouling, and drastic reductions in noise. It is also very practical from the standpoint of cost, complexity, ruggedness, etc. Successful development of this technology is also expected to have far reaching impact in the IT sector from the standpointpoint of solving the 'Thermal Brick Wall' problem (which currently limits CPU clocks speeds to {approx}3 GHz), and increasing concern about the the electrical power consumption of our nation's information technology infrastructure.

  11. Design of Heat Exchanger for Heat Recovery in CHP Systems

    E-Print Network [OSTI]

    Kozman, T. A.; Kaur, B.; Lee, J.

    with a heat exchanger to work as a Combined Heat and Power system for the University which will supplement the chilled water supply and electricity. The design constraints of the heat recovery unit are the specifications of the turbine and the chiller...

  12. Integrated Approach to Revamping Heat Exchangers Networks

    E-Print Network [OSTI]

    Glass, K. E.; Dhole, V.; Wang, Y.

    geometry configurations for a given set of process conditions. Develop simulation model (in Aspen Plus) incorporating rigorous heat exchanger (Aspen Hetran) models for the 1) Validate existing preheat train performance & evaluate the existing and de...-bottlenecked cases de-bottlenecked performance Initiate pinch analysis (using Aspen Pinch) directly 2) Determine feasible energy saving from (Aspen Plus) simulation results Heat exchanger network pinch analysis (using Aspen Pinch) incorporating rigorous (Aspen...

  13. Method of fabricating a heat exchanger for Stirling engine

    SciTech Connect (OSTI)

    Rao, V.D.

    1980-10-28T23:59:59.000Z

    A heat exchange assembly and method for making same is disclosed which is useful for Stirling engine heater head constructions. The assembly is comprised entirely of a low cost extrudable material, such as silicon, which when fused in a carburizing furnace provides a rigid highly durable ceramic. Heater tubes are arranged within a chamber, the tubes carry ambient pressure high temperature combusted gases and the chamber containing high pressure lower temperature working gases about the exterior of each tube. Heat exchange can additionally be improved by increasing the exterior surface area of each tube relative to the interior surface thereof.

  14. Heat Exchanger With Internal Pin Elements

    DOE Patents [OSTI]

    Gerstmann, Joseph (Framingham, MA); Hannon, Charles L. (Arlington, MA)

    2004-01-13T23:59:59.000Z

    A heat exchanger/heater comprising a tubular member having a fluid inlet end, a fluid outlet end and plurality of pins secured to the interior wall of the tube. Various embodiments additionally comprise a blocking member disposed concentrically inside the pins, such as a core plug or a baffle array. Also disclosed is a vapor generator employing an internally pinned tube, and a fluid-heater/heat-exchanger utilizing an outer jacket tube and fluid-side baffle elements, as well as methods for heating a fluid using an internally pinned tube.

  15. Demonstration and Performance Monitoring of Foundation Heat Exchangers...

    Energy Savers [EERE]

    for New and Existing Homes: Foundation Heat Exchanger, Oak Ridge, Tennessee Performance Analysis of Air-Source Variable Speed Heat Pumps and Various Electric Water Heating Options...

  16. Design Development Analyses in Support of a Heat pipe-Brayton Cycle Heat Exchanger

    SciTech Connect (OSTI)

    Steeve, Brian E. [NASA Marshall Space Flight Center, Huntsville, AL 35812 (United States); Kapernick, Richard J. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2004-07-01T23:59:59.000Z

    One of the power systems under consideration for future space exploration applications, including nuclear electric propulsion or as a planetary surface power source, is a heat pipe-cooled reactor coupled to a Brayton cycle. In this system, power is transferred from the heat pipes to the Brayton gas via a heat exchanger attached to the heat pipes. This paper discusses the fluid, thermal and structural analyses that were performed in support of the design of the heat exchanger to be tested in the SAFE-100 experimental program at the Marshall Space Flight Center. An important consideration throughout the design development of the heat exchanger was its capability to be utilized for higher power and temperature applications. This paper also discusses this aspect of the design and presents designs for specific applications that are under consideration. (authors)

  17. Research on thermophoretic and inertial aspects of the ash particle deposition on heat exchanger surfaces in coal-fired equipment

    SciTech Connect (OSTI)

    Rosner, D.E.

    1986-12-01T23:59:59.000Z

    In support of the above mentioned objectives, we have initiated theoretical studies in the following three interrelated areas : (a) Interaction of inertial- and thermophoretic effects in well-defined laminar dusty-gas'' flows. (b) Self-regulated sticking and deposit erosion in the simultaneous presence of vapor or submicron glue'' (c) Use of packed bed and tube-bank heat transfer and friction correlations to provide the basis for future tube-bank fouling predictions.During the first three months of Grant DE-FG22-86 PC 90756, we have: (1) Designed and initiated construction of the microcombustor particle-laden jet facility described in Section 3.1. (2) Initiated theoretical studies of the interaction of inertial and thermophoretic effects, the role of simultaneous vapor arrival in determining particle sticking and erosion probabilities, and mass transport phenomena in deep tube banks.

  18. Research on thermophoretic and inertial aspects of ash particle deposition on heat exchanger surfaces in coal-fired equipment

    SciTech Connect (OSTI)

    Rosner, D.E.

    1990-05-01T23:59:59.000Z

    The overall goal of this research in the area of ash transport was to advance the capability of making reliable engineering predictions of the dynamics and consequences of net deposit growth for surfaces exposed to the products of coal combustion. To accomplish this for a wide variety of combustor types, coal types, and operating conditions, this capability must be based on a quantitative understanding of each of the important mechanisms of mineral matter transport, as well as the nature of the interactions between these substances and the prevailing fireside'' surface of the deposit. This level of understanding and predictive capability could ultimately be translated into very significant cost reductions for coal-fired equipment design, development and operation.

  19. Optimization of Heat Exchanger Cleaning

    E-Print Network [OSTI]

    Siegell, J. H.

    yiven in equations (7) and (8) results in the TFRE curves shown in Figure 6. In performing the calculations to compare chemical and mechanical cleaning, it is important to remember to include the value of the 20 MBtu/Hr heat lost between... MBtu/hr/day 20 Data From Operating Unit 10 20 30 40 50 60 70 ...., ........ ...................... ~.... ---- Time (Days) Figure 4. Comparison of Models for Heat Recovery ~ecay to Simulated Operating Data. MECHANICAL CLEANING W 100 MBtu...

  20. Heat Transfer Characteristics of a Generalized Divided Flow Heat Exchanger

    E-Print Network [OSTI]

    Singh, K. P.

    1979-01-01T23:59:59.000Z

    The concept of a "Divided-flow" heat exchanger is generalized by locating the shell inlet (or outlet) nozzle off-center such that the two shell sub-streams are unequal and traverse unequal flow paths. The governing equations for heat transfer...

  1. Research on thermophoretic and inertial aspects of ash particle deposition on heat exchanger surfaces in coal-fired equipment

    SciTech Connect (OSTI)

    Rosner, D.E.

    1987-03-01T23:59:59.000Z

    In support of the above mentioned objectives, we are carrying out theoretical studies in the following three interrelated areas: (a) Interaction of inertial- and thermophoretic effects in well-defined laminar dusty-gas'' flows; (b) Self-regulated sticking and deposit erosion in the simultaneous presence of vapor or submicron glue''; (c) Use of packed bed and tube-bank heat transfer and friction correlations to provide the basis for future tube-bank fouling predictions. During this second quarter of Grant DE-FG22-86 PC 90756. we have: (1) done preliminary gas velocity and temperature calibrations of the micro-combustor exit gas flow jet and initiated the development of both a monodispersed droplet feed system and powder feed system to provide monodispersed particle laden jets covering a broad spectrum of particle sizes (ca. 0.5--50 m diameter); and, (2) demonstrated the ability of impacting supermicron particles to remove predeposited submicron particles on a platinum target, using real-time optical reflectivity methods. These preliminary experiments will be extended and discussed in our next Quarterly Technical Report.

  2. Research on thermophoretic and inertial aspects of ash particle deposition on heat exchanger surfaces in coal-fired equipment

    SciTech Connect (OSTI)

    Rosner, D.E.

    1988-03-01T23:59:59.000Z

    During the present reporting period, we have initiated work on (a) the interpretation of our recent data (see QTR5) on deposition rates under the simultaneous influence of inertia and thermophoresis, (b) the possible rate of particle photophoresis in environments characterized by high radiative heat loads. and (c) the influence of particle size distributions on total mass deposition rates. The fruits of these initiatives will be reported in subsequent quarterly technical reports. Here, we focus on our recent theoretical results in the important but previously uncharted area of the relations between particulate deposition mechanisms, deposit microstructure and deposit properties. Experimental verification of some of the most interesting predictions will be the subject of future HTCRE-Lab studies. Recent discussions with fouling engineers have convinced us that despite recent advances in our ability to predict particle deposition rates in convective-diffusion environments, the important connection between resulting deposit properties (effective thermal conductivity permeability, [hor ellipsis]) and deposition mechanism remain poorly understood and only scarcely studied. Accordingly, as part of this DOE-PETC program we have developed a discrete stochastic model to simulate particulate deposition processes resulting from a combination of deposition mechanisms.

  3. Research on thermophoretic and inertial aspects of ash particle deposition on heat exchanger surfaces in coal-fired equipment

    SciTech Connect (OSTI)

    Rosner, D.E.

    1987-06-01T23:59:59.000Z

    During this third quarter of Grant DE-FG22-86 PC 90756, we have obtained preliminary experimental results on the deposition behavior of submicron and supermicron solid particles (MgO, Al[sub 2]O[sub 3]) on a two-dimensional surface exposed to a high temperature/velocity particle laden'' atmospheric pressure jet. The uniform velocity ( plug flow'') jet, with temperatures up to about 1520 K, derives from a pressurized gaseous fuel microcombustion chamber (110 cc) equipped with a platinum guiding (exit) channel. Particles were generated by several methods (Berglund-Liu type aerosol generator, ultrasonic nebulizer, or syringe feeder with aerodynamic particle off-take) and were introduced into the combustion chamber with a carrier stream of nitrogen or air. Laser light scattering and reflectivity techniques were used for the study of particle deposition, supplemented by post-mortem microscopy on the exposed surface. We observed a linear deposition rate of submicron particles due to the thermophoretic mechanism (until the first layer was developed) under both high and low velocity conditions. On the contrary, supermicron particle deposits reach a steady-state, evidently due to a dynamic equilibrium between particle deposition and dislodging caused by the impacting particles. At several temperatures particle-free subsonic gas jets (up to 120 m/sec) were unable to remove the submicron particle layer.

  4. Heat exchanger for coal gasification process

    DOE Patents [OSTI]

    Blasiole, George A. (Greensburg, PA)

    1984-06-19T23:59:59.000Z

    This invention provides a heat exchanger, particularly useful for systems requiring cooling of hot particulate solids, such as the separated fines from the product gas of a carbonaceous material gasification system. The invention allows effective cooling of a hot particulate in a particle stream (made up of hot particulate and a gas), using gravity as the motive source of the hot particulate. In a preferred form, the invention substitutes a tube structure for the single wall tube of a heat exchanger. The tube structure comprises a tube with a core disposed within, forming a cavity between the tube and the core, and vanes in the cavity which form a flow path through which the hot particulate falls. The outside of the tube is in contact with the cooling fluid of the heat exchanger.

  5. Heat exchanger containing a component capable of discontinuous movement

    DOE Patents [OSTI]

    Wilson, David Gordon

    2001-04-17T23:59:59.000Z

    Regenerative heat exchangers are described for transferring heat between hot and cold fluids. The heat exchangers have seal-leakage rates significantly less than those of conventional regenerative heat exchangers because the matrix is discontinuously moved and is releasably sealed while in a stationary position. Both rotary and modular heat exchangers are described. Also described are methods for transferring heat between a hot and cold fluid using the discontinuous movement of matrices.

  6. Heat exchanger containing a component capable of discontinuous movement

    DOE Patents [OSTI]

    Wilson, David Gordon (Winchester, MA)

    2002-01-01T23:59:59.000Z

    Regenerative heat exchangers are described for transferring heat between hot and cold fluids. The heat exchangers have seal-leakage rates significantly less than those of conventional regenerative heat exchangers because the matrix is discontinuously moved and is releasably sealed while in a stationary position. Both rotary and modular heat exchangers are described. Also described are methods for transferring heat between a hot and cold fluid using the discontinuous movement of matrices.

  7. Heat exchanger containing a component capable of discontinuous movement

    DOE Patents [OSTI]

    Wilson, David G. (Winchester, MA)

    1993-01-01T23:59:59.000Z

    Regenerative heat exchangers are described for transferring heat between hot and cold fluids. The heat exchangers have seal-leakage rates significantly less than those of conventional regenerative heat exchangers because the matrix is discontinuously moved and is releasably sealed while in a stationary position. Both rotary and modular heat exchangers are described. Also described are methods for transferring heat between a hot and cold fluid using the discontinuous movement of matrices.

  8. Research on thermophoretic and inertial aspects of ash particle deposition on heat exchanger surfaces in coal-fired equipment

    SciTech Connect (OSTI)

    Rosner, D.E.

    1988-12-01T23:59:59.000Z

    A real-time laser light-reflectivity technique is being used to study simultaneous thermophoretic and inertial influences on the deposition behavior of MgO particles produced via ultrasonic nebulization (submicrometer range). The deposition surface (a concave platinum ribbon) is exposed to a high velocity/temperature jet of alkali sulfate-free combustion products exiting from a seeded (C3[sub 3]H[sub 8]/air) microcombustor (110 cm[sup 3]). The reflectivity data were calibrated against deposition rates obtained from SEM pictures of the target, and were normalized with the nominal particle feed rate, in order to obtain the mass transfer Stanton number, St[sub m], trends depicted in Figure 1. For the submicron (ca. 0.7[mu]m) particles inertial effects appear to set in at Stokes (Stk) numbers of O(10[sup [minus]2]) (an order of magnitude lower than the ones needed for pure'' inertial impaction), affecting significantly the dominant thermophoretic deposition mechanism. A first order (in Stk) theoretical analysis of the problem in which particle inertia is treated as equivalent to pressure diffusion,'' cannot explain the observed dependence of the deposition rate on Stk. We are presently formulating a Lagrangian approach, valid for all values of Stk, in order to interpret these data. In addition, a Single Particle Counter (SPC) and Transit Time Velocimeter (TTV), are being developed, to allow more precise measurements of particle feed rates and velocities.

  9. Measurements and Predictions of the Heat Transfer at the Tube-Fin Junction for Louvered Fin Heat Exchangers

    E-Print Network [OSTI]

    Thole, Karen A.

    Measurements and Predictions of the Heat Transfer at the Tube-Fin Junction for Louvered Fin Heat Transfer at the Tube-Fin Junction for Louvered Fin Heat Exchangers Abstract The dominant thermal resistance used to increase heat transfer by initiating new boundary layer growth and increasing surface area

  10. Carbon nanotube heat-exchange systems

    DOE Patents [OSTI]

    Hendricks, Terry Joseph (Arvada, CO); Heben, Michael J. (Denver, CO)

    2008-11-11T23:59:59.000Z

    A carbon nanotube heat-exchange system (10) and method for producing the same. One embodiment of the carbon nanotube heat-exchange system (10) comprises a microchannel structure (24) having an inlet end (30) and an outlet end (32), the inlet end (30) providing a cooling fluid into the microchannel structure (24) and the outlet end (32) discharging the cooling fluid from the microchannel structure (24). At least one flow path (28) is defined in the microchannel structure (24), fluidically connecting the inlet end (30) to the outlet end (32) of the microchannel structure (24). A carbon nanotube structure (26) is provided in thermal contact with the microchannel structure (24), the carbon nanotube structure (26) receiving heat from the cooling fluid in the microchannel structure (24) and dissipating the heat into an external medium (19).

  11. Dealing with Uncertainties During Heat Exchanger Design

    E-Print Network [OSTI]

    Polley, G. T.; Pugh, S. J.

    heat capacity flow rate of 30 kW/K. The cold stream flowing through E I bas a heat capacity flow rate of 55 kW/K and that flowing through E2 a value of 35 kW/K. 123 ESL-IE-01-05-20 Proceedings from the Twenty-third National Industrial Energy... Technology Conference, Houston, TX, May 1-4, 2001 E2 Area = 100 m 2 cp= 35 kW/K El Area = 300 m 2 Figure 1. Simple Heat Exchanger Network CP = 30 kW/K CP= 55 kWIK Assume that exchangers EI (of heat transfer area 100 m 2 ) and E2 (of 300 m 2...

  12. Foundation Heat Exchanger Model and Design Tool Development and Validation

    E-Print Network [OSTI]

    Heat Exchangers for Residential Ground Source Heat Pump Systems - Numerical Modeling and Experimental. Fisher, J. Shonder, P. Im. 2010. Residential Ground Source Heat Pump Systems Utilizing Foundation Heat. Feasibility of foundation heat exchangers in ground source heat pump systems in the United States. ASHRAE

  13. Triple loop heat exchanger for an absorption refrigeration system

    DOE Patents [OSTI]

    Reimann, Robert C. (Lafayette, NY)

    1984-01-01T23:59:59.000Z

    A triple loop heat exchanger for an absorption refrigeration system is disclosed. The triple loop heat exchanger comprises portions of a strong solution line for conducting relatively hot, strong solution from a generator to a solution heat exchanger of the absorption refrigeration system, conduit means for conducting relatively cool, weak solution from the solution heat exchanger to the generator, and a bypass system for conducting strong solution from the generator around the strong solution line and around the solution heat exchanger to an absorber of the refrigeration system when strong solution builds up in the generator to an undesirable level. The strong solution line and the conduit means are in heat exchange relationship with each other in the triple loop heat exchanger so that, during normal operation of the refrigeration system, heat is exchanged between the relatively hot, strong solution flowing through the strong solution line and the relatively cool, weak solution flowing through the conduit means. Also, the strong solution line and the bypass system are in heat exchange relationship in the triple loop heat exchanger so that if the normal flow path of relatively hot, strong solution flowing from the generator to an absorber is blocked, then this relatively, hot strong solution which will then be flowing through the bypass system in the triple loop heat exchanger, is brought into heat exchange relationship with any strong solution which may have solidified in the strong solution line in the triple loop heat exchanger to thereby aid in desolidifying any such solidified strong solution.

  14. aluminum heat exchangers: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Heat Exchangers, Heat Transfer, Energy, Phase Change and multiphase process, Renewable energy (Solan, Tidal), Energy Storage, Conversion Cessi, Paola 62 Dealing with...

  15. absorption heat exchange: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Heat Exchangers, Heat Transfer, Energy, Phase Change and multiphase process, Renewable energy (Solan, Tidal), Energy Storage, Conversion Cessi, Paola 63 Dealing with...

  16. alloy heat exchanger: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Heat Exchangers, Heat Transfer, Energy, Phase Change and multiphase process, Renewable energy (Solan, Tidal), Energy Storage, Conversion Cessi, Paola 53 Dealing with...

  17. Fouling of HVAC fin and tube heat exchangers

    E-Print Network [OSTI]

    Siegel, Jeffrey; Carey, Van P.

    2001-01-01T23:59:59.000Z

    air ? air ? part ? part FPI HVAC REFERENCES Anonymous, 1987,LBNL-47668 Fouling of HVAC Fin and Tube Heat ExchangersCIEE SPONSOR. FOULING OF HVAC FIN AND TUBE HEAT EXCHANGERS

  18. Modeling of Heat Transfer in Geothermal Heat Exchangers

    E-Print Network [OSTI]

    Cui, P.; Man, Y.; Fang, Z.

    2006-01-01T23:59:59.000Z

    , University of Lund, Sweden, [7] Fang, Z., Diao, N., and Cui, P., Discontinuous operation of geothermal heat exchangers [J], Tsinghua Science and Technology. , 2002, 7 194?197. [8] Hellstrom, G., Ground heat storage -- Thermal analysis of duct storage... systems [D], Department of Mathem Sweden, 1991. [9] Mei, V. C. and Baxter, V. D., Performance of a ground-coupled heat pump with multiple dissimilar U-tu Transactions, 1986, 92 Part 2, 22-25. [10] Yavuzturk, C., Spitler, J. D. and Rees, S. J., A...

  19. Hierarchical Modeling for Population-Based Heat Exchanger Design

    E-Print Network [OSTI]

    Geb, David

    2013-01-01T23:59:59.000Z

    transfer in tube banks in crossflow. [60] Zukauskas, A. ,law based optimisation of crossflow plate-fin heat exchanger

  20. Heat exchanger support apparatus in a fluidized bed

    DOE Patents [OSTI]

    Lawton, Carl W. (West Hartford, CT)

    1982-01-01T23:59:59.000Z

    A heat exchanger is mounted in the upper portion of a fluidized combusting bed for the control of the temperature of the bed. A support, made up of tubes, is extended from the perforated plate of the fluidized bed up to the heat exchanger. The tubular support framework for the heat exchanger has liquid circulated therethrough to prevent deterioration of the support.

  1. Optimizing PT Arun LNG main heat exchanger

    SciTech Connect (OSTI)

    Irawan, B. [PT Arun NGL Co., Sumatra (Indonesia)

    1995-12-01T23:59:59.000Z

    The capacity of a LNG liquefaction unit has been increased by upgrading the refrigeration system, without making changes to the main heat exchanger (MHE). It is interesting, that after all modifications were completed, a higher refrigerant circulation alone could not increase LNG production. However, by optimizing the refrigerant component ratio, the UA of the MHE increased and LNG production improved. This technical evaluation will provide recommendations and show how the evaluation of the internal temperature profile helped optimize the MHE operating conditions.

  2. Investigation of combined heat and mass transfer from a wet heat exchanger. Part 2. Experimental results and operational characteristics of heat exchangers in dry/wet operations

    SciTech Connect (OSTI)

    Hauser, S.G.; Kreid, D.K.; Johnson, B.M.

    1981-04-01T23:59:59.000Z

    This second part of a two-part paper summarizes the experimental evaluation of a plate finned heat exchanger both with and without the surface wetted by a flowing film of water. The results indicate an increase in heat transfer during wet operation of two to five times over that of dry operation for the same meteorological conditions. The deluge model is shown to accurately predict the wet performance using an experimentally determined deluge film coefficient and the dry performance characteristics.

  3. Heat treatment of exchangers to remove coke

    SciTech Connect (OSTI)

    Turner, J.D.

    1990-02-20T23:59:59.000Z

    This patent describes a process for preparing furfural coke for removal from metallic surfaces. It comprises: heating the furfural coke without causing an evolution of heat capable of undesirably altering metallurgical properties of the surfaces in the presence of a gas containing molecular oxygen at a sufficient temperature below 800{degrees}F (427{degrees}C) for a sufficient time to change the crush strength of the coke so as to permit removal with a water jet at a pressure of five thousand pounds per square inch.

  4. The effects of outdoor heat exchanger hydrophobic treatment on the performance of an air source heat pump

    E-Print Network [OSTI]

    Parker, Brandon DeWayne

    1995-01-01T23:59:59.000Z

    mode, the system must remove heat from the cold outdoor air and provide it to the conditioned space. To remove the heat from the outdoor air, the refrigerant entering the outdoor heat exchanger must be colder than the outdoor air. The outdoor air... is pulled across the heat exchanger surface by the outdoor fan Hence, the cold liquid refrigerant passing through the evaporator coil receives heat from the outdoor ambient air passing over the coil, causing the refrigerant to vaporize into a cool gas...

  5. A simplified methodology for sizing ground coupled heat pump heat exchangers in cooling dominated climatesá

    E-Print Network [OSTI]

    Gonzalez, Jose Antonio

    1993-01-01T23:59:59.000Z

    between GSIM and two commercially available heat exchanger sizing methods, the National Water Well Association (NWWA) and the International Ground Source Heat Pump Association (IGSHPA) methods, was performed. GSIM heat exchanger lengths for Dallas were... Pump Capacity and Cooling Load. . . . . Oversizing and Undersizing the Heat Pump. . . . . . . . . . . . . . Summary. . 72 74 76 78 80 82 85 87 90 92 IX COMPARISON OF HEAT EXCHANGER SIZING METHODS . . 93 International Ground Source Heat...

  6. CORRELATING EVAPORATION HEAT TRANSFER COEFFICIENT OF REFRIGERANT R-134a IN A PLATE HEAT EXCHANGER

    E-Print Network [OSTI]

    Kandlikar, Satish

    1 CORRELATING EVAPORATION HEAT TRANSFER COEFFICIENT OF REFRIGERANT R-134a IN A PLATE HEAT EXCHANGER for evaporation heat transfer coefficient of refrigerant R-134a flowing in a plate heat exchanger. Correlation schemes proposed by Yan and Lin (1999b) for modeling the heat transfer coefficient in both a single- phase

  7. Applications of the Strong Heat Transformation by Pulse Flow in the Shell and Tube Heat Exchangerá

    E-Print Network [OSTI]

    Chen, Y.; Zhao, J.

    2006-01-01T23:59:59.000Z

    This article deals with the heat exchange coefficient varied with pulse frequency in the pulsation tube with different flow forms. The findings show that heat can be exchanged coefficient with the pulse frequency, and it has an optimal frequency...

  8. Applications of the Strong Heat Transformation by Pulse Flow in the Shell and Tube Heat Exchanger

    E-Print Network [OSTI]

    Chen, Y.; Zhao, J.

    2006-01-01T23:59:59.000Z

    This article deals with the heat exchange coefficient varied with pulse frequency in the pulsation tube with different flow forms. The findings show that heat can be exchanged coefficient with the pulse frequency, and it has an optimal frequency...

  9. Heat exchanger for fuel cell power plant reformer

    DOE Patents [OSTI]

    Misage, Robert (Manchester, CT); Scheffler, Glenn W. (Tolland, CT); Setzer, Herbert J. (Ellington, CT); Margiott, Paul R. (Manchester, CT); Parenti, Jr., Edmund K. (Manchester, CT)

    1988-01-01T23:59:59.000Z

    A heat exchanger uses the heat from processed fuel gas from a reformer for a fuel cell to superheat steam, to preheat raw fuel prior to entering the reformer and to heat a water-steam coolant mixture from the fuel cells. The processed fuel gas temperature is thus lowered to a level useful in the fuel cell reaction. The four temperature adjustments are accomplished in a single heat exchanger with only three heat transfer cores. The heat exchanger is preheated by circulating coolant and purge steam from the power section during startup of the latter.

  10. Rapid electron exchange between surface-exposed bacterial cytochromes...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    electron exchange between surface-exposed bacterial cytochromes and Fe(III) minerals. Rapid electron exchange between surface-exposed bacterial cytochromes and Fe(III) minerals....

  11. Heat transfer augmentation along the tube wall of a louvered fin heat exchanger using practical delta winglets

    E-Print Network [OSTI]

    Thole, Karen A.

    delta winglets Michael J. Lawson *, Karen A. Thole Mechanical and Nuclear Engineering Department the formation of streamwise vortices and increase heat transfer between a working fluid and the surface on which importance for fuel econ- omy. Advantages to decreasing heat exchanger size include weight savings, as well

  12. Geothermal: Sponsored by OSTI -- Chapter 11. Heat Exchangers

    Office of Scientific and Technical Information (OSTI)

    1. Heat Exchangers Geothermal Technologies Legacy Collection HelpFAQ | Site Map | Contact Us HomeBasic Search About Publications Advanced Search New Hot Docs News Related Links...

  13. Advanced heat exchanger development for molten salts

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Sabharwall, Piyush; Clark, Denis; Glazoff, Michael; Zheng, Guiqiu; Sridharan, Kumar; Anderson, Mark

    2014-12-01T23:59:59.000Z

    This study addresses present work concerned with advanced heat exchanger development for molten salt in nuclear and non nuclear thermal systems. The molten salt systems discussed herein use alloys, such as Hastelloy N and 242, which show corrosion resistance to molten salt at nominal operating temperatures up to 700░C. These alloys were diffusion welded, and the corresponding information is presented. Test specimens were prepared for exposing diffusion welds to molten salt environments. Hastelloy N and 242 were found to be weldable by diffusion welding, with ultimate tensile strengths about 90% of base metal values. Both diffusion welds and sheet materialmoreá╗in Hastelloy N were corrosion tested in?58 mol% KF and 42 mol% ZrF4 at 650, 700, and 850░C for 200, 500, and 1,000 hours. Corrosion rates found were similar between welded and nonwelded materials, typically źáless

  14. Effects of winglets to augment tube wall heat transfer in louvered fin heat exchangers

    E-Print Network [OSTI]

    Thole, Karen A.

    Effects of winglets to augment tube wall heat transfer in louvered fin heat exchangers Paul A transfer along the tube wall of the compact heat exchanger through the use of winglets placed of attack, aspect ratio, direction, and shape, were all evaluated based on heat transfer augmentation

  15. MODELING OF VERTICAL GROUND LOOP HEAT EXCHANGERS FOR GROUND SOURCE

    E-Print Network [OSTI]

    MODELING OF VERTICAL GROUND LOOP HEAT EXCHANGERS FOR GROUND SOURCE HEAT PUMP SYSTEMS By CENK SOURCE HEAT PUMP SYSTEMS Thesis Approved: ___________________________________________ Thesis Adviser scale test data. The short-term behavior of ground-coupled heat pump systems is important for the design

  16. Deposition of Biological Aerosols on HVAC Heat Exchangers

    E-Print Network [OSTI]

    LBNL-47669 Deposition of Biological Aerosols on HVAC Heat Exchangers Jeffrey Siegel and Iain Walker of Biological Aerosols on HVAC Heat Exchangers Jeffrey A. Siegel Iain S. Walker, Ph.D. ASHRAE Student Member that are found in commercial and residential HVAC systems of 1 - 6 m/s (200 - 1200 ft/min), particle diameters

  17. atmosphere-surface exchange processes: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    heat transfer conductance. 4.1.1 Principles: Ron Zevenhoven 4-1 4. Heat exchangers, steam, steam processes Vrmevxlare, nga, ngprocesser 4.1 Heat exchangers Heat...

  18. Circulating heat exchangers for oscillating wave engines and refrigerators

    DOE Patents [OSTI]

    Swift, Gregory W.; Backhaus, Scott N.

    2003-10-28T23:59:59.000Z

    An oscillating-wave engine or refrigerator having a regenerator or a stack in which oscillating flow of a working gas occurs in a direction defined by an axis of a trunk of the engine or refrigerator, incorporates an improved heat exchanger. First and second connections branch from the trunk at locations along the axis in selected proximity to one end of the regenerator or stack, where the trunk extends in two directions from the locations of the connections. A circulating heat exchanger loop is connected to the first and second connections. At least one fluidic diode within the circulating heat exchanger loop produces a superimposed steady flow component and oscillating flow component of the working gas within the circulating heat exchanger loop. A local process fluid is in thermal contact with an outside portion of the circulating heat exchanger loop.

  19. Heat Transfer Enhancement for Finned-Tube Heat Exchangers with Vortex Generators: Experimental and Numerical Results

    SciTech Connect (OSTI)

    O'Brien, James Edward; Sohal, Manohar Singh; Huff, George Albert

    2002-08-01T23:59:59.000Z

    A combined experimental and numerical investigation is under way to investigate heat transfer enhancement techniques that may be applicable to large-scale air-cooled condensers such as those used in geothermal power applications. The research is focused on whether air-side heat transfer can be improved through the use of finsurface vortex generators (winglets,) while maintaining low heat exchanger pressure drop. A transient heat transfer visualization and measurement technique has been employed in order to obtain detailed distributions of local heat transfer coefficients on model fin surfaces. Pressure drop measurements have also been acquired in a separate multiple-tube row apparatus. In addition, numerical modeling techniques have been developed to allow prediction of local and average heat transfer for these low-Reynolds-number flows with and without winglets. Representative experimental and numerical results presented in this paper reveal quantitative details of local fin-surface heat transfer in the vicinity of a circular tube with a single delta winglet pair downstream of the cylinder. The winglets were triangular (delta) with a 1:2 height/length aspect ratio and a height equal to 90% of the channel height. Overall mean fin-surface Nusselt-number results indicate a significant level of heat transfer enhancement (average enhancement ratio 35%) associated with the deployment of the winglets with oval tubes. Pressure drop measurements have also been obtained for a variety of tube and winglet configurations using a single-channel flow apparatus that includes four tube rows in a staggered array. Comparisons of heat transfer and pressure drop results for the elliptical tube versus a circular tube with and without winglets are provided. Heat transfer and pressure-drop results have been obtained for flow Reynolds numbers based on channel height and mean flow velocity ranging from 700 to 6500.

  20. Progress Report for Diffusion Welding of the NGNP Process Application Heat Exchangers

    SciTech Connect (OSTI)

    R.E. Mizia; D.E. Clark; M.V. Glazoff; T.E. Lister; T.L. Trowbridge

    2011-12-01T23:59:59.000Z

    The U.S. Department of Energy selected the high temperature gas-cooled reactor as the basis for the Next Generation Nuclear Plant (NGNP). The NGNP will demonstrate the use of nuclear power for electricity, hydrogen production, and process heat applications. The NGNP Project is currently investigating the use of metallic, diffusion welded, compact heat exchangers to transfer heat from the primary (reactor side) heat transport system to the secondary heat transport system. An intermediate heat exchanger will transfer this heat to downstream applications such as hydrogen production, process heat, and electricity generation. The channeled plates that make up the heat transfer surfaces of the intermediate heat exchanger will have to be assembled into an array by diffusion welding. This report describes the preliminary results of a scoping study that evaluated the diffusion welding process parameters and the resultant mechanical properties of diffusion welded joints using Alloy 800H. The long-term goal of the program is to progress towards demonstration of small heat exchanger unit cells fabricated with diffusion welds. Demonstration through mechanical testing of the unit cells will support American Society of Mechanical Engineers rules and standards development, reduce technical risk, and provide proof of concept for heat exchanger fabrication methods needed to deploy heat exchangers in several potential NGNP configurations.1 Researchers also evaluated the usefulness of modern thermodynamic and diffusion computational tools (Thermo-Calc and Dictra) in optimizing the parameters for diffusion welding of Alloy 800H. The modeling efforts suggested a temperature of 1150 C for 1 hour with an applied pressure of 5 MPa using 15 {micro}m nickel foil as joint filler to reduce chromium oxidation on the welded surfaces. Good agreement between modeled and experimentally determined concentration gradients was achieved

  1. Ceramic heat-exchanger applications study

    SciTech Connect (OSTI)

    McFarlin, D.J.; Sgamboti, C.T.; Lessard, R.D.

    1982-10-01T23:59:59.000Z

    To put the potential benefits of ceramic heat exchangers (CHX) applications into quantitative perspective, several industrial cogeneration and electric utiity power generation systems were surveyed and evaluated. This study was focused on coal-based fuel fired applications, for which system performance and economic assessments were made. Seven CHX applications in the industrial cogeneration sector were selected for evaluation. These include (1) Gasified Coal-Fired Gas Turbine, (2) Pressurized Fluidized Bed Combustor (PFBC)-Gas Turbine, (3) Atmospheric Fluidized Bed Combustor (AFBC)-Gas Turbine, (4 and 5) AFBC Combined Cycle with and without reheat and (6 and 7) Indirect Coal-Fired Gas Turbine and Combined Cycle. The performance and economics of these cogeneration systems were evaluated and compared with other competing systems (both advanced and State-of-the-Art). For the electric utility power generation sector five applications utilizing a CHX were selected and evaluated; their performance and cost factors were compared to those of a reference pulverized coal-fired steam plant with flue gas desulfurization. These five applications included (1) PFBC-Combined Cycle, (2) AFBC-Combined Cycle, (3) Industrial Coal Gasifier-Combined Cycle, (4) Indirect Coal-Fired Combined Cycle, and (5) Indirect Coal-Fired Simple Cycle. Of the five CHX applications evaluated in the power generation sector, only the AFBC system showed a clear gain over the reference pulverized coal system.

  2. Generator-absorber-heat exchange heat transfer apparatus and method and use thereof in a heat pump

    DOE Patents [OSTI]

    Phillips, Benjamin A. (Benton Harbor, MI); Zawacki, Thomas S. (St. Joseph, MI); Marsala, Joseph (Glen Ellyn, IL)

    1994-11-29T23:59:59.000Z

    Numerous embodiments and related methods for generator-absorber heat exchange (GAX) are disclosed, particularly for absorption heat pump systems. Such embodiments and related methods use the working solution of the absorption system for the heat transfer medium.

  3. Error Analysis of Heat Transfer for Finned-Tube Heat-Exchanger Text-Boardá

    E-Print Network [OSTI]

    Chen, Y.; Zhang, J.

    2006-01-01T23:59:59.000Z

    In order to reduce the measurement error of heat transfer in water and air side for finned-tube heat-exchanger as little as possible, and design a heat-exchanger test-board measurement system economically, based on the principle of test-board system...

  4. Emerging Heat Exchanger Technologies for the Mitigation of Fouling in Crude Oil Pre-Heat Trains

    E-Print Network [OSTI]

    Polley, G. T.; Pugh, S. J.; King, D. C.

    -heat train exchangers foul is controlled by fluid velocity and by wall temperature. Technologies which promote the heat transfer on the crude oil side of an exchanger are therefore favoured. (Note: promotion of the heat transfer on the hot side of the unit...

  5. Compact heat exchangers for condensation applications: Yesterday, today and tomorrow

    SciTech Connect (OSTI)

    Panchal, C.B.

    1993-07-01T23:59:59.000Z

    Compact heat exchangers are being increasingly considered for condensation applications in the process, cryogenic, aerospace, power and refrigeration industries. In this paper, different configurations available for condensation applications are analyzed and the current state-of-the-knowledge for the design of compact condensers is evaluated. The key technical issues for the design and development of compact heat exchangers for condensation applications are analyzed and major advantages are identified. The experimental data and performance prediction methods reported in the literature are analyzed to evaluate the present design capabilities for different compact heat-exchanger configurations. The design flexibility is evaluated for the development of new condensation applications, including integration with other process equipment.

  6. Heat exchanger and water tank arrangement for passive cooling system

    DOE Patents [OSTI]

    Gillett, J.E.; Johnson, F.T.; Orr, R.S.; Schulz, T.L.

    1993-11-30T23:59:59.000Z

    A water storage tank in the coolant water loop of a nuclear reactor contains a tubular heat exchanger. The heat exchanger has tube sheets mounted to the tank connections so that the tube sheets and tubes may be readily inspected and repaired. Preferably, the tubes extend from the tube sheets on a square pitch and then on a rectangular pitch there between. Also, the heat exchanger is supported by a frame so that the tank wall is not required to support all of its weight. 6 figures.

  7. A Lightweight Material for Heat Exchange Applications

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    exchangers have been manufactured from metal because metals are effective in conducting thermal energy. Plastics, although cheaper, lighter, and less energy intensive to make...

  8. Acoustically enhanced heat exchange and drying apparatus

    DOE Patents [OSTI]

    Bramlette, T.T.; Keller, J.O.

    1987-07-10T23:59:59.000Z

    A heat transfer drying apparatus includes an acoustically augmented heat transfer chamber for receiving material to be dried. The chamber includes a first heat transfer gas inlet, a second heat transfer gas inlet, a material inlet, and a gas outlet which also serves as a dried material and gas outlet. A non-pulsing first heat transfer gas source provides a first drying gas to the acoustically augmented heat transfer chamber through the first heat transfer gas inlet. A valveless, continuous second heat transfer gas source provides a second drying gas to the acoustically augmented heat transfer chamber through the second heat transfer gas inlet. The second drying gas also generates acoustic waves which bring about acoustical coupling with the gases in the acoustically augmented heat transfer chamber. The second drying gas itself oscillates at an acoustic frequency of approximately 180 Hz due to fluid mechanical motion in the gas. The oscillations of the second heat transfer gas coupled to the first heat transfer gas in the acoustically augmented heat transfer chamber enhance heat and mass transfer by convection within the chamber. 3 figs.

  9. SILICON CARBIDE CERAMICS FOR COMPACT HEAT EXCHANGERS

    SciTech Connect (OSTI)

    DR. DENNIS NAGLE; DR. DAJIE ZHANG

    2009-03-26T23:59:59.000Z

    Silicon carbide (SiC) materials are prime candidates for high temperature heat exchangers for next generation nuclear reactors due to their refractory nature and high thermal conductivity at elevated temperatures. This research has focused on demonstrating the potential of liquid silicon infiltration (LSI) for making SiC to achieve this goal. The major advantage of this method over other ceramic processing techniques is the enhanced capability of making high dense, high purity SiC materials in complex net shapes. For successful formation of net shape SiC using LSI techniques, the carbon preform reactivity and pore structure must be controlled to allow the complete infiltration of the porous carbon structure which allows complete conversion of the carbon to SiC. We have established a procedure for achieving desirable carbon properties by using carbon precursors consisting of two readily available high purity organic materials, crystalline cellulose and phenolic resin. Phenolic resin yields a glassy carbon with low chemical reactivity and porosity while the cellulose carbon is highly reactive and porous. By adjusting the ratio of these two materials in the precursor mixtures, the properties of the carbons produced can be controlled. We have identified the most favorable carbon precursor composition to be a cellulose resin mass ratio of 6:4 for LSI formation of SiC. The optimum reaction conditions are a temperature of 1800 C, a pressure of 0.5 Torr of argon, and a time of 120 minutes. The fully dense net shape SiC material produced has a density of 2.96 g cm{sup -3} (about 92% of pure SiC) and a SiC volume fraction of over 0.82. Kinetics of the LSI SiC formation process was studied by optical microscopy and quantitative digital image analysis. This study identified six reaction stages and provided important understanding of the process. Although the thermal conductivity of pure SiC at elevated temperatures is very high, thermal conductivities of most commercial SiC materials are much lower due to phonon scattering by impurities (e.g., sintering aids located at the grain boundaries of these materials). The thermal conductivity of our SiC was determined using the laser flash method and it is 214 W/mK at 373 K and 64 W/mK at 1273 K. These values are very close to those of pure SiC and are much higher than those of SiC materials made by industrial processes. This SiC made by our LSI process meets the thermal properties required for use in high temperature heat exchanger. Cellulose and phenolic resin carbons lack the well-defined atomic structures associated with common carbon allotropes. Atomic-scale structure was studied using high resolution transmission electron microscopy (HRTEM), nitrogen gas adsorption and helium gas pycnometry. These studies revealed that cellulose carbon exhibits a very high degree of atomic disorder and angstrom-scale porosity. It has a density of only 93% of that of pure graphite, with primarily sp2 bonding character and a low concentration of graphene clusters. Phenolic resin carbon shows more structural order and substantially less angstrom-scale porosity. Its density is 98% of that of pure graphite, and Fourier transform analysis of its TEM micrographs has revealed high concentrations of sp3 diamond and sp2 graphene nano-clusters. This is the first time that diamond nano-clusters have been observed in carbons produced from phenolic resin. AC and DC electrical measurements were made to follow the thermal conversion of microcrystalline cellulose to carbon. This study identifies five regions of electrical conductivity that can be directly correlated to the chemical decomposition and microstructural evolution during carbonization. In Region I, a decrease in overall AC conductivity occurs due to the initial loss of the polar groups from cellulose molecules. In Region II, the AC conductivity starts to increase with heat treatment temperature due to the formation and growth of conducting carbon clusters. In Region III, a further increase of AC conductivity with increasing heat treatment temperature is obs

  10. Process Heat Exchanger Options for Fluoride Salt High Temperature Reactor

    SciTech Connect (OSTI)

    Piyush Sabharwall; Eung Soo Kim; Michael McKellar; Nolan Anderson

    2011-04-01T23:59:59.000Z

    The work reported herein is a significant intermediate step in reaching the final goal of commercial-scale deployment and usage of molten salt as the heat transport medium for process heat applications. The primary purpose of this study is to aid in the development and selection of the required heat exchanger for power production and process heat application, which would support large-scale deployment.

  11. Process Heat Exchanger Options for the Advanced High Temperature Reactor

    SciTech Connect (OSTI)

    Piyush Sabharwall; Eung Soo Kim; Michael McKellar; Nolan Anderson

    2011-06-01T23:59:59.000Z

    The work reported herein is a significant intermediate step in reaching the final goal of commercial-scale deployment and usage of molten salt as the heat transport medium for process heat applications. The primary purpose of this study is to aid in the development and selection of the required heat exchanger for power production and process heat application, which would support large-scale deployment.

  12. A Simplified Procedure for Sizing Vertical Ground Coupled Heat Pump Heat Exchangers for Residences in Texasá

    E-Print Network [OSTI]

    O'Neal, D. L.; Gonzalez, J. A.; Aldred, W.

    1994-01-01T23:59:59.000Z

    the simplified method were compared to two available heat exchanger sizing methods: the National Water Well Association (NWWA) and the International Ground Source Heat Pump Association (IGSHPA). The simplified method predicted shorter lengths than those from...

  13. Heat Transfer of a Multiple Helical Coil Heat Exchanger Using a Microencapsulated Phase Change Material Slurryá

    E-Print Network [OSTI]

    Gaskill, Travis

    2012-02-14T23:59:59.000Z

    The present study has focused on the use of coil heat exchangers (CHEs) with microencapsulated phase change material (MPCM) slurries to understand if CHEs can yield greater rates of heat transfer. An experimental study was conducted using a...

  14. Heat Transfer of a Multiple Helical Coil Heat Exchanger Using a Microencapsulated Phase Change Material Slurry

    E-Print Network [OSTI]

    Gaskill, Travis

    2012-02-14T23:59:59.000Z

    The present study has focused on the use of coil heat exchangers (CHEs) with microencapsulated phase change material (MPCM) slurries to understand if CHEs can yield greater rates of heat transfer. An experimental study was conducted using a...

  15. A Simplified Procedure for Sizing Vertical Ground Coupled Heat Pump Heat Exchangers for Residences in Texas

    E-Print Network [OSTI]

    O'Neal, D. L.; Gonzalez, J. A.; Aldred, W.

    1994-01-01T23:59:59.000Z

    the simplified method were compared to two available heat exchanger sizing methods: the National Water Well Association (NWWA) and the International Ground Source Heat Pump Association (IGSHPA). The simplified method predicted shorter lengths than those from...

  16. Design and Test of Tube & Shell Heat Exchangers for Potential

    E-Print Network [OSTI]

    Design and Test of Tube & Shell Heat Exchangers for Potential OTEC Application Jeong-Tae Kwon1 University, South Korea 2Department of Mechanical Engineering, Sunmoon University, South Korea 3Offshore CCS

  17. IntroductiontoProcessEngineering(PTG) 4. Heat exchangers;

    E-Print Network [OSTI]

    Zevenhoven, Ron

    Temperature distributions of fluid in (a) counterflow, (b) parallel flow, and (c) 1 shell pass and 2 tubes Temperature distribution in a counter-flow heat exchanger. Note: the exit temperature TC,o of the cold stream

  18. A Plastic-Core Compact Heat Exchanger for Energy Conservation

    E-Print Network [OSTI]

    Lazaridis, A.; Rafailidis, E.

    This paper describes a compact, single-pass, cross-flow type, gas-to-gas heat exchanger with a polyolefin (polyethylene or polypropylene) core whose seams are welded through a proprietary process. It is constructed of several extruded polyolefin...

  19. Oscillating side-branch enhancements of thermoacoustic heat exchangers

    DOE Patents [OSTI]

    Swift, Gregory W.

    2003-05-13T23:59:59.000Z

    A regenerator-based engine or refrigerator has a regenerator with two ends at two different temperatures, through which a gas oscillates at a first oscillating volumetric flow rate in the direction between the two ends and in which the pressure of the gas oscillates, and first and second heat exchangers, each of which is at one of the two different temperatures. A dead-end side branch into which the gas oscillates has compliance and is connected adjacent to one of the ends of the regenerator to form a second oscillating gas flow rate additive with the first oscillating volumetric flow rate, the compliance having a volume effective to provide a selected total oscillating gas volumetric flow rate through the first heat exchanger. This configuration enables the first heat exchanger to be configured and located to better enhance the performance of the heat exchanger rather than being confined to the location and configuration of the regenerator.

  20. A Plastic-Core Compact Heat Exchanger for Energy Conservationá

    E-Print Network [OSTI]

    Lazaridis, A.; Rafailidis, E.

    1995-01-01T23:59:59.000Z

    This paper describes a compact, single-pass, cross-flow type, gas-to-gas heat exchanger with a polyolefin (polyethylene or polypropylene) core whose seams are welded through a proprietary process. It is constructed of several extruded polyolefin...

  1. 1-MWE heat exchangers for OTEC. Final design report

    SciTech Connect (OSTI)

    Sprouse, A.M.

    1980-06-19T23:59:59.000Z

    The design of a 1 MWe OTEC heat exchanger is documented, including the designs of the evaporator and associated systems, condenser, instrumentation, and materials for corrosion/erosion control and fabrication processes. (LEW)

  2. Experimental results and operational characteristics of heat exchangers in dry/wet operations

    SciTech Connect (OSTI)

    Hauser, S.G.; Kreid, D.K.; Johnson, B.M.

    1982-08-01T23:59:59.000Z

    This second part of a two-part paper summarizes the experimental evaluation of three air-cooled finned heat exchangers, both with and without the finned surface, wetted by flowing water. In addition, the performance of one of the heat exchangers is compared with predictions from the model which was presented in Part 1. The experimental results are in close agreement with the predictions based on the model. Once the effective film coefficient of the deluge film was determined, deluge performance was predicted using dry heat transfer correlations.

  3. Pressure drop across spined heat exchangers in crossflowá

    E-Print Network [OSTI]

    Carranza, Richard Guy

    1987-01-01T23:59:59.000Z

    PRESSURE DROP ACROSS SPINED HEAT EXCHANGERS IN CROSSFLOW A Thesis by R]CHARD GUY CARRANZA Submitted to the Graduate College of Texas AE M University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE December 1987... Major Subject: Chemical Engineering PRESSURE DROP ACROSS SPINED HEAT EXCHANGERS IN CROSSFLOW A Thesis by RICHARD GUY CARRANZA Approved as to style and content by: M. T. pie (Chairman of Committee) C. Glover (Member) N. K. Anand (Member) R...

  4. DOE/ANL/HTRI heat exchanger tube vibration data bank

    SciTech Connect (OSTI)

    Halle, H.; Chenoweth, J.M.; Wambsganss, M.W.

    1981-01-01T23:59:59.000Z

    This addendum to the DOE/ANL/HTRI Heat Exchanger Tube Vibration Data Bank includes 16 new case histories of field experiences. The cases include several exchangers that did not experience vibration problems and several for which acoustic vibration was reported.

  5. Acoustically enhanced heat exchange and drying apparatus

    DOE Patents [OSTI]

    Bramlette, T. Tazwell (Livermore, CA); Keller, Jay O. (Oakland, CA)

    1989-01-01T23:59:59.000Z

    A heat transfer apparatus includes a first chamber having a first heat transfer gas inlet, a second heat transfer gas inlet, and an outlet. A first heat transfer gas source provides a first gas flow to the first chamber through the first heat transfer gas inlet. A second gas flow through a second chamber connected to the side of the first chamber, generates acoustic waves which bring about acoustical coupling of the first and second gases in the acoustically augmented first chamber. The first chamber may also include a material inlet for receiving material to be dried, in which case the gas outlet serves as a dried material and gas outlet.

  6. Self-defrosting recuperative air-to-air heat exchanger

    DOE Patents [OSTI]

    Drake, R.L.

    1993-12-28T23:59:59.000Z

    A heat exchanger is described which includes a stationary spirally or concentrically wound heat exchanger core with rotating baffles on upper and lower ends thereof. The rotating baffles include rotating inlets and outlets which are in communication with respective fixed inlets and outlets via annuli. The rotation of the baffles causes a concurrent rotation of the temperature distribution within the stationary exchanger core, thereby preventing frost build-up in some applications and preventing the formation of hot spots in other applications. 3 figures.

  7. Model based methodology development for energy recovery in flash heat exchange systems

    E-Print Network [OSTI]

    McCarthy, John E.

    Model based methodology development for energy recovery in flash heat exchange systems Problem with a condensing heat exchanger can be used when heat exchange is required between two streams and where at leastH, consistency etc.). To increase the efficiency of heat exchange, a cascade of these units in series can be used

  8. Heat Exchanger Network Targeting, Design and Analysis: The MIDAS Package

    E-Print Network [OSTI]

    Barton, I.; Jones, D. H.; Smith, G. J.

    are: o Improved utility targeting for constrained problems and wide range utilities. . o Advanced heat exchanger network area targeting. o Optimization of temperature driving forces for minimum total cost. o Automated HEN design using a... counter current conditions. 2. Finite temperature driving forces are required for heat transfer in any real system~ A minimum driving force of l'ITmln is assumed to prevail within the network, i.e. a stream giving up heat (said to be "hot...

  9. PERFORMANCE OF RESIDENTIAL AIR-TO-AIR HEAT EXCHANGERS: TEST METHODS AND RESULTS

    E-Print Network [OSTI]

    Fisk, William J.

    2013-01-01T23:59:59.000Z

    2. SCHEMATIC DIAGRAM OF A CROSSFLOW HEAT EXCHANGER. H RMED Rthe same direction. In a crossflow exchanger, (Fig- ure 2)Heat Exchanger (Figure 11) has a crossflow and core, two two

  10. Fast reactor power plant design having heat pipe heat exchanger

    DOE Patents [OSTI]

    Huebotter, P.R.; McLennan, G.A.

    1984-08-30T23:59:59.000Z

    The invention relates to a pool-type fission reactor power plant design having a reactor vessel containing a primary coolant (such as liquid sodium), and a steam expansion device powered by a pressurized water/steam coolant system. Heat pipe means are disposed between the primary and water coolants to complete the heat transfer therebetween. The heat pipes are vertically oriented, penetrating the reactor deck and being directly submerged in the primary coolant. A U-tube or line passes through each heat pipe, extended over most of the length of the heat pipe and having its walls spaced from but closely proximate to and generally facing the surrounding walls of the heat pipe. The water/steam coolant loop includes each U-tube and the steam expansion device. A heat transfer medium (such as mercury) fills each of the heat pipes. The thermal energy from the primary coolant is transferred to the water coolant by isothermal evaporation-condensation of the heat transfer medium between the heat pipe and U-tube walls, the heat transfer medium moving within the heat pipe primarily transversely between these walls.

  11. Fast reactor power plant design having heat pipe heat exchanger

    DOE Patents [OSTI]

    Huebotter, Paul R. (Western Springs, IL); McLennan, George A. (Downers Grove, IL)

    1985-01-01T23:59:59.000Z

    The invention relates to a pool-type fission reactor power plant design having a reactor vessel containing a primary coolant (such as liquid sodium), and a steam expansion device powered by a pressurized water/steam coolant system. Heat pipe means are disposed between the primary and water coolants to complete the heat transfer therebetween. The heat pipes are vertically oriented, penetrating the reactor deck and being directly submerged in the primary coolant. A U-tube or line passes through each heat pipe, extended over most of the length of the heat pipe and having its walls spaced from but closely proximate to and generally facing the surrounding walls of the heat pipe. The water/steam coolant loop includes each U-tube and the steam expansion device. A heat transfer medium (such as mercury) fills each of the heat pipes. The thermal energy from the primary coolant is transferred to the water coolant by isothermal evaporation-condensation of the heat transfer medium between the heat pipe and U-tube walls, the heat transfer medium moving within the heat pipe primarily transversely between these walls.

  12. Generator-absorber-heat exchange heat transfer apparatus and method and use thereof in a heat pump

    DOE Patents [OSTI]

    Phillips, Benjamin A. (Benton Harbor, MI); Zawacki, Thomas S. (St. Joseph, MI)

    1996-12-03T23:59:59.000Z

    Numerous embodiments and related methods for generator-absorber heat exchange (GAX) are disclosed, particularly for absorption heat pump systems. Such embodiments and related methods use the working solution of the absorption system for the heat transfer medium. A combination of weak and rich liquor working solution is used as the heat transfer medium.

  13. Experimental evaluation of dry/wet air-cooled heat exchangers. Progress report

    SciTech Connect (OSTI)

    Hauser, S.G.; Gruel, R.L.; Huenefeld, J.C.; Eschbach, E.J.; Johnson, B.M.; Kreid, D.K.

    1982-08-01T23:59:59.000Z

    The ultimate goal of this project was to contribute to the development of improved cooling facilities for power plants. Specifically, the objective during FY-81 was to experimentally determine the thermal performance and operating characteristics of an air-cooled heat exchanger surface manufactured by the Unifin Company. The performance of the spiral-wound finned tube surface (Unifin) was compared with two inherently different platefin surfaces (one developed by the Trane Co. and the other developed by the HOETERV Institute) which were previously tested as a part of the same continuing program. Under dry operation the heat transfer per unit frontal area per unit inlet temperature difference (ITD) of the Unifin surface was 10% to 20% below that of the other two surfaces at low fan power levels. At high fan power levels, the performances of the Unifin and Trane surfaces were essentially the same, and 25% higher than the HOETERV surface. The design of the Unifin surface caused a significantly larger air-side pressure drop through the heat exchanger both in dry and deluge operation. Generally higher overall heat transfer coefficients were calculated for the Unifin surface under deluged operation. They ranged from 2.0 to 3.5 Btu/hr-ft/sup 2/-/sup 0/F as compared to less than 2.0 Btu hr-ft/sup 2/-/sup 0/F for the Trane and HOETERV surfaces under similar conditions. The heat transfer enhancement due to the evaporative cooling effect was also measureably higher with the Unifin surface as compared to the Trane surface. This can be primarily attributed to the better wetting characteristics of the Unifin surface. If the thermal performance of the surfaces are compared at equal face velocities, the Unifin surface is as much as 35% better. This method of comparison accounts for the wetting characteristics while neglecting the effect of pressure drop. Alternatively the surfaces when compared at equal pressure drop essentially the same thermal performance.

  14. Assessment of next generation nuclear plant intermediate heat exchanger design.

    SciTech Connect (OSTI)

    Majumdar, S.; Moisseytsev, A.; Natesan, K.; Nuclear Engineering Division

    2008-10-17T23:59:59.000Z

    The Next Generation Nuclear Plant (NGNP), which is an advanced high temperature gas reactor (HTGR) concept with emphasis on production of both electricity and hydrogen, involves helium as the coolant and a closed-cycle gas turbine for power generation with a core outlet/gas turbine inlet temperature of 900-1000 C. In the indirect cycle system, an intermediate heat exchanger is used to transfer the heat from primary helium from the core to the secondary fluid, which can be helium, nitrogen/helium mixture, or a molten salt. The system concept for the vary high temperature reactor (VHTR) can be a reactor based on the prismatic block of the GT-MHR developed by a consortium led by General Atomics in the U.S. or based on the PBMR design developed by ESKOM of South Africa and British Nuclear Fuels of U.K. This report has made an assessment on the issues pertaining to the intermediate heat exchanger (IHX) for the NGNP. A detailed thermal hydraulic analysis, using models developed at ANL, was performed to calculate heat transfer, temperature distribution, and pressure drop. Two IHX designs namely, shell and straight tube and compact heat exchangers were considered in an earlier assessment. Helical coil heat exchangers were analyzed in the current report and the results were compared with the performance features of designs from industry. In addition, a comparative analysis is presented between the shell and straight tube, helical, and printed circuit heat exchangers from the standpoint of heat exchanger volume, primary and secondary sides pressure drop, and number of tubes. The IHX being a high temperature component, probably needs to be designed using ASME Code Section III, Subsection NH, assuming that the IHX will be classified as a class 1 component. With input from thermal hydraulic calculations performed at ANL, thermal conduction and stress analyses were performed for the helical heat exchanger design and the results were compared with earlier-developed results on shell and straight tube and printed circuit heat exchangers.

  15. THERMOSIPHON WATER HEATERS WITH HEAT EXCHANGERS

    E-Print Network [OSTI]

    Mertol, Atila

    2012-01-01T23:59:59.000Z

    The Performance of Solar Water Heater With Natural Ci rculperformance of solar thermos i phon water heaters with heatSolar Jubilee, Phoenix, AZ, June 2-6, 1980 THERMOSIPHON WATER HEATERS

  16. Thermodynamic Efficiency of Heat Exchange Devices

    E-Print Network [OSTI]

    Witte, L. C.; Shamsundar, N.

    1982-01-01T23:59:59.000Z

    irreversibilities. The reclamation of what was formerly 'waste heat' by using additional, or more efficient, equipment has become not only economically feasible, but sometimes essential. A thermodynamic efficiency based on the second law of thermodynamics...

  17. Liquid Salt Heat Exchanger Technology for VHTR Based Applications

    SciTech Connect (OSTI)

    Anderson, Mark; Sridhara, Kumar; Allen, Todd; Peterson, Per

    2012-10-11T23:59:59.000Z

    The objective of this research is to evaluate performance of liquid salt fluids for use as a heat carrier for transferring high-temperature process heat from the very high-temperature reactor (VHTR) to chemical process plants. Currently, helium is being considered as the heat transfer fluid; however, the tube size requirements and the power associated with pumping helium may not be economical. Recent work on liquid salts has shown tremendous potential to transport high-temperature heat efficiently at low pressures over long distances. This project has two broad objectives: To investigate the compatibility of Incoloy 617 and coated and uncoated SiC ceramic composite with MgCl2-KCl molten salt to determine component lifetimes and aid in the design of heat exchangers and piping; and, To conduct the necessary research on the development of metallic and ceramic heat exchangers, which are needed for both the helium-to-salt side and salt-to-process side, with the goal of making these heat exchangers technologically viable. The research will consist of three separate tasks. The first task deals with material compatibility issues with liquid salt and the development of techniques for on-line measurement of corrosion products, which can be used to measure material loss in heat exchangers. Researchers will examine static corrosion of candidate materials in specific high-temperature heat transfer salt systems and develop an in situ electrochemical probe to measure metallic species concentrations dissolved in the liquid salt. The second task deals with the design of both the intermediate and process side heat exchanger systems. Researchers will optimize heat exchanger design and study issues related to corrosion, fabrication, and thermal stresses using commercial and in-house codes. The third task focuses integral testing of flowing liquid salts in a heat transfer/materials loop to determine potential issues of using the salts and to capture realistic behavior of the salts in a small scale prototype system. This includes investigations of plugging issues, heat transfer, pressure drop, and the corrosion and erosion of materials in the flowing system.

  18. Effect of Heat Exchanger Material and Fouling on Thermoelectric Exhaust Heat Recovery

    SciTech Connect (OSTI)

    Love, Norman [University of Texas, El Paso; Szybist, James P [ORNL; Sluder, Scott [ORNL

    2011-01-01T23:59:59.000Z

    This study is conducted in an effort to better understand and improve the performance of thermoelectric heat recovery systems for automotive use. For this purpose an experimental investigation of thermoelectrics in contact with clean and fouled heat exchangers of different materials is performed. The thermoelectric devices are tested on a bench-scale thermoelectric heat recovery apparatus that simulates automotive exhaust. The thermoelectric apparatus consists of a series of thermoelectric generators contacting a hot-side and a cold-side heat exchanger. The thermoelectric devices are tested with two different hot-side heat exchanger materials, stainless steel and aluminum, and at a range of simulated exhaust gas flowrates (40 to 150 slpm), exhaust gas temperatures (240 C and 280 C), and coolant-side temperatures (40 C and 80 C). It is observed that for higher exhaust gas flowrates, thermoelectric power output increases while overall system efficiency decreases. Degradation of the effectiveness of the EGR-type heat exchangers over a period of driving is also simulated by exposing the heat exchangers to diesel engine exhaust under thermophoretic conditions to form a deposit layer. For the fouled EGR-type heat exchangers, power output and system efficiency is observed to be significantly lower for all conditions tested. The study found, however, that heat exchanger material is the dominant factor in the ability of the system to convert heat to electricity with thermoelectric generators. This finding is thought to be unique to the heat exchangers used for this study, and not a universal trend for all system configurations.

  19. DETAILED LOOP MODEL (DLM) ANALYSIS OF LIQUID SOLAR THERMOSIPHONS WITH HEAT EXCHANGERS

    E-Print Network [OSTI]

    Mertol, A.

    2013-01-01T23:59:59.000Z

    Warm Water Hot Water Heater Water Tank Heat flow from low-water heaters with heat exchangers in storage tanks. Thewater heater with a heat exchanger in the storage tank. The

  20. Research on thermophoretic and inertial aspects of ash particle deposition on heat exchanger surfaces in coal-fired equipment. Final technical report, September 1, 1986--April 30, 1990

    SciTech Connect (OSTI)

    Rosner, D.E.

    1990-05-01T23:59:59.000Z

    The overall goal of this research in the area of ash transport was to advance the capability of making reliable engineering predictions of the dynamics and consequences of net deposit growth for surfaces exposed to the products of coal combustion. To accomplish this for a wide variety of combustor types, coal types, and operating conditions, this capability must be based on a quantitative understanding of each of the important mechanisms of mineral matter transport, as well as the nature of the interactions between these substances and the prevailing ``fireside`` surface of the deposit. This level of understanding and predictive capability could ultimately be translated into very significant cost reductions for coal-fired equipment design, development and operation.

  1. Recovery of Water from Boiler Flue Gas Using Condensing Heat Exchangers

    SciTech Connect (OSTI)

    Levy, Edward; Bilirgen, Harun; DuPont, John

    2011-03-31T23:59:59.000Z

    Most of the water used in a thermoelectric power plant is used for cooling, and DOE has been focusing on possible techniques to reduce the amount of fresh water needed for cooling. DOE has also been placing emphasis on recovery of usable water from sources not generally considered, such as mine water, water produced from oil and gas extraction, and water contained in boiler flue gas. This report deals with development of condensing heat exchanger technology for recovering moisture from flue gas from coal-fired power plants. The report describes: Ľ An expanded data base on water and acid condensation characteristics of condensing heat exchangers in coal-fired units. This data base was generated by performing slip stream tests at a power plant with high sulfur bituminous coal and a wet FGD scrubber and at a power plant firing highmoisture, low rank coals. Ľ Data on typical concentrations of HCl, HNO{sub 3} and H{sub 2}SO{sub 4} in low temperature condensed flue gas moisture, and mercury capture efficiencies as functions of process conditions in power plant field tests. Ľ Theoretical predictions for sulfuric acid concentrations on tube surfaces at temperatures above the water vapor dewpoint temperature and below the sulfuric acid dew point temperature. Ľ Data on corrosion rates of candidate heat exchanger tube materials for the different regions of the heat exchanger system as functions of acid concentration and temperature. Ľ Data on effectiveness of acid traps in reducing sulfuric acid concentrations in a heat exchanger tube bundle. Ľ Condensed flue gas water treatment needs and costs. Ľ Condensing heat exchanger designs and installed capital costs for full-scale applications, both for installation immediately downstream of an ESP or baghouse and for installation downstream of a wet SO{sub 2} scrubber. Ľ Results of cost-benefit studies of condensing heat exchangers.

  2. Recovery of Water from Boiler Flue Gas Using Condensing Heat Exchangers

    SciTech Connect (OSTI)

    Edward Levy; Harun Bilirgen; John DuPoint

    2011-03-31T23:59:59.000Z

    Most of the water used in a thermoelectric power plant is used for cooling, and DOE has been focusing on possible techniques to reduce the amount of fresh water needed for cooling. DOE has also been placing emphasis on recovery of usable water from sources not generally considered, such as mine water, water produced from oil and gas extraction, and water contained in boiler flue gas. This report deals with development of condensing heat exchanger technology for recovering moisture from flue gas from coal-fired power plants. The report describes: (1) An expanded data base on water and acid condensation characteristics of condensing heat exchangers in coal-fired units. This data base was generated by performing slip stream tests at a power plant with high sulfur bituminous coal and a wet FGD scrubber and at a power plant firing high-moisture, low rank coals. (2) Data on typical concentrations of HCl, HNO{sub 3} and H{sub 2}SO{sub 4} in low temperature condensed flue gas moisture, and mercury capture efficiencies as functions of process conditions in power plant field tests. (3) Theoretical predictions for sulfuric acid concentrations on tube surfaces at temperatures above the water vapor dewpoint temperature and below the sulfuric acid dew point temperature. (4) Data on corrosion rates of candidate heat exchanger tube materials for the different regions of the heat exchanger system as functions of acid concentration and temperature. (5) Data on effectiveness of acid traps in reducing sulfuric acid concentrations in a heat exchanger tube bundle. (6) Condensed flue gas water treatment needs and costs. (7) Condensing heat exchanger designs and installed capital costs for full-scale applications, both for installation immediately downstream of an ESP or baghouse and for installation downstream of a wet SO{sub 2} scrubber. (8) Results of cost-benefit studies of condensing heat exchangers.

  3. Materials, Turbomachinery and Heat Exchangers for Supercritical CO2 Systems

    SciTech Connect (OSTI)

    Anderson, Mark; Nellis, Greg; Corradini, Michael

    2012-10-19T23:59:59.000Z

    The objective of this project is to produce the necessary data to evaluate the performance of the supercritical carbon dioxide cycle. The activities include a study of materials compatibility of various alloys at high temperatures, the heat transfer and pressure drop in compact heat exchanger units, and turbomachinery issues, primarily leakage rates through dynamic seals. This experimental work will serve as a test bed for model development and design calculations, and will help define further tests necessary to develop high-efficiency power conversion cycles for use on a variety of reactor designs, including the sodium fast reactor (SFR) and very high-temperature gas reactor (VHTR). The research will be broken into three separate tasks. The first task deals with the analysis of materials related to the high-temperature S-CO{sub 2} Brayton cycle. The most taxing materials issues with regard to the cycle are associated with the high temperatures in the reactor side heat exchanger and in the high-temperature turbine. The system could experience pressures as high as 20MPa and temperatures as high as 650░C. The second task deals with optimization of the heat exchangers required by the S-CO{sub 2} cycle; the S-CO{sub 2} flow passages in these heat exchangers are required whether the cycle is coupled with a VHTR or an SFR. At least three heat exchangers will be required: the pre-cooler before compression, the recuperator, and the heat exchanger that interfaces with the reactor coolant. Each of these heat exchangers is unique and must be optimized separately. The most challenging heat exchanger is likely the pre-cooler, as there is only about a 40░C temperature change but it operates close to the CO{sub 2} critical point, therefore inducing substantial changes in properties. The proposed research will focus on this most challenging component. The third task examines seal leakage through various dynamic seal designs under the conditions expected in the S-CO{sub 2} cycle, including supercritical, choked, and two-phase flow conditions.

  4. Diffusion Welding of Compact Heat Exchangers for Nuclear Applications

    SciTech Connect (OSTI)

    Denis Clark; Ron Mizia; Dr. Michael V. Glazoff; Mr. Michael W. Patterson

    2012-06-01T23:59:59.000Z

    The next-ş-generation nuclear plant (NGNP) is designed to be a flexible source of energy, producing various mixes of electrical energy and process heat (for example, for hydrogen generation) on demand. Compact heat exchangers provide an attractive way to move energy from the helium primary reactor coolant to process heat uses. For process heat efficiency, reactor outlet temperatures of 750-ş-900░C are desirable. There are minor but deleterious components in the primary coolant; the number of alloys that can handle this environment is small. The present work concentrates on Alloys 800H and 617.

  5. Research on thermophoretic and inertial aspects of ash particle deposition on heat exchanger surfaces in coal-fired equipment. Quarterly techical report, December 1, 1986--February 28, 1987

    SciTech Connect (OSTI)

    Rosner, D.E.

    1987-03-01T23:59:59.000Z

    In support of the above mentioned objectives, we are carrying out theoretical studies in the following three interrelated areas: (a) Interaction of inertial- and thermophoretic effects in well-defined laminar ``dusty-gas`` flows; (b) Self-regulated sticking and deposit erosion in the simultaneous presence of vapor or submicron ``glue``; (c) Use of packed bed and tube-bank heat transfer and friction correlations to provide the basis for future tube-bank fouling predictions. During this second quarter of Grant DE-FG22-86 PC 90756. we have: (1) done preliminary gas velocity and temperature calibrations of the micro-combustor exit gas flow jet and initiated the development of both a monodispersed droplet feed system and powder feed system to provide monodispersed particle laden jets covering a broad spectrum of particle sizes (ca. 0.5--50 m diameter); and, (2) demonstrated the ability of impacting supermicron particles to remove predeposited submicron particles on a platinum target, using real-time optical reflectivity methods. These preliminary experiments will be extended and discussed in our next Quarterly Technical Report.

  6. Ground Source Heat Pump Sub-Slab Heat Exchange Loop Performance in a Cold Climate

    SciTech Connect (OSTI)

    Mittereder, N.; Poerschke, A.

    2013-11-01T23:59:59.000Z

    This report presents a cold-climate project that examines an alternative approach to ground source heat pump (GSHP) ground loop design. The innovative ground loop design is an attempt to reduce the installed cost of the ground loop heat exchange portion of the system by containing the entire ground loop within the excavated location beneath the basement slab. Prior to the installation and operation of the sub-slab heat exchanger, energy modeling using TRNSYS software and concurrent design efforts were performed to determine the size and orientation of the system. One key parameter in the design is the installation of the GSHP in a low-load home, which considerably reduces the needed capacity of the ground loop heat exchanger. This report analyzes data from two cooling seasons and one heating season. Upon completion of the monitoring phase, measurements revealed that the initial TRNSYS simulated horizontal sub-slab ground loop heat exchanger fluid temperatures and heat transfer rates differed from the measured values. To determine the cause of this discrepancy, an updated model was developed utilizing a new TRNSYS subroutine for simulating sub-slab heat exchangers. Measurements of fluid temperature, soil temperature, and heat transfer were used to validate the updated model.

  7. Heat Exchanger Fouling- Prediction, Measurement and Mitigation

    E-Print Network [OSTI]

    Peterson, G. R.

    wall. The fouling probe has been successfully tested in the laboratory at flue gas temperatures up to 2200░F and a local heat flux up to 41,000 BTU/hr-ft2. The probe has been field tested at a coal-fired boiler plant. Future tests at a municipal waste...

  8. Condensing Heat Exchangers Optimize Steam Boilers

    E-Print Network [OSTI]

    Sullivan, B.; Sullivan, P. A.

    1983-01-01T23:59:59.000Z

    the flue gas from the p~oducts of combustion faom natural gas from 300 to the dew point of 129 results in an efficiency increase of 3%. Further cooling, resulting in condensa tion of water vapor, increases the rate of heat recovery dramatically and a...

  9. Optimized design of a heat exchanger for an air-to-water reversible heat pump working with propane (R290)

    E-Print Network [OSTI]

    Fernßndez de Cˇrdoba, Pedro

    Optimized design of a heat exchanger for an air-to-water reversible heat pump working with propane-to-water reversible heat pump unit was carried out using two different fin-and-tube heat exchanger ``coil'' designs concepts. The performance of the heat pump was evaluated for each coil design at different superheat

  10. Heat Pump Cycle with Solution Circuit and Internal Heat Exchange

    E-Print Network [OSTI]

    Radermacher, R.

    Vapor compression heat pumps which employ working fluid mixtures rather than pure substances offer significant advantages leading to larger temperature lifts at low pressure ratios or to completely new applications. The main feature of such cycles...

  11. Energy Recovery By Direct Contact Gas-Liquid Heat Exchange

    E-Print Network [OSTI]

    Fair, J. R.; Bravo, J. L.

    ENERGY RECOVERY BY DIRECf CONTACf GAS-LIQUID HEAT EXCHANGE James R. Fair and Jose L. Bravo Separations Research Program The University o/Texas at Austin Austin, Texas ABSIRACf Energy from hot gas discharge streams can be recovered... by transfer directly to a coolant liquid in one of several available gas-liquid contacting devices. The design of the device is central to the theme of this paper, and experimental work has verified that the analogy between heat transfer and mass transfer...

  12. Secondary heat exchanger design and comparison for advanced high temperature reactor

    SciTech Connect (OSTI)

    Sabharwall, P. [Idaho National Laboratory, Idaho Falls, ID 83415-3860 (United States); Kim, E. S. [Seoul National Univ., P.O. Box 1625, Idaho Falls, ID 83415-3860 (United States); Siahpush, A.; McKellar, M.; Patterson, M. [Idaho National Laboratory, Idaho Falls, ID 83415-3860 (United States)

    2012-07-01T23:59:59.000Z

    Next generation nuclear reactors such as the advanced high temperature reactor (AHTR) are designed to increase energy efficiency in the production of electricity and provide high temperature heat for industrial processes. The efficient transfer of energy for industrial applications depends on the ability to incorporate effective heat exchangers between the nuclear heat transport system and the industrial process heat transport system. This study considers two different types of heat exchangers - helical coiled heat exchanger and printed circuit heat exchanger - as possible options for the AHTR secondary heat exchangers with distributed load analysis and comparison. Comparison is provided for all different cases along with challenges and recommendations. (authors)

  13. Waste Heat Recovery From Stacks Using Direct-Contact Condensing Heat Exchangeá

    E-Print Network [OSTI]

    Thorn, W. F.

    1986-01-01T23:59:59.000Z

    Similarly, the recuperator can be interfaced with the auxiliary tank, heat exchanger and boiler controls in a In considering multiple boiler installations, the CON variety of ways. Several recuperators, individually installed X recuperator may...

  14. Xenon Recirculation-Purification with a Heat Exchanger

    E-Print Network [OSTI]

    K. L. Giboni; E. Aprile; B. Choi; T. Haruyama; R. F. Lang; K. E. Lim; A. J. Melgarejo; G. Plante

    2011-03-04T23:59:59.000Z

    Liquid-xenon based particle detectors have been dramatically growing in size during the last years, and are now exceeding the one-ton scale. The required high xenon purity is usually achieved by continuous recirculation of xenon gas through a high-temperature getter. This challenges the traditional way of cooling these large detectors, since in a thermally well insulated detector, most of the cooling power is spent to compensate losses from recirculation. The phase change during recondensing requires five times more cooling power than cooling the gas from ambient temperature to -100C (173 K). Thus, to reduce the cooling power requirements for large detectors, we propose to use the heat from the purified incoming gas to evaporate the outgoing xenon gas, by means of a heat exchanger. Generally, a heat exchanger would appear to be only of very limited use, since evaporation and liquefaction occur at zero temperature difference. However, the use of a recirculation pump reduces the pressure of the extracted liquid, forces it to evaporate, and thus cools it down. We show that this temperature difference can be used for an efficient heat exchange process. We investigate the use of a commercial parallel plate heat exchanger with a small liquid xenon detector. Although we expected to be limited by the available cooling power to flow rates of about 2 SLPM, rates in excess of 12 SLPM can easily be sustained, limited only by the pump speed and the impedance of the flow loop. The heat exchanger operates with an efficiency of (96.8 +/- 0.5)%. This opens the possibility for fast xenon gas recirculation in large-scale experiments, while minimizing thermal losses.

  15. Generator-absorber-heat exchange heat transfer apparatus and method and use thereof in a heat pump

    DOE Patents [OSTI]

    Phillips, Benjamin A. (Benton Harbor, MI); Zawacki, Thomas S. (St. Joseph, MI)

    1998-07-21T23:59:59.000Z

    Numerous embodiments and related methods for generator-absorber heat exchange (GAX) are disclosed, particularly for absorption heat pump systems. Such embodiments and related methods use, as the heat transfer medium, the working fluid of the absorption system taken from the generator at a location where the working fluid has a rich liquor concentration.

  16. Generator-absorber-heat exchange heat transfer apparatus and method and use thereof in a heat pump

    DOE Patents [OSTI]

    Phillips, B.A.; Zawacki, T.S.

    1998-07-21T23:59:59.000Z

    Numerous embodiments and related methods for generator-absorber heat exchange (GAX) are disclosed, particularly for absorption heat pump systems. Such embodiments and related methods use, as the heat transfer medium, the working fluid of the absorption system taken from the generator at a location where the working fluid has a rich liquor concentration. 5 figs.

  17. Advanced Rotating Heat Exchangers | Department of Energy

    Office of Environmental Management (EM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 1112011AT&T, Inc.'s Reply Comments AT&T,FACT S HEET FACT S HEET FACT S HEET|Rotating Heat

  18. Integral collector storage system with heat exchange apparatus

    DOE Patents [OSTI]

    Rhodes, Richard O.

    2004-04-20T23:59:59.000Z

    The present invention relates to an integral solar energy collector storage systems. Generally, an integral collector storage system includes a tank system, a plurality of heat exchange tubes with at least some of the heat exchange tubes arranged within the tank system, a first glazing layer positioned over the tank system and a base plate positioned under the tank system. In one aspect of the invention, the tank system, the first glazing layer an the base plate each include protrusions and a clip is provided to hold the layers together. In another aspect of the invention, the first glazing layer and the base plate are ribbed to provide structural support. This arrangement is particularly useful when these components are formed from plastic. In yet another aspect of the invention, the tank system has a plurality of interconnected tank chambers formed from tubes. In this aspect, a supply header pipe and a fluid return header pipe are provided at a first end of the tank system. The heat exchange tubes have inlets coupled to the supply header pipe and outlets coupled to the return header pipe. With this arrangement, the heat exchange tubes may be inserted into the tank chambers from the first end of the tank system.

  19. Using Plate Heat Exchangers to Increase Energy Efficiency

    E-Print Network [OSTI]

    Bailey, K.

    result in a heat exchanger that is extremely economical and efficient, especially in energy recovery applications where low LMTD's are common. This paper will review PHE design and construction and show how PHE's can be used to recover energy in many...

  20. Fouling characteristics of compact heat exchangers and enhanced tubes.

    SciTech Connect (OSTI)

    Panchal, C. B.; Rabas, T. J.

    1999-07-15T23:59:59.000Z

    Fouling is a complex phenomenon that (1) encompasses formation and transportation of precursors, and (2) attachment and possible removal of foulants. A basic understanding of fouling mechanisms should guide the development of effective mitigation techniques. The literature on fouling in complex flow passages of compact heat exchangers is limited; however, significant progress has been made with enhanced tubes.

  1. Condensing Heat Exchanger for Optimization of Energy Efficiencyá

    E-Print Network [OSTI]

    Carrigan, J. F.; Johnson, D. W.; DiVitto, J. G.; Schulze, K. H.

    1995-01-01T23:59:59.000Z

    Historically, boiler efficiency has been limited due to the minimum temperature allowed at the stack. Heat lost up the stack was in exchange for keeping the flue gas temperature above the water vapor dew point. If water vapor was allowed to condense...

  2. Boundary geometric control of a counter-current heat exchanger

    E-Print Network [OSTI]

    Boyer, Edmond

    control of a counter-current heat exchanger whose control is designed considering a model based on two differential equation describing the temperature of the internal fluid, and the manipulated control regulation and tracking performances. The robustness of the controller has also been studied when velocities

  3. Heat exchanger with leak detecting double wall tubes

    SciTech Connect (OSTI)

    Bieberbach, George (Tampa, FL); Bongaards, Donald J. (Seminole, FL); Lohmeier, Alfred (Tampa, FL); Duke, James M. (St. Petersburg, all of, FL)

    1981-01-01T23:59:59.000Z

    A straight shell and tube heat exchanger utilizing double wall tubes and three tubesheets to ensure separation of the primary and secondary fluid and reliable leak detection of a leak in either the primary or the secondary fluids to further ensure that there is no mixing of the two fluids.

  4. Condensing Heat Exchanger for Optimization of Energy Efficiency

    E-Print Network [OSTI]

    Carrigan, J. F.; Johnson, D. W.; DiVitto, J. G.; Schulze, K. H.

    Historically, boiler efficiency has been limited due to the minimum temperature allowed at the stack. Heat lost up the stack was in exchange for keeping the flue gas temperature above the water vapor dew point. If water vapor was allowed to condense...

  5. Novel Power Electronics Three-Dimensional Heat Exchanger: Preprint

    SciTech Connect (OSTI)

    Bennion, K.; Cousineau, J.; Lustbader, J.; Narumanchi, S.

    2014-08-01T23:59:59.000Z

    Electric drive systems for vehicle propulsion enable technologies critical to meeting challenges for energy, environmental, and economic security. Enabling cost-effective electric drive systems requires reductions in inverter power semiconductor area. As critical components of the electric drive system are made smaller, heat removal becomes an increasing challenge. In this paper, we demonstrate an integrated approach to the design of thermal management systems for power semiconductors that matches the passive thermal resistance of the packaging with the active convective cooling performance of the heat exchanger. The heat exchanger concept builds on existing semiconductor thermal management improvements described in literature and patents, which include improved bonded interface materials, direct cooling of the semiconductor packages, and double-sided cooling. The key difference in the described concept is the achievement of high heat transfer performance with less aggressive cooling techniques by optimizing the passive and active heat transfer paths. An extruded aluminum design was selected because of its lower tooling cost, higher performance, and scalability in comparison to cast aluminum. Results demonstrated a heat flux improvement of a factor of two, and a package heat density improvement over 30%, which achieved the thermal performance targets.

  6. Secondary Heat Exchanger Design and Comparison for Advanced High Temperature Reactor

    SciTech Connect (OSTI)

    Piyush Sabharwall; Ali Siahpush; Michael McKellar; Michael Patterson; Eung Soo Kim

    2012-06-01T23:59:59.000Z

    The goals of next generation nuclear reactors, such as the high temperature gas-cooled reactor and advance high temperature reactor (AHTR), are to increase energy efficiency in the production of electricity and provide high temperature heat for industrial processes. The efficient transfer of energy for industrial applications depends on the ability to incorporate effective heat exchangers between the nuclear heat transport system and the industrial process heat transport system. The need for efficiency, compactness, and safety challenge the boundaries of existing heat exchanger technology, giving rise to the following study. Various studies have been performed in attempts to update the secondary heat exchanger that is downstream of the primary heat exchanger, mostly because its performance is strongly tied to the ability to employ more efficient conversion cycles, such as the Rankine super critical and subcritical cycles. This study considers two different types of heat exchangersŚhelical coiled heat exchanger and printed circuit heat exchangerŚas possible options for the AHTR secondary heat exchangers with the following three different options: (1) A single heat exchanger transfers all the heat (3,400 MW(t)) from the intermediate heat transfer loop to the power conversion system or process plants; (2) Two heat exchangers share heat to transfer total heat of 3,400 MW(t) from the intermediate heat transfer loop to the power conversion system or process plants, each exchanger transfers 1,700 MW(t) with a parallel configuration; and (3) Three heat exchangers share heat to transfer total heat of 3,400 MW(t) from the intermediate heat transfer loop to the power conversion system or process plants. Each heat exchanger transfers 1,130 MW(t) with a parallel configuration. A preliminary cost comparison will be provided for all different cases along with challenges and recommendations.

  7. Heat Exchangers for Solar Water Heating Systems | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33Frequently20,000 RussianBy: Thomas P. D'Agostino,GlenLearning andDesign inImage of a heat

  8. Heat Exchangers for Solar Water Heating Systems | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page onYouTube YouTube Note: Since the.pdfBreaking of Blythe Solar Power ProjectHawai'i EstablishesChillerEast WingHeat

  9. Foundation heat exchangers for residential ground source heat pump systems Numerical modeling and experimental validation

    SciTech Connect (OSTI)

    Xing, Lu [Oklahoma State University; Cullin, James [Oklahoma State University; Spitler, Jeffery [Oklahoma State University; Im, Piljae [ORNL; Fisher, Daniel [Oklahoma State University

    2011-01-01T23:59:59.000Z

    A new type of ground heat exchanger that utilizes the excavation often made for basements or foundations has been proposed as an alternative to conventional ground heat exchangers. This article describes a numerical model that can be used to size these foundation heat exchanger (FHX) systems. The numerical model is a two-dimensional finite-volume model that considers a wide variety of factors, such as soil freezing and evapotranspiration. The FHX numerical model is validated with one year of experimental data collected at an experimental house located near Oak Ridge, Tennessee. The model shows good agreement with the experimental data-heat pump entering fluid temperatures typically within 1 C (1.8 F) - with minor discrepancies due to approximations, such as constant moisture content throughout the year, uniform evapotranspiration over the seasons, and lack of ground shading in the model.

  10. Forming liquid sprays in compressed-gas energy storage systems for effective heat exchange

    DOE Patents [OSTI]

    McBride, Troy O; Bell, Alexander; Bollinger, Benjamin R; Shang, Andrew; Chmiel, David; Richter, Horst; Magari, Patrick; Cameron, Benjamin

    2013-07-02T23:59:59.000Z

    In various embodiments, efficiency of energy storage and recovery systems compressing and expanding gas is improved via heat exchange between the gas and a heat-transfer fluid.

  11. Forming liquid sprays in compressed-gas energy storage systems for effective heat exchange

    DOE Patents [OSTI]

    McBride, Troy O.; Bell, Alexander; Bollinger, Benjamin R.

    2012-08-07T23:59:59.000Z

    In various embodiments, efficiency of energy storage and recovery systems compressing and expanding gas is improved via heat exchange between the gas and a heat-transfer fluid.

  12. air-to-air heat exchangers: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Heat Exchangers, Heat Transfer, Energy, Phase Change and multiphase process, Renewable energy (Solan, Tidal), Energy Storage, Conversion Cessi, Paola 62 Dealing with...

  13. air-cooled heat exchangers: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Heat Exchangers, Heat Transfer, Energy, Phase Change and multiphase process, Renewable energy (Solan, Tidal), Energy Storage, Conversion Cessi, Paola 66 Dealing with...

  14. air-to-air heat exchanger: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Heat Exchangers, Heat Transfer, Energy, Phase Change and multiphase process, Renewable energy (Solan, Tidal), Energy Storage, Conversion Cessi, Paola 62 Dealing with...

  15. Design of compact intermediate heat exchangers for gas cooled fast reactors

    E-Print Network [OSTI]

    Gezelius, Knut, 1978-

    2004-01-01T23:59:59.000Z

    Two aspects of an intermediate heat exchanger (IHX) for GFR service have been investigated: (1) the intrinsic characteristics of the proposed compact printed circuit heat exchanger (PCHE); and (2) a specific design optimizing ...

  16. Implementation issues for realtime optimization of a crude unit heat exchanger network

    E-Print Network [OSTI]

    Skogestad, Sigurd

    1 Implementation issues for realştime optimization of a crude unit heat exchanger network Tore Lidş mentation of real time optimization results in a crude unit heat exchanger network. Two di#erent control

  17. Implementation issues for real-time optimization of a crude unit heat exchanger network

    E-Print Network [OSTI]

    Skogestad, Sigurd

    1 Implementation issues for real-time optimization of a crude unit heat exchanger network Tore Lid of real time optimization results in a crude unit heat exchanger network. Two different control strategies

  18. The Cost of Heat Exchanger Fouling in the U. S. Industriesá

    E-Print Network [OSTI]

    Rebello, W. J.; Richlen, S. L.; Childs, F.

    1988-01-01T23:59:59.000Z

    Fouling of heat exchangers costs the U.S. industries hundreds of millions of dollars every year in increased equipment costs, maintenance costs, energy losses and losses in production. The designer of heat exchangers usually allows for fouling...

  19. Research for Advanced Heat Exchangers- The U.S. DOE Programá

    E-Print Network [OSTI]

    Richlen, S. L.

    1986-01-01T23:59:59.000Z

    Since its beginning, the Advanced Heat Exchangers Program of the U.S. Department of Energy - Office of Industrial Programs has made significant contributions to the development of advanced heat exchanger technology to save energy for U.S. industry...

  20. A Zero Emission Mechanical Seal with Integral Micro Heat Exchangerá

    E-Print Network [OSTI]

    Khonsari, M.

    2005-01-01T23:59:59.000Z

    are all manifestations of surface damage that emanate from heat and eventually result in the leakage of the process fluid to the ambient. Accordingly, adverse environmental impact, safety concerns, and economic loss due to forced shut down...

  1. A self-circulating heat exchanger for use in stirling and thermoacoustic-stirling engines

    SciTech Connect (OSTI)

    Backhaus, S. N. (Scott N.); Reid, R. S. (Robert Stowers)

    2004-01-01T23:59:59.000Z

    A major technical hurdle to the implementation of large Stirling engines or thermoacoustic engines is the reliability, performance, and manufacturability of the hot heat exchanger that brings high-temperature heat into the engine. Unlike power conversion devices that utilize steady flow, the oscillatory nature of the flow in Stirling and thermoacoustic engines restricts the length of a traditional hot heat exchanger to a peak-to-peak gas displacement, which is usually around 0.2 meters or less. To overcome this restriction, a new hot heat exchanger has been devised that uses a fluid diode in a looped pipe, which is resonantly driven by the oscillating gas pressure in the engine itself, to circulate the engine's working fluid around the loop. Instead of thousands of short, intricately interwoven passages that must be individually sealed, this new design consists of a few pipes that are typically 10 meters long. This revolutionary approach eliminates thousands of hermetic joints, pumps the engine's working fluid to and from a remote heat source without using moving parts, and does so without compromising on heat transfer surface area. Test data on a prototype loop integrated with a 1-kW thermoacoustic engine will be presented.

  2. Fluidized bed heat exchanger with water cooled air distributor and dust hopper

    DOE Patents [OSTI]

    Jukkola, Walfred W. (Westport, CT); Leon, Albert M. (Mamaroneck, NY); Van Dyk, Jr., Garritt C. (Bethel, CT); McCoy, Daniel E. (Williamsport, PA); Fisher, Barry L. (Montgomery, PA); Saiers, Timothy L. (Williamsport, PA); Karstetter, Marlin E. (Loganton, PA)

    1981-11-24T23:59:59.000Z

    A fluidized bed heat exchanger is provided in which air is passed through a bed of particulate material containing fuel. A steam-water natural circulation system is provided for heat exchange and the housing of the heat exchanger has a water-wall type construction. Vertical in-bed heat exchange tubes are provided and the air distributor is water-cooled. A water-cooled dust hopper is provided in the housing to collect particulates from the combustion gases and separate the combustion zone from a volume within said housing in which convection heat exchange tubes are provided to extract heat from the exiting combustion gases.

  3. (Solar clothes dryer and wastewater heat exchanger). Final report

    SciTech Connect (OSTI)

    Baer, B.F.

    1984-12-04T23:59:59.000Z

    The first project investigated the technical possibilities of adapting a domestic electric clothes dryer to utilize solar-heated water as the heat source, replacing electric resistance heat. The second project attempted to extract wastewater heat from a commercial dishwasher to preheat fresh water to be used in the next dish washing cycle. It is felt that the clothes dryer project has met all of intended goals. Although a solar application has some real-world practical problems, the application of a dryer connected directly to the home heating system will prove to be cost-beneficial over the life of a dryer. The additional cost of a heat exchanger is not excessive, and the installation cost, if installed with the initial house plumbing is less than $100. From a practical point of view, the complexity of installing a wastewater heat extracter is considered impractical. The environment in which such equipment must operate is difficult at best, and most restaurants prefer to maintain as simple an operation as possible. If problems were to occur in this type of equipment, the kitchen would effectively be crippled. In conclusion, further research in the concept is not recommended. Recent advances in commercial dishwashers have also considerably reduced the heat losses which accompanied equipment only a few years old.

  4. Thermal performance of direct contact heat exchangers for mixed hydrocarbons

    SciTech Connect (OSTI)

    Sharpe, L. Jr.; Coswami, D.Y.; Demuth, O.J.; Mines, G.

    1985-01-01T23:59:59.000Z

    This paper describes a physical and a mathematical model for evaluating the tray efficiencies for a direct contact heat exchanger (DCHX). The model is then used to determine the efficiencies for tests conducted on a 60kW sieve tray DCHX as heat is transferred from a geofluid (brine) to a working fluid (mixed hydrocarbons). It is assumed that there are three distinct regions in the column based on the state of the working fluid, as follows: Region I - Preheating with no vaporization; Region II - Preheating with moderate vaporization; and Region III - Major vaporization. The boundaries of these regions can be determined from the experimental data. In the model, mass balance and energy balance is written for a tray ''N'' in each of these regions. Finally, the ''tray efficiency'' or ''heat transfer'' effectiveness of the tray is calculated based on the definition that it is the ratio of the actual heat transfer to the maximum possible, thermodynamically.

  5. Microcomputer analysis of regenerative heat exchangers for oscillating flow

    SciTech Connect (OSTI)

    Hutchinson, R.A.; Lyke, S.E.

    1987-03-01T23:59:59.000Z

    Regenerative heat exchangers for use in oscillating flows such as those occurring in Stirling engines present considerable analytical problems to the thermal engineer. A simplified finite element analysis has been implemented in a spreadsheet, providing improved access to analytical assumptions and allowing parametric analysis of current heat transfer data. In addition, an irreversibility analysis has been implemented using the thermal and friction results in the spreadsheet. It is suited for evaluation and insights into loss tradeoffs inside operating regenerators, to suggest new regenerator design concepts, and to focus experimental work. 22 refs., 13 figs.

  6. Horizontal Heat Exchanger Design and Analysis for Passive Heat Removal Systems

    SciTech Connect (OSTI)

    Vierow, Karen

    2005-08-29T23:59:59.000Z

    This report describes a three-year project to investigate the major factors of horizontal heat exchanger performance in passive containment heat removal from a light water reactor following a design basis accident LOCA (Loss of Coolant Accident). The heat exchanger studied in this work may be used in advanced and innovative reactors, in which passive heat removal systems are adopted to improve safety and reliability The application of horizontal tube-bundle condensers to passive containment heat removal is new. In order to show the feasibility of horizontal heat exchangers for passive containment cooling, the following aspects were investigated: 1. the condensation heat transfer characteristics when the incoming fluid contains noncondensable gases 2. the effectiveness of condensate draining in the horizontal orientation 3. the conditions that may lead to unstable condenser operation or highly degraded performance 4. multi-tube behavior with the associated secondary-side effects This project consisted of two experimental investigations and analytical model development for incorporation into industry safety codes such as TRAC and RELAP. A physical understanding of the flow and heat transfer phenomena was obtained and reflected in the analysis models. Two gradute students (one funded by the program) and seven undergraduate students obtained research experience as a part of this program.

  7. Heat exchanger bypass system for an absorption refrigeration system

    DOE Patents [OSTI]

    Reimann, Robert C. (Lafayette, NY)

    1984-01-01T23:59:59.000Z

    A heat exchanger bypass system for an absorption refrigeration system is disclosed. The bypass system operates to pass strong solution from the generator around the heat exchanger to the absorber of the absorption refrigeration system when strong solution builds up in the generator above a selected level indicative of solidification of strong solution in the heat exchanger or other such blockage. The bypass system includes a bypass line with a gooseneck located in the generator for controlling flow of strong solution into the bypass line and for preventing refrigerant vapor in the generator from entering the bypass line during normal operation of the refrigeration system. Also, the bypass line includes a trap section filled with liquid for providing a barrier to maintain the normal pressure difference between the generator and the absorber even when the gooseneck of the bypass line is exposed to refrigerant vapor in the generator. Strong solution, which may accumulate in the trap section of the bypass line, is diluted, to prevent solidification, by supplying weak solution to the trap section from a purge system for the absorption refrigeration system.

  8. Industrial Waste Heat Recovery Using Heat Pipesá

    E-Print Network [OSTI]

    Ruch, M. A.

    1981-01-01T23:59:59.000Z

    For almost a decade now, heat pipes with secondary finned surfaces have been utilized in counter flow heat exchangers to recover sensible energy from industrial exhaust gases. Over 3,000 such heat exchangers are now in service, recovering...

  9. Study on the heat transfer of heat exchangers for the Stirling Engine

    SciTech Connect (OSTI)

    Kanzaka, M. (Nagasaki Research and Development Center (JP)); Iwabuchi, M. (Advanced Technology Research Center, Mitsubishi Heavy Industries, Ltd. (JP))

    1991-01-01T23:59:59.000Z

    This paper reports that heat-transfer characteristics in heated tubes under periodically reversing flow conditions have been investigated experimentally using a test apparatus that simulates the heat exchangers for the actual Sterling engine. It was shown that the heat-transfer characteristics under these conditions were greatly affected by the piston phase-angle difference that generates the reversing flow of the working gas, and this phenomenon was proper to the heat transfer under the periodically reversing flow and was different from conventional heat transfer in steady flow. The experimental correlation considering the influence of the piston phase-angle difference for the heat-transfer coefficient has been induced by the use of the working gas velocity evaluated from the Schmidt cycle model which is one of the ideal Sterling cycles.

  10. A surface renewal model to analyze infrared image sequences of the ocean surface for the study of air-sea heat

    E-Print Network [OSTI]

    Garbe, Christoph S.

    A surface renewal model to analyze infrared image sequences of the ocean surface for the study of air-sea heat and gas exchange C. S. Garbe Interdisciplinary Center for Scientific Computing renewal, the net heat flux, and the heat transfer velocity during nighttime. The techniques are based

  11. An overview of heat exchanger enhancement techniques for industrial applications

    SciTech Connect (OSTI)

    Somasundaram, S. (Pacific Northwest Lab., Richland, WA (United States)); Ohadi, M.M. (Maryland Univ., Baltimore, MD (United States)); Richlen, S. (US Dept. of Energy, Washington, DC (US))

    1992-06-01T23:59:59.000Z

    An assessment is make of selected currently available heat exchanger enhancement techniques for single- and two-phase heat transfer mechanisms to determine their practicality and commercialization potential for different industrial applications. The assessment includes a screening review of the major techniques being investigated in the research community, and identification of selected passive techniques and determine their potential limitations with respect to industrial applications. A more detailed study of the research needs and the technology gaps is being conducted to address the issues of concern for each practical application of the chosen techniques. The technical and economic feasibility and the performance benefits of incorporating a particular technique in a heat transfer process is also discussed. The potential design, operational, and manufacturing cost issues that have prevented a technique from being widely commercialized are identified.

  12. AN OPTIMIZED TWO-CAPACITY ADVANCED ELECTRIC HEAT PUMP S. E. Veyo, Manager, Heat Exchange Systems Research

    E-Print Network [OSTI]

    Oak Ridge National Laboratory

    #12;AN OPTIMIZED TWO-CAPACITY ADVANCED ELECTRIC HEAT PUMP S. E. Veyo S. E. Veyo, Manager, Heat 15235 KEYWORDS: heat pump, air conditioner, electric, residential, energy, compressor, fan, blower, heat exchanger, comfort. #12;AN OPTIMIZED TWO-CAPACITY ADVANCED ELECTRIC HEAT PUMP S. E. Veyo* ABSTRACT A two

  13. Thermal Performance of Microencapsulated Phase Material (MPCM) Slurry in a Coaxial Heat Exchanger

    E-Print Network [OSTI]

    Yu, Kun

    2014-05-08T23:59:59.000Z

    Microencapsulated phase change material (MPCM) slurries and coil heat exchangers had been recently studied separately as enhancers of convective heat transfer processes. Due to the larger apparent heat related to the phase change process...

  14. Clean Boiler Waterside Heat Transfer Surfaces

    SciTech Connect (OSTI)

    Not Available

    2006-01-01T23:59:59.000Z

    This revised ITP tip sheet on cleaning boiler water-side heat transfer surfaces provides how-to advice for improving industrial steam systems using low-cost, proven practices and technologies.

  15. Vertical Concentric Tube Ground Couoled Heat Exchangers V. C. Mei and S. K. Fischer*

    E-Print Network [OSTI]

    Oak Ridge National Laboratory

    to extract heat from or reject heat to the environment. The majority of heat pumps use ambient air of the air. Ground water is a better heat source/sink for heat pump application (due to its superior thermal exchangers for use in heat-pump applications is described. The experimental apparatus consists

  16. Xenon Recirculation-Purification with a Heat Exchanger

    E-Print Network [OSTI]

    Giboni, K L; Choi, B; Haruyama, T; Lang, R F; Lim, K E; Melgarejo, A J; Plante, G; 10.1088/1748-0221/6/03/P03002

    2011-01-01T23:59:59.000Z

    Liquid-xenon based particle detectors have been dramatically growing in size during the last years, and are now exceeding the one-ton scale. The required high xenon purity is usually achieved by continuous recirculation of xenon gas through a high-temperature getter. This challenges the traditional way of cooling these large detectors, since in a thermally well insulated detector, most of the cooling power is spent to compensate losses from recirculation. The phase change during recondensing requires five times more cooling power than cooling the gas from ambient temperature to -100C (173 K). Thus, to reduce the cooling power requirements for large detectors, we propose to use the heat from the purified incoming gas to evaporate the outgoing xenon gas, by means of a heat exchanger. Generally, a heat exchanger would appear to be only of very limited use, since evaporation and liquefaction occur at zero temperature difference. However, the use of a recirculation pump reduces the pressure of the extracted liquid...

  17. Simulation model air-to-air plate heat exchanger

    SciTech Connect (OSTI)

    Wetter, Michael

    1999-01-01T23:59:59.000Z

    A simple simulation model of an air-to-air plate heat exchanger is presented. The model belongs to a collection of simulation models that allows the eflcient computer simulation of heating, ventilation, and air-conditioning (HVAC) systems. The main emphasis of the models is to shorten computation time and to use only input data that are known in the design process of an HVAC system. The target of the models is to describe the behavior of HVAC components in the part-load operation mode, which is becoming increasingly important in energy eficient HVAC systems. The models are intended to be used for yearly energy calculations or load calculations with time steps of about 10 minutes or larger. Short- time dynamic effects, which are of interest for different aspects of control theory, are neglected. The part-load behavior is expressed in terms of the nominal condition and the dimensionless variation of the heat transfer with change of mass flow and temperature. The effectiveness- NTU relations are used to parametrize the convective heat transfer at nominal conditions and to compute the part-load condition. If the heat transfer coefficients on the two exchanger sides are not equal (i. e. due to partial bypassing of air), their ratio can be easily calculated and set as a parameter. The model is static and uses explicit equations only. The explicit model formulation ensures short computation time and numerical stability, which allows using the model with sophisticated engineering methods like automatic system optimization. This paper fully outlines the algorithm description and its simplifications. It is not tailored for any particular simulation program to ensure easy implementation in any simulation program.

  18. Energy-efficiency comparison of advanced ammonia heat-exchanger types

    SciTech Connect (OSTI)

    Panchal, C.; Rabas, T.

    1990-01-01T23:59:59.000Z

    Ammonia is the most cost-effective working fluid for many Rankine power cycles and is widely utilized in industrial refrigeration applications. For example, it was selected as the most advantageous working fluid for the comprehensive closed-cycle Ocean Thermal Energy Conversion investigations where the heat source and sink are the warm, surface seawater and the cold, deep seawater, respectively. An essential part of this investigation was to measure the performance of many advanced heat-exchanger types using ammonia as the working fluid and to compare these results with those for conventional shell-and-tube designs. This paper presents an overview of these experiments and their potential significance for improved energy efficiency for industrial refrigeration applications. The heat exchangers used for industrial refrigeration systems account for about 50% of the equipment cost. However, current practice is to use state-of-the-art designs -- the shell-and-tube type without enhanced tubes. Substantial energy savings are possible through the use of advanced ammonia evaporator and condenser heat-exchanger types. 31 refs., 10 figs., 6 tabs.

  19. The effects of outdoor heat exchanger hydrophobic treatment on the performance of an air source heat pumpá

    E-Print Network [OSTI]

    Parker, Brandon DeWayne

    1995-01-01T23:59:59.000Z

    compared to tests that utilized coated aluminum outdoor heat exchangers. The overall performance of each test was analyzed. These tests were carried out for cooling and heating mode conditions. The adhesion strength of water droplets to a bare aluminum...

  20. Dry/wet performance of a plate-fin air-cooled heat exchanger with continuous corrugated fins

    SciTech Connect (OSTI)

    Hauser, S.G.; Kreid, D.K.; Johnson, B.M.

    1981-01-01T23:59:59.000Z

    The performance and operating characteristics of a plate-fin heat exchanger in dry/wet or deluge operations was experimentally determined. Development of the deluge heat/mass transfer model continued. The experiments were conducted in a specially-designed wind tunnel at the PNL. Air that was first heated and humidified to specified conditions was circulated at a controlled rate through a 2 ft x 6 ft heat exchanger module. The heat exchanger used in the tests was a wavy surface, plate fin on tube configuration. Hot water was circulated through the tubes at high flow rates to maintain an essentially isothermal condition on the tube side. Deionized water sprayed on the top of the vertically oriented plate fins was collected at the bottom of the core and recirculated. Instrumentation was provided for measurement of flow rates and thermodynamic conditions in the air, in the core circulation water, and in the deluge water. Measurements of the air side pressure drop and heat rejection rate were made as a function of air flow rate, air inlet temperature and humidity, deluge water flow rate, and the core inclination from the vertical. An overall heat transfer coefficient and an effective deluge film convective coefficient was determined. The deluge model, for predicting heat transfer from a wet finned heat exchanger was further developed and refined, and a major extension of the model was formulated that permits simultaneous calculation of both the heat transfer and evaporation rates from the wetted surface. The experiments showed an increase in the heat rejection rate due to wetting, accompanied by a proportional increase in the air side pressure drop. For operation at the same air side pressure drop, the enhancement ratio Q/sub w//Q/sub d/ varied between 2 and 5 for the conditions tested. Thus, the potential enhancement of heat transfer due to wetting can be substantial.

  1. Permeation Barrier Coatings for the Helical Heat Exchanger

    SciTech Connect (OSTI)

    Korinko, P.S.

    1999-05-26T23:59:59.000Z

    A permeation barrier coating was specified for the Helical Heat Exchanger (HHE) to minimize contamination through emissions and/or permeation into the nitrogen system for ALARA reasons. Due to the geometry of the HHE, a special coating practice was needed since the conventional method of high temperature pack aluminization was intractable. A survey of many coating companies was undertaken; their coating capabilities and technologies were assessed and compared to WSRC needs. The processes and limitations to coating the HHE are described. Slurry coating appears to be the most technically sound approach for coating the HHE.

  2. Aging management guideline for commercial nuclear power plants - heat exchangers

    SciTech Connect (OSTI)

    Booker, S.; Lehnert, D.; Daavettila, N.; Palop, E.

    1994-06-01T23:59:59.000Z

    This Aging Management Guideline (AMG) describes recommended methods for effective detection and mitigation of age-related degradation mechanisms in commercial nuclear power plant heat exchangers important to license renewal. The intent of this AMG is to assist plant maintenance and operations personnel in maximizing the safe, useful life of these components. It also supports the documentation of effective aging management programs required under the License Renewal Rule 10 CFR 54. This AMG is presented in a manner that allows personnel responsible for performance analysis and maintenance to compare their plant-specific aging mechanisms (expected or already experienced) and aging management program activities to the more generic results and recommendations presented herein.

  3. ADVANCED HEAT EXCHANGERS USING TUNABLE NANOSCALE-MOLECULAR ASSEMBLY

    SciTech Connect (OSTI)

    Kwang J. Kim; Thomas W. Bell; Srinivas Vemuri; Sailaja Govindaraju

    2004-01-01T23:59:59.000Z

    Steam condensation heat transfer on smooth horizontal tubes and enhanced tubes (TURBO-CDI and TURBO-CSL) along with nanoscale hydrophobic coated tubes was studied experimentally. Hydrophobic coatings have been created through self-assembled mono layers (SAMs) on copper alloy (99.9% Cu, 0.1% P) surfaces to enhance steam condensation through dropwise condensation. In general, a SAM system with a long-chain, hydrophobic group is nano-resistant, meaning that such a system forms a protective hydrophobic layer with negligible heat transfer resistance but a much stronger bond. When compared to complete filmwise condensation, the SAM coating on a plain tube increased the condensation heat transfer rate by a factor of 3 for copper alloy surfaces, under vacuum pressure (33.86 kPa) and by a factor of about 8 times when operated at atmospheric pressure (101 kPa). Lifetime of maintaining dropwise condensation is greatly dependent on the processing conditions.

  4. The Cost of Heat Exchanger Fouling in the U. S. Industries

    E-Print Network [OSTI]

    Rebello, W. J.; Richlen, S. L.; Childs, F.

    and other industries. The 1982 U.S. sales of all industrial heat exchangers, excepting boilers and automotive radiators, was about 285,000 units amounting to about $1.6 billion. The total heat duty of all the heat exchangers in industrial operation...

  5. Optimal Scheduling for Biocide and Heat Exchangers Maintenance Towards Environmentally Friendly Seawater Cooling Systemsá

    E-Print Network [OSTI]

    Binmahfouz, Abdullah

    2012-10-19T23:59:59.000Z

    the heat exchanger tubes in the system. In some instances, even a 250 micrometer thickness of fouling film can reduce the heat exchanger's heat transfer coefficient by 50 percent. On the other hand, macrofouling is the blockage caused by relatively large...

  6. Performance studies of a solar energy storing heat exchanger

    SciTech Connect (OSTI)

    Bushnell, D.L. (Northern Illinois Univ., DeKalb (USA))

    1988-01-01T23:59:59.000Z

    The design, construction, and performance of a solar energy storing heat exchanger is presented as a step toward a solar cooking concept. The solid-solid transition of pentaerythritol is the principal mechanism for energy storage. The methods for describing the system performance are explained and applied to a test system containing a controllable replacement for the solar input power. This first stage of the project will be followed by another in which the heat exchanger is connected to a concentrating array of CPC cylindrical troughs. Although a size appropriate to commercial cooking may prove easier to design from the point of view of economics in the US, the system discussed herein is sized for domestic use and addresses the question of what solar collector area and PCM mass are needed in order to provide adequate energy for several family-size meals with sufficient storage to cook at night and one or two days later. The performance is described from efficiency measurements and the determination of a figure of merit.

  7. SPECIAL ANALYSIS FOR SLIT TRENCH DISPOSAL OF THE REACTOR PROCESS HEAT EXCHANGERS

    SciTech Connect (OSTI)

    Hamm, L.; Collard, L.; Aleman, S.; Gorensek, M.; Butcher, T.

    2012-06-18T23:59:59.000Z

    The Savannah River National Laboratory (SRNL), in response to a request from Solid Waste Management (SWM), conducted a Special Analysis (SA) to evaluate the performance of nineteen heat exchangers that are to be disposed in the E-Area low level waste facility Slit Trench 9 (ST 9). Although these nineteen heat exchangers were never decontaminated, the majority of the radionuclides in the heat exchanger inventory list were determined to be acceptable for burial because they are less than the 'generic' waste form inventory limits given in the 2008 Performance Assessment (PA) (WSRC, 2008). However, as generic waste, the H-3 and C-14 inventories resulted in unacceptable sum-of-fractions (SOFs). Initial scoping analyses performed by SRNL indicated that if alterations were made to certain external nozzles to mitigate various potential leak paths, acceptable SOFs could be achieved through the use of a 'Special' waste form. This SA provides the technical basis for this new 'Special' waste form and provides the inventory limits for H-3 and C-14 for these nineteen heat exchangers such that the nineteen heat exchangers can be disposed in ST 9. This 'Special' waste form is limited to these nineteen heat exchangers in ST 9 and applies for H-3 and C-14, which are designated as H-3X and C-14X, respectively. The SA follows the same methodology used in the 2008 PA and the 2008 SA except for the modeling enhancements noted below. Infiltration rates above the heat exchangers are identical to those used in the 2008 PA; however, flow through the heat exchangers is unique. Because it is unknown exactly how sealed heat exchanger openings will perform and how surface and embedded contaminants will be released, multiple base cases or scenarios were established to investigate a set of performances. Each scenario consists of flow options (based on the performance of sealed openings) and a near-field release of contaminants (based on corrosion and diffusion performance). Two disposal configurations were analyzed where heat exchangers were assumed to be disposed four across and five lengthwise (the 4x5 configuration, with one empty) and three across and seven lengthwise (the 3x7 configuration, with two empty). A large range of conditions was considered. For example, peak well concentrations at the 100-m boundary for H-3 are shown in Figure ES-1 for a wide range of configurations (i.e. release mechanism and degree of sealing options). The maximum contaminant level (MCL) and a 10% SOF goal for H-3 are also shown. The 10% goal was based on an estimated volume fraction that these nineteen heat exchangers would consume in ST 9 and was solely used for scoping purposes to assess disposal feasibility and sealing requirements. Because various line breaks and poor sealing greatly exceeded that 10% goal, the determination was made that mitigating activities were needed, such as protection from line breaks and better sealing. An initial set of scenarios was run to assess the requirements for sealing the heat exchanger openings and the need to ensure that the sealed heat exchangers stayed sealed during transit and disposal operations. After discovering that such mitigating activities were required, additional scenarios were run that included the mitigating activities. Scenarios deemed to have a very low probability of occurrence were excluded from consideration for calculating inventory limits (for example, those scenarios that assumed an instantaneous release of contaminants along with poor sealing). The SA used the most recent K{sub d} values for the C-14 analyses and the most recent Dose Conversion Factors for H-3 and C-14 which have been updated since the 2008 PA was issued. This SA took into account the location and the disposal timing of these heat exchangers. The disposal location is within a small area of the overall Slit Trench unit (about 6% of the total) and is behind a line that is 200 ft from the down-gradient edge of ST 9. The disposal timing is assumed to be after July 1, 2012 (because disposals cannot occur until this document is approved and miti

  8. Analytical Study on Thermal and Mechanical Design of Printed Circuit Heat Exchanger

    SciTech Connect (OSTI)

    Su-Jong Yoon; Piyush Sabharwall; Eung-Soo Kim

    2013-09-01T23:59:59.000Z

    The analytical methodologies for the thermal design, mechanical design and cost estimation of printed circuit heat exchanger are presented in this study. In this study, three flow arrangements of parallel flow, countercurrent flow and crossflow are taken into account. For each flow arrangement, the analytical solution of temperature profile of heat exchanger is introduced. The size and cost of printed circuit heat exchangers for advanced small modular reactors, which employ various coolants such as sodium, molten salts, helium, and water, are also presented.

  9. Erosion of heat exchanger tubes in fluidized beds

    SciTech Connect (OSTI)

    Johnson, E.K.; Flemmer, R.L.C.

    1991-01-01T23:59:59.000Z

    This final report describes the activities of the 3-year project entitled Erosion of Heat Exchanger Tubes In Fluidized Beds.'' which was completed at the end of 1990. Project accomplishments include the collection of a substantial body of wear data In a 24in. [times] 24in. fluidized bed, comparative wear results In a 6in. [times] 6in. fluidized bed, the development of a dragometer and the collection of a comprehensive set of drag force data in the 24in. [times] 24in. bed, Fast Fourier Transform (FFT) analysis of bubble probe data to establish dominant bubble frequencies in the 24in. [times] 24in. bed, the use of a heat flux gauge for measurement of heat transfer coefficients in the 24in. [times] 24in. bed and the modeling of the tube wear in the 24in. [times] 24in. bed. Analysis of the wear data from the 24in. square bed indicates that tube wear increases with increase in superficial velocity, and with increase in tube height. The latter effect is a result of the tubes higher up in the bed seeing greater movement of dense phase than tubes lower down In the bed. In addition, tube wear was found to decrease with increase in particle size, for constant superficial velocity. Three models of tube wear were formulated and provided acceptable prediction of wear when compared with the experimental data.

  10. Improved Design Tools for Surface Water and Standing Column Well Heat Pump Systems (DE-EE0002961)

    SciTech Connect (OSTI)

    Spitler, J.D.; Culling, J.R.; Conjeevaram, K.; Ramesh, M.; Selvakumar, M.

    2012-11-30T23:59:59.000Z

    Ground-source heat pump (GSHP) systems are perhaps the most widely used ôsustainableö heating and cooling systems, with an estimated 1.7 million installed units with total installed heating capacity on the order of 18 GW. They are widely used in residential, commercial, and institutional buildings. Standing column wells (SCW) are one form of ground heat exchanger that, under the right geological conditions, can provide excellent energy efficiency at a relatively low capital cost. Closed-loop surface water heat pump (SWHP) systems utilize surface water heat exchangers (SWHE) to reject or extract heat from nearby surface water bodies. For building near surface water bodies, these systems also offer a high degree of energy efficiency at a low capital cost. However, there have been few design tools available for properly sizing standing column wells or surface water heat exchangers. Nor have tools for analyzing the energy consumption and supporting economics-based design decisions been available. The main contributions of this project lie in providing new tools that support design and energy analysis. These include a design tool for sizing surface water heat exchangers, a design tool for sizing standing column wells, a new model of surface water heat pump systems implemented in EnergyPlus and a new model of standing column wells implemented in EnergyPlus. These tools will better help engineers design these systems and determine the economic and technical feasibility.

  11. Heat exchanger design for thermoelectric electricity generation from low temperature flue gas streams

    E-Print Network [OSTI]

    Latcham, Jacob G. (Jacob Greco)

    2009-01-01T23:59:59.000Z

    An air-to-oil heat exchanger was modeled and optimized for use in a system utilizing a thermoelectric generator to convert low grade waste heat in flue gas streams to electricity. The NTU-effectiveness method, exergy, and ...

  12. A testing and HVAC design methodology for air-to-air heat pipe heat exchangers

    SciTech Connect (OSTI)

    Guo, P.; Ciepliski, D.L.; Besant, R.W. [Univ. of Saskatchewan, Saskatoon, Saskatchewan (Canada). Dept. of Mechanical Engineering

    1998-10-01T23:59:59.000Z

    Air-to-air heat pipe heat exchangers were tested using ASHRAE Standard 84-1991 as a guide. Some changes are introduced for the test facility and methods of calculating effectiveness. ASME PTC 19.1-1985 is used as a guide for uncertainty analysis. Tests were done for a range of mass flux [1.574 to 2.912 kg/(m{sup 2}{center_dot}s)], ratios of mass flow rates (0.6 to 1.85), supply air temperatures ({minus}10 C to 40 C), and heat exchanger tilt angles ({minus}8.9{degree} to 11.2{degree}). Because humidity changes in the exhaust and supply air streams were negligible, only the effectiveness of sensible and of total energy was considered. Measured and calculated results show significant variations in the effectiveness of sensible and of total energy, and uncertainties with each independent variable. For balanced exhaust and supply flow rates at {minus}10 C supply air temperature and 1.574 kg/(m{sup 2}{center_dot}s) mass flux, the measured effectiveness for sensible and total energy was calculated to be 0.48 and 0.44, respectively, with uncertainties of 0.057 and 0.052. These measurements decreased to 0.42 and 0.37, with uncertainties of 0.016 and 0.018 for a mass flux of 2.912 kg/(m{sup 2}{center_dot}s). Because water vapor condensation effects were small or negligible, the difference between the effectiveness for the sensible and total energy was within the overlapping uncertainty range of each. Based on counterflow heat exchanger theory and convective heat transfer equations, expressions are presented to extrapolate the effectiveness data between and beyond the measured data points. These effectiveness equations, which represent the variation in effectiveness with several independent operating variables, are used for HVAC design that is aimed at achieving minimum life-cycle costs.

  13. Optimal Allocation of Heat Exchanger Inventory in a Serial Type Diabatic Distillation Column

    E-Print Network [OSTI]

    Salamon, Peter

    Optimal Allocation of Heat Exchanger Inventory in a Serial Type Diabatic Distillation Column Edward Abstract Diabatic distillation is a separation process in which heat is transferred on the trays inside savings is through diabatic distillation. Instead of just one heat source (the reboiler) and one heat sink

  14. Energy, Exergy and Uncertainty Analyses of the Thermal Response Test for a Ground Heat Exchanger

    E-Print Network [OSTI]

    Al-Shayea, Naser Abdul-Rahman

    exchanger, Ground coupled heat pump Corresponding author, Tel.: +1-617-308-7214, Fax: +1-617-253-3484, E calibration DAS data acquisition system g ground H heater loss1 losses from the heating section loss2 losses heating and cooling, water heating, crop drying, agricultural greenhouses, etc. In vertical U

  15. Deposition of biological aerosols on HVAC heat exchangers

    SciTech Connect (OSTI)

    Siegel, Jeffrey; Walker, Ian

    2001-09-01T23:59:59.000Z

    Many biologically active materials are transported as bioaerosols 1-10 {micro}m in diameter. These particles can deposit on cooling and heating coils and lead to serious indoor air quality problems. This paper investigates several of the mechanisms that lead to aerosol deposition on fin and tube heat exchangers. A model has been developed that incorporates the effects of several deposition mechanisms, including impaction, Brownian and turbulent diffusion, turbophoresis, thermophoresis, diffusiophoresis, and gravitational settling. The model is applied to a typical range of air velocities that are found in commercial and residential HVAC systems 1 - 6 m/s (200 - 1200 ft/min), particle diameters from 1 - 8 {micro}m, and fin spacings from 3.2 - 7.9 fins/cm (8 - 16 fins/inch or FPI). The results from the model are compared to results from an experimental apparatus that directly measures deposition on a 4.7 fins/cm (12 FPI) coil. The model agrees reasonably well with this measured data and suggests that cooling coils are an important sink for biological aerosols and consequently a potential source of indoor air quality problems.

  16. Feasibility Study of Secondary Heat Exchanger Concepts for the Advanced High Temperature Reactor

    SciTech Connect (OSTI)

    Piyush Sabharwall

    2011-09-01T23:59:59.000Z

    The work reported herein represents a significant step in the preliminary design of heat exchanger options (material options, thermal design, selection and evaluation methodology with existing challenges). The primary purpose of this study is to aid in the development and selection of the required heat exchanger for power production using either a subcritical or supercritical Rankine cycle.

  17. On-line optimization of a crude unit heat exchanger Statoil Mongstad

    E-Print Network [OSTI]

    Skogestad, Sigurd

    On-line optimization of a crude unit heat exchanger network Tore Lid #3; Statoil Mongstad N-5954 modeling and on-line optimization of a crude unit heat exchanger network at the Statoil Mongstad re#12;nery. The objective is to minimize the energy input in the gas #12;red heater by optimally distributing the cold crude

  18. Impact of External Heat-shielding Techniques on Shell Surface...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    External Heat-shielding Techniques on Shell Surface Temperatures and Dynamic Shell Thermal Deformation of Diesel Engine Emission Control Systems Impact of External Heat-shielding...

  19. Hierarchical Modeling for Population-Based Heat Exchanger Design

    E-Print Network [OSTI]

    Geb, David

    2013-01-01T23:59:59.000Z

    Catton, I. , 2001, "NON-INTRUSIVE HEAT TRANSFER COEFFICIENTCatton, I. , 2010, "Non- Intrusive Heat Transfer Coefficientthis section, the non-intrusive induction heating transient

  20. AN URBAN SURFACE EXCHANGE PARAMETERISATION FOR MESOSCALE MODELS

    E-Print Network [OSTI]

    AN URBAN SURFACE EXCHANGE PARAMETERISATION FOR MESOSCALE MODELS ALBERTO MARTILLI1, , ALAIN CLAPPIER. A scheme to represent the impact of urban buildings on airflow in mesoscale atmospheric models is presented the presence of the buildings. The parameterisation is introduced into a mesoscale model and tested

  1. Numerical Study on Crossflow Printed Circuit Heat Exchanger for Advanced Small Modular Reactors

    SciTech Connect (OSTI)

    Yoon, Su-Jong [Idaho National Laboratory (INL), Idaho Falls, ID (United States); Sabharwall, Piyush [Idaho National Laboratory (INL), Idaho Falls, ID (United States); Kim, Eung-Soo [Seoul National Univ., Seoul (Korea, Republic of)

    2014-03-01T23:59:59.000Z

    Various fluids such as water, gases (helium), molten salts (FLiNaK, FLiBe) and liquid metal (sodium) are used as a coolant of advanced small modular reactors (SMRs). The printed circuit heat exchanger (PCHE) has been adopted as the intermediate and/or secondary heat exchanger of SMR systems because this heat exchanger is compact and effective. The size and cost of PCHE can be changed by the coolant type of each SMR. In this study, the crossflow PCHE analysis code for advanced small modular reactor has been developed for the thermal design and cost estimation of the heat exchanger. The analytical solution of single pass, both unmixed fluids crossflow heat exchanger model was employed to calculate a two dimensional temperature profile of a crossflow PCHE. The analytical solution of crossflow heat exchanger was simply implemented by using built in function of the MATLAB program. The effect of fluid property uncertainty on the calculation results was evaluated. In addition, the effect of heat transfer correlations on the calculated temperature profile was analyzed by taking into account possible combinations of primary and secondary coolants in the SMR systems. Size and cost of heat exchanger were evaluated for the given temperature requirement of each SMR.

  2. Heat exchanger materials for fluidized bed coal combustors

    SciTech Connect (OSTI)

    Godfrey, T G; Copper, R H; DeVan, J H; Drake, K R

    1980-01-01T23:59:59.000Z

    The 4500-h test in the FluiDyne AFBC tells us three things: (1) ferritic and austenitic superheater alloys perform well to approximately 590/sup 0/C (1100/sup 0/F), (2) high-temperature alloys can perform well at approximately 870/sup 0/C (1600/sup 0/F), and (3) they also may fail miserably at approximately 870/sup 0/C (1600/sup 0/F). Additional studies are clearly needed to develop a fundamental understanding of corrosion mechanisms in AFBC and to determine the envelope of safe operating conditions, which will depend upon alloy sensitivity, the oxygen and sulfur activities, and the many parameters that affect mixing and homogeneity within an operating AFBC. Ultimately long-term tests for periods to 20,000 h will be needed to assure the operability of in-bed heat exchanger and structural materials for the anticipated lifetime of a plant. Good design and well-controlled operations will yield good material performance in AFBC. The key to reliable material usage is operation within the safe envelope. Results from the present experiment suggest that this envelope is large for utility steam systems but smaller for high-temperature tubes and uncooled components in AFBC.

  3. Description of emission control using fluidized-bed, heat-exchange technology

    SciTech Connect (OSTI)

    Vogel, G.J.; Grogan, P.J.

    1980-06-01T23:59:59.000Z

    Environmental effects of fluidized-bed, waste-heat recovery technology are identified. The report focuses on a particular configuration of fluidized-bed, heat-exchange technology for a hypothetical industrial application. The application is a lead smelter where a fluidized-bed, waste-heat boiler (FBWHB) is used to control environmental pollutants and to produce steam for process use. Basic thermodynamic and kinetic information for the major sulfur dioxide (SO/sub 2/) and NO/sub x/ removal processes is presented and their application to fluidized-bed, waste heat recovery technology is discussed. Particulate control in fluidized-bed heat exchangers is also discussed.

  4. The Role of Filtration in Maintaining Clean Heat Exchanger Coils

    SciTech Connect (OSTI)

    Li Yang; James E. Braun; Eckhard A. Groll

    2004-06-30T23:59:59.000Z

    The main purpose of the study was to investigate the role of filtration in maintaining clean heat exchanger coils and overall performance. Combinations of 6 different levels of filtration (MERV 14, 11, 8, 6, 4, and no filter) and 4 different coils (an eight-row lanced-fin coil, HX8L), (an eight-row wavy-fin coil, HX8W), (a four-row lanced-fin coil, HX4L) and (a two-row lanced-fin coil, HX2L) were tested at 4 different air velocities (1.52, 2.03, 2.54,3.05 m/s (300, 400, 500, 600 ft/min)). The fouled conditions were obtained after injection of 600 grams of ASHRAE standard dust upstream of the filter/coil combination. This magnitude of dust is representative of a year of normal operation for an air conditioning system. The air-side pressure drops of the coils and filters and air-side heat transfer coefficients of the coils were determined from the measurements under the clean and fouled conditions. Depending upon the filter and coil test, the coil pressure drops increased in the range of 6%-30% for an air velocity at 2.54 m/s (500 ft/min). The impact was significantly greater for tests performed without a filter. The largest relative effect of fouling on pressure drop occurs for coils with fewer rows and having lanced fins. Coils with a greater number of rows can hold more dust so that a fixed amount of dust has a relatively smaller impact. The impact of fouling on air-side heat transfer coefficients was found to be relatively small. In some cases, heat transfer was actually enhanced due to additional turbulence caused by the presence of dust. The experimental results for pressure drops and heat transfer coefficients were correlated and the correlations were implemented within computer models of prototypical rooftop air conditioners and used to evaluate the impact of fouling on cooling capacity and EER. The equipment cooling capacity is reduced with fouling primarily because of a decrease in air flow due to the increase pressure drop rather than due to changes in h eat transfer coefficient. In most cases, the EER was reduced with fouling primarily due to increased fan power. However, the changes in EER were relatively small, in the range of 1%-9% (10%). For most cases, equipment having low efficiency filters had higher EER after fouling than equipment with high efficiency filters, because the high efficiency filter caused significantly higher pressure drops than the low efficiency filters. The extra filter pressure drop outweighed the reduced coil pressure drop after fouling. The impact of fan efficiency curves was also investigated in the study. The energy penalty associated with high efficiency filters was reduced considerably with higher efficiency fans. There is an energy penalty associated with the use of high efficiency filtration. However, the primary reason for selecting high efficiency filters for a particular application would be improved air quality. For HX8L, the quantity of dust passing through the coil with a MERV4 filter was approximately 30 times the dust passing the coil with a MERV14 filter. Without an upstream filter, the quantity of dust passing through the coil was approximately 60 times the value for a MERV14 filter.

  5. Generator-Absorber heat exchange transfer apparatus and method using an intermediate liquor

    DOE Patents [OSTI]

    Phillips, Benjamin A. (Benton Harbor, MI); Zawacki, Thomas S. (St. Joseph, MI)

    1996-11-05T23:59:59.000Z

    Numerous embodiments and related methods for generator-absorber heat exchange (GAX) are disclosed, particularly for absorption heat pump systems. Such embodiments and related methods use the working solution of the absorption system for the heat transfer medium where the working solution has an intermediate liquor concentration.

  6. Statistical properties of the energy exchanged between two heat baths coupled by thermal fluctuations

    E-Print Network [OSTI]

    Paris-Sud XI, UniversitÚ de

    particles kept at different temperatures and coupled by an elastic force. We measure the heat flowingStatistical properties of the energy exchanged between two heat baths coupled by thermal systems in contact with a single heat bath and driven out of equilibrium by external forces [1, 2, 3, 4, 5

  7. MULTI-SCALE MODELING AND APPROXIMATION ASSISTED OPTIMIZATION OF BARE TUBE HEAT EXCHANGERS

    SciTech Connect (OSTI)

    Bacellar, Daniel [University of Maryland, College Park; Ling, Jiazhen [University of Maryland, College Park; Aute, Vikrant [University of Maryland, College Park; Radermacher, Reinhard [University of Maryland, College Park; Abdelaziz, Omar [ORNL

    2014-01-01T23:59:59.000Z

    Air-to-refrigerant heat exchangers are very common in air-conditioning, heat pump and refrigeration applications. In these heat exchangers, there is a great benefit in terms of size, weight, refrigerant charge and heat transfer coefficient, by moving from conventional channel sizes (~ 9mm) to smaller channel sizes (< 5mm). This work investigates new designs for air-to-refrigerant heat exchangers with tube outer diameter ranging from 0.5 to 2.0mm. The goal of this research is to develop and optimize the design of these heat exchangers and compare their performance with existing state of the art designs. The air-side performance of various tube bundle configurations are analyzed using a Parallel Parameterized CFD (PPCFD) technique. PPCFD allows for fast-parametric CFD analyses of various geometries with topology change. Approximation techniques drastically reduce the number of CFD evaluations required during optimization. Maximum Entropy Design method is used for sampling and Kriging method is used for metamodeling. Metamodels are developed for the air-side heat transfer coefficients and pressure drop as a function of tube-bundle dimensions and air velocity. The metamodels are then integrated with an air-to-refrigerant heat exchanger design code. This integration allows a multi-scale analysis of air-side performance heat exchangers including air-to-refrigerant heat transfer and phase change. Overall optimization is carried out using a multi-objective genetic algorithm. The optimal designs found can exhibit 50 percent size reduction, 75 percent decrease in air side pressure drop and doubled air heat transfer coefficients compared to a high performance compact micro channel heat exchanger with same capacity and flow rates.

  8. Research on thermophoretic and inertial aspects of ash particle deposition on heat exchanger surfaces in coal-fired equipment. Quarterly technical report No. 10, December 1, 1988--February 28, 1989

    SciTech Connect (OSTI)

    Rosner, D.E.

    1989-03-01T23:59:59.000Z

    Little is yet known (theoretically or experimentally) about the simultaneous effects of particle inertia, particle thermophoresis and high mass loading on the important engineering problem of predicting deposition rates from flowing ``dusty`` gases. For this reason, we investigate the motion of particles present at nonnegligible mass loading in a flowing nonisothermal gaseous medium and their deposition on strongly cooled or heated solid objects by examining the instructive case of steady axisymmetric ``dusty gas`` flow between two infinite disks: an inlet (porous) disk and the impermeable ``target`` disk -- a flow not unlike that encountered in recent seeded-flame experiments. Since this stagnation flow/geometry admits interesting self-similar solutions at all Reynolds numbers, we are able to predict laminar flow mass-, momentum- and energy-transfer rate coefficients over a wide range of particle mass loadings, dimensionless particle relaxation times (Stokes numbers), dimensionless thermophoretic diffusivities, and gas Reynolds numbers. As a by-product, we illustrate the accuracy and possible improvement of our previous ``diffusion model`` for tightly coupled dusty gas systems. Moreover, we report new results illustrating the dependence of the important ``critical`` Stokes number (for incipient particle impaction) on particle mass loading and wall/gas temperature ratio for dust-laden gas motion towards ``overheated`` solid surfaces. The present formulation and insulating transport coefficients should not only be useful in explaining/predicting recent deposition rate trends in ``seeded`` flame experiments, but also highly mass-loaded systems of technological interest.

  9. Light weight and economical exhaust heat exchanger for waste...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Dual Loop ParallelSeries Waste Heat Recovery System CNG-Hybrid: A Practical Path to "Net Zero Emissions" in Commuter Rail Improving Process Heating System Performance: A...

  10. Design Method for the Heating/Cooling Coil in the AHU Based on Fuzzy Logic - Part Two: Design of the Minimum Heat-Exchanging Unit

    E-Print Network [OSTI]

    Zhang, J.; Chen, Y.; Liang, Z.

    2006-01-01T23:59:59.000Z

    Considering a heating/cooling coil with adjustable heat-exchange area, an unequal type is put forward in this paper. Aiming at the application of such heat exchanger in an air-handling unit, restriction conditions are given for the minimum heat...

  11. Plate Fin Heat Exchanger Model with Axial Conduction and Variable Properties

    SciTech Connect (OSTI)

    Hansen, B.J.; White, M.J.; Klebaner, A.; /Fermilab

    2011-06-10T23:59:59.000Z

    Future superconducting radio frequency (SRF) cavities, as part of Project X at Fermilab, will be cooled to superfluid helium temperatures by a cryogenic distribution system supplying cold supercritical helium. To reduce vapor fraction during the final Joule-Thomson (J-T) expansion into the superfluid helium cooling bath, counter-flow, plate-fin heat exchangers will be utilized. Due to their compact size and ease of fabrication, plate-fin heat exchangers are an effective option. However, the design of compact and high-effectiveness cryogenic heat exchangers operating at liquid helium temperatures requires consideration of axial heat conduction along the direction of flow, in addition to variable fluid properties. Here we present a numerical model that includes the effects of axial conduction and variable properties for a plate fin heat exchanger. The model is used to guide design decisions on heat exchanger material choice and geometry. In addition, the J-T expansion process is modeled with the heat exchanger to analyze the effect of heat load and cryogenic supply parameters. A numerical model that includes the effects of axial conduction and variable properties for a plate fin heat exchanger was developed and the effect of various design parameters on overall heat exchanger size was investigated. It was found that highly conductive metals should be avoided in the design of compact JT heat exchangers. For the geometry considered, the optimal conductivity is around 3.5 W/m-K and can range from 0.3-10 W/m-K without a large loss in performance. The model was implemented with an isenthalpic expansion process. Increasing the cold side inlet temperature from 2K to 2.2 K decreased the liquid fraction from 0.856 to 0.839 which corresponds to a 0.12 g/s increase in supercritical helium supply needed to maintain liquid level in the cooling bath. Lastly, it was found that the effectiveness increased when the heat load was below the design value. Therefore, the heat exchanger should be sized on the high end of the required heat load.

  12. Nano-engineering the boiling surface for optimal heat transfer rate and critical heat flux

    E-Print Network [OSTI]

    Phillips, Bren Andrew

    2011-01-01T23:59:59.000Z

    The effects on pool boiling characteristics such as critical heat flux and the heat transfer coefficient of different surface characteristics such as surface wettability, roughness, morphology, and porosity are not well ...

  13. Visualization of flow boiling in an annular heat exchanger under reduced gravity conditions

    E-Print Network [OSTI]

    Westheimer, David Thomas

    2000-01-01T23:59:59.000Z

    This work examines the effects of gravitational acceleration on the flow boiling process. A test facility focusing on an annular heat exchanger was designed, built out of borosilicate glass, and flown on NASA's KC-135 reduced gravity airplane...

  14. Heat Exchanger Monitoring and Its Application to Cleaning and Antifoulant Use

    E-Print Network [OSTI]

    Garcia, E.; Leach, S. H.; VanNostrand, W. L.

    1983-01-01T23:59:59.000Z

    Many refineries and chemical plants are presently experiencing considerable fuel savings and reduced maintenance costs as a result of their heat exchanger monitoring activities. Significant energy credits can be generated with proper applications...

  15. air heat exchanger: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Summary: Solar air heating system for combined DHW and space heating solar air collector PV-panel fannon-return valve DHW tank mantle cold waterhot water roof Solar Energy Centre...

  16. air heat exchangers: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Summary: Solar air heating system for combined DHW and space heating solar air collector PV-panel fannon-return valve DHW tank mantle cold waterhot water roof Solar Energy Centre...

  17. Development of ASME performance test code 12.5, single phase heat exchangers

    SciTech Connect (OSTI)

    Lestina, T. [MPR Associates, Alexandria, VA (United States); Scott, B. [Baltimore Gas and Electric Co., Lusby, MD (United States). Calvert Cliffs Nuclear Power Plant

    1998-12-31T23:59:59.000Z

    Testing of heat exchanger performance is conducted to (1) confirm that the installed unit meets design specifications, (2) troubleshoot degradation, and (3) assess process improvements. Standard test methods are needed to ensure that highly accurate and reliable test results are obtained. These methods need to predict heat exchanger performance at design conditions based on test measurements at different conditions. ASME Performance Test Code 12.5, Single Phase Heat Exchangers, is under development to meet these needs. This paper summarizes the content of PTC 12.5 which is ready for industry review. The new PTC improves upon existing guidelines because methods to minimize and quantify uncertainty are provided. Overall uncertainty as low as 8% in heat transfer rate and overall heat transfer coefficient is possible for a well designed and properly instrumented thermal performance test.

  18. Design of chemical reactors of the heat exchanger type

    E-Print Network [OSTI]

    McBeth, Lloyd Theodore

    1956-01-01T23:59:59.000Z

    , of the coolant varies with respect to its position in the tubes. A heat balance on the reactants is shown below. Heat balance on the reacting mass during time ae Heat in by generation = rV QR& 9 R R Heat transferred from p i = the tubes to the mass: na... at constant temper- ature, less and less heat must be removed as the reaction proceeds. This is accomplished by the gradual reduction of the coolant flow rate. A mefhod for the determination of the inanner in which the coolant rate must be varied...

  19. Transition boiling heat transfer from a horizontal surface

    E-Print Network [OSTI]

    Berenson Paul Jerome

    1960-01-01T23:59:59.000Z

    An experiment, utilising a condensing fluid as the heat source, was performed to determine the heat flux vs. temperature difference curve for transition pool boiling from a horisontal surface. The boiling cure was determined ...

  20. Heat as a tracer to determine streambed water exchanges Jim Constantz1

    E-Print Network [OSTI]

    Heat as a tracer to determine streambed water exchanges Jim Constantz1 Received 13 March 2008 of heat as a tracer of shallow groundwater movement and describes current temperature-based approaches relying on traditional observation wells, and remote sensing and other large-scale advanced temperature

  1. Design considerations of a 15kW heat exchanger for the CSPonD Project

    E-Print Network [OSTI]

    Adames, Adrian A

    2010-01-01T23:59:59.000Z

    The objective of this work was to develop a 15 kW heat exchanger model for the CSPonD molten salt receiver that will shuttle the molten salt's thermal energy for conversion to electric power. A heat extraction system ...

  2. NGNP/HTE full-power operation at reduced high-temperature heat exchanger temperatures.

    SciTech Connect (OSTI)

    VIlim, R.; Nuclear Engineering Division

    2009-03-12T23:59:59.000Z

    Operation of the Next Generation Nuclear Plant (NGNP) with reduced reactor outlet temperature at full power was investigated for the High Temperature Electrolysis (HTE) hydrogen-production application. The foremost challenge for operation at design temperature is achieving an acceptably long service life for heat exchangers. In both the Intermediate Heat Exchanger (IHX) and the Process Heat Exchanger (PHX) (referred to collectively as high temperature heat exchangers) a pressure differential of several MPa exists with temperatures at or above 850 C. Thermal creep of the heat exchanger channel wall may severely limit heat exchanger life depending on the alloy selected. This report investigates plant performance with IHX temperatures reduced by lowering reactor outlet temperature. The objective is to lower the temperature in heat transfer channels to the point where existing materials can meet the 40 year lifetime needed for this component. A conservative estimate for this temperature is believed to be about 700 C. The reactor outlet temperature was reduced from 850 C to 700 C while maintaining reactor power at 600 MWt and high pressure compressor outlet at 7 MPa. We included a previously reported design option for reducing temperature at the PHX. Heat exchanger lengths were adjusted to reflect the change in performance resulting from coolant property changes and from resizing related to operating-point change. Turbomachine parameters were also optimized for the new operating condition. An integrated optimization of the complete system including heat transfer equipment was not performed. It is estimated, however, that by performing a pinch analysis the combined plant efficiency can be increased from 35.5 percent obtained in this report to a value between 38.5 and 40.1 percent. Then after normalizing for a more than three percent decrease in commodities inventory compared to the reference plant, the commodities-normalized efficiency lies between 40.0 and 41.3. This compares with a value of 43.9 for the reference plant. This latter plant has a reactor outlet temperature of 850 C and the two high temperature heat exchangers. The reduction in reactor outlet temperature from 850 C to 700 C reduces the tritium permeability rate in the IHX metal by a factor of three and thermal creep by five orders of magnitude. The design option for reducing PHX temperature from 800 C to 200 C reduces the permeability there by three orders of magnitude. In that design option this heat exchanger is the single 'choke-point' for tritium migration from the nuclear to the chemical plant.

  3. Investigation of flow maldistribution in a concentric-tube, counterflow, laminar heat exchanger

    SciTech Connect (OSTI)

    Ratts, E.B. [Univ. of Michigan, Dearborn, MI (United States). Dept. of Mechanical Engineering

    1998-07-01T23:59:59.000Z

    An analysis is made to quantify the effect of flow maldistribution on the performance of a laminar, counterflow, high-effectiveness heat exchanger. An investigation of the ability of thermally connected fins in one passage (screen mesh) to correct the uneven heat transfer distribution from the maldistributed mass flow in the other passage is made. A heat transfer model is developed for both passages. A parametric study presents the effect of adding thermal paths to correct the uneven heat transfer. A redefined fin efficiency is proposed to incorporate the fins` ability to correct uneven heat transfer. Data are compared to the model.

  4. Heat Exchanger Design Options and Tritium Transport Study for the VHTR System

    SciTech Connect (OSTI)

    Chang H. Oh; Eung S. Kim

    2008-09-01T23:59:59.000Z

    This report presents the results of a study conducted to consider heat exchanger options and tritium transport in a very high temperature reactor (VHTR) system for the Next Generation Nuclear Plant Project. The heat exchanger options include types, arrangements, channel patterns in printed circuit heat exchangers (PCHE), coolant flow direction, and pipe configuration in shell-and-tube designs. Study considerations include: three types of heat exchanger designs (PCHE, shell-and-tube, and helical coil); single- and two-stage unit arrangements; counter-current and cross flow configurations; and straight pipes and U-tube designs in shell-and-tube type heat exchangers. Thermal designs and simple stress analyses were performed to estimate the heat exchanger options, and the Finite Element Method was applied for more detailed calculations, especially for PCHE designs. Results of the options study show that the PCHE design has the smallest volume and heat transfer area, resulting in the least tritium permeation and greatest cost savings. It is theoretically the most reliable mechanically, leading to a longer lifetime. The two-stage heat exchanger arrangement appears to be safer and more cost effective. The recommended separation temperature between first and second stages in a serial configuration is 800oC, at which the high temperature unit is about one-half the size of the total heat exchanger core volume. Based on simplified stress analyses, the high temperature unit will need to be replaced two or three times during the plantĺs lifetime. Stress analysis results recommend the off-set channel pattern configuration for the PCHE because stress reduction was estimated at up to 50% in this configuration, resulting in a longer lifetime. The tritium transport study resulted in the development of a tritium behavior analysis code using the MATLAB Simulink code. In parallel, the THYTAN code, previously performed by Ohashi and Sherman (2007) on the Peach Bottom data, was revived and verified. The 600 MWt VHTR core input file developed in preparation for the transient tritium analysis of VHTR systems was replaced with the original steady-state inputs for future calculations. A Finite Element Method analysis was performed using COMSOL Multiphysics software to accurately predict tritium permeation through the PCHE type heat exchanger walls. This effort was able to estimate the effective thickness for tritium permeations and develop a correlation for general channel configurations, which found the effective thickness to be much shorter than the average channel distance because of dead spots on the channel side.

  5. Correlation Of Surface Heat Loss And Total Energy Production...

    Open Energy Info (EERE)

    Correlation Of Surface Heat Loss And Total Energy Production For Geothermal Systems Jump to: navigation, search OpenEI Reference LibraryAdd to library Conference Paper: Correlation...

  6. Foundation Heat Exchanger Final Report: Demonstration, Measured Performance, and Validated Model and Design Tool

    SciTech Connect (OSTI)

    Hughes, Patrick [ORNL; Im, Piljae [ORNL

    2012-01-01T23:59:59.000Z

    Geothermal heat pumps, sometimes called ground-source heat pumps (GSHPs), have been proven capable of significantly reducing energy use and peak demand in buildings. Conventional equipment for controlling the temperature and humidity of a building, or supplying hot water and fresh outdoor air, must exchange energy (or heat) with the building's outdoor environment. Equipment using the ground as a heat source and heat sink consumes less non-renewable energy (electricity and fossil fuels) because the earth is cooler than outdoor air in summer and warmer in winter. The most important barrier to rapid growth of the GSHP industry is high first cost of GSHP systems to consumers. The most common GSHP system utilizes a closed-loop ground heat exchanger. This type of GSHP system can be used almost anywhere. There is reason to believe that reducing the cost of closed-loop systems is the strategy that would achieve the greatest energy savings with GSHP technology. The cost premium of closed-loop GSHP systems over conventional space conditioning and water heating systems is primarily associated with drilling boreholes or excavating trenches, installing vertical or horizontal ground heat exchangers, and backfilling the excavations. This project investigates reducing the cost of horizontal closed-loop ground heat exchangers by installing them in the construction excavations, augmented when necessary with additional trenches. This approach applies only to new construction of residential and light commercial buildings or additions to such buildings. In the business-as-usual scenario, construction excavations are not used for the horizontal ground heat exchanger (HGHX); instead the HGHX is installed entirely in trenches dug specifically for that purpose. The potential cost savings comes from using the construction excavations for the installation of ground heat exchangers, thereby minimizing the need and expense of digging additional trenches. The term foundation heat exchanger (FHX) has been coined to refer exclusively to ground heat exchangers installed in the overcut around the basement walls. The primary technical challenge undertaken by this project was the development and validation of energy performance models and design tools for FHX. In terms of performance modeling and design, ground heat exchangers in other construction excavations (e.g., utility trenches) are no different from conventional HGHX, and models and design tools for HGHX already exist. This project successfully developed and validated energy performance models and design tools so that FHX or hybrid FHX/HGHX systems can be engineered with confidence, enabling this technology to be applied in residential and light commercial buildings. The validated energy performance model also addresses and solves another problem, the longstanding inadequacy in the way ground-building thermal interaction is represented in building energy models, whether or not there is a ground heat exchanger nearby. Two side-by-side, three-level, unoccupied research houses with walkout basements, identical 3,700 ft{sup 2} floor plans, and hybrid FHX/HGHX systems were constructed to provide validation data sets for the energy performance model and design tool. The envelopes of both houses are very energy efficient and airtight, and the HERS ratings of the homes are 44 and 45 respectively. Both houses are mechanically ventilated with energy recovery ventilators, with space conditioning provided by water-to-air heat pumps with 2 ton nominal capacities. Separate water-to-water heat pumps with 1.5 ton nominal capacities were used for water heating. In these unoccupied research houses, human impact on energy use (hot water draw, etc.) is simulated to match the national average. At House 1 the hybrid FHX/HGHX system was installed in 300 linear feet of excavation, and 60% of that was construction excavation (needed to construct the home). At House 2 the hybrid FHX/HGHX system was installed in 360 feet of excavation, 50% of which was construction excavation. There are six pipes in all excavations (three par

  7. Surface-induced heating of cold polar molecules

    E-Print Network [OSTI]

    Stefan Yoshi Buhmann; M. R. Tarbutt; Stefan Scheel; E. A. Hinds

    2009-12-14T23:59:59.000Z

    We study the rotational and vibrational heating of diatomic molecules placed near a surface at finite temperature on the basis of macroscopic quantum electrodynamics. The internal molecular evolution is governed by transition rates that depend on both temperature and position. Analytical and numerical methods are used to investigate the heating of several relevant molecules near various surfaces. We determine the critical distances at which the surface itself becomes the dominant source of heating and we investigate the transition between the long-range and short-range behaviour of the heating rates. A simple formula is presented that can be used to estimate the surface-induced heating rates of other molecules of interest. We also consider how the heating depends on the thickness and composition of the surface.

  8. Boiling heat transfer on superhydrophilic, superhydrophobic, and superbiphilic surfaces

    E-Print Network [OSTI]

    Attinger, Daniel

    Boiling heat transfer on superhydrophilic, superhydrophobic, and superbiphilic surfaces Amy Rachel in revised form 30 October 2012 Accepted 31 October 2012 Keywords: Superhydrophobic Superhydrophilic Biphilic- and nanofabrication, superhydrophilic and superhydrophobic surfaces have been developed. The statics and dynamics

  9. Review of Current Experience on Intermediate Heat Exchanger (IHX) and A Recommended Code Approach

    SciTech Connect (OSTI)

    Duane Spencer; Kevin McCoy

    2010-02-02T23:59:59.000Z

    The purpose of the ASME/DOE Gen IV Task 7 Part I is to review the current experience on various high temperature reactor intermediate heat exchanger (IHX) concepts. There are several different IHX concepts that could be envisioned for HTR/VHTR applications in a range of temperature from 850C to 950C. The concepts that will be primarily discussed herein are: (1) Tubular Helical Coil Heat Exchanger (THCHE); (2) Plate-Stamped Heat Exchanger (PSHE); (3) Plate-Fin Heat Exchanger (PFHE); and (4) Plate-Machined Heat Exchanger (PMHE). The primary coolant of the NGNP is potentially subject to radioactive contamination by the core as well as contamination from the secondary loop fluid. To isolate the radioactivity to minimize radiation doses to personnel, and protect the primary circuit from contamination, intermediate heat exchangers (IHXs) have been proposed as a means for separating the primary circuit of the NGNP (Next Generation Nuclear Plant) or other process heat application from the remainder of the plant. This task will first review the different concepts of IHX that could be envisioned for HTR/VHTR applications in a range of temperature from 850 to 950 C. This will cover shell-and-tube and compact designs (including the platefin concept). The review will then discuss the maturity of the concepts in terms of design, fabricability and component testing (or feedback from experience when applicable). Particular attention will be paid to the feasibility of developing the IHX concepts for the NGNP with operation expected in 2018-2021. This report will also discuss material candidates for IHX applications and will discuss specific issues that will have to be addressed in the context of the HTR design (thermal aging, corrosion, creep, creep-fatigue, etc). Particular attention will be paid to specific issues associated with operation at the upper end of the creep regime.

  10. Woven graphite fiber structures for use in ultra-light weigth heat exchangers

    SciTech Connect (OSTI)

    Hemrick, James Gordon [ORNL; Lara-Curzio, Edgar [ORNL; Loveland, Erick R [ORNL; Sharp, Keith W [ORNL; Schartow, Robert [3TEX Incorporated

    2011-01-01T23:59:59.000Z

    As part of U.S. Department of Energy efforts to find novel approaches for thermal management and heat recovery, work was undertaken at Oak Ridge National Laboratory (ORNL) to investigate the use of graphite-based materials for heat exchanger and thermal management devices. From this effort, lightweight, robust woven graphite-fiber structures were developed which provide high conductivity paths along the direction of the graphite fibers. These structures were produced and characterized for air permeability/pressure drop and thermal (heat transfer) performance. Results have been shown to be favorable for using such structures in ultra-light weight heat exchanger applications such as vehicle radiators or other areas where light weight, compact, conformable heat transfer devices are needed.

  11. Research on thermophoretic and inertial aspects of the ash particle deposition on heat exchanger surfaces in coal-fired equipment. Quarterly technical report, September 1, 1986--November 30, 1986

    SciTech Connect (OSTI)

    Rosner, D.E.

    1986-12-01T23:59:59.000Z

    In support of the above mentioned objectives, we have initiated theoretical studies in the following three interrelated areas : (a) Interaction of inertial- and thermophoretic effects in well-defined laminar ``dusty-gas`` flows. (b) Self-regulated sticking and deposit erosion in the simultaneous presence of vapor or submicron ``glue`` (c) Use of packed bed and tube-bank heat transfer and friction correlations to provide the basis for future tube-bank fouling predictions.During the first three months of Grant DE-FG22-86 PC 90756, we have: (1) Designed and initiated construction of the microcombustor particle-laden jet facility described in Section 3.1. (2) Initiated theoretical studies of the interaction of inertial and thermophoretic effects, the role of simultaneous vapor arrival in determining particle sticking and erosion probabilities, and mass transport phenomena in deep tube banks.

  12. Automatic Tube Cleaning Systems for Condensers & Heat Exchangers

    E-Print Network [OSTI]

    Someah, K.

    .0001 h'ft .0F/Btu in the condenser-tube fouling thermal resistance causes a corresponding increase of 1.1% in the compressor power requirement (2). A significant factor affecting the heat transfer capability of water-cooled condensers and heat... available space - that is, the length of piping The operation of rubber balt cleaning for the strainer section. The strainer spool with systems is based on the circulation of a single screen will occupy twice the pipe length. elastomeric, slightly...

  13. Design and Development of a Plastic Film Heat Exchanger

    E-Print Network [OSTI]

    Guyer, E. C.; Gollin, M. K.; Brownell, D. L.

    be liquid, gas, or a condensing vapor. The low thermal conductivity of the plastic is off set by the use of thin films so that overall heat transfer rates are achieved which are comparable 'to conventional units. Potential.uses for such? a unit are low... grade heat recovery, flu?e gas condensing, and liquid dessicant dehumidification systems. This paper discusses the range of plastic films available and compares their individual properties with those desirable in materials to be used in a PFHX...

  14. HEAT TRANSFER ANALYSIS FOR ION-EXCHANGE COLUMN SYSTEM

    SciTech Connect (OSTI)

    Lee, S.; King, W.

    2011-05-23T23:59:59.000Z

    Models have been developed to simulate the thermal characteristics of Crystalline Silicotitanate (CST) ion exchange media fully loaded with radioactive cesium in a column configuration and distributed within a waste storage tank. This work was conducted to support the Small Column Ion Exchange (SCIX) program which is focused on processing dissolved, high-sodium salt waste for the removal of specific radionuclides (including Cs-137, Sr-90, and actinides) within a High Level Waste (HLW) storage tank at the Savannah River Site. The SCIX design includes CST columns inserted and supported in the tank top risers for cesium removal. Temperature distributions and maximum temperatures across the column were calculated with a focus on process upset conditions. A two-dimensional computational modeling approach for the in-column ion-exchange domain was taken to include conservative, bounding estimates for key parameters such that the results would provide the maximum centerline temperatures achievable under the design configurations using a feed composition known to promote high cesium loading on CST. The current full-scale design for the CST column includes one central cooling pipe and four outer cooling tubes. Most calculations assumed that the fluid within the column was stagnant (i.e. no buoyancy-induced flow) for a conservative estimate. A primary objective of these calculations was to estimate temperature distributions across packed CST beds immersed in waste supernate or filled with dry air under various accident scenarios. Accident scenarios evaluated included loss of salt solution flow through the bed, inadvertent column drainage, and loss of active cooling in the column. The modeling results demonstrate that the baseline design using one central and four outer cooling tubes provides a highly efficient cooling mechanism for reducing the maximum column temperature.

  15. Research on thermophoretic and inertial aspects of ash particle deposition on heat exchanger surfaces in coal-fired equipment. Quarterly technical report No. 6, December 1, 1987--February 28, 1988

    SciTech Connect (OSTI)

    Rosner, D.E.

    1988-03-01T23:59:59.000Z

    During the present reporting period, we have initiated work on (a) the interpretation of our recent data (see QTR5) on deposition rates under the simultaneous influence of inertia and thermophoresis, (b) the possible rate of particle photophoresis in environments characterized by high radiative heat loads. and (c) the influence of particle size distributions on total mass deposition rates. The fruits of these initiatives will be reported in subsequent quarterly technical reports. Here, we focus on our recent theoretical results in the important but previously uncharted area of the relations between particulate deposition mechanisms, deposit microstructure and deposit properties. Experimental verification of some of the most interesting predictions will be the subject of future HTCRE-Lab studies. Recent discussions with fouling engineers have convinced us that despite recent advances in our ability to predict particle deposition rates in convective-diffusion environments, the important connection between resulting deposit properties (effective thermal conductivity permeability, {hor_ellipsis}) and deposition mechanism remain poorly understood and only scarcely studied. Accordingly, as part of this DOE-PETC program we have developed a discrete stochastic model to simulate particulate deposition processes resulting from a combination of deposition mechanisms.

  16. Research on thermophoretic and inertial aspects of ash particle deposition on heat exchanger surfaces in coal-fired equipment. Quarterly technical report No. 3, March 1, 1987--May 31, 1987

    SciTech Connect (OSTI)

    Rosner, D.E.

    1987-06-01T23:59:59.000Z

    During this third quarter of Grant DE-FG22-86 PC 90756, we have obtained preliminary experimental results on the deposition behavior of submicron and supermicron solid particles (MgO, Al{sub 2}O{sub 3}) on a two-dimensional surface exposed to a high temperature/velocity particle ``laden`` atmospheric pressure jet. The uniform velocity (``plug flow``) jet, with temperatures up to about 1520 K, derives from a pressurized gaseous fuel microcombustion chamber (110 cc) equipped with a platinum guiding (exit) channel. Particles were generated by several methods (Berglund-Liu type aerosol generator, ultrasonic nebulizer, or syringe feeder with aerodynamic particle off-take) and were introduced into the combustion chamber with a carrier stream of nitrogen or air. Laser light scattering and reflectivity techniques were used for the study of particle deposition, supplemented by post-mortem microscopy on the exposed surface. We observed a linear deposition rate of submicron particles due to the thermophoretic mechanism (until the first layer was developed) under both high and low velocity conditions. On the contrary, supermicron particle deposits reach a steady-state, evidently due to a dynamic equilibrium between particle deposition and dislodging caused by the impacting particles. At several temperatures particle-free subsonic gas jets (up to 120 m/sec) were unable to remove the submicron particle layer.

  17. Boiling Heat Transfer on Superhydrophilic, Superhydrophobic, and Superbiphilic Surfaces

    E-Print Network [OSTI]

    Betz, Amy Rachel; Kim, Chang-Jin 'CJ'; Attinger, Daniel

    2012-01-01T23:59:59.000Z

    With recent advances in micro- and nanofabrication, superhydrophilic and superhydrophobic surfaces have been developed. The statics and dynamics of fluids on these surfaces have been well characterized. However, few investigations have been made into the potential of these surfaces to control and enhance other transport phenomena. In this article, we characterize pool boiling on surfaces with wettabilities varied from superhydrophobic to superhydrophilic, and provide nucleation measurements. The most interesting result of our measurements is that the largest heat transfer coefficients are reached not on surfaces with spatially uniform wettability, but on biphilic surfaces, which juxtapose hydrophilic and hydrophobic regions. We develop an analytical model that describes how biphilic surfaces effectively manage the vapor and liquid transport, delaying critical heat flux and maximizing the heat transfer coefficient. Finally, we manufacture and test the first superbiphilic surfaces (juxtaposing superhydrophobic ...

  18. Hydraulic transmissivity and heat exchange efficiency of open fractures: a model based on lowpass filtered apertures

    E-Print Network [OSTI]

    Neuville, AmÚlie; Schmittbuhl, Jean; 10.1111/j.1365-246X.2011.05126.x

    2011-01-01T23:59:59.000Z

    Natural open joints in rocks commonly present multi-scale self-affine apertures. This geometrical complexity affects fluid transport and heat exchange between the flow- ing fluid and the surrounding rock. In particular, long range correlations of self-affine apertures induce strong channeling of the flow which influences both mass and heat advection. A key question is to find a geometrical model of the complex aperture that describes at best the macroscopic properties (hydraulic conductivity, heat exchange) with the smallest number of parameters. Solving numerically the Stokes and heat equa- tions with a lubrication approximation, we show that a low pass filtering of the aperture geometry provides efficient estimates of the effective hydraulic and thermal properties (apertures). A detailed study of the influence of the bandwidth of the lowpass filtering on these transport properties is also performed. For instance, keeping the information of amplitude only of the largest Fourier length scales allows us to rea...

  19. Stability analysis of direct contact heat exchangers subject to system perturbations. Final report, Task 2

    SciTech Connect (OSTI)

    Jacobs, H.R.

    1985-01-01T23:59:59.000Z

    This report includes a project summary, copies of two papers resulting from the work and the Ph.D. Dissertation of Dr. Mehdi Golafshani entitled, ''Stability of a Direct Contact Heat Exchanger''. Specifically, the work deals with the operational stability of a spray column type heat exchanger subject to disturbances typical of those which can occur for geothermal applications. A computer program was developed to solve the one-dimensional transient two-phase flow problem and it was applied to the design of a spray column. The operation and design of the East Mesa 500kW/sub e/ direct contactor was assessed. It is shown that the heat transfer is governed by the internal resistance of the dispersed phase. In fact, the performance is well-represented by diffusion of heat within the drops. 5 refs.

  20. Heat exchanges in fast, high-performance liquid chromatography. A complete thermodynamic study

    SciTech Connect (OSTI)

    Gritti, Fabrice [University of Tennessee, Knoxville (UTK); Guiochon, Georges A [ORNL

    2008-01-01T23:59:59.000Z

    The successive physical transformations of the mobile phase that take place in very high pressure liquid chromatography were studied based on the formalism of classical thermodynamics. The eluent is initially under atmospheric pressure (P{sup 0}) and at ambient temperature (T{sub ext}). In a first step, it is compressed to a high pressure (P{sub max} of the order of 1 kbar) in the pump heads of the chromatograph. In a second step, the pressurized eluent is transferred to the inlet of the chromatographic column, along which, in a third step, it is decompressed to atmospheric pressure. Both the compression and the decompression of the fluid were considered to take place under conditions that can be either adiabatic or nonadiabatic and either reversible or irreversible. Applications of the first and second principles of thermodynamics allow the determination of the heat and energy exchanged between the eluent and the external surroundings during each transformation. Experimental data were acquired using acetonitrile as the mobile phase. The true state equation, {rho}(P, T), of liquid acetonitrile was used in the theoretical calculations. A series of four different flow rates (0.55, 0.85, 1.15, and 1.45 mL/min, corresponding to inlet pressures of 357.2, 559.5, 765.1, and 972.9 bar, respectively), were applied to a 2.1 x 100 mm column packed with 1.7-{micro}m bridged ethane-silicon hybrid particles. Thermocouples were used to measure the eluent temperature before and after its passage through the column. These data provide estimates of the variation of the internal energy of the eluent. The heat lost through the external wall of the column during the eluent decompression was estimated by measuring the surface temperature of the column tube under steady state. Both the compression and the decompression of acetonitrile were found to be nonadiabatic and irreversible transformations. The results showed that, during the eluent decompression, the heat released by the friction forces serves four different purposes: (1) it increases the eluent entropy at constant temperature (for 35%); (2) it increases the temperature of the eluent (for 5%); (3) it provides heat to the laboratory atmosphere (for 5%); and (4) it provides some work inside the column (for 5%). This quantitative heat balance description accounts well for the actual performance of the new, very high pressure liquid chromatographic technique.

  1. advanced heat exchangers: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of difl'erent metals (e. g. aluminum, copper, steel), the spined tube is made by shaving small strips from the surface of a smooth bare tube. Since the spine is lifted from...

  2. active heat exchange: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of difl'erent metals (e. g. aluminum, copper, steel), the spined tube is made by shaving small strips from the surface of a smooth bare tube. Since the spine is lifted from...

  3. Enhanced heat transfer surface for cast-in-bump-covered cooling surfaces and methods of enhancing heat transfer

    DOE Patents [OSTI]

    Chiu, Rong-Shi Paul (Glenmont, NY); Hasz, Wayne Charles (Pownal, VT); Johnson, Robert Alan (Simpsonville, SC); Lee, Ching-Pang (Cincinnati, OH); Abuaf, Nesim (Lincoln City, OR)

    2002-01-01T23:59:59.000Z

    An annular turbine shroud separates a hot gas path from a cooling plenum containing a cooling medium. Bumps are cast in the surface on the cooling side of the shroud. A surface coating overlies the cooling side surface of the shroud, including the bumps, and contains cooling enhancement material. The surface area ratio of the cooling side of the shroud with the bumps and coating is in excess of a surface area ratio of the cooling side surface with bumps without the coating to afford increased heat transfer across the element relative to the heat transfer across the element without the coating.

  4. Research on thermophoretic and inertial aspects of ash particle deposition on heat exchanger surfaces in coal-fired equipment. Quarterly report No. 9, September 1, 1988--November 30, 1988

    SciTech Connect (OSTI)

    Rosner, D.E.

    1988-12-01T23:59:59.000Z

    A real-time laser light-reflectivity technique is being used to study simultaneous thermophoretic and inertial influences on the deposition behavior of MgO particles produced via ultrasonic nebulization (submicrometer range). The deposition surface (a concave platinum ribbon) is exposed to a high velocity/temperature jet of alkali sulfate-free combustion products exiting from a seeded (C3{sub 3}H{sub 8}/air) microcombustor (110 cm{sup 3}). The reflectivity data were calibrated against deposition rates obtained from SEM pictures of the target, and were normalized with the nominal particle feed rate, in order to obtain the mass transfer Stanton number, St{sub m}, trends depicted in Figure 1. For the submicron (ca. 0.7{mu}m) particles inertial effects appear to set in at Stokes (Stk) numbers of O(10{sup {minus}2}) (an order of magnitude lower than the ones needed for ``pure`` inertial impaction), affecting significantly the dominant thermophoretic deposition mechanism. A first order (in Stk) theoretical analysis of the problem in which particle inertia is treated as equivalent to ``pressure diffusion,`` cannot explain the observed dependence of the deposition rate on Stk. We are presently formulating a Lagrangian approach, valid for all values of Stk, in order to interpret these data. In addition, a Single Particle Counter (SPC) and Transit Time Velocimeter (TTV), are being developed, to allow more precise measurements of particle feed rates and velocities.

  5. The Influence of Availability Costs on Optimal Heat Exchanger Size

    E-Print Network [OSTI]

    Witte, L. C.

    3.62 2272.5 2230.2 2691.5 0.1433 110 3.86 2321. 3 2129.6 2740.3 0.4154 145 4.03 2344.5 2066.2 2763.5 0.7005 165 . 4.29 2371. 0 1960.0 2790.0 1. 3978 195 2385.0 4.67 230 2804.0 1813.8 2.795 2370.7 5.24 270 2789.7 1605.2 5.499 The scheme... clearly affects the optimal NTU hat will result. Thus the effect of the s r roundings and function of a particularlheat exchanger on its irreversibility costs is inherently contained in the curves of iq ure 2. The parameter Thi/Tci ranges ftom 1...

  6. High-Performance Refrigerator Using Novel Rotating Heat Exchanger |

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page onYouTube YouTube Note: Since the.pdfBreaking of Blythe Solar PowerCommercial Cold Climate Heat PumpDepartment of

  7. An Analysis of the Use of Fluidized-Bed Heat Exchangers for Heat Recovery

    E-Print Network [OSTI]

    Vogel, G. J.; Grogan, P. J.

    1980-01-01T23:59:59.000Z

    The principles of fluidized-bed operation and the factors affecting the performance of a fluidized-bed waste heat boiler (FBWHB) are discussed in detail. Factors included in the discussion are bed temperature and pressure, heat transfer coefficient...

  8. Written date: January 19, 2012 Preliminary study on the mechanical behaviour of heat exchanger pile

    E-Print Network [OSTI]

    Paris-Sud XI, UniversitÚ de

    Written date: January 19, 2012 Preliminary study on the mechanical behaviour of heat exchanger pile piles are necessary to be taken into account in geotechnical design. In this preliminary study, the behaviour of an axially loaded pile under thermal cycles was investigated using a physical model. After

  9. Corrosion of Aluminum-fin, Copper-tube Heat Exchange Coils

    E-Print Network [OSTI]

    Field, J. E.

    2002-01-01T23:59:59.000Z

    Over the past several years the HVAC industry has experienced a large increase in instances of leaks in the central portion of aluminum-finned, coppertube heat exchange coils. These leaks are characterized as being very small in size and very high...

  10. When to clean and how to clean biofilms in heat exchangers

    E-Print Network [OSTI]

    Pogiatzis, T.A.; Vassiliadis, V.S.; MergulhŃo, F.J.; Wilson, D.I.

    2014-07-02T23:59:59.000Z

    in refinery preheat trains. Energy & Fuels. 2009, 23, 1323-37. [4] Lavaja, J.H., Bagajewicz, M.J. On a new MILP model for the planning of heat-exchanger network cleaning. Industrial & Engineering Chemistry Research. 2004, 43, 3924-38. [5] Rodriguez, C., Smith...

  11. Simulation of Heat Exchange Phenomena and Water Regime in Green Roof Substrates

    E-Print Network [OSTI]

    Paris-Sud XI, UniversitÚ de

    187 Simulation of Heat Exchange Phenomena and Water Regime in Green Roof Substrates S. Charpentier UR EPHor Agrocampus-Ouest Centre d'Angers 2, rue Le N˘tre, F49045 Angers France Keywords: green roof roofs increases in Western European and North American cities. It is estimated that 12% of all flat

  12. Corrosion of Aluminum-fin, Copper-tube Heat Exchange Coilsá

    E-Print Network [OSTI]

    Field, J. E.

    2002-01-01T23:59:59.000Z

    Over the past several years the HVAC industry has experienced a large increase in instances of leaks in the central portion of aluminum-finned, coppertube heat exchange coils. These leaks are characterized as being very small in size and very high...

  13. Experimental shellside flow visualization in a shell and tube heat exchangerá

    E-Print Network [OSTI]

    Fischer, Matthew Winslow

    1998-01-01T23:59:59.000Z

    information in the shellside flow. A scale-model shell and tube heat exchanger with an outer diameter of 30.5 cm and a length of 61 cm was designed and constructed out of acrylic. Water was utilized as the working fluid and flowrates ranging from 0.32 to 2...

  14. Bond Graph Model of a Vertical U-Tube Steam Condenser Coupled with a Heat Exchanger

    E-Print Network [OSTI]

    Paris-Sud XI, UniversitÚ de

    turbines, distillation industries using water as a solvent, etc. System-level modeling of steam condensersBond Graph Model of a Vertical U-Tube Steam Condenser Coupled with a Heat Exchanger K. Medjaher1+ A A simulation model for a vertical U-tube steam condenser in which the condensate is stored at the bottom well

  15. Applying Learnable Evolution Model to Heat Exchanger Design Kenneth A. Kaufman and Ryszard S. Michalski*

    E-Print Network [OSTI]

    Michalski, Ryszard S.

    of the evaporator tubes in the heat exchanger of an air conditioner. This is a very difficult problem because conditioner, refrigerant flows through a loop. It is superheated and placed in contact with cooler outside air conditions, manufacturers of air conditioning systems currently assume in their models average operating

  16. Experimental Evaluation of a Pt-based Heat Exchanger Methanol Reformer for a HTPEM Fuel Cell Stack

    E-Print Network [OSTI]

    Berning, Torsten

    Experimental Evaluation of a Pt-based Heat Exchanger Methanol Reformer for a HTPEM Fuel Cell Stack as e.g. methanol as the hydrogen carrier and reforming it to a hydrogen rich gas can solve some of these storage issues. The work presented here examines the use of a heat exchanger methanol reformer for use

  17. Rapid infrared heating of a surface

    DOE Patents [OSTI]

    Sikka, Vinod K. (Oak Ridge, TN); Blue, Craig A. (Concord, TN); Ohriner, Evan Keith (Knoxville, TN)

    2002-01-01T23:59:59.000Z

    High energy flux infrared heaters are used to treat an object having a surface section and a base section such that a desired characteristic of the surface section is physically, chemically, or phasically changed while the base section remains unchanged.

  18. Rapid infrared heating of a surface

    DOE Patents [OSTI]

    Sikka, Vinod K. (Oak Ridge, TN); Blue, Craig A. (Concord, TN); Ohriner, Evan Keith (Knoxville, TN)

    2001-01-01T23:59:59.000Z

    High energy flux infrared heaters are used to treat an object having a surface section and a base section such that a desired characteristic of the surface section is physically, chemically, or phasically changed while the base section remains unchanged.

  19. Condensation heat transfer on nanoengineered surfaces

    E-Print Network [OSTI]

    Paxson, Adam Taylor

    2011-01-01T23:59:59.000Z

    This thesis presents a series of three related studies with the aim of developing a surface that promotes robust dropwise condensation. Due to their remarkably low droplet adhesion, superhydrophobic surfaces were investigated ...

  20. Rapid infrared heating of a surface

    DOE Patents [OSTI]

    Sikka, Vinod K.; Blue, Craig A.; Ohriner, Evan Keith

    2003-12-23T23:59:59.000Z

    High energy flux infrared heaters are used to treat an object having a surface section and a base section such that a desired characteristic of the surface section is physically, chemically, or phasically changed while the base section remains unchanged.

  1. Continuous-wave radar to detect defects within heat exchangers and steam generator tubes.

    SciTech Connect (OSTI)

    Nassersharif, Bahram (New Mexico State University, Las Cruces, NM); Caffey, Thurlow Washburn Howell; Jedlicka, Russell P. (New Mexico State University, Las Cruces, NM); Garcia, Gabe V. (New Mexico State University, Las Cruces, NM); Rochau, Gary Eugene

    2003-01-01T23:59:59.000Z

    A major cause of failures in heat exchangers and steam generators in nuclear power plants is degradation of the tubes within them. The tube failure is often caused by the development of cracks that begin on the outer surface of the tube and propagate both inwards and laterally. A new technique was researched for detection of defects using a continuous-wave radar method within metal tubing. The experimental program resulted in a completed product development schedule and the design of an experimental apparatus for studying handling of the probe and data acquisition. These tests were completed as far as the prototypical probe performance allowed. The prototype probe design did not have sufficient sensitivity to detect a defect signal using the defined radar technique and did not allow successful completion of all of the project milestones. The best results from the prototype probe could not detect a tube defect using the radar principle. Though a more precision probe may be possible, the cost of design and construction was beyond the scope of the project. This report describes the probe development and the status of the design at the termination of the project.

  2. Automatic Tube Cleaning Systems for Condensers and Heat Exchangers

    E-Print Network [OSTI]

    Someah, K.

    and wiping action of the balls which prevents the de position of scale forming deposits inside the tube surface. The balls are collected by means of a special strainer installed in the outlet part of the condenser. The balls are then recirculated... and re injected back into the supply line. The major components of this type of cleaning systems are the ball strainer, the ball recirculation system and the control system. The ball collection is accomplished by two half sized electrical screens...

  3. Surface energy exchanges along a tundra-forest transition and feedbacks to climate

    E-Print Network [OSTI]

    McGuire, A. David

    Surface energy exchanges along a tundra-forest transition and feedbacks to climate Jason Beringer a 21 October 2004; accepted 17 May 2005 Abstract Surface energy exchanges were measured in a sequence of five sites representing the major vegetation types in the transition from arctic tundra to forest

  4. Heat transfer between elastic solids with randomly rough surfaces

    E-Print Network [OSTI]

    B. N. J. Persson; B. Lorenz; A. I. Volokitin

    2009-08-27T23:59:59.000Z

    We study the heat transfer between elastic solids with randomly rough surfaces. We include both the heat transfer from the area of real contact, and the heat transfer between the surfaces in the noncontact regions. We apply a recently developed contact mechanics theory, which accounts for the hierarchical nature of the contact between solids with roughness on many different length scales. For elastic contact, at the highest (atomic) resolution the area of real contact typically consists of atomic (nanometer) sized regions, and we discuss the implications of this for the heat transfer. For solids with very smooth surfaces, as is typical in many modern engineering applications, the interfacial separation in the non-contact regions will be very small, and for this case we show the importance of the radiative heat transfer associated with the evanescent electromagnetic waves which exist outside of all bodies.

  5. Micro-scale heat-exchangers for Joule-Thomson cooling.

    SciTech Connect (OSTI)

    Gross, Andrew John

    2014-01-01T23:59:59.000Z

    This project focused on developing a micro-scale counter flow heat exchangers for Joule-Thomson cooling with the potential for both chip and wafer scale integration. This project is differentiated from previous work by focusing on planar, thin film micromachining instead of bulk materials. A process will be developed for fabricating all the devices mentioned above, allowing for highly integrated micro heat exchangers. The use of thin film dielectrics provides thermal isolation, increasing efficiency of the coolers compared to designs based on bulk materials, and it will allow for wafer-scale fabrication and integration. The process is intended to implement a CFHX as part of a Joule-Thomson cooling system for applications with heat loads less than 1mW. This report presents simulation results and investigation of a fabrication process for such devices.

  6. Experimental study on corrugated cross-flow air-cooled plate heat exchangers

    SciTech Connect (OSTI)

    Kim, Minsung; Baik, Young-Jin; Park, Seong-Ryong; Ra, Ho-Sang [Solar Thermal and Geothermal Research Center, Korea Institute of Energy Research, Daejeon 305-343 (Korea); Lim, Hyug [Research and Development Center, LHE Co., Ltd., Gimhae 621-874 (Korea)

    2010-11-15T23:59:59.000Z

    Experimental study on cross-flow air-cooled plate heat exchangers (PHEs) was performed. The two prototype PHEs were manufactured in a stack of single-wave plates and double-wave plates in parallel. Cooling air flows through the PHEs in a crosswise direction against internal cooling water. The heat exchanger aims to substitute open-loop cooling towers with closed-loop water circulation, which guarantees cleanliness and compactness. In this study, the prototype PHEs were tested in a laboratory scale experiments. From the tests, double-wave PHE shows approximately 50% enhanced heat transfer performance compared to single-wave PHE. However, double-wave PHE costs 30% additional pressure drop. For commercialization, a wide channel design for air flow would be essential for reliable performance. (author)

  7. Technology Development Roadmap for the Advanced High Temperature Reactor Secondary Heat Exchanger

    SciTech Connect (OSTI)

    P. Sabharwall; M. McCllar; A. Siahpush; D. Clark; M. Patterson; J. Collins

    2012-09-01T23:59:59.000Z

    This Technology Development Roadmap (TDRM) presents the path forward for deploying large-scale molten salt secondary heat exchangers (MS-SHX) and recognizing the benefits of using molten salt as the heat transport medium for advanced high temperature reactors (AHTR). This TDRM will aid in the development and selection of the required heat exchanger for: power production (the first anticipated process heat application), hydrogen production, steam methane reforming, methanol to gasoline production, or ammonia production. This TDRM (a) establishes the current state of molten salt SHX technology readiness, (b) defines a path forward that systematically and effectively tests this technology to overcome areas of uncertainty, (c) demonstrates the achievement of an appropriate level of maturity prior to construction and plant operation, and (d) identifies issues and prioritizes future work for maturing the state of SHX technology. This study discusses the results of a preliminary design analysis of the SHX and explains the evaluation and selection methodology. An important engineering challenge will be to prevent the molten salt from freezing during normal and off-normal operations because of its high melting temperature (390░C for KF ZrF4). The efficient transfer of energy for industrial applications depends on the ability to incorporate cost-effective heat exchangers between the nuclear heat transport system and industrial process heat transport system. The need for efficiency, compactness, and safety challenge the capabilities of existing heat exchanger technology. The description of potential heat exchanger configurations or designs (such as printed circuit, spiral or helical coiled, ceramic, plate and fin, and plate type) were covered in an earlier report (Sabharwall et al. 2011). Significant future work, much of which is suggested in this report, is needed before the benefits and full potential of the AHTR can be realized. The execution of this TDRM will focuses research efforts on the near-term qualification, selection, or maturation strategy as detailed in this report. Development of the integration methodology feasibility study, along with research and development (R&D) needs, are ongoing tasks that will be covered in the future reports as work progresses. Section 2 briefly presents the integration of AHTR technology with conventional chemical industrial processes., See Idaho National Laboratory (INL) TEV-1160 (2011) for further details

  8. Measuring the heat exchange of a quantum process

    E-Print Network [OSTI]

    John Goold; Ulrich Poschinger; Kavan Modi

    2014-08-19T23:59:59.000Z

    Very recently, interferometric methods have been proposed to measure the full statistics of work performed on a driven quantum system [Dorner et al. Phys. Rev. Lett. 110 230601 (2013)] and [Mazzola et al. Phys. Rev. Lett. 110 230602 (2013)]. The advantage of such schemes is that they replace the necessity to make projective measurements by performing phase estimation on an appropriately coupled ancilla qubit. These proposals are one possible route to the tangible experimental exploration of quantum thermodynamics, a subject which is the centre of much current attention due to the current control of mesoscopic quantum systems. In this Letter we demonstrate that a modification of the phase estimation protocols can be used in order to measure the heat distribution of a quantum process. In addition we demonstrate how our scheme may be implemented using ion trap technology. Our scheme should pave the way for the first experimental explorations of the Landauer principle and hence the intricate energy to information conversion in mesoscopic quantum systems.

  9. Interface Exchange as an Indicator for Eddy Heat Transport

    SciTech Connect (OSTI)

    Petersen, Mark R. [Los Alamos National Laboratory; Williams, Sean J. [Los Alamos National Laboratory; Hecht, Matthew W. [Los Alamos National Laboratory; Maltrud, Mathew E. [Los Alamos National Laboratory; Hamann, Bernd [U of California Davis; Patchett, John M. [Los Alamos National Laboratory; Ahrens, James P. [Los Alamos National Laboratory

    2012-06-12T23:59:59.000Z

    The ocean contains many large-scale, long-lived vortices, called mesoscale eddies, that are believed to have a role in the transport and redistribution of salt, heat, and nutrients throughout the ocean. Determining this role, however, has proven to be a challenge, since the mechanics of eddies are only partly understood; a standard definition for these ocean eddies does not exist and, therefore, scientifically meaningful, robust methods for eddy extraction, characterization, tracking and visualization remain a challenge. In order to shed light on the nature and potential roles of eddies, we have combined our previous research on eddy identification and tracking, and have used those approaches as the basis for analysis-driven computational experiments on the nature of eddies. Based on the resulting visualizations of eddy behavior, we have devised a new metric to characterize the transfer of water into and out of eddies across their boundary, and have developed visualization methods for this new metric to provide clues about the role eddies play in the global ocean and, potentially, climate change.

  10. Thermal hydraulic performance testing of printed circuit heat exchangers in a high-temperature helium test facility

    SciTech Connect (OSTI)

    Sai K. Mylavarapu; Xiaodong Sun; Richard E. Glosup; Richard N. Christensen; Michael W. Patterson

    2014-04-01T23:59:59.000Z

    In high-temperature gas-cooled reactors, such as a very high temperature reactor (VHTR), an intermediate heat exchanger (IHX) is required to efficiently transfer the core thermal output to a secondary fluid for electricity generation with an indirect power cycle and/or process heat applications. Currently, there is no proven high-temperature (750ľ800 ░C or higher) compact heat exchanger technology for high-temperature reactor design concepts. In this study, printed circuit heat exchanger (PCHE), a potential IHX concept for high-temperature applications, has been investigated for their heat transfer and pressure drop characteristics under high operating temperatures and pressures. Two PCHEs, each having 10 hot and 10 cold plates with 12 channels (semicircular cross-section) in each plate are fabricated using Alloy 617 plates and tested for their performance in a high-temperature helium test facility (HTHF). The PCHE inlet temperature and pressure were varied from 85 to 390 ░C/1.0ľ2.7 MPa for the cold side and 208ľ790 ░C/1.0ľ2.7 MPa for the hot side, respectively, while the mass flow rate of helium was varied from 15 to 49 kg/h. This range of mass flow rates corresponds to PCHE channel Reynolds numbers of 950 to 4100 for the cold side and 900 to 3900 for the hot side (corresponding to the laminar and laminar-to-turbulent transition flow regimes). The obtained experimental data have been analyzed for the pressure drop and heat transfer characteristics of the heat transfer surface of the PCHEs and compared with the available models and correlations in the literature. In addition, a numerical treatment of hydrodynamically developing and hydrodynamically fully-developed laminar flow through a semicircular duct is presented. Relations developed for determining the hydrodynamic entrance length in a semicircular duct and the friction factor (or pressure drop) in the hydrodynamic entry length region for laminar flow through a semicircular duct are given. Various hydrodynamic entrance region parameters, such as incremental pressure drop number, apparent Fanning friction factor, and hydrodynamic entrance length in a semicircular duct have been numerically estimated.

  11. Separate effects of surface roughness, wettability and porosity on boiling heat transfer and critical heat flux and optimization of boiling surfaces

    E-Print Network [OSTI]

    O'Hanley, Harrison Fagan

    2012-01-01T23:59:59.000Z

    The separate effects of surface wettability, porosity, and roughness on critical heat flux (CHF) and heat transfer coefficient (HTC) were examined using carefully-engineered surfaces. All test surfaces were prepared on ...

  12. Ultra-Thin Antifouling Surface Treatments for Industrial Heat Exchangers

    Energy Savers [EERE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnual Siteof Energy 2, 2015 -Helicopter AccidentSeptemberDepartment

  13. Three important parts of an integrated plant are reactors, separators and a heat exchanger network (HEN) for heat recovery. Within the process engineering community, much

    E-Print Network [OSTI]

    Skogestad, Sigurd

    exchanger network (HEN) for heat recovery. Within the process engineering community, much attention has beeni ABSTRACT Three important parts of an integrated plant are reactors, separators and a heat and in particular to optimal operation of HENs. The purpose of heat integration is to save energy, but the HEN also

  14. Directly connected heat exchanger tube section and coolant-cooled structure

    DOE Patents [OSTI]

    Chainer, Timothy J; Coico, Patrick A; Graybill, David P; Iyengar, Madhusudan K; Kamath, Vinod; Kochuparambil, Bejoy J; Schmidt, Roger R; Steinke, Mark E

    2014-04-01T23:59:59.000Z

    A cooling apparatus for an electronics rack is provided which includes an air-to-liquid heat exchanger, one or more coolant-cooled structures and a tube. The heat exchanger, which is associated with the electronics rack and disposed to cool air passing through the rack, includes a plurality of distinct, coolant-carrying tube sections, each tube section having a coolant inlet and a coolant outlet, one of which is coupled in fluid communication with a coolant loop to facilitate flow of coolant through the tube section. The coolant-cooled structure(s) is in thermal contact with an electronic component(s) of the rack, and facilitates transfer of heat from the component(s) to the coolant. The tube connects in fluid communication one coolant-cooled structure and the other of the coolant inlet or outlet of the one tube section, and facilitates flow of coolant directly between that coolant-carrying tube section of the heat exchanger and the coolant-cooled structure.

  15. Multiple pollutant removal using the condensing heat exchanger: Phase 1 final report, October 1995--July 1997

    SciTech Connect (OSTI)

    Bailey, R.T.; Jankura, B.J.; Kudlac, G.A.

    1998-06-01T23:59:59.000Z

    The Integrated Flue Gas Treatment (IFGT) system is a new concept whereby a Teflon{reg_sign} covered condensing heat exchanger is adapted to remove certain flue gas constitutents, both particulate and gaseous, while recovering low level heat. Phase 1 includes two experimental tasks. One task dealt principally with the pollutant removal capabilities of the IFGT at a scale of about 1.2MW{sub t}. The other task studied the durability of the Teflon{reg_sign} covering to withstand the rigors of abrasive wear by fly ash emitted as a result of coal combustion. The pollutant removal characteristics of the IFGT system were measured over a wide range of operating conditions. The coals tested included high, medium and low-sulfur coals. The flue gas pollutants studied included ammonia, hydrogen chloride, hydrogen fluoride, particulate, sulfur dioxide, gas phase and particle phase mercury and gas phase and particle phase trace elements. The particulate removal efficiency and size distribution was investigated. These test results demonstrated that the IFGT system is an effective device for both acid gas absorption and fine particulate collection. The durability of the Teflon{reg_sign} covered heat exchanger tubes was studied on a pilot-scale single-stage condensing heat exchanger (CHX{reg_sign}). Data from the test indicate that virtually no decrease in Teflon{reg_sign} thickness was observed for the coating on the first two rows of heat exchanger tubes, even at high inlet particulate loadings. Evidence of wear was present only at the microscopic level, and even then was very minor in severity.

  16. Open-cycle magnetohydrodynamic power plant based upon direct-contact closed-loop high-temperature heat exchanger

    DOE Patents [OSTI]

    Berry, Gregory F. (Naperville, IL); Minkov, Vladimir (Skokie, IL); Petrick, Michael (Joliet, IL)

    1988-01-01T23:59:59.000Z

    A magnetohydrodynamic (MHD) power generating system in which ionized combustion gases with slag and seed are discharged from an MHD combustor and pressurized high temperature inlet air is introduced into the combustor for supporting fuel combustion at high temperatures necessary to ionize the combustion gases, and including a heat exchanger in the form of a continuous loop with a circulating heat transfer liquid such as copper oxide. The heat exchanger has an upper horizontal channel for providing direct contact between the heat transfer liquid and the combustion gases to cool the gases and condense the slag which thereupon floats on the heat transfer liquid and can be removed from the channel, and a lower horizontal channel for providing direct contact between the heat transfer liquid and pressurized air for preheating the inlet air. The system further includes a seed separator downstream of the heat exchanger.

  17. Open-cycle magnetohydrodynamic power plant based upon direct-contact closed-loop high-temperature heat exchanger

    DOE Patents [OSTI]

    Berry, G.F.; Minkov, V.; Petrick, M.

    1981-11-02T23:59:59.000Z

    A magnetohydrodynamic (MHD) power generating system is described in which ionized combustion gases with slag and seed are discharged from an MHD combustor and pressurized high temperature inlet air is introduced into the combustor for supporting fuel combustion at high temperatures necessary to ionize the combustion gases, and including a heat exchanger in the form of a continuous loop with a circulating heat transfer liquid such as copper oxide. The heat exchanger has an upper horizontal channel for providing direct contact between the heat transfer liquid and the combustion gases to cool the gases and condense the slag which thereupon floats on the heat transfer liquid and can be removed from the channel, and a lower horizontal channel for providing direct contact between the heat transfer liquid and pressurized air for preheating the inlet air. The system further includes a seed separator downstream of the heat exchanger.

  18. ORIGINAL PAPER Transient Heat Conduction Between Rough Sliding Surfaces

    E-Print Network [OSTI]

    Barber, James R.

    ORIGINAL PAPER Transient Heat Conduction Between Rough Sliding Surfaces Yuwei Liu Ě J. R. Barber+Business Media New York 2014 Abstract When two rough bodies slide against each other, asperities on the opposing contact pressure as functions of the separation between reference planes in the two surfaces. We find

  19. Waste Heat Recovery From Stacks Using Direct-Contact Condensing Heat Exchange

    E-Print Network [OSTI]

    Thorn, W. F.

    is mainly for general interest and to illustrate the analysis methodology. Two key parameters from Table A-I are needed for a heat recovery analysis. First is the weight of water vapor in the flue gas per unit weight of fuel burned and the second... ........_ ...._ ...._ ...._ ...._ ...._ ....--1 200 260 300 360 400 460 600 660 HEAT RECOVERY UNIT INLET FLUE GAS TEMPERATURE, OF FJpre 2. Efficiency Variation With Heat Recovery Unit Inlet Flue Gas Temperature 428 ESL-IE-86-06-69 Proceedings from the Eighth Annual Industrial Energy...

  20. Discussions on Disposal Forms of Auxiliary Heat Source in Surface Water Heat Pump Systemá

    E-Print Network [OSTI]

    Qian, J.; Sun, D.; Li, X.; Li, G.

    2006-01-01T23:59:59.000Z

    This paper presents two common forms of auxiliary heat source in surface water heat pump system and puts forward the idea that the disposal forms affect operation cost. It deduces operation cost per hour of the two forms. With a project...

  1. Discussions on Disposal Forms of Auxiliary Heat Source in Surface Water Heat Pump System

    E-Print Network [OSTI]

    Qian, J.; Sun, D.; Li, X.; Li, G.

    2006-01-01T23:59:59.000Z

    This paper presents two common forms of auxiliary heat source in surface water heat pump system and puts forward the idea that the disposal forms affect operation cost. It deduces operation cost per hour of the two forms. With a project...

  2. Two-dimensional numerical simulation of a Stirling engine heat exchanger

    SciTech Connect (OSTI)

    Ibrahim, M.B. [Cleveland State Univ., OH (United States); Tew, R.C.; Dudenhoefer, J.E. [Lewis Research Center, Cleveland, OH (United States)

    1994-09-01T23:59:59.000Z

    This paper describes the first phase of an effort to develop multidimensional models of Stirling engine components; the ultimate goal is to model an entire engine working space. More specifically, this paper describes parallel plate and tubular heat exchanger models with emphasis on the central part of the channel (i.e., ignoring hydrodynamic and thermal end effects). The model assumes: Laminar, incompressible flow with constant thermophysical properties. In addition, a constant axial temperature gradient is imposed. The governing equations, describing the model, have been solved Crack-Nicloson finite-difference scheme. Model predictions have been compared with analytical solutions for oscillating/reversing flow and heat transfer in order to check numerical accuracy. The simplifying assumptions will later be relaxed to permit modeling of incompressible, laminar/turbulent flow that occurs in Stirling heat exchanger. Excellent agreement has been obtained for the model predictions with analytical solutions available for both flow in circular tubes and between parallel plates. Also the heat transfer computational results are in good agreement with the heat transfer analytical results for parallel plates.

  3. Liquid metal heat exchanger for efficient heating of soils and geologic formations

    DOE Patents [OSTI]

    DeVault, Robert C. (Knoxville, TN) [Knoxville, TN; Wesolowski, David J. (Kingston, TN) [Kingston, TN

    2010-02-23T23:59:59.000Z

    Apparatus for efficient heating of subterranean earth includes a well-casing that has an inner wall and an outer wall. A heater is disposed within the inner wall and is operable within a preselected operating temperature range. A heat transfer metal is disposed within the outer wall and without the inner wall, and is characterized by a melting point temperature lower than the preselected operating temperature range and a boiling point temperature higher than the preselected operating temperature range.

  4. Liquid over-feeding refrigeration system and method with integrated accumulator-expander-heat exchanger

    DOE Patents [OSTI]

    Mei, Viung C. (Oak Ridge, TN); Chen, Fang C. (Knoxville, TN)

    1997-01-01T23:59:59.000Z

    A refrigeration system having a vapor compression cycle utilizing a liquid over-feeding operation with an integrated accumulator-expander-heat exchanger. Hot, high-pressure liquid refrigerant from the condenser passes through one or more lengths of capillary tubing substantially immersed in a pool liquid refrigerant in the accumulator-expander-heat exchanger for simultaneously sub-cooling and expanding the liquid refrigerant while vaporizing liquid refrigerant from the pool for the return thereof to the compressor as saturated vapor. The sub-cooling of the expanded liquid provides for the flow of liquid refrigerant into the evaporator for liquid over-feeding the evaporator and thereby increasing the efficiency of the evaporation cycle.

  5. Liquid over-feeding refrigeration system and method with integrated accumulator-expander-heat exchanger

    DOE Patents [OSTI]

    Mei, V.C.; Chen, F.C.

    1997-04-22T23:59:59.000Z

    A refrigeration system is described having a vapor compression cycle utilizing a liquid over-feeding operation with an integrated accumulator-expander-heat exchanger. Hot, high-pressure liquid refrigerant from the condenser passes through one or more lengths of capillary tubing substantially immersed in a pool liquid refrigerant in the accumulator-expander-heat exchanger for simultaneously sub-cooling and expanding the liquid refrigerant while vaporizing liquid refrigerant from the pool for the return thereof to the compressor as saturated vapor. The sub-cooling of the expanded liquid provides for the flow of liquid refrigerant into the evaporator for liquid over-feeding the evaporator and thereby increasing the efficiency of the evaporation cycle. 4 figs.

  6. Effect of nonuniform inlet air flow on air-cooled heat-exchanger performance

    SciTech Connect (OSTI)

    Soler, A.I.; Singh, K.P.; Ng, T.L.

    1983-01-01T23:59:59.000Z

    Blowers used to propel air across tube bundles generate a non-uniform flow field due to their construction details. A formalism to evaluate heat transfer degradation due to non-uniform airflow has been developed. Certain symmetry relations for cross flowheat exchangers, heretofore unavailable in the open literature, have been derived. The solution presented here was developed to model a 4 tube pass air blast heat exchanger for the Clinch River Breeder Reactor Plant Project. This case is utilized to show how this method can be used as a design tool to select the most suitable blower construction for a particular application. A numerical example is used to illustrate the salient points of the solution.

  7. Eddy current inspection of power plant heat-exchanger tubing in the USA

    SciTech Connect (OSTI)

    Fishkin, P.; Nash, J. [MQS Inspection, Inc., Chicago, IL (United States)

    1995-02-01T23:59:59.000Z

    The latest experience in the eddy current inspection of heat-exchanger tubing by means of ID probes is reported and generalized. The authors demonstrate the feasibility of using modern, general-purpose, digital eddy current flaw detectors equipped with microprocessors, displays, the capability for recording inspection results on paper or magnetic media, sound and visual alarms. The NDE personnel qualification and certification requirements are described.

  8. Continuous-Wave Radar to Detect Defects Within Heat Exchangers and Steam Generator Tubes ; Revised September 3, 2003

    SciTech Connect (OSTI)

    Gary E. Rochau and Thurlow W.H. Caffey, Sandia National Laboratories, Albuquerque, NM 87185-0740; Bahram Nassersharif and Gabe V. Garcia, Department of Mechanical Engineering, New Mexico State University, Las Cruces, NM 88003-8001; Russell P. Jedlicka, Klipsch School of Electrical and Computer Engineering, New Mexico State University, Las Cruces, NM 88003-8001

    2003-05-01T23:59:59.000Z

    OAK B204 Continuous-Wave Radar to Detect Defects Within Heat Exchangers and Steam Generator Tubes ; Revised September 3, 2003. A major cause of failures in heat exchangers and steam generators in nuclear power plants is degradation of the tubes within them. The tube failure is often caused by the development of cracks that begin on the outer surface of the tube and propagate both inwards and laterally. A new technique was researched for detection of defects using a continuous-wave radar method within metal tubing. The technique is 100% volumetric, and may find smaller defects, more rapidly, and less expensively than present methods. The project described in this report was a joint development effort between Sandia National Laboratories (SNL) and New Mexico State University (NMSU) funded by the US Department of Energy. The goal of the project was to research, design, and develop a new concept utilizing a continuous wave radar to detect defects inside metallic tubes and in particular nuclear plant steam generator tubing. The project was divided into four parallel tracks: computational modeling, experimental prototyping, thermo-mechanical design, and signal detection and analysis.

  9. Surface Exchange and Bulk Diffusivity of LSCF as SOFC Cathode: Electrical Conductivity Relaxation and Isotope Exchange Characterizations

    SciTech Connect (OSTI)

    Li, Yihong; Gerdes, Kirk; Horita, Teruhisa; Liu, Xingbo

    2013-05-05T23:59:59.000Z

    The oxygen diffusion coefficient (D) and surface exchange coefficient (k) of a typical SOFC cathode material, La{sub 0.6}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3-?} (LSCF) were characterized by both electrical conductivity relaxation (ECR) and oxygen isotope exchange (IE) methods. Conductivity relaxation experiments were conducted at 800░C for small step changes in partial pressure of oxygen (P{sub O{sub 2}} ), both decreasing and increasing, from 0.02 atm to 0.20 atm. The results revealed P{sub O{sub 2}} dependent hysteresis with the reduction process requiring more equilibration time than oxidation. Analysis of the experimental data indicated that the surface exchange coefficient is a function of the final oxygen partial pressure in an isothermal system. In addition, both forward and backward oxygen reduction reaction constants, which are vital for the fundamental understanding of SOFC cathode reaction mechanisms, are investigated based on the relationship between surface exchange coefficient and P{sub O{sub 2}} . The direct comparisons between the results from both ECR and IE were presented and the possible experimental errors in both methods were discussed.

  10. Heat transfer mechanism with thin filaments including ceramic high temperature heat exchanger

    DOE Patents [OSTI]

    Im, Kwan H. (Naperville, IL); Ahluwalia, Rajesh K. (Burr Ridge, IL)

    1994-01-01T23:59:59.000Z

    A radiative heat transfer mechanism in a furnace having burners through which pulverized coal and air are burned producing combustion gases and contaminants. A plurality of elongated conduits are positioned inside the furnace proximate to the burners generally parallel to the flow of combustion gases in the furnace. A plurality of thin filaments are inside each of the elongated hollow conduits, the filaments having diameters in the range of from about 1 micrometer to about 1,000 micrometers and having an infrared radiation cross-section sufficient to cause the filaments to heat upon exposure to infrared radiation. Blower mechanism is associated with the elongated conduits for limiting the amount of soot and ash which deposit on the conduits to preserve the radiative and convective transfer of heat energy from the combustion gases to the conduits.

  11. Heat transfer mechanism with thin filaments including ceramic high temperature heat exchanger

    DOE Patents [OSTI]

    Im, K.H.; Ahluwalia, R.K.

    1994-10-18T23:59:59.000Z

    A radiative heat transfer mechanism in a furnace is described having burners through which pulverized coal and air are burned producing combustion gases and contaminants. A plurality of elongated conduits are positioned inside the furnace proximate to the burners generally parallel to the flow of combustion gases in the furnace. A plurality of thin filaments are inside each of the elongated hollow conduits, the filaments having diameters in the range of from about 1 micrometer to about 1,000 micrometers and having an infrared radiation cross-section sufficient to cause the filaments to heat upon exposure to infrared radiation. Blower mechanism is associated with the elongated conduits for limiting the amount of soot and ash which deposit on the conduits to preserve the radiative and convective transfer of heat energy from the combustion gases to the conduits. 7 figs.

  12. Co-flow anode/cathode supply heat exchanger for a solid-oxide fuel cell assembly

    DOE Patents [OSTI]

    Haltiner, Jr., Karl J.; Kelly, Sean M.

    2005-11-22T23:59:59.000Z

    In a solid-oxide fuel cell assembly, a co-flow heat exchanger is provided in the flow paths of the reformate gas and the cathode air ahead of the fuel cell stack, the reformate gas being on one side of the exchanger and the cathode air being on the other. The reformate gas is at a substantially higher temperature than is desired in the stack, and the cathode gas is substantially cooler than desired. In the co-flow heat exchanger, the temperatures of the reformate and cathode streams converge to nearly the same temperature at the outlet of the exchanger. Preferably, the heat exchanger is formed within an integrated component manifold (ICM) for a solid-oxide fuel cell assembly.

  13. Gas-Surface Energy Exchange in Collisions of Helium Atoms with Aligned Single-Walled Carbon

    E-Print Network [OSTI]

    Maruyama, Shigeo

    1 Gas-Surface Energy Exchange in Collisions of Helium Atoms with Aligned Single-Walled Carbon #12;2 ABSTRACT Since gas flows in micro/nano devices are dominated by the interaction of gas molecules accommodation of gas molecules on surfaces. The scattering of gas molecules on quartz surfaces covered with VA

  14. Numerical modeling of a 2K J-T heat exchanger used in Fermilab Vertical Test Stand VTS-1

    SciTech Connect (OSTI)

    Gupta, Prabhat Kumar [Raja Ramanna Centre for Advanced Technology (RRCAT), Indore (MP), India; Rabehl, Roger [FNAL

    2014-07-01T23:59:59.000Z

    Fermilab Vertical Test Stand-1 (VTS-1) is in operation since 2007 for testing the superconducting RF cavities at 2 K. This test stand has single layer coiled finned tubes heat exchanger before J-T valve. A finite difference based thermal model has been developed in Engineering Equation Solver (EES) to study its thermal performance during filling and refilling to maintain the constant liquid level of test stand. The model is also useful to predict its performance under other various operating conditions and will be useful to design the similar kind of heat exchanger for future needs. Present paper discusses the different operational modes of this heat exchanger and its thermal characteristics under these operational modes. Results of this model have also been compared with the experimental data gathered from the VTS-1 heat exchanger and they are in good agreement with the present model.

  15. SCALE RESISTANT HEAT EXCHANGER FOR LOW TEMPERATURE GEOTHERMAL BINARY CYCLE POWER PLANT

    SciTech Connect (OSTI)

    HAYS, LANCE G

    2014-11-18T23:59:59.000Z

    Phase 1 of the investigation of improvements to low temperature geothermal power systems was completed. The improvements considered were reduction of scaling in heat exchangers and a hermetic turbine generator (eliminating seals, seal system, gearbox, and lube oil system). A scaling test system with several experiments was designed and operated at Coso geothermal resource with brine having a high scaling potential. Several methods were investigated at the brine temperature of 235 ║F. One method, circulation of abradable balls through the brine passages, was found to substantially reduce scale deposits. The test heat exchanger was operated with brine outlet temperatures as low as 125 ║F, which enables increased heat input available to power conversion systems. For advanced low temperature cycles, such as the Variable Phase Cycle (VPC) or Kalina Cycle, the lower brine temperature will result in a 20-30% increase in power production from low temperature resources. A preliminary design of an abradable ball system (ABS) was done for the heat exchanger of the 1 megawatt VPC system at Coso resource. The ABS will be installed and demonstrated in Phase 2 of this project, increasing the power production above that possible with the present 175 ║F brine outlet limit. A hermetic turbine generator (TGH) was designed and manufacturing drawings produced. This unit will use the working fluid (R134a) to lubricate the bearings and cool the generator. The 200 kW turbine directly drives the generator, eliminating a gearbox and lube oil system. Elimination of external seals eliminates the potential of leakage of the refrigerant or hydrocarbon working fluids, resulting in environmental improvement. A similar design has been demonstrated by Energent in an ORC waste heat recovery system. The existing VPC power plant at Coso was modified to enable the ôpiggybackö demonstration of the TGH. The existing heat exchanger, pumps, and condenser will be operated to provide the required process conditions for the TGH demonstration. Operation of the TGH with and without the ABS system will demonstrate an increase in geothermal resource productivity for the VPC from 1 MW/(million lb) of brine to 1.75 MW/(million lb) of brine, a 75% increase.

  16. Keywordscondensation tube, surface modification, waste heat and condensation water recovery system

    E-Print Network [OSTI]

    Leu, Tzong-Shyng "Jeremy"

    Keywordscondensation tube, surface modification, waste heat and condensation water recovery techniques is waste heat and condensation water recovery system. Waste heat and condensation water recovery system is one of the most important facilities in power plants. High efficiency waste heat

  17. Fabrication and Design Aspects of High-Temperature Compact Diffusion Bonded Heat Exchangers

    SciTech Connect (OSTI)

    Mylavarapu, Sai K. [Ohio State University; Sun, Xiaodong [Ohio State University; Christensen, Richard N. [Ohio State University; Glosup, Richard E. [Ohio State University; Unocic, Raymond R [ORNL

    2012-01-01T23:59:59.000Z

    The very high temperature reactor (VHTR), using gas-cooled reactor technology, is one of the six reactor concepts selected by the Generation IV International Forum and is anticipated to be the reactor type for the next generation nuclear plant (NGNP). In this type of reactor with an indirect power cycle system, a high-temperature and high integrity intermediate heat exchanger (IHX) with high effectiveness is required to efficiently transfer the core thermal output to secondary fluid for electricity production, process heat, or hydrogen cogeneration. The current Technology Readiness Level status issued by NGNP to all components associated with the IHX for reactor core outlet temperatures of 750-800oC is 3 on a scale of 1 to 10 with 10 being the most ready. At present, there is no proven high-temperature IHX concept for VHTRs. Amongst the various potential IHX concepts available, diffusion bonded heat exchangers (henceforth called printed circuit heat exchangers, or PCHEs) appear promising for NGNP applications. The design and fabrication of this key component of NGNP is the primary focus of this paper. In the current study, two PCHEs were fabricated using Alloy 617 plates and will be experimentally investigated for their thermal-hydraulic performance in a high-temperature helium test facility (HTHF). The HTHF was primarily designed and constructed to test the thermal-hydraulic performance of PCHEs The test facility is primarily of Alloy 800H construction and is designed to facilitate experiments at temperatures and pressures up to 800oC and 3 MPa, respectively. The PCHE fabrication related processes, i.e., photochemical machining and diffusion bonding are briefly discussed for Alloy 617 plates. Diffusion bonding of Alloy 617 plates with and without a Ni interlayer is discussed. Furthermore, preliminary microstructural and mechanical characterization studies of representative diffusion bonded Alloy 617 specimens are presented.

  18. Heat transfer and pressure drop of supercritical carbon dioxide flowing in several printed circuit heat exchanger channel patterns

    SciTech Connect (OSTI)

    Carlson, M. [Univ. of Wisconsin - Madison, 839 Engineering Research Building, 1500 Engineering Drive, Madison, WI 53706 (United States); Kruizenga, A. [Sandia National Laboratory (United States); Anderson, M.; Corradini, M. [Univ. of Wisconsin - Madison, 839 Engineering Research Building, 1500 Engineering Drive, Madison, WI 53706 (United States)

    2012-07-01T23:59:59.000Z

    Closed-loop Brayton cycles using supercritical carbon dioxide (SCO{sub 2}) show potential for use in high-temperature power generation applications including High Temperature Gas Reactors (HTGR) and Sodium-Cooled Fast Reactors (SFR). Compared to Rankine cycles SCO{sub 2} Brayton cycles offer similar or improved efficiency and the potential for decreased capital costs due to a reduction in equipment size and complexity. Compact printed-circuit heat exchangers (PCHE) are being considered as part of several SCO{sub 2} Brayton designs to further reduce equipment size with increased energy density. Several designs plan to use a gas cooler operating near the pseudo-critical point of carbon dioxide to benefit from large variations in thermophysical properties, but further work is needed to validate correlations for heat transfer and pressure-drop characteristics of SCO{sub 2} flows in candidate PCHE channel designs for a variety of operating conditions. This paper presents work on experimental measurements of the heat transfer and pressure drop behavior of miniature channels using carbon dioxide at supercritical pressure. Results from several plate geometries tested in horizontal cooling-mode flow are presented, including a straight semi-circular channel, zigzag channel with a bend angle of 80 degrees, and a channel with a staggered array of extruded airfoil pillars modeled after a NACA 0020 airfoil with an 8.1 mm chord length facing into the flow. Heat transfer coefficients and bulk temperatures are calculated from measured local wall temperatures and local heat fluxes. The experimental results are compared to several methods for estimating the friction factor and Nusselt number of cooling-mode flows at supercritical pressures in millimeter-scale channels. (authors)

  19. Estimation of turbulent surface heat fluxes using sequences of remotely sensed land surface temperature

    E-Print Network [OSTI]

    Bateni, Sayed Mohyeddin

    2011-01-01T23:59:59.000Z

    Fluxes of heat and moisture at the land-surface play a significant role in the climate system. These fluxes interact with the overlying atmosphere and influence the characteristics of the planetary boundary layer (e.g. ...

  20. Fabrication and Design Aspects of High-Temperature Compact Diffusion Bonded Heat Exchangers

    SciTech Connect (OSTI)

    Sai K. Mylavarapu; Richard N. Christensen; Raymond R. Unocic; Richard E. Glosup; Mike W. Patterson

    2012-08-01T23:59:59.000Z

    The Very High Temperature Reactor (VHTR) using gas-cooled reactor technology is anticipated to be the reactor type for the Next Generation Nuclear Plant (NGNP). In this reactor concept with an indirect power cycle system, a high-temperature and high integrity Intermediate Heat Exchanger (IHX) with high effectiveness is required to efficiently transfer the core thermal output to a secondary fluid for electricity generation, hydrogen production, and/or industrial process heat applications. At present, there is no proven IHX concept for VHTRs. The current Technology Readiness Level (TRL) status issued by NGNP to all components associated with the IHX for reduced nominal reactor outlet temperatures of 750ľ800 degrees C is 3 on a 1ľ10 scale, with 10 indicating omplete technological maturity. Among the various potential IHX concepts available, diffusion bonded heat exchangers (henceforth called printed circuit heat exchangers, or PCHEs) appear promising for NGNP applications. The design and fabrication of this key component of NGNP with Alloy 617, a candidate high-temperature structural material for NGNP applications, are the primary focus of this paper. In the current study, diffusion bonding of Alloy 617 has been demonstrated, although the optimum diffusion bonding process parameters to engineer a quasi interface-free joint are yet to be determined. The PCHE fabrication related processes, i.e., photochemical etching and diffusion bonding are discussed for Alloy 617 plates. In addition, the authorsĺ experiences with these non-conventional machining and joining techniques are discussed. Two PCHEs are fabricated using Alloy 617 plates and are being experimentally investigated for their thermal-hydraulic performance in a High-Temperature Helium Facility (HTHF). The HTHF is primarily of Alloy 800H construction and is designed to facilitate experiments at temperatures and pressures up to 800 degrees C and 3 MPa, respectively. Furthermore, some preliminary microstructural and mechanical property characterization studies of representative diffusion bonded Alloy 617 specimens are presented. The characterization studies are restricted and less severe from an NGNP perspective but provide sufficient confidence to ensure safe operation of the heat exchangers in the HTHF. The test results are used to determine the design operating conditions for the PCHEs fabricated.

  1. Modeling a Printed Circuit Heat Exchanger with RELAP5-3D for the Next Generation Nuclear Plant

    SciTech Connect (OSTI)

    Not Available

    2010-12-01T23:59:59.000Z

    The main purpose of this report is to design a printed circuit heat exchanger (PCHE) for the Next Generation Nuclear Plant and carry out Loss of Coolant Accident (LOCA) simulation using RELAP5-3D. Helium was chosen as the coolant in the primary and secondary sides of the heat exchanger. The design of PCHE is critical for the LOCA simulations. For purposes of simplicity, a straight channel configuration was assumed. A parallel intermediate heat exchanger configuration was assumed for the RELAP5 model design. The RELAP5 modeling also required the semicircular channels in the heat exchanger to be mapped to rectangular channels. The initial RELAP5 run outputs steady state conditions which were then compared to the heat exchanger performance theory to ensure accurate design is being simulated. An exponential loss of pressure transient was simulated. This LOCA describes a loss of coolant pressure in the primary side over a 20 second time period. The results for the simulation indicate that heat is initially transferred from the primary loop to the secondary loop, but after the loss of pressure occurs, heat transfers from the secondary loop to the primary loop.

  2. High Performance Trays and Heat Exchangers in Heat Pumped Distillation Columns

    E-Print Network [OSTI]

    Wisz, M. W.; Antonelli, R.; Ragi, E. G.

    1981-01-01T23:59:59.000Z

    AND LIQUID now PATHS fOA IltO TltAYS I A number of engineering contractors and 1 operating companies have employed Union Carbide'\\s High Flux and Multiple Downcomer tray technolog~es to improve performance, decrease utilities and I lower operating costs... ? Fi,?'d as nll\\ximum within hf'l~ht n'!:-;tl'ie-tlon. The control scheme for a heat pump can be de signed to be no more complex than a conventional steam/cooling water system which relies on flow and level controllers to set the various column flow...

  3. An Analysis of the Use of Fluidized-Bed Heat Exchangers for Heat Recoveryá

    E-Print Network [OSTI]

    Vogel, G. J.; Grogan, P. J.

    1980-01-01T23:59:59.000Z

    . the Fifth International Conf. on Fluidized Bed Combustion, Washington, D.C., Dec. 1977, MITRE Corp., M78-68 (Dec. 1978). 11. 3. Virr, M.J., "Commercialization of Small Scale Fluidized Combustion Techniques," Proc. of the Fourth International Conf.... on Fluidized-Bed Com- 12. bustion, McLean, Va., Dec. 1975,MITRE Corp., M76-36 (1976). 4. Elliott, D.E., and M.J. Virr, "Small-Scale 13. Applications of Fluidized-Bed Combustion and Heat Transfer," Proc. of the Third International Conf. on Fluidized...

  4. High Performance Trays and Heat Exchangers in Heat Pumped Distillation Columnsá

    E-Print Network [OSTI]

    Wisz, M. W.; Antonelli, R.; Ragi, E. G.

    1981-01-01T23:59:59.000Z

    AND LIQUID now PATHS fOA IltO TltAYS I A number of engineering contractors and 1 operating companies have employed Union Carbide'\\s High Flux and Multiple Downcomer tray technolog~es to improve performance, decrease utilities and I lower operating costs... ? Fi,?'d as nll\\ximum within hf'l~ht n'!:-;tl'ie-tlon. The control scheme for a heat pump can be de signed to be no more complex than a conventional steam/cooling water system which relies on flow and level controllers to set the various column flow...

  5. Tube vibration in industrial-size test heat exchanger (90/sup 0/ square layout)

    SciTech Connect (OSTI)

    Halle, H.; Wambsganss, M.W.

    1983-02-01T23:59:59.000Z

    Tube vibrations in heat exchangers are being systematically investigated in a series of tests performed with an industrial-size test exchanger. Results from waterflow tests of eleven different tube bundles, in six- and eight-crosspass configurations on a 90/sup 0/ square layout with a pitch-to-diameter ratio of 1.25 are reported. The test cases include full tube bundles, no-tubes-in-window bundles, finned tube bundles, and proposed field and design fixes. The testing focused on identification of the lowest critical flowrate to initiate fluidelastic instability (large amplitude tube motion) and the location within the bundle of the tubes which first experience instability. The test results are tabulated to permit comparison with results obtained from previous tests with a 30/sup 0/ triangular layout tube bundle. Instability criteria are evaluated preliminarily. Pressure drop data are also generated and reported.

  6. Tube vibration in industrial size test heat exchanger (30/sup 0/ triangular layout - six crosspass configuration)

    SciTech Connect (OSTI)

    Wambsganss, M.W.; Halle, H.; Lawrence, W.P.

    1981-10-01T23:59:59.000Z

    Tube vibrations in heat exchangers are being systematically studied in a series of tests performed with an industrial-size test exchanger. Results from flow tests of nine different tube bundles, in a basic 5-baffle, 6-crosspass configuration on a 30/sup 0/-triangular layout with a pitch-to-diameter ratio of 1.25, are reported. the test cases include a full tube bundle, no-tubes-in-window bundle, finned tube bundle, and several proposed field fixes. The testing focused on identification of the lowest critical flowrate to initiate fluidelastic instability (large amplitude tube motion) and the location within the bundle of the tubes which first experience instability. The threshold flowrates are determined from a combination of methods based on sensory observations, vibration amplitude data, and frequency response information. Pressure drop data are also generated and reported.

  7. EXPERIMENTAL AND THEORETICAL INVESTIGATIONS OF NEW POWER CYCLES AND ADVANCED FALLING FILM HEAT EXCHANGERS

    SciTech Connect (OSTI)

    Arsalan Razani; Kwang J. Kim

    2001-12-01T23:59:59.000Z

    The final report for the DOE/UNM grant number DE-FG26-98FT40148 discusses the accomplishments of both the theoretical analysis of advanced power cycles and experimental investigation of advanced falling film heat exchangers. This final report also includes the progress report for the third year (period of October 1, 2000 to September 30, 2001). Four new cycles were studied and two cycles were analyzed in detail based on the second law of thermodynamics. The first cycle uses a triple combined cycle, which consists of a topping cycle (Brayton/gas), an intermediate cycle (Rankine/steam), and a bottoming cycle (Rankine/ammonia). This cycle can produce high efficiency and reduces the irreversibility of the Heat Recovery Steam Generator (HRSC) of conventional combined power cycles. The effect of important system parameters on the irreversibility distribution of all components in the cycle under reasonable practical constraints was evaluated. The second cycle is a combined cycle, which consists of a topping cycle (Brayton/gas) and a bottoming cycle (Rankine/ammonia) with integrated compressor inlet air cooling. This innovative cycle can produce high power and efficiency. This cycle is also analyzed and optimized based on the second the second law to obtain the irreversibility distribution of all components in the cycle. The results of the studies have been published in peer reviewed journals and ASME conference proceeding. Experimental investigation of advanced falling film heat exchangers was conducted to find effective additives for steam condensation. Four additives have been selected and tested in a horizontal tube steam condensation facility. It has been observed that heat transfer additives have been shown to be an effective way to increase the efficiency of conventional tube bundle condenser heat exchangers. This increased condensation rate is due to the creation of a disturbance in the liquid condensate surround the film. The heat transfer through such a film has increased due to the onset of Maranogni convection as well as the population of ''dropwise-like'' condensation increased. The results have been published in peer reviewed journals.

  8. Development of Monitoring Control and Fuzzy Control Test of Finned-Tube Heat-Exchanger Test-Board

    E-Print Network [OSTI]

    Chen, Y.; Zhang, J.; Zhang, B.; Gao, F.

    2006-01-01T23:59:59.000Z

    In order to satisfy the testing requirement of finned-tube heat-exchanger test-board, this paper designs an exclusive auto-monitor and control subsystem, studies the fuzzy control means for the supply air temperature of the heat...

  9. A simplified methodology for sizing ground coupled heat pump heat exchangers in cooling dominated climates

    E-Print Network [OSTI]

    Gonzalez, Jose Antonio

    1993-01-01T23:59:59.000Z

    of the end nodes as shown in Figure 4. 2. Tn + Tn + r 2 (4 6) The first law was then applied to each element during the on-cycle: mc(T +T~, i) ? hPdz(T. ? T ) =ply. (4. 7) T +T dt This said that the energy entering the element by advection minus... that the energy removed by the heat putnp, Q. , must equal the load on the home, Qc. The energy balance when the unit is on is given by: f Q ddt ? f g. dt = mC(T2 ? Ti) (4. 1 1) The right side of equation 4, 11 yields the energy removed from the home during...

  10. Improved Design Tools for Surface Water and Standing Column Well Heat Pump Systems

    Broader source: Energy.gov [DOE]

    This project will improve the capability of engineers to design heat pump systems that utilize surface water or standing column wells (SCW) as their heat sources and sinks.

  11. RELAP5-3D Modeling of Heat Transfer Components (Intermediate Heat Exchanger and Helical-Coil Steam Generator) for NGNP Application

    SciTech Connect (OSTI)

    N. A. Anderson; P. Sabharwall

    2014-01-01T23:59:59.000Z

    The Next Generation Nuclear Plant project is aimed at the research and development of a helium-cooled high-temperature gas reactor that could generate both electricity and process heat for the production of hydrogen. The heat from the high-temperature primary loop must be transferred via an intermediate heat exchanger to a secondary loop. Using RELAP5-3D, a model was developed for two of the heat exchanger options a printed-circuit heat exchanger and a helical-coil steam generator. The RELAP5-3D models were used to simulate an exponential decrease in pressure over a 20 second period. The results of this loss of coolant analysis indicate that heat is initially transferred from the primary loop to the secondary loop, but after the decrease in pressure in the primary loop the heat is transferred from the secondary loop to the primary loop. A high-temperature gas reactor model should be developed and connected to the heat transfer component to simulate other transients.

  12. Heating requirements and non-adiabatic surface effects for a model in the National Transonic Facility

    E-Print Network [OSTI]

    Pare, Louis Alphonse

    1984-01-01T23:59:59.000Z

    insulated, adiabatic surface. A heat transfer analysis intended to yield a conservative estimate of the non-adiabatic condition was performed. A Finite element heat transfer computer code was developed and used to compute the steady state temperature... identified regions on the surface of the model susceptible to surface heating and the magnitude of the respective surface temperatures. The addition of insulation within the cavity to limit surface heating was also investigated. The geometry...

  13. Preliminary studies on the heat exchanger option for S-CO{sub 2} power conversion cycle coupled to water cooled SMR

    SciTech Connect (OSTI)

    Ahn, Y.; Lee, J. [Dept. of Nuclear and Quantum Engineering, Korea Advanced Inst. of Science and Technology, 373-1 Guseong-dong Yuseong-gu, Daejeon, 305-701 (Korea, Republic of); Lee, J. I. [Dept. of Nuclear and Quantum Engineering, Korea Advanced Inst. of Science and Technology, 373-1 Guseong-dong Yuseong-gu, Daejeon, 305-701 (Korea, Republic of); Dept. of Nuclear Engineering, Khalifa Univ. of Science, Technology and Research (KUSTAR), P.O.Box 127788, Abu Dhabi (United Arab Emirates)

    2012-07-01T23:59:59.000Z

    For more than a half century, the steam Rankine cycle had been the major power conversion cycle for a nuclear power plant. However, as the interest on the next generation reactors grows, a variety of alternative power conversion systems have been studied. Among them, the S-CO{sub 2} cycle (Supercritical carbon dioxide Brayton cycle) is considered as a promising candidate due to several benefits such as 1) Relatively high thermal efficiency at relatively low turbine inlet temperature, 2) High efficiency with simple lay-out 3) Compactness of turbo-machineries. 4) Compactness of total cycle combined with PCHE (Printed Circuit Heat Exchanger). According to the conventional classification of heat exchangers (HE), there are three kind of HE, 1) Tubular HEs, 2) Plate-type HEs, 3) Extended surface HEs. So far, the researcher has mostly assumed PCHE type HE for the S-CO{sub 2} cycle due to its compactness with reasonably low pressure drop. However, PCHE is currently one of the most expensive components in the cycle, which can have a negative effect on the economics of the cycle. Therefore, an alternative for the HE should be seriously investigated. By comparing the operating condition (pressure and temperature) there are three kind of HE in the S-CO{sub 2} cycle, 1) IHX (Intermediate Heat exchanger) 2) Recuperator and 3) Pre-cooler. In each heat exchanger, hot side and cold side coolants are different, i.e. reactor coolant to S-CO{sub 2} (IHX), S-CO{sub 2} to S-CO{sub 2}(Recuperator), S-CO{sub 2} to water (Pre-cooler). By considering all the attributes mentioned above, all existing types of heat exchangers are compared to find a possible alternative to PCHE. The comparing factors are 1) Size(volume), 2) Cost. Plate fin type HEs are considered to be the most competitive heat exchanger regarding the size and the cost after some improvements on the design limit are made. (authors)

  14. Flow-induced tube vibration thresholds in heat exchangers from shellside water tests

    SciTech Connect (OSTI)

    Halle, H.; Chenoweth, J.M.; Wambsganss, M.W.

    1984-01-01T23:59:59.000Z

    Typical industrial shell-and-tube heat exchanger configurations are investigated experimentally for the occurrence of potentially damaging tube vibration as a function of flowrate. The effort is part of a program to develop vibration avoidance criteria to be integrated and optimized with the advanced thermal, hydraulic, and mechanical design methods now available. The tests use a 0.6-m (2-ft)-diameter, 3.7-m (12-ft)-long shell containing a removable tube bundle whose components are readily rearranged or replaced. The 15 different full tube bundle configurations tested represent various combinations of parameters: triangular or square tube layout patterns with different orientations to the flow, number of crosspasses, sizes of nozzles, plain or finned tubes. All bundles have 19-mm (0.75-in.)-diameter tubes spaced with a pitch-to-diameter ratio of 1.25. The heat exchanger is tested with waterflow on the shellside to determine a critical threshold, above which a small increase in the flowrate initiates a fluidelastic instability resulting in large amplitude vibration. The test conditions, the critical flowrates, the vibration frequencies, and the locations of the tubes most susceptible to vibration are presented. The given data are used for a comparison with a presently recognized method of vibration prediction and will permit updated evaluations as more advanced methods become available in the future.

  15. CHARACTERIZATION OF ELEVATED TEMPERATURE PROPERTIES OF HEAT EXCHANGER AND STEAM GENERATOR ALLOYS

    SciTech Connect (OSTI)

    J.K. Wright; L.J. Carroll; C.J. Cabet; T. Lillo; J.K. Benz; J.A. Simpson; A. Chapman; R.N. Wright

    2012-10-01T23:59:59.000Z

    The Next Generation Nuclear Plant project is considering Alloy 800H and Alloy 617 for steam generator and intermediate heat exchangers. It is envisioned that a steam generator would operate with reactor outlet temperatures from 750 to 800 C, while an intermediate heat exchanger for primary to secondary helium would operate up to an outlet temperature of 950 C. Although both alloys are of interest due in part to their technical maturity, a number of specific properties require further characterization for design of nuclear components. Strain rate sensitivity of both alloys has been characterized and is found to be significant above 600 C. Both alloys also exhibit dynamic strain aging, characterized by serrated flow, over a wide range of temperatures and strain rates. High temperature tensile testing of Alloy 617 has been conducted over a range of temperatures. Dynamic strain aging is a concern for these materials since it is observed to result in reduced ductility for many solid solution alloys. Creep, fatigue, and creep-fatigue properties of Alloy 617 have been measured as well, with the goal of determining the influence of the temperature, strain rate and atmosphere on the creep fatigue life of Alloy 617. Elevated temperature properties and implications for codification of the alloys will be described.

  16. Penetrative turbulence associated with mesoscale surface heat flux variations

    E-Print Network [OSTI]

    Alam, Jahrul M

    2015-01-01T23:59:59.000Z

    This article investigates penetrative turbulence in the atmospheric boundary layer. Using a large eddy simulation approach, we study characteristics of the mixed layer with respect to surface heat flux variations in the range from 231.48 W/m$^2$ to 925.92 W/m$^2$, and observe that the surface heterogeneity on a spatial scale of $20$ km leads to downscale turbulent kinetic energy cascade. Coherent fluctuations of mesoscale horizontal wind is observed at 100m above the ground. Such a surface induced temporal oscillations in the horizontal wind suggest a rapid jump in mesocale wind forecasts, which is difficult to parameterize using traditional one-dimensional ensemble-mean models. Although the present work is idealized at a typical scale (20km) of surface heterogeneity, the results help develop effective subgrid scale parameterization schemes for classical weather forecasting mesoscale models.

  17. Diesel particulate filter regeneration via resistive surface heating

    DOE Patents [OSTI]

    Gonze, Eugene V; Ament, Frank

    2013-10-08T23:59:59.000Z

    An exhaust system that processes exhaust generated by an engine is provided. The system includes: a particulate filter (PF) that filters particulates from the exhaust wherein an upstream end of the PF receives exhaust from the engine; and a grid of electrically resistive material that is applied to an exterior upstream surface of the PF and that selectively heats exhaust passing through the grid to initiate combustion of particulates within the PF.

  18. Design of a continuous fiber ceramic composite heat exchanger for high-temperature, high-pressure applications

    SciTech Connect (OSTI)

    Cho, S.M.; Seltzer, A.H.; Narayanan, T.V. [Foster Wheeler Development Corp., Livingston, NJ (United States); Shah, A.C.; Weddell, J.K. [DuPont Lanxide Composites Inc., Newark, DE (United States)

    1996-12-31T23:59:59.000Z

    A conceptual design of a continuous fiber ceramic composite (CFCC) heat exchanger for high-temperature, high-pressure applications is presented. The CFCC materials under consideration are SiC reinforced with SiC fibers manufactured using the continuous vapor infiltration process and alumina reinforced with SiC or alumina fibers manufactured using the directed metal oxidation process. These composite materials are highly resistant to high-temperature corrosive environment and possess a greater creep strength than metallic materials. Heat exchangers constructed of CFCC material may be utilized for high-temperature, high-pressure applications such as air/gas heaters in advanced energy systems and high-temperature energy recovery systems. This paper presents a design of a gas-to-air CFCC heat exchanger for the high temperature advanced furnace (HITAF) in the high-performance power system (HIPPS). The 1.38 MPa (200 psia) air is heated from 760 C (1,400 F) to 982 C (1,800 F) using the combustion products at 1,650 C (3,000 F). The heat exchanger is of a cross-parallel/counter flow type in which the tube-side air flow makes a combined parallel and counter flow arrangement with a cross-flowing combustion gas in such a way that the maximum CFCC tube temperature will not exceed a 1,260 C (2,300 F) design limit. The main heat transfer mechanism from the external hot gas to the tube-side air is that of gaseous radiation for the first few rows of the tubes, followed by convective heat transfer across the remainder of the tube bundle. The design characteristics of this high-temperature, high-pressure CFCC heat exchanger with supporting thermal, flow, structural, and vibrational analyses are presented in detail in the paper.

  19. Conceptual design study for the HCRF direct contact heat exchanger modification

    SciTech Connect (OSTI)

    Wahl, E. F.

    1984-06-01T23:59:59.000Z

    The conceptual design of sieve trays for modifying the HCRF direct contact heat exchanger was developed as follows. The models of the prior work, EG&G subcontract No. K-7752, were extended and modified so the predicted heat transfer coincided with the experimental data of the 60 KW Raft River tests conducted by EG&G. Using these models, a hole diameter of 0.25 inches and a hole velocity of 1.3 ft/sec or greater was selected to accomplish the required heat transfer while minimizing mass transferred to the geothermal fluid. Using the above information, a conceptual design for a sieve tray column was developed. It was determined that the column should operate as a working fluid filled, working fluid dispersed column. This is accomplished by level control of the geothermal fluid below the bottom tray. The dimensions and configuration of the trays and downcomers, and the number of holes and their diameters is summarized in Wahl Company drawings 84144001 and 84144003 submitted with this report. The performance of this design is expected to be 12,000 lbs/hr of geothermal fluid for single component fluids and 11,800 to 12,000 lbs/hr for mixed fluids at a working fluid flow rate of 71% of the geothermal fluid flow rate. The flow rate limit of the geothermal fluid will vary from 9800 to 13,000 lbs/hr as the ratio varies from 83% to 62%.

  20. Erosion of heat exchanger tubes in fluidized beds. Annual report, 1990

    SciTech Connect (OSTI)

    Johnson, E.K.; Flemmer, R.L.C.

    1991-01-01T23:59:59.000Z

    This final report describes the activities of the 3-year project entitled ``Erosion of Heat Exchanger Tubes In Fluidized Beds.`` which was completed at the end of 1990. Project accomplishments include the collection of a substantial body of wear data In a 24in. {times} 24in. fluidized bed, comparative wear results In a 6in. {times} 6in. fluidized bed, the development of a dragometer and the collection of a comprehensive set of drag force data in the 24in. {times} 24in. bed, Fast Fourier Transform (FFT) analysis of bubble probe data to establish dominant bubble frequencies in the 24in. {times} 24in. bed, the use of a heat flux gauge for measurement of heat transfer coefficients in the 24in. {times} 24in. bed and the modeling of the tube wear in the 24in. {times} 24in. bed. Analysis of the wear data from the 24in. square bed indicates that tube wear increases with increase in superficial velocity, and with increase in tube height. The latter effect is a result of the tubes higher up in the bed seeing greater movement of dense phase than tubes lower down In the bed. In addition, tube wear was found to decrease with increase in particle size, for constant superficial velocity. Three models of tube wear were formulated and provided acceptable prediction of wear when compared with the experimental data.

  1. Determination of the Number of Tube Rows to Obtain Closure for Volume Averaging Theory Based Model of Fin-and-Tube Heat Exchangers

    E-Print Network [OSTI]

    Zhou, Feng; Hansen, Nicholas E; Geb, David J; Catton, Ivan

    2011-01-01T23:59:59.000Z

    can be evaluated for a representative elementary volume (and-tube heat exchanger, representative elementary volumeand (2) on a selected representative elementary volume (REV)

  2. Development of nondestructive evaluation techniques for high-temperature ceramic heat exchanger components. Tenth quarterly report, January-March 1980

    SciTech Connect (OSTI)

    Kupperman, D.S.; Yuhas, D.; Caines, M.J.

    1980-04-01T23:59:59.000Z

    The effectiveness of several conventional and unconventional NDE techniques for specific high-temperature ceramic components was determined. Techniques under study at ANL include dye-enhanced radiography, acoustic microscopy, conventional ultrasonic testing, acoustic-emission detection, acoustic impact testing, holography, interferometry, infrared scanning, internal friction measurements, and overload proof testing. The current effort involves SiC heat-exchanger tubes; previous ceramic NDE efforts at ANL have involved silicon-nitride gas-turbine rotors. Recent results on inspection of SiC heat-exchanger tubing by means of ultrasonic acoustic microscopy techniques and efforts initiated and planned for NDE of ceramic joints are discussed.

  3. Radiative heat transfer at nanoscale mediated by surface plasmons for highly doped Emmanuel Rousseau

    E-Print Network [OSTI]

    Paris-Sud XI, UniversitÚ de

    Radiative heat transfer at nanoscale mediated by surface plasmons for highly doped silicon the role of surface plasmons for nanoscale radiative heat transfer between doped silicon surfaces. We derive a new accurate and closed-form expression of the radiative near- field heat transfer. We also

  4. Advanced Heat Exchanger Development for Molten Salts in Nuclear and Non Nuclear Systems

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Sabharwall, Piyush; Clark, Denis; Sridharan, Kumar; Zheng, Guiqiu; Anderson, Mark

    2014-12-01T23:59:59.000Z

    This study addresses present work concerned with advanced heat exchanger development for molten salt in nuclear and non nuclear thermal systems. The molten salt systems discussed herein use alloys, such as Hastelloy N and 242, which show corrosion resistance to molten salt at nominal operating temperatures up to 700░C. These alloys were diffusion welded, and the corresponding information is presented. Test specimens were prepared for exposing diffusion welds to molten salt environments. Hastelloy N and 242 were found to be weldable by diffusion welding, with ultimate tensile strengths about 90% of base metal values. Both diffusion welds and sheet materialmoreá╗in Hastelloy N were corrosion tested in?58 mol% KF and 42 mol% ZrF4 at 650, 700, and 850░C for 200, 500, and 1,000 hours. Corrosion rates found were similar between welded and nonwelded materials, typically źáless

  5. Thorough approach to measurement uncertainty analysis applied to immersed heat exchanger testing

    SciTech Connect (OSTI)

    Farrington, R.B.; Wells, C.V.

    1986-04-01T23:59:59.000Z

    This paper discusses the value of an uncertainty analysis, discusses how to determine measurement uncertainty, and then details the sources of error in instrument calibration, data acquisition, and data reduction for a particular experiment. Methods are discussed to determine both the systematic (or bias) error in an experiment as well as to determine the random (or precision) error in the experiment. The detailed analysis is applied to two sets of conditions in measuring the effectiveness of an immersed coil heat exchanger. It shows the value of such analysis as well as an approach to reduce overall measurement uncertainty and to improve the experiment. This paper outlines how to perform an uncertainty analysis and then provides a detailed example of how to apply the methods discussed in the paper. The authors hope this paper will encourage researchers and others to become more concerned with their measurement processes and to report measurement uncertainty with all of their test results.

  6. Uncertainty in calculated surface temperature and surface heat flux of THTF heater rods

    SciTech Connect (OSTI)

    Childs, K.W.

    1980-12-01T23:59:59.000Z

    This report presents a procedure for determining the uncertainty in the output of a complex computer code resulting from uncertainties in its input variables. This method is applied to ORINC (Oak Ridge Inverse Code) to estimate the uncertainty in the calculated surface temperature and surface heat flux of a THTF heater during a blowdown transient. The significant input variables are identified and 95% confidence bands are calculated for the code outputs based on the uncertainty in these input variables. 21 refs., 43 figs.

  7. Uncertainty in calculated surface temperature and surface heat flux of THTF heater rods

    SciTech Connect (OSTI)

    Childs, K.W.

    1980-12-01T23:59:59.000Z

    The report presents a procedure for determining the uncertainty in the output of a complex computer code resulting from uncertainties in its input variables. This method is applied to ORINC (Oak Ridge Inverse Code) to estimate the uncertainty in the calculated surface temperature and surface heat flux of a THTF heater during a blowdown transient. The significant input variables are identified and 95% confidence bands are calculated for the code outputs based on the uncertainty in these input variables.

  8. Design and Analysis of High-Performance Air-Cooled Heat Exchanger with an Integrated Capillary-Pumped Loop Heat Pipe

    E-Print Network [OSTI]

    McCarthy, Matthew

    We report the design and analysis of a high-power air-cooled heat exchanger capable of dissipating over 1000 W with 33 W of input electrical power and an overall thermal resistance of less than 0.05 K/W. The novelty of the ...

  9. Advanced Heat Exchanger Development for Molten Salts in Nuclear and Non Nuclear Systems

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Sabharwall, Piyush; Clark, Denis; Sridharan, Kumar; Zheng, Guiqiu; Anderson, Mark

    2014-12-01T23:59:59.000Z

    This study addresses present work concerned with advanced heat exchanger development for molten salt in nuclear and non nuclear thermal systems. The molten salt systems discussed herein use alloys, such as Hastelloy N and 242, which show corrosion resistance to molten salt at nominal operating temperatures up to 700░C. These alloys were diffusion welded, and the corresponding information is presented. Test specimens were prepared for exposing diffusion welds to molten salt environments. Hastelloy N and 242 were found to be weldable by diffusion welding, with ultimate tensile strengths about 90% of base metal values. Both diffusion welds and sheet material in Hastelloy N were corrosion tested in?58 mol% KF and 42 mol% ZrF4 at 650, 700, and 850░C for 200, 500, and 1,000 hours. Corrosion rates found were similar between welded and nonwelded materials, typically <10 mils per year. For materials of construction, nickel and alloys with dense nickel coatings are effectively inert to corrosion in fluorides, but not so in chlorides. Hence, additional testing of selected alloys for resistance to intergranular corrosion is needed, as is a determination of corrosion rate as a function of contaminant type and alloy composition with respect to chromium and carbon to better define the optimal chromium and carbon composition, independent of galvanic or differential solubility effects. Also presented is the division of the nuclear reactor and high temperature components per ASME standards, along with design requirements for a subcritical Rankine power cycle heat exchanger that has to overcome pressure difference of about 17 MPa.

  10. Oxygen Surface Exchange Kinetics on Sr-Substituted Lanthanum Manganite and Ferrite Thin-Film Microelectrodes

    E-Print Network [OSTI]

    la O', Gerardo Jose

    The surface oxygen exchange kinetics occurring on dense La0.8Sr0.2MnO3 (65nm thick) and La0.8Sr0.2FeO3 (110nm thick) thin films were investigated by electrochemical impedance spectroscopy (EIS). Rutherford backscattering ...

  11. Heat transfer via dropwise condensation on hydrophobic microstructured surfaces

    E-Print Network [OSTI]

    Ruleman, Karlen E. (Karlen Elizabeth)

    2009-01-01T23:59:59.000Z

    Dropwise condensation has the potential to greatly increase heat transfer rates. Heat transfer coefficients by dropwise condensation and film condensation on microstructured silicon chips were compared. Heat transfer ...

  12. OPTIMIZATION OF INTERNAL HEAT EXCHANGERS FOR HYDROGEN STORAGE TANKS UTILIZING METAL HYDRIDES

    SciTech Connect (OSTI)

    Garrison, S.; Tamburello, D.; Hardy, B.; Anton, D.; Gorbounov, M.; Cognale, C.; van Hassel, B.; Mosher, D.

    2011-07-14T23:59:59.000Z

    Two detailed, unit-cell models, a transverse fin design and a longitudinal fin design, of a combined hydride bed and heat exchanger are developed in COMSOL{reg_sign} Multiphysics incorporating and accounting for heat transfer and reaction kinetic limitations. MatLab{reg_sign} scripts for autonomous model generation are developed and incorporated into (1) a grid-based and (2) a systematic optimization routine based on the Nelder-Mead downhill simplex method to determine the geometrical parameters that lead to the optimal structure for each fin design that maximizes the hydrogen stored within the hydride. The optimal designs for both the transverse and longitudinal fin designs point toward closely-spaced, small cooling fluid tubes. Under the hydrogen feed conditions studied (50 bar), a 25 times improvement or better in the hydrogen storage kinetics will be required to simultaneously meet the Department of Energy technical targets for gravimetric capacity and fill time. These models and methodology can be rapidly applied to other hydrogen storage materials, such as other metal hydrides or to cryoadsorbents, in future work.

  13. Measurement of laser heating in spin exchange optical pumping by NMR diffusion sensitization gradients

    SciTech Connect (OSTI)

    Parnell, Steven R.; Deppe, Martin H.; Ajraoui, Salma; Parra-Robles, Juan; Wild, Jim M. [Unit of Academic Radiology, University of Sheffield, Royal Hallamshire Hospital, Glossop Road, Sheffield, S10 2JF (United Kingdom); Boag, Stephen [ISIS, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX (United Kingdom)

    2010-05-15T23:59:59.000Z

    This paper details pulsed gradient NMR measurements of the {sup 3}He diffusion coefficient in sealed cells during spin exchange optical pumping. The potential of ultra low field magnetic resonance imgaing (MRI) and NMR for noninvasive measurement of cell pressure is demonstrated. Diffusion sensitization gradients allow measurement of the {sup 3}He diffusion coefficient from which the pressure and/or temperature of the gas can be determined during optical pumping. The pressure measurements were compared with neutron time of flight transmission measurements. Good agreement was observed between the temperature/pressure measurements and predictions based on Chapman-Enskog theory. The technique had sufficient sensitivity to observe the diffusion coefficient increasing with temperature in a sealed cell. With this method, evidence for laser heating of the {sup 3}He during optical pumping was found. The results show that NMR diffusion measurements allow noninvasive measurement of the cell temperature and/or pressure in an optical pumping setup. The method can be expanded using MRI to probe the spatial distribution of the diffusion coefficient. These techniques can be applied to the further investigation of polarization limiting effects such as laser heating.

  14. Solid State Joining of High Temperature Alloy Tubes for USC and Heat-Exchanger Systems

    SciTech Connect (OSTI)

    Bimal Kad

    2011-12-31T23:59:59.000Z

    The principal objective of this project was to develop materials enabling joining technologies for use in forward looking heat-exchanger fabrication in Brayton cycle HIPPS, IGCC, FutureGen concepts capable of operating at temperatures in excess of 1000{degree}C as well as conventional technology upgrades via Ultra Super-Critical (USC) Rankine-cycle boilers capable of operating at 760{degree}C (1400F)/38.5MPa (5500psi) steam, while still using coal as the principal fossil fuel. The underlying mission in Rankine, Brayton or Brayton-Rankine, or IGCC combined cycle heat engine is a steady quest to improving operating efficiency while mitigating global environmental concerns. There has been a progressive move to higher overall cycle efficiencies, and in the case of fossil fuels this has accelerated recently in part because of concerns about greenhouse gas emissions, notably CO{sub 2}. For a heat engine, the overall efficiency is closely related to the difference between the highest temperature in the cycle and the lowest temperature. In most cases, efficiency gains are prompted by an increase in the high temperature, and this in turn has led to increasing demands on the materials of construction used in the high temperature end of the systems. Our migration to new advanced Ni-base and Oxide Dispersion Strengthened (ODS) alloys poses significant fabrication challenges, as these materials are not readily weldable or the weld performs poorly in the high temperature creep regime. Thus the joining challenge is two-fold to a) devise appropriate joining methodologies for similar/dissimilar Ni-base and ODS alloys while b) preserving the near baseline creep performance in the welded region. Our program focus is on solid state joining of similar and dissimilar metals/alloys for heat exchanger components currently under consideration for the USC, HIPPS and IGCC power systems. The emphasis is to manipulate the joining methods and variables available to optimize joint creep performance compared to the base material creep performance. Similar and dissimilar butt joints were fabricated of MA956, IN740 alloys and using inertia welding techniques. We evaluated joining process details and heat treatments and its overall effect on creep response. Fixed and incrementally accelerated temperature creep tests were performed for similar and dissimilar joints and such incremental creep life data is compiled and reported. Long term MA956-MA556 joint tests indicate a firm 2Ksi creep stress threshold performance at 850{degree}C with a maximum exposure of over 9725 hours recorded in the current program. A Larsen Miller Parameter (LMP) of 48.50 for a 2Ksi test at 850{degree}C was further corroborated with tests at 2Ksi stress at 900{degree}C yielding a LMP=48.80. Despite this threshold the joints exhibit immense temperature sensitivity and fail promptly when test temperature raised above 900{degree}C. In comparison the performance of dissimilar joints was inferior, perhaps dictated by the creep characteristics of the mating nickel-base alloys. We describe a parametric window of joint development, and post weld heat treatment (PWHT) in dissimilar joints with solid solution (IN601, IN617) and precipitate strengthened (IN740) materials. Some concerns are evident regarding the diffusion of aluminum in dissimilar joints during high temperature recrystallization treatments. It is noted that aggressive treatments rapidly deplete the corrosion protecting aluminum reservoir in the vicinity of the joint interface. Subsequently, the impact of varying PWHT has been evaluated in the context on ensuing creep performance.

  15. Next Generation Nuclear Plant Steam Generator and Intermediate Heat Exchanger Materials Research and Development Plan

    SciTech Connect (OSTI)

    J. K. Wright

    2010-09-01T23:59:59.000Z

    DOE has selected the High Temperature Gas-cooled Reactor (HTGR) design for the Next Generation Nuclear Plant (NGNP) Project. The NGNP will demonstrate the use of nuclear power for electricity and hydrogen production. It will have an outlet gas temperature in the range of 900░C and a plant design service life of 60 years. The reactor design will be a graphite moderated, helium-cooled, prismatic or pebble-bed reactor and use low-enriched uranium, Tri-Isotopic (TRISO)-coated fuel. The plant size, reactor thermal power, and core configuration will ensure passive decay heat removal without fuel damage or radioactive material releases during accidents. The NGNP Materials Research and Development (R&D) Program is responsible for performing R&D on likely NGNP materials in support of the NGNP design, licensing, and construction activities. Todayĺs high-temperature alloys and associated ASME Codes for reactor applications are approved up to 760░C. However, some primary system components, such as the Intermediate Heat Exchanger (IHX) for the NGNP will require use of materials that can withstand higher temperatures. The thermal, environmental, and service life conditions of the NGNP will make selection and qualification of some high-temperature materials a significant challenge. Examples include materials for the core barrel and core internals, such as the control rod sleeves. The requirements of the materials for the IHX are among the most demanding. Selection of the technology and design configuration for the NGNP must consider both the cost and risk profiles to ensure that the demonstration plant establishes a sound foundation for future commercial deployments. The NGNP challenge is to achieve a significant advancement in nuclear technology while at the same time setting the stage for an economically viable deployment of the new technology in the commercial sector soon after 2020. A number of solid solution strengthened nickel based alloys have been considered for application in heat exchangers and core internals for the NGNP. The primary candidates are Inconel 617, Haynes 230, Incoloy 800H and Hastelloy XR. Based on the technical maturity, availability in required product forms, experience base, and high temperature mechanical properties all of the vendor pre-conceptual design studies have specified Alloy 617 as the material of choice for heat exchangers. Also a draft code case for Alloy 617 was developed previously. Although action was suspended before the code case was accepted by ASME, this draft code case provides a significant head start for achieving codification of the material. Similarly, Alloy 800H is the material of choice for control rod sleeves. In addition to the above listed considerations, Alloy 800H is already listed in the nuclear section of the ASME Code; although the maximum use temperature and time need to be increased.

  16. Next Generation Nuclear Plant Intermediate Heat Exchanger Materials Research and Development Plan (PLN-2804)

    SciTech Connect (OSTI)

    J. K. Wright

    2008-04-01T23:59:59.000Z

    DOE has selected the High Temperature Gas-cooled Reactor (HTGR) design for the Next Generation Nuclear Plant (NGNP) Project. The NGNP will demonstrate the use of nuclear power for electricity and hydrogen production. It will have an outlet gas temperature in the range of 900░C and a plant design service life of 60 years. The reactor design will be a graphite moderated, helium-cooled, prismatic or pebble-bed reactor and use low-enriched uranium, Tri-Isotopic (TRISO)-coated fuel. The plant size, reactor thermal power, and core configuration will ensure passive decay heat removal without fuel damage or radioactive material releases during accidents. The NGNP Materials Research and Development (R&D) Program is responsible for performing R&D on likely NGNP materials in support of the NGNP design, licensing, and construction activities. Todayĺs high-temperature alloys and associated ASME Codes for reactor applications are approved up to 760░C. However, some primary system components, such as the Intermediate Heat Exchanger (IHX) for the NGNP will require use of materials that can withstand higher temperatures. The thermal, environmental, and service life conditions of the NGNP will make selection and qualification of some high-temperature materials a significant challenge. Examples include materials for the core barrel and core internals, such as the control rod sleeves. The requirements of the materials for the IHX are among the most demanding. Selection of the technology and design configuration for the NGNP must consider both the cost and risk profiles to ensure that the demonstration plant establishes a sound foundation for future commercial deployments. The NGNP challenge is to achieve a significant advancement in nuclear technology while at the same time setting the stage for an economically viable deployment of the new technology in the commercial sector soon after 2020. A number of solid solution strengthened nickel based alloys have been considered for application in heat exchangers and core internals for the NGNP. The primary candidates are Inconel 617, Haynes 230, Incoloy 800H and Hastelloy XR. Based on the technical maturity, availability in required product forms, experience base, and high temperature mechanical properties all of the vendor pre-conceptual design studies have specified Alloy 617 as the material of choice for heat exchangers. Also a draft code case for Alloy 617 was developed previously. Although action was suspended before the code case was accepted by ASME, this draft code case provides a significant head start for achieving codification of the material. Similarly, Alloy 800H is the material of choice for control rod sleeves. In addition to the above listed considerations, Alloy 800H is already listed in the nuclear section of the ASME Code; although the maximum use temperature and time need to be increased.

  17. Hydraulic transmissivity and heat exchanges: aperture lowpass filtering model 1 Natural open joints in rocks commonly present multi-scale self-affine apertures. This

    E-Print Network [OSTI]

    Paris-Sud XI, UniversitÚ de

    Hydraulic transmissivity and heat exchanges: aperture lowpass filtering model 1 SUMMARY Natural aperture that describes at best the macroscopic properties (hydraulic conductivity, heat exchange of the effective hydraulic and thermal properties (apertures). A detailed study of the influence of the bandwidth

  18. Inverse estimation of surface heating condition in a three-dimensional object using conjugate gradient method

    E-Print Network [OSTI]

    Zhang, Yuwen

    heat conduction Laser Gaussian profile Conjugate gradient method a b s t r a c t Temperature and heat gradient method Jianhua Zhou, Yuwen Zhang *, J.K. Chen, Z.C. Feng Department of Mechanical and Aerospace gradient method (CGM) with temperature and heat flux measured on back surface (opposite to the heated

  19. Guidelines for Measuring Air Infiltration Heat Exchange Effectiveness (IHEE), Submitted to the Texas Higher Education Coordination Board Energy Research Application Program Project #227

    E-Print Network [OSTI]

    Liu, M.; Claridge, D. E.

    1993-01-01T23:59:59.000Z

    ESL-TR-93/09-01 Guidelines for Measuring Air Infiltration Heat Exchange Effectiveness (IHEE) Submitted to the Texas Higher Education Coordination Board Energy Research Application Program Project #227 i Dr. Mingsheng Liu Dr. David E. Claridge... Method 3 Co-heating Method 4 STAM Method 8 Conclusions 10 Reference 12 Appendix A 14 Appendix B 15 Appendix C 21 Guidelines for Measuring IHEE, P. 1 Guidelines for Measuring Air Infiltration Heat Exchange Effectiveness (IHEE) Introduction The rate of air...

  20. Micro and nanostructured surfaces for enhanced phase change heat transfer

    E-Print Network [OSTI]

    Chu, Kuang-Han, Ph. D. Massachusetts Institute of Technology

    2013-01-01T23:59:59.000Z

    Two-phase microchannel heat sinks are of significant interest for thermal management applications, where the latent heat of vaporization offers an efficient method to dissipate large heat fluxes in a compact device. However, ...

  1. Fabrication and heating rate study of microscopic surface electrode ion traps

    E-Print Network [OSTI]

    Daniilidis, N.

    We report heating rate measurements in a microfabricated gold-on-sapphire surface electrode ion trap with a trapping height of approximately 240 ?m. Using the Doppler recooling method, we characterize the trap heating rates ...

  2. The corrosive environment in the fluidized-bed heat-exchanger for CCGT service

    SciTech Connect (OSTI)

    Rocazella, M.A.; Holt, C.F.; Wright, I.C.

    1983-01-01T23:59:59.000Z

    Corrosion and combustion diagnostic data were gathered in Battelle's 0.6m diameter coal-fired atmospheric fluidized-bed combustor (AFBC). Corrosion probes, constructed from ring specimens of candidate heatexchanger alloys, were exposed to the fluidized-bed environment during three different combustion experiments (50%, 20% and 0% excess air). An in-situ oxygen probe was used to monitor the oxygen partial pressure at the exposure locations. Two different mechanisms of material degradation were identified, i.e., both corrosion and erosion. An adherent deposit of bed material formed on all areas of the corrosion probes. The corrosion behavior of the alloys beneath the deposit, and the corresponding corrosion product morphologies, appeared to correlate well with predictions based on the oxygen partial pressure measurements from the exposure location. The results suggest the oxygen probe may be a useful diagnostic tool for locating regions with high corrosive potentials. However, the upstream faces of the corrosion probes were subjected to enhanced mechanical damage, and this periodic removal of both the deposit and corrosion products resulted in significantly more metal degradation. Also, this corrosion/erosion process may locally deplete the alloy in chromium, leaving it susceptible to severe sulfidation and/or accelerated oxidation. It was suggested that these locations would be the first to experience heat-exchanger tube failure, and the coupled corrosion/erosion process would be the failure mechanism.

  3. Standard practice for in situ examination of ferromagnetic Heat-Exchanger tubes using remote field testing

    E-Print Network [OSTI]

    American Society for Testing and Materials. Philadelphia

    2010-01-01T23:59:59.000Z

    1.1 This practice describes procedures to be followed during remote field examination of installed ferromagnetic heat-exchanger tubing for baseline and service-induced discontinuities. 1.2 This practice is intended for use on ferromagnetic tubes with outside diameters from 0.500 to 2.000 in. [12.70 to 50.80 mm], with wall thicknesses in the range from 0.028 to 0.134 in. [0.71 to 3.40 mm]. 1.3 This practice does not establish tube acceptance criteria; the tube acceptance criteria must be specified by the using parties. 1.4 UnitsŚThe values stated in either inch-pound units or SI units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this practice to establ...

  4. HIGH-TEMPERATURE HEAT EXCHANGER TESTING IN A PILOT-SCALE SLAGGING FURNACE SYSTEM

    SciTech Connect (OSTI)

    Michael E. Collings; Bruce A. Dockter; Douglas R. Hajicek; Ann K. Henderson; John P. Hurley; Patty L. Kleven; Greg F. Weber

    1999-12-01T23:59:59.000Z

    The University of North Dakota Energy & Environmental Research Center (EERC), in partnership with United Technologies Research Center (UTRC) under a U.S. Department of Energy (DOE) contract, has designed, constructed, and operated a 3.0-million Btu/hr (3.2 x 10{sup 6} kJ/hr) slagging furnace system (SFS). Successful operation has demonstrated that the SFS meets design objectives and is well suited for testing very high-temperature heat exchanger concepts. Test results have shown that a high-temperature radiant air heater (RAH) panel designed and constructed by UTRC and used in the SFS can produce a 2000 F (1094 C) process air stream. To support the pilot-scale work, the EERC has also constructed laboratory- and bench-scale equipment which was used to determine the corrosion resistance of refractory and structural materials and develop methods to improve corrosion resistance. DOE projects that from 1995 to 2015, worldwide use of electricity will double to approach 20 trillion kilowatt hours. This growth comes during a time of concern over global warming, thought by many policy makers to be caused primarily by increases from coal-fired boilers in carbon dioxide (CO{sub 2}) emissions through the use of fossil fuels. Assuming limits on CO{sub 2} emissions from coal-fired boilers are imposed in the future, the most economical CO{sub 2} mitigation option may be efficiency improvements. Unless efficiency improvements are made in coal-fired power plants, utilities may be forced to turn to more expensive fuels or buy CO{sub 2} credits. One way to improve the efficiency of a coal-fired power plant is to use a combined cycle involving a typical steam cycle along with an indirectly fired turbine cycle using very high-temperature but low-pressure air as the working fluid. At the heart of an indirectly fired turbine combined-cycle power system are very high-temperature heat exchangers that can produce clean air at up to 2600 F (1427 C) and 250 psi (17 bar) to turn an aeroderivative turbine. The overall system design can be very similar to that of a typical pulverized coal-fired boiler system, except that ceramics and alloys are used to carry the very high-temperature air rather than steam. This design makes the combined-cycle system especially suitable as a boiler-repowering technology. With the use of a gas-fired duct heater, efficiencies of 55% can be achieved, leading to reductions in CO{sub 2} emissions of 40% as compared to today's coal-fired systems. On the basis of work completed to date, the high-temperature advanced furnace (HITAF) concept appears to offer a higher-efficiency technology option for coal-fired power generation systems than conventional pulverized coal firing. Concept analyses have demonstrated the ability to achieve program objectives for emissions (10% of New Source Performance Standards, i.e., 0.003 lb/MMBtu of particulate), efficiency (47%-55%), and cost of electricity (10%-25% below today's cost). Higher-efficiency technology options for new plants as well as repowering are important to the power generation industry in order to conserve valuable fossil fuel resources, reduce the quantity of pollutants (air and water) and solid wastes generated per MW, and reduce the cost of power production in a deregulated industry. Possibly more important than their potential application in a new high-temperature power system, the RAH panel and convective air heater tube bank are potential retrofit technology options for existing coal-fired boilers to improve plant efficiencies. Therefore, further development of these process air-based high-temperature heat exchangers and their potential for commercial application is directly applicable to the development of enabling technologies in support of the Vision 21 program objectives. The objective of the work documented in this report was to improve the performance of the UTRC high-temperature heat exchanger, demonstrate the fuel flexibility of the slagging combustor, and test methods for reducing corrosion of brick and castable refractory in such combustion environments. Specif

  5. Correlating Humidity-Dependent Ionically Conductive Surface Area with Transport Phenomena in Proton-Exchange Membranes

    SciTech Connect (OSTI)

    He, Qinggang; Kusoglu, Ahmet; Lucas, Ivan T.; Clark, Kyle; Weber, Adam Z.; Kostecki, Robert

    2011-08-01T23:59:59.000Z

    The objective of this effort was to correlate the local surface ionic conductance of a Nafion? 212 proton-exchange membrane with its bulk and interfacial transport properties as a function of water content. Both macroscopic and microscopic proton conductivities were investigated at different relative humidity levels, using electrochemical impedance spectroscopy and current-sensing atomic force microscopy (CSAFM). We were able to identify small ion-conducting domains that grew with humidity at the surface of the membrane. Numerical analysis of the surface ionic conductance images recorded at various relative humidity levels helped determine the fractional area of ion-conducting active sites. A simple square-root relationship between the fractional conducting area and observed interfacial mass-transport resistance was established. Furthermore, the relationship between the bulk ionic conductivity and surface ionic conductance pattern of the Nafion? membrane was examined.

  6. Heat exchanger temperature response for duty-cycle transients in the NGNP/HTE.

    SciTech Connect (OSTI)

    Vilim, R. B.; Nuclear Engineering Division

    2009-03-12T23:59:59.000Z

    Control system studies were performed for the Next Generation Nuclear Plant (NGNP) interfaced to the High Temperature Electrolysis (HTE) plant. Temperature change and associated thermal stresses are important factors in determining plant lifetime. In the NGNP the design objective of a 40 year lifetime for the Intermediate Heat Exchanger (IHX) in particular is seen as a challenge. A control system was designed to minimize temperature changes in the IHX and more generally at all high-temperature locations in the plant for duty-cycle transients. In the NGNP this includes structures at the reactor outlet and at the inlet to the turbine. This problem was approached by identifying those high-level factors that determine temperature rates of change. First are the set of duty cycle transients over which the control engineer has little control but which none-the-less must be addressed. Second is the partitioning of the temperature response into a quasi-static component and a transient component. These two components are largely independent of each other and when addressed as such greater understanding of temperature change mechanisms and how to deal with them is achieved. Third is the manner in which energy and mass flow rates are managed. Generally one aims for a temperature distribution that minimizes spatial non-uniformity of thermal expansion in a component with time. This is can be achieved by maintaining a fixed spatial temperature distribution in a component during transients. A general rule of thumb for heat exchangers is to maintain flow rate proportional to thermal power. Additionally the product of instantaneous flow rate and heat capacity should be maintained the same on both sides of the heat exchanger. Fourth inherent mechanisms for stable behavior should not be compromised by active controllers that can introduce new feedback paths and potentially create under-damped response. Applications of these principles to the development of a plant control strategy for the reference NGNP/HTE plant can be found in the body of this report. The outcome is an integrated plant/control system design. The following conclusions are drawn from the analysis: (1) The plant load schedule can be managed to maintain near-constant hot side temperatures over the load range in both the nuclear and chemical plant. (2) The reactor open-loop response is inherently stable resulting mainly from a large Doppler temperature coefficient compared to the other reactivity temperature feedbacks. (3) The typical controller used to manage reactor power production to maintain reactor outlet temperature at a setpoint introduces a feedback path that tends to destabilize reactor power production in the NGNP. (4) A primary loop flow controller that forces primary flow to track PCU flow rate is effective in minimizing spatial temperature differentials within the IHX. (5) Inventory control in both the primary and PCU system during ramp load change transients is an effective means of maintaining high NGNP thermal efficiency while at reduced electric load. (6) Turbine bypass control is an effective means for responding to step changes in generator load when equipment capacity limitations prevent inventory control from being effective. (7) Turbine bypass control is effective in limiting PCU shaft over speed for the loss of generator load upset event. (8) The proposed control strategy is effective in limiting time variation of the differential spatial temperature distribution in the IHX during transients. Essentially the IHX can be made to behave in a manner where each point in the IHX experiences approximately the same temperature rate of change during a transient. (9) The stability of the closed-loop Brayton cycle was found to be sensitive to where one operates on the turbo-machine performance maps. There are competing interests: more stable operation means operating on the curves at points that reduce overall cycle efficiency. Future work should address in greater detail elements that came to light in the course of this work. Specifically: (1) A stability analysi

  7. Dual source heat pump

    DOE Patents [OSTI]

    Ecker, Amir L. (Dallas, TX); Pietsch, Joseph A. (Dallas, TX)

    1982-01-01T23:59:59.000Z

    What is disclosed is a heat pump apparatus for conditioning a fluid characterized by a fluid handler and path for circulating the fluid in heat exchange relationship with a refrigerant fluid; at least two refrigerant heat exchangers, one for effecting heat exchange with the fluid and a second for effecting heat exchange between refrigerant and a heat exchange fluid and the ambient air; a compressor for efficiently compressing the refrigerant; at least one throttling valve for throttling liquid refrigerant; a refrigerant circuit; refrigerant; a source of heat exchange fluid; heat exchange fluid circulating device and heat exchange fluid circuit for circulating the heat exchange fluid in heat exchange relationship with the refrigerant; and valves or switches for selecting the heat exchangers and direction of flow of the refrigerant therethrough for selecting a particular mode of operation. The heat exchange fluid provides energy for defrosting the second heat exchanger when operating in the air source mode and also provides a alternate source of heat.

  8. The (safety-related) heat exchangers aging management guideline for commercial nuclear power plants, and developments since 1994

    SciTech Connect (OSTI)

    Clauss, J.M.

    1998-08-01T23:59:59.000Z

    The US Department of Energy (DOE), in cooperation with the Electric Power Research Institute (EPRI) and US nuclear power plant utilities, is preparing a series of aging management guidelines (AMGs) for commodity types of components (e.g., heat exchangers, electrical cable and terminations, pumps). Commodities are included in this series based on their importance to continued nuclear plant operation and license renewal. The AMGs contain a detailed summary of operating history, stressors, aging mechanisms, and various types of maintenance and surveillance practices that can be combined to create an effective aging management program. Each AMG is intended for use by the systems engineers and plant maintenance staff (i.e., an AMG is intended to be a hands-on technical document rather than a licensing document). The heat exchangers AMG, published in June 1994, includes the following information of interest to nondestructive examination (NDE) personnel: aging mechanisms determined to be non-significant for all applications; aging mechanisms determined to be significant for some applications; effective conventional programs for managing aging; and effective unconventional programs for managing aging. Since the AMG on heat exchangers was published four years ago, a brief review has been conducted to identify emerging regulatory issues, if any. The results of this review and lessons learned from the collective set of AMGs are presented.

  9. Nanoscale modification of key surface parameters to augment pool boiling heat transfer and critical heat flux in water and dielectric fluids

    E-Print Network [OSTI]

    Forrest, Eric Christopher

    2009-01-01T23:59:59.000Z

    Surface effects on pool boiling heat transfer and the critical heat flux are well documented but poorly understood. This study investigates the pool boiling characteristics of various fluids, and demonstrates that surface ...

  10. Separate effects of surface roughness, wettability, and porosity on the boiling critical heat flux

    E-Print Network [OSTI]

    O'Hanley, Harry

    The separate effects of surface wettability, porosity, and roughness on the critical heat flux (CHF) of water were examined using engineered surfaces. Values explored were 0, 5, 10, and 15??m for Rz (roughness), <5░, ?75░, ...

  11. Optimum Design of Micro Bare-Tube Heat Exchanger Tomohisa OKU, Nobuhide KASAGI and Yuji SUZUKI

    E-Print Network [OSTI]

    Tokyo, University of

    for automobiles, electronic equipement cooling system, and recuperator for micro gas turbine. Key words : Heat

  12. Investigation of boiling heat transfer at a surface with a system of cylindrical cavities under conditions of free motion

    SciTech Connect (OSTI)

    Danilova, G.N.; Reznikov, V.I.

    1988-01-01T23:59:59.000Z

    The authors propose a mathematical model for the intensification of boiling heat transfer and the subsequent increase in thermal efficiency of the cylindrical heat transfer surfaces in an evaporative cooling system. The boiling curves for water, ethanol, and freon 113 are calculated for a surface with artificial nucleation sites. The model incorporates such coolant properties as surface tension, specific heat, and vaporization heat.

  13. Field and Laboratory Study of a Ground-Coupled Water Source Heat Pump with an Integral Enthalpy Exchange System for Classrooms

    E-Print Network [OSTI]

    Domitrovic, R.; Hayzen, G. J.; Johnson, W. S.; Chen, F. C.

    2002-01-01T23:59:59.000Z

    technologies is needed to increase the dehumidification abilities of equipment without compromising energy efficiency or the need for fresh ventilation air. To study the effectiveness of integrated heat pump and enthalpy exchange equipment, a nominal 4-ton...

  14. Industrial Waste Heat Recovery

    E-Print Network [OSTI]

    Ward, M. E.; Solomon, N. G.; Tabb, E. S.

    1980-01-01T23:59:59.000Z

    INDUSTRIAL WASTE HEAT RECOVREY M. E. Ward and N. G. Solomon E. S. Tabb Solar Turbines International and Gas Research Institute San Diego, California Chicago, Illinois ABSTRACT i I One hundred fifty reports were reviewed along with interviews... tests, promising low temperature heat exchanger tube alloys and coated surfaces were identified. 1INTROUCTION of advanced technology heat recovery techniques 1_ Recovering waste heat from the flue gases of the pr~ary objective. Specific objectives...

  15. Tritiation of aerogel matrices: T sub 2 O, tritiated organics and tritium exchange on aerogel surfaces

    SciTech Connect (OSTI)

    Ellefson, R.E.; Gill, J.T. (EG and G Mound Applied Technologies, Miamisburg, OH (USA)); Shepodd, T.J. (Sandia Labs., Livermore, CA (USA)); Leonard, L.E. (USDOE, Washington, DC (USA))

    1990-01-01T23:59:59.000Z

    Three methods for incorporation of tritium into the phoshor/aerogel matrix have been demonstrated: (1) adsorption of T{sub 2}O by the aerogel, (2) incorporation of tritiated organic into the pores of the aerogel and (3) isotopic exchange of tritium from T{sub 2} gas for the H residing on the surface of the aerogel. Adsorption of T{sub 2}O produces the brightest light (4.4 fL) to date but the tritium is loosely bound. Incorporation of tritiated organics into the pores of the aerogel produces less that theoretical luminance and intensity diminishes rapidly due to precipitation and darkening of the organic from radiation damage. Isotopic exchange produces a stable lamp by tritiating H sites on the surface of the aerogel. A lamp with stable luminance of 1.1 fL has been produced; a theoretical limit for a mono-layer coverage fo the aerogel surface is 2 to 3 fL. 7 refs., 4 figs., 2 tabs.

  16. Design study of a coal-fired thermionic (THX) topped power plant. Volume IV. Thermionic heat exchanger design and costing

    SciTech Connect (OSTI)

    Dick, R.S.; Britt, E.J.

    1980-10-15T23:59:59.000Z

    This volume deals with the details of how thermionic conversion works, and how it is used in a coal-fired furnace to achieve power plant efficiencies of 45%, and overall costs of 36.3 mills/kWh. A review of the fundamental technical aspects of thermionic conversion is given. The overall Thermionic Heat Exchanger (THX) design, the heat pipe design, and the interaction of the heat pipes with the furnace are presented. Also, the operational characteristics of thermionic converters are described. Details on the computer program used to perform the parametric study are given. The overall program flow is reviewed along with the specifics of how the THX subroutine designed the converter to match the conditions imposed. Also, input costs and variables effecting the THX's performance are detailed. The efficiencies of the various power plants studied are given as a function of the air preheat temperature, size of the power plant, and thermionic level of performance.

  17. Evidence for thermalization of surface-desorbed molecules at heating rates of 108

    E-Print Network [OSTI]

    Zare, Richard N.

    Evidence for thermalization of surface-desorbed molecules at heating rates of 108 K/s C. R of aniline-d7 from a single-crystal surface 0001 of sapphire Al2O3 at a heating rate on the order of 108 K/s was studied using pulsed infrared laser radiation for desorption and resonance enhanced multiphoton ionization

  18. Dehumidification heat transfer on copper surfaces Abhay Varghese Thomas, Nikhil Koratkar, Yoav Peles

    E-Print Network [OSTI]

    Peles, Yoav

    and Background When a cooled surface is placed in an air-steam mixture, liquid water droplets or film form Heat transfer Condensation Humid air a b s t r a c t Heat transfer during dehumidification on the surface if its temperature is sufficiently low. In this dehumidification process, the ambient airşsteam

  19. Energy Savings by Use of Disk/Donut Baffling in Tubular Heat Exchangers

    E-Print Network [OSTI]

    Taborek, J. J.; Klein, D. E.; Fair, J. R.

    . Support Bracke. Figure 1. ConslrUction elements of a single tube pan shell-and?wbe heal exchanger. ESL-IE-88-09-26 Proceedings from the Tenth Annual Industrial Energy Technology Conference, Houston, TX, September 13-15, 1988 This exchanger has a fixed...

  20. Near-field heat transfer between a nanoparticle and a rough surface

    E-Print Network [OSTI]

    Svend-Age Biehs; Jean-Jacques Greffet

    2011-03-11T23:59:59.000Z

    In this work we focus on the surface roughness correction to the near-field radiative heat transfer between a nanoparticle and a material with a rough surface utilizing a direct perturbation theory up to second order in the surface profile. We discuss the different distance regimes for the local density of states above the rough material and the heat flux analytically and numerically. We show that the heat transfer rate is larger than that corresponding to a flat surface at short distances. At larger distances it can become smaller due to surface polariton scattering by the rough surface. For distances much smaller than the correlation length of the surface profile, we show that the results converge to a proximity approximation, whereas in the opposite limit the rough surface can be replaced by an equivalent surface layer.

  1. Enhanced convective and film boiling heat transfer by surface gas injection

    SciTech Connect (OSTI)

    Duignan, M.R.; Greene, G.A. [Brookhaven National Lab., Upton, NY (United States); Irvine, T.F., Jr. [State Univ. of New York, Stony Brook, NY (United States). Dept. of Mechanical Engineering

    1992-04-01T23:59:59.000Z

    Heat transfer measurements were made for stable film boiling of water over a horizontal, flat stainless steel plate from the minimum film boiling point temperature, T{sub SURFACE} {approximately}500K, to T{sub SURFACE} {approximately}950K. The pressure at the plate was approximately 1 atmosphere and the temperature of the water pool was maintained at saturation. The data were compared to the Berenson film-boiling model, which was developed for minimum film-boiling-point conditions. The model accurately represented the data near the minimum film-boiling point and at the highest temperatures measured, as long it was corrected for the heat transferred by radiation. On the average, the experimental data lay within {plus_minus}7% of the model. Measurements of heat transfer were made without film boiling for nitrogen jetting into an overlying pool of water from nine 1-mm- diameter holes, drilled in the heat transfer plate. The heat flux was maintained constant at approximately 26.4 kW/m{sup 2}. For water-pool heights of less than 6cm the heat transfer coefficient deceased linearly with a decrease in heights. Above 6cm the heat transfer coefficient was unaffected. For the entire range of gas velocities measured [0 to 8.5 cm/s], the magnitude of the magnitude of the heat transfer coefficient only changed by approximately 20%. The heat transfer data bound the Konsetov model for turbulent pool heat transfer which was developed for vertical heat transfer surfaces. This agreement suggests that surface orientation may not be important when the gas jets do not locally affect the surface heat transfer. Finally, a database was developed for heat transfer from the plate with both film boiling and gas jetting occurring simultaneously, in a pool of water maintained at its saturation temperature. The effect of passing nitrogen through established film boiling is to increase the heat transfer from that surface. 60 refs.

  2. Enhanced convective and film boiling heat transfer by surface gas injection

    SciTech Connect (OSTI)

    Duignan, M.R.; Greene, G.A. (Brookhaven National Lab., Upton, NY (United States)); Irvine, T.F., Jr. (State Univ. of New York, Stony Brook, NY (United States). Dept. of Mechanical Engineering)

    1992-04-01T23:59:59.000Z

    Heat transfer measurements were made for stable film boiling of water over a horizontal, flat stainless steel plate from the minimum film boiling point temperature, T{sub SURFACE} {approximately}500K, to T{sub SURFACE} {approximately}950K. The pressure at the plate was approximately 1 atmosphere and the temperature of the water pool was maintained at saturation. The data were compared to the Berenson film-boiling model, which was developed for minimum film-boiling-point conditions. The model accurately represented the data near the minimum film-boiling point and at the highest temperatures measured, as long it was corrected for the heat transferred by radiation. On the average, the experimental data lay within {plus minus}7% of the model. Measurements of heat transfer were made without film boiling for nitrogen jetting into an overlying pool of water from nine 1-mm- diameter holes, drilled in the heat transfer plate. The heat flux was maintained constant at approximately 26.4 kW/m{sup 2}. For water-pool heights of less than 6cm the heat transfer coefficient deceased linearly with a decrease in heights. Above 6cm the heat transfer coefficient was unaffected. For the entire range of gas velocities measured (0 to 8.5 cm/s), the magnitude of the magnitude of the heat transfer coefficient only changed by approximately 20%. The heat transfer data bound the Konsetov model for turbulent pool heat transfer which was developed for vertical heat transfer surfaces. This agreement suggests that surface orientation may not be important when the gas jets do not locally affect the surface heat transfer. Finally, a database was developed for heat transfer from the plate with both film boiling and gas jetting occurring simultaneously, in a pool of water maintained at its saturation temperature. The effect of passing nitrogen through established film boiling is to increase the heat transfer from that surface. 60 refs.

  3. Electricity-producing heating apparatus utilizing a turbine generator in a semi-closed brayton cycle

    DOE Patents [OSTI]

    Labinov, Solomon D.; Christian, Jeffrey E.

    2003-10-07T23:59:59.000Z

    The present invention provides apparatus and methods for producing both heat and electrical energy by burning fuels in a stove or boiler using a novel arrangement of a surface heat exchanger and microturbine-powered generator and novel surface heat exchanger. The equipment is particularly suited for use in rural and relatively undeveloped areas, especially in cold regions and highlands.

  4. Analytical solution for thermal runaway in the surface heating of plates

    SciTech Connect (OSTI)

    Lamar, C.R. (Strategic Defense Command, Huntsville, AL (United States))

    1993-09-01T23:59:59.000Z

    An analytical solution is developed for the high-energy heating of metals in which the surface heat flux increases with temperature. Two cases are studied in particular: a case of an insulated rear surface and a convectively cooled rear surface. The solutions result in purely imaginary eigenvalues, which lead to temperature solutions that can increase exponentially with time. A simple expression for avoiding such a temperature solution is derived. 4 refs.

  5. Fabrication and heating rate study of microscopic surface electrode ion traps

    E-Print Network [OSTI]

    N. Daniilidis; S. Narayanan; S. A. M÷ller; R. Clark; T. E. Lee; P. J. Leek; A. Wallraff; St. Schulz; F. Schmidt-Kaler; H. Hńffner

    2010-09-15T23:59:59.000Z

    We report heating rate measurements in a microfabricated gold-on-sapphire surface electrode ion trap with trapping height of approximately 240 micron. Using the Doppler recooling method, we characterize the trap heating rates over an extended region of the trap. The noise spectral density of the trap falls in the range of noise spectra reported in ion traps at room temperature. We find that during the first months of operation the heating rates increase by approximately one order of magnitude. The increase in heating rates is largest in the ion loading region of the trap, providing a strong hint that surface contamination plays a major role for excessive heating rates. We discuss data found in the literature and possible relation of anomalous heating to sources of noise and dissipation in other systems, namely impurity atoms adsorbed on metal surfaces and amorphous dielectrics.

  6. Assessment of strength limiting flaws in ceramic heat exchanger components: Phase 1, Final report, September 28, 1984-June 30, 1986

    SciTech Connect (OSTI)

    Powers, T.; Snyder, J.

    1986-10-01T23:59:59.000Z

    Assurance of energy efficient design lifetimes of high temperature structural ceramics requires the ability to specify acceptance criteria and to test to those criteria. These criteria will be established through nondestructive testing, to determine which defects are detectable, together with fracture mechanics, to calculate effects of indetectable flaws. The first phase of this program is to examine heat exchanger material with four test methods which have shown promise for use in ceramics; ultrasonic scanning, microfocus x-ray, Scanning Laser Acoustic Microscope, and Acoustic Holography. The capabilities, limits, and potential for improvement of these are presented in this report. Destructive testing, material sectioning, and fractography are included. 24 refs., 68 figs., 6 tabs.

  7. Multiple source heat pump

    DOE Patents [OSTI]

    Ecker, Amir L. (Duncanville, TX)

    1983-01-01T23:59:59.000Z

    A heat pump apparatus for conditioning a fluid characterized by a fluid handler and path for circulating a fluid in heat exchange relationship with a refrigerant fluid, at least three refrigerant heat exchangers, one for effecting heat exchange with the fluid, a second for effecting heat exchange with a heat exchange fluid, and a third for effecting heat exchange with ambient air; a compressor for compressing the refrigerant; at least one throttling valve connected at the inlet side of a heat exchanger in which liquid refrigerant is vaporized; a refrigerant circuit; refrigerant; a source of heat exchange fluid; heat exchange fluid circuit and pump for circulating the heat exchange fluid in heat exchange relationship with the refrigerant; and valves or switches for selecting the heat exchangers and directional flow of refrigerant therethrough for selecting a particular mode of operation. Also disclosed are a variety of embodiments, modes of operation, and schematics therefor.

  8. Study of the Effects of Surface Morphology and Droplet Growth Dynamics on Condensation Heat Transfer

    E-Print Network [OSTI]

    Yao, Chun-Wei

    2014-04-23T23:59:59.000Z

    system 2 on Sample 3 (50??m micropillar spacing hybrid surface) ............................................................................................... 66 Figure 24. Environmental scanning electron microscopy (ESEM) time- sequence images... tension gradients to promote and induce a droplet removal mechanism. They concluded that their gradient surface exhibited a higher heat transfer coefficient than a hydrophobic silane based surface. More recently, environmental scanning electron...

  9. PTG exam 9 April 2014 short answers 123. Heat given off = surface * heat transfer coefficient * temperature = A * h * T

    E-Print Network [OSTI]

    Zevenhoven, Ron

    depends on Grnumber Gr = gL3 T/2 = 1,09109 , with given (~ 1/T), and L = 0.75 m. GrPr = 0,78109 > 108 . Nu (average for surface) = 0,13(GrPr)1/3 = 119 gives h (average for surface) = 4,14 W/m2 K Finally this gives with A = 2,25 m2 , heat given off = 186,3 W. 124. Using the steam tables

  10. Heat pump system

    DOE Patents [OSTI]

    Swenson, Paul F. (Cleveland, OH); Moore, Paul B. (Fedhaurn, FL)

    1982-01-01T23:59:59.000Z

    An air heating and cooling system for a building includes an expansion-type refrigeration circuit and a heat engine. The refrigeration circuit includes two heat exchangers, one of which is communicated with a source of indoor air from the building and the other of which is communicated with a source of air from outside the building. The heat engine includes a heat rejection circuit having a source of rejected heat and a primary heat exchanger connected to the source of rejected heat. The heat rejection circuit also includes an evaporator in heat exchange relation with the primary heat exchanger, a heat engine indoor heat exchanger, and a heat engine outdoor heat exchanger. The indoor heat exchangers are disposed in series air flow relationship, with the heat engine indoor heat exchanger being disposed downstream from the refrigeration circuit indoor heat exchanger. The outdoor heat exchangers are also disposed in series air flow relationship, with the heat engine outdoor heat exchanger disposed downstream from the refrigeration circuit outdoor heat exchanger. A common fluid is used in both of the indoor heat exchanges and in both of the outdoor heat exchangers. In a first embodiment, the heat engine is a Rankine cycle engine. In a second embodiment, the heat engine is a non-Rankine cycle engine.

  11. Engineering Analysis of Intermediate Loop and Process Heat Exchanger Requirements to Include Configuration Analysis and Materials Needs

    SciTech Connect (OSTI)

    T.M. Lillo; R.L. Williamson; T.R. Reed; C.B. Davis; D.M. Ginosar

    2005-09-01T23:59:59.000Z

    The need to locate advanced hydrogen production facilities a finite distance away from a nuclear power source necessitates the need for an intermediate heat transport loop (IHTL). This IHTL must not only efficiently transport energy over distances up to 500 meters but must also be capable of operating at high temperatures (>850oC) for many years. High temperature, long term operation raises concerns of material strength, creep resistance and general material stability (corrosion resistance). IHTL design is currently in the initial stages. Many questions remain to be answered before intelligent design can begin. The report begins to look at some of the issues surrounding the main components of an IHTL. Specifically, a stress analysis of a compact heat exchanger design under expected operating conditions is reported. Also the results of a thermal analysis performed on two ITHL pipe configurations for different heat transport fluids are presented. The configurations consist of separate hot supply and cold return legs as well as annular design in which the hot fluid is carried in an inner pipe and the cold return fluids travels in the opposite direction in the annular space around the hot pipe. The effects of insulation configurations on pipe configuration performance are also reported. Finally, a simple analysis of two different process heat exchanger designs, one a tube in shell type and the other a compact or microchannel reactor are evaluated in light of catalyst requirements. Important insights into the critical areas of research and development are gained from these analyses, guiding the direction of future areas of research.

  12. Gas exchange in terrestrial environments comes at the cost of evaporative water loss from respiratory surfaces.

    E-Print Network [OSTI]

    Franz, Nico M.

    3477 Gas exchange in terrestrial environments comes at the cost of evaporative water loss from of gas exchange, both within and among species (Lighton, 1998; Shelton and Appel, 2001; Chown, 2002). The classical pattern is that of discontinuous gas exchange, or discontinuous gas-exchange cycles (DGC; Lighton

  13. Enhanced surfaces lead to increased heat transfer and power density.

    E-Print Network [OSTI]

    electric vehicles (HEVs) and electric vehicles (EVs) to con- vert DC battery power into a form that can IHTC-14, Washington, DC, USA. Moreno, G., 2010,"Characterization and Development of Advanced Heat

  14. PNNL Enhanced Pool-Boiling Heat Transfer Using Nanostructured Surfaces

    ScienceCinema (OSTI)

    None

    2012-12-31T23:59:59.000Z

    Close-up video of boiling taking place on a nanostructured surface in a controlled laboratory experiment.

  15. Forced-convection surface-boiling heat transfer and burnout in tubes of small diameters

    E-Print Network [OSTI]

    Bergles A. E.

    1962-01-01T23:59:59.000Z

    A basic heat-transfer apparatus was designed and constructed for the study of forced-convection boiling in small channels. The various regions of forced-convection surface boiling were studied experimentally and analytically. ...

  16. Effect of surface conditions on boiling heat transfer of refrigerants in shell-and-tube evaporators

    SciTech Connect (OSTI)

    Danilova, G.N.; Dyundin, V.A.; Borishanskaya, A.V.; Soloviyov, A.G.; Vol'nykh, Y.A.; Kozyrev, A.A.

    1990-01-01T23:59:59.000Z

    Experimental results are presented for the boiling heat transfer performance of R 22 and R 717 on surfaces with porous metallized coatings. A calculational-theoretical model is given for predicting the heat transfer of refrigerants boiling on a bundle of finned tubes.

  17. Inferring surface heat flux distributions guided by a global seismic model: particular application to Antarctica

    E-Print Network [OSTI]

    Shapiro, Nikolai

    -flow measurements are rare or entirely absent. This will result in a smooth global heat-flow map that may proveInferring surface heat flux distributions guided by a global seismic model: particular application to Antarctica Nikolai M. Shapiro*, Michael H. Ritzwoller Department of Physics, Center for Imaging the Earth

  18. THERMAL PERFORMANCE OF A DUAL-CHANNEL, HELIUM-COOLED, TUNGSTEN HEAT EXCHANGER

    E-Print Network [OSTI]

    California at Los Angeles, University of

    high heat fluxes. The high temperature helium can then be used to power a gas turbine for high the high efficiency power conversion available from new generation gas turbines. It is envisioned

  19. Numerical Investigation of Thermal Hydraulic Behavior of Supercritical Carbon Dioxide in Compact Heat Exchangers

    E-Print Network [OSTI]

    Fatima, Roma

    2012-02-14T23:59:59.000Z

    volume method using a commercial software FLUENT. Three dimensional Computational Fluid Dynamics (CFD) models were developed to simulate the flow and heat transfer for three different geometries ľ a single semi-circular channel, a series of nine parallel...

  20. DETAILED LOOP MODEL (DLM) ANALYSIS OF LIQUID SOLAR THERMOSIPHONS WITH HEAT EXCHANGERS

    E-Print Network [OSTI]

    Mertol, A.

    2013-01-01T23:59:59.000Z

    Warm Water Hot Water Heater Water Tank Heat flow from low-of Solar Domestic Hot Water Heaters in California,n inBradley, J.M. , Water Heater Construe on. u Administration

  1. Research for Advanced Heat Exchangers- The U.S. DOE Program

    E-Print Network [OSTI]

    Richlen, S. L.

    Annual Industrial Energy Technology Conference, Houston, TX, June 17-19, 1986 CooIGu __ Ex_ Brush and Ilfg Finned Heal Transfer Tube Figure 6. Aerojet Shallow Bed FBWHR The Thermo-Electron FBWHRS is a moving bed system that circulates the particle... large fluidized bed waste heat boiler and another fluidized bed waste heat recuperator is being readied for field tests. As a result of technology "needs" areas being identified during the development phases of these large systems, a stronger...

  2. On the Interaction between Marine Boundary Layer Cellular Cloudiness and Surface Heat Fluxes

    SciTech Connect (OSTI)

    Kazil, J.; Feingold, G.; Wang, Hailong; Yamaguchi, T.

    2014-01-02T23:59:59.000Z

    The interaction between marine boundary layer cellular cloudiness and surface uxes of sensible and latent heat is investigated. The investigation focuses on the non-precipitating closed-cell state and the precipitating open-cell state at low geostrophic wind speed. The Advanced Research WRF model is used to conduct cloud-system-resolving simulations with interactive surface fluxes of sensible heat, latent heat, and of sea salt aerosol, and with a detailed representation of the interaction between aerosol particles and clouds. The mechanisms responsible for the temporal evolution and spatial distribution of the surface heat fluxes in the closed- and open-cell state are investigated and explained. It is found that the horizontal spatial structure of the closed-cell state determines, by entrainment of dry free tropospheric air, the spatial distribution of surface air temperature and water vapor, and, to a lesser degree, of the surface sensible and latent heat flux. The synchronized dynamics of the the open-cell state drives oscillations in surface air temperature, water vapor, and in the surface fluxes of sensible and latent heat, and of sea salt aerosol. Open-cell cloud formation, cloud optical depth and liquid water path, and cloud and rain water path are identified as good predictors of the spatial distribution of surface air temperature and sensible heat flux, but not of surface water vapor and latent heat flux. It is shown that by enhancing the surface sensible heat flux, the open-cell state creates conditions by which it is maintained. While the open-cell state under consideration is not depleted in aerosol, and is insensitive to variations in sea-salt fluxes, it also enhances the sea-salt flux relative to the closed-cell state. In aerosol-depleted conditions, this enhancement may replenish the aerosol needed for cloud formation, and hence contribute to the perpetuation of the open-cell state as well. Spatial homogenization of the surface fluxes is found to have only a small effect on cloud properties in the investigated cases. This indicates that sub-grid scale spatial variability in the surface flux of sensible and latent heat and of sea salt aerosol may not be required in large scale and global models to describe marine boundary layer cellular cloudiness.

  3. Critical thickness of an optimum extended surface characterized by uniform heat transfer coefficient

    E-Print Network [OSTI]

    Leontiou, Theodoros

    2015-01-01T23:59:59.000Z

    We consider the heat transfer problem associated with a periodic array of extended surfaces (fins) subjected to convection heat transfer with a uniform heat transfer coefficient. Our analysis differs from the classical approach as (i) we consider two-dimensional heat conduction and (ii) the base of the fin is included in the heat transfer process. The problem is modeled as an arbitrary two-dimensional channel whose upper surface is flat and isothermal, while the lower surface has a periodic array of extensions/fins which are subjected to heat convection with a uniform heat transfer coefficient. Using the generalized Schwarz-Christoffel transformation the domain is mapped onto a straight channel where the heat conduction problem is solved using the boundary element method. The boundary element solution is subsequently used to pose a shape optimization problem, i.e. an inverse problem, where the objective function is the normalized Shape Factor and the variables of the optimization are the parameters of the Sch...

  4. Influence of Heat Treatment on Mercury Cavitation Resistance of Surface Hardened 316LN Stainless Steel

    SciTech Connect (OSTI)

    Pawel, Steven J [ORNL; Hsu, Julia [Massachusetts Institute of Technology (MIT)

    2010-11-01T23:59:59.000Z

    The cavitation-erosion resistance of carburized 316LN stainless steel was significantly degraded but not destroyed by heat treatment in the temperature range 500-800 C. The heat treatments caused rejection of some carbon from the carburized layer into an amorphous film that formed on each specimen surface. Further, the heat treatments encouraged carbide precipitation and reduced hardness within the carburized layer, but the overall change did not reduce surface hardness fully to the level of untreated material. Heat treatments as short as 10 min at 650 C substantially reduced cavitation-erosion resistance in mercury, while heat treatments at 500 and 800 C were found to be somewhat less detrimental. Overall, the results suggest that modest thermal excursions perhaps the result of a weld made at some distance to the carburized material or a brief stress relief treatment will not render the hardened layer completely ineffective but should be avoided to the greatest extent possible.

  5. Effects of surface parameters on boiling heat transfer phenomena

    E-Print Network [OSTI]

    Truong, Bao H. (Bao Hoai)

    2011-01-01T23:59:59.000Z

    Nanofluids, engineered colloidal dispersions of nanoparticles in fluid, have been shown to enhance pool and flow boiling CHF. The CHF enhancement was due to nanoparticle deposited on the heater surface, which was verified ...

  6. 255FEBRUARY 2002AMERICAN METEOROLOGICAL SOCIETY | he Surface Heat Budget of the Arctic Ocean

    E-Print Network [OSTI]

    Shupe, Matthew

    that determine the surface energy budget and the seaşice mass balance in the Arctic (Moritz et al. 1993; Perovich of the vertical and horizontal energy exchanges within the oceanşiceşatmosphere system. The SHEBA pro- gram for Atmospheric Research, Boulder, Colorado; TURENNE--Canadian Coast Guard, Quebec City, Quebec, Canada; SERREZE

  7. Aerosol Effects on Cloud Emissivity and Surface Longwave Heating in the Arctic TIMOTHY J. GARRETT1,*

    E-Print Network [OSTI]

    ) studies show that in the Arctic cloud cover generally acts to warm the surface, while coolingAerosol Effects on Cloud Emissivity and Surface Longwave Heating in the Arctic TIMOTHY J. GARRETT1 in the atmosphere tend to increase the reflectance of solar (shortwave) radiation from water clouds, which can lead

  8. Integrated three-dimensional module heat exchanger for power electronics cooling

    DOE Patents [OSTI]

    Bennion, Kevin; Lustbader, Jason

    2013-09-24T23:59:59.000Z

    Embodiments discussed herein are directed to a power semiconductor packaging that removes heat from a semiconductor package through one or more cooling zones that are located in a laterally oriented position with respect to the semiconductor package. Additional embodiments are directed to circuit elements that are constructed from one or more modular power semiconductor packages.

  9. Transient response of an industrial fin tube heat exchanger to flow variations

    E-Print Network [OSTI]

    Rana, Gopalji Motiram

    1967-01-01T23:59:59.000Z

    . Tho most impor ant assumptions made were that the proper- tiess Gl. t t e s Leais ar!d w, !ter and heat transfer coe f f ic ients for the stean! and water side did not vary with posi ion. l, spies: transform techniques were utilized to obtain the...

  10. Moving-Boundary Heat Exchanger Models with Variable Outlet Phase, ASME Journal of Dynamic Systems, Measurement, and Controlá

    E-Print Network [OSTI]

    Eldredge, B.D; Rasmussen, B.P.; Alleyne, A.

    2008-01-01T23:59:59.000Z

    equations for the receiver. #6; #8; d#1;g dPc Vgug + d#1; f dPc Vfuf + dug dPc #1;gVg + duf dPc #1; fVf ? #8; #1;gug ? #1; fuf #1;g ? #1; f #3; #8; d#1;g dPc Vg + d#1; f dPc Vf #7;P? c + #6; #1;gug ? #1; fuf #1;g ? #1; f #7; m?rec = m?inhin ? m... the refrigerant and the surrounding air. The PDEs are inte- rated using the Leibniz integration rule given in Eq. #3;4#4;. The onservation of momentum equation is neglected by assuming a niform pressure along the length of the heat exchanger #1;6ľ9#2;. #3;Cp#1;A#4...

  11. Rapid electron exchange between surface-exposed bacterial cytochromes and Fe(III) minerals

    SciTech Connect (OSTI)

    White, Gaye F.; Shi, Zhi; Shi, Liang; Wang, Zheming; Dohnalkova, Alice; Marshall, Matthew J.; Fredrickson, Jim K.; Zachara, John M.; Butt, Julea N.; Richardson, David; Clarke, Thomas A.

    2013-04-16T23:59:59.000Z

    The mineral respiring bacterium Shewanella oneidensis uses a protein complex, MtrCAB, composed of two decaheme cytochromes brought together inside a transmembrane porin to transport electrons across the outer membrane to a variety of mineral-based electron acceptors. A proteoliposome system that contains methyl viologen as an internalised electron carrier has been used to investigate how the topology of the MtrCAB complex relates to its ability to transport electrons across a lipid bilayer to externally-located Fe(III) oxides. With MtrA facing the interior and MtrC exposed on the outer surface of the phospholipid bilayer, direct electron transfer from the interior through MtrCAB to solid-phase Fe(III) oxides was demonstrated. The observed rates of conduction through the protein complex were 2 to 3 orders of magnitude higher than that observed in whole cells, demonstrating that direct electron exchange between MtrCAB and Fe(III) oxides is efficient enough to support in-vivo, anaerobic, solid phase iron respiration.

  12. *sja@iet.aau.dkwww.iet.aau.dk Initial experiments with a Pt based heat exchanger methanol reformer for a HTPEM fuel cell system

    E-Print Network [OSTI]

    Andreasen, S°ren Juhl

    *sja@iet.aau.dkwww.iet.aau.dk Initial experiments with a Pt based heat exchanger methanol reformer, PontoppidanstrŠde 101, 9220 Aalborg East, Denmark Motivation Methanol Reformer Test Conclusions The use of a liquid reformed hydro- carbon as fuel for fuel cells can redu- ce fuel storage volume considerably. The PBI

  13. Study on Micro-scale Ceramic Catalytic Combustor with Embedded Heat Exchange Channels Takashi OKAMASA, Gwang-Goo LEE, Yuji SUZUKI, and Nobuhide KASAGI

    E-Print Network [OSTI]

    Kasagi, Nobuhide

    Study on Micro-scale Ceramic Catalytic Combustor with Embedded Heat Exchange Channels Takashi combustion of butane is investigated. A cost-effective and robust ceramic combustor is developed using high anodic oxidation of aluminum layer. In order to increase the thermal efficiency, a combustor

  14. Fluid Mechanics -1 An oil is used in a heat exchanger. The internal geometry consists of many small diameter tubes of fixed length

    E-Print Network [OSTI]

    Virginia Tech

    Fluid Mechanics - 1 An oil is used in a heat exchanger. The internal geometry consists of many small diameter tubes of fixed length (mounted in a bundle as indicated in the sketch). The oil is pumped). Assume the steady flow of the oil through each small tube is in the laminar regime. It is proposed

  15. Field and Laboratory Study of a Ground-Coupled Water Source Heat Pump with an Integral Enthalpy Exchange System for Classroomsá

    E-Print Network [OSTI]

    Domitrovic, R.; Hayzen, G. J.; Johnson, W. S.; Chen, F. C.

    2002-01-01T23:59:59.000Z

    water-source heat pump, coupled with a geothermal water loop and incorporating a forced fresh-air enthalpy exchange system was installed in a typical middle school classroom in Oak Ridge, Tennessee. This project is a joint effort among Oak Ridge School...

  16. On-Line Monitoring and Diagnostics of the Integrity of Nuclear Plant Steam Generators and Heat Exchangers.

    SciTech Connect (OSTI)

    Belle R. Upadhyaya; J. Wesley Hines

    2004-09-27T23:59:59.000Z

    The overall purpose of this Nuclear Engineering Education Research (NEER) project was to integrate new, innovative, and existing technologies to develop a fault diagnostics and characterization system for nuclear plant steam generators (SG) and heat exchangers (HX). Issues related to system level degradation of SG and HX tubing, including tube fouling, performance under reduced heat transfer area, and the damage caused by stress corrosion cracking, are the important factors that influence overall plant operation, maintenance, and economic viability of nuclear power systems. The research at The University of Tennessee focused on the development of techniques for monitoring process and structural integrity of steam generators and heat exchangers. The objectives of the project were accomplished by the completion of the following tasks. All the objectives were accomplished during the project period. This report summarizes the research and development activities, results, and accomplishments during June 2001-September 2004. (1) Development and testing of a high-fidelity nodal model of a U-tube steam generator (UTSG) to simulate the effects of fouling and to generate a database representing normal and degraded process conditions. Application of the group method of data handling (GMDH) method for process variable prediction. (2) Development of a laboratory test module to simulate particulate fouling of HX tubes and its effect on overall thermal resistance. Application of the GMDH technique to predict HX fluid temperatures, and to compare with the calculated thermal resistance. (3) Development of a hybrid modeling technique for process diagnosis and its evaluation using laboratory heat exchanger test data. (4) Development and testing of a sensor suite using piezo-electric devices for monitoring structural integrity of both flat plates (beams) and tubing. Experiments were performed in air, and in water with and without bubbly flow. (5) Development of advanced signal processing methods using wavelet transforms and image processing techniques for isolating flaw types. (6) Development and implementation of a new nonlinear and non-stationary signal processing method, called the Hilbert-Huang transform (HHT), for flaw detection and location. This is a more robust and adaptive approach compared to the wavelet transform. (7) Implementation of a moving-window technique in the time domain for detecting and quantifying flaw types in tubular structures. A window zooming technique was also developed for flaw location in tubes. (8) Theoretical study of elastic wave propagation (longitudinal and shear waves) in metallic flat plates and tubing with and without flaws. (9) Simulation of the Lamb wave propagation using the finite-element code ABAQUS. This enabled the verification of the experimental results. The research tasks included both analytical research and experimental studies. The experimental results helped to enhance the robustness of fault monitoring methods and to provide a systematic verification of the analytical results. The results of this research were disseminated in scientific meetings. A journal manuscript was submitted for publication. The new findings of this research have potential applications in aerospace and civil structures. The report contains a complete bibliography that was developed during the course of the project.

  17. On-Line Monitoring and Diagnostics of the Integrity of Nuclear Plant Steam Generators and Heat Exchangers, Volumes 1, 2.

    SciTech Connect (OSTI)

    Upadhyaya, Belle R.; Hines, J. Wesley; Lu, Baofu; Huang, Xuedong; Penha, Rosani, L.; Perillo, Sergio, R.; Zhao, Ke

    2005-06-03T23:59:59.000Z

    The overall purpose of this Nuclear Engineering Education Research (NEER) project was to integrate new, innovative, and existing technologies to develop a fault diagnostics and characterization system for nuclear plant steam generators (SG) and heat exchangers (HX). Issues related to system level degradation of SG and HX tubing, including tube fouling, performance under reduced heat transfer area, and the damage caused by stress corrosion cracking, are the important factors that influence overall plant operation, maintenance, and economic viability of nuclear power systems. The research at The University of Tennessee focused on the development of techniques for monitoring process and structural integrity of steam generators and heat exchangers. The objectives of the project were accomplished by the completion of the following tasks. All the objectives were accomplished during the project period. This report summarizes the research and development activities, results, and accomplishments during June 2001 ├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬? September 2004. ├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬Ě Development and testing of a high-fidelity nodal model of a U-tube steam generator (UTSG) to simulate the effects of fouling and to generate a database representing normal and degraded process conditions. Application of the group method of data handling (GMDH) method for process variable prediction. ├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬Ě Development of a laboratory test module to simulate particulate fouling of HX tubes and its effect on overall thermal resistance. Application of the GMDH technique to predict HX fluid temperatures, and to compare with the calculated thermal resistance. ├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬Ě Development of a hybrid modeling technique for process diagnosis and its evaluation using laboratory heat exchanger test data. ├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬Ě Development and testing of a sensor suite using piezo-electric devices for monitoring structural integrity of both flat plates (beams) and tubing. Experiments were performed in air, and in water with and without bubbly flow. ├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬Ě Development of advanced signal processing methods using wavelet transforms and image processing techniques for isolating flaw types. ├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬?├?┬Ě Development and implementation of a new nonlinear and non-stationary signal processing method, called the Hilbert-Huang transform (HHT), for flaw detection and location. This is a more robust and adaptive approach compared to the wavelet transform

  18. Belgirate, Italy, 28-30 September 2005 MICROMACHINED HEAT EXCHANGER FOR A CRYOSURGICAL PROBE

    E-Print Network [OSTI]

    Paris-Sud XI, Universit├ę de

    with large refrigeration capacity [2-4] and techniques for real-time monitoring using ultrasound or magnetic that surrounds the cold end of the probe is controlled by the refrigeration power and surface temperature probe. The isobars Refrigeration Load isenthalps Entropy, S Temperature,T (1) (5) (2) (4) (3) (1) (5) (2

  19. Combined refrigeration system with a liquid pre-cooling heat exchanger

    DOE Patents [OSTI]

    Gaul, Christopher J.

    2003-07-01T23:59:59.000Z

    A compressor-pump unit for use in a vapor-compression refrigeration system is provided. The compressor-pump unit comprises a driving device including a rotatable shaft. A compressor is coupled with a first portion of the shaft for compressing gaseous refrigerant within the vapor-compression refrigeration system. A liquid pump is coupled with a second portion of the shaft for receiving liquid refrigerant having a first pressure and for discharging the received liquid refrigerant at a second pressure with the second pressure being higher than the first pressure by a predetermined amount such that the discharged liquid refrigerant is subcooled. A pre-cooling circuit is connected to the liquid pump with the pre-cooling circuit being exposed to the gaseous refrigerant whereby the gaseous refrigerant absorbs heat from the liquid refrigerant, prior to the liquid refrigerant entering the liquid pump.

  20. Surface hardening of titanium alloys with melting depth controlled by heat sink

    DOE Patents [OSTI]

    Oden, Laurance L. (Albany, OR); Turner, Paul C. (Albany, OR)

    1995-01-01T23:59:59.000Z

    A process for forming a hard surface coating on titanium alloys includes providing a piece of material containing titanium having at least a portion of one surface to be hardened. The piece having a portion of a surface to be hardened is contacted on the backside by a suitable heat sink such that the melting depth of said surface to be hardened may be controlled. A hardening material is then deposited as a slurry. Alternate methods of deposition include flame, arc, or plasma spraying, electrodeposition, vapor deposition, or any other deposition method known by those skilled in the art. The surface to be hardened is then selectively melted to the desired depth, dependent on the desired coating thickness, such that a molten pool is formed of the piece surface and the deposited hardening material. Upon cooling a hardened surface is formed.

  1. Driving Oxygen Coordinated Ligand Exchange at Nanocrystal Surfaces using Trialkylsilylated Chalcogenides

    E-Print Network [OSTI]

    Caldwell, Marissa A.

    2011-01-01T23:59:59.000Z

    ligand exchange with TMS-S-TEG. (*) denotes residual nativetetraoxotridecane (TMS-S-TEG) was selected as the exchangeperformed by adding TMS- S-TEG (2 - 7 Î 10 4 equivalents per

  2. Near-Surface Eddy Heat and Momentum Fluxes in the Antarctic Circumpolar Current in Drake Passage

    E-Print Network [OSTI]

    Sprintall, Janet

    Near-Surface Eddy Heat and Momentum Fluxes in the Antarctic Circumpolar Current in Drake Passage Antarctic Circumpolar Current (ACC) momentum balance. The observations span 7 yr and are compared to eddy Current (ACC) pathway is marked by exceptionally high mesoscale eddy activity (e.g., Stammer 1998; Hughes

  3. Surface Urban Heat Island Across 419 Global Big Cities Shushi Peng,

    E-Print Network [OSTI]

    Myneni, Ranga B.

    aspects of human impacts on the earth system. Here we assess the diurnal and seasonal variation of surface of human impact on the earth system.1 It is well-known that urban centers experience higher temperatures-11 this urban heat island effect has gained in importance.3,4 In the context of global warming it has been

  4. Characterization of the effect of Froude number on surface waves and heat transfer in inclined turbulent

    E-Print Network [OSTI]

    Abdou, Mohamed

    turbulent open channel water flows B. Freeze, S. Smolentsev *, N. Morley, M. Abdou UCLA, Department Abstract Interfacial heat transport in open channel turbulent flows is strongly dependent on surface waves and mass transport across a flowing liquid interface has become an increasingly important topic during

  5. Vehicle cabin cooling system for capturing and exhausting heated boundary layer air from inner surfaces of solar heated windows

    DOE Patents [OSTI]

    Farrington, Robert B. (Golden, CO); Anderson, Ren (Broomfield, CO)

    2001-01-01T23:59:59.000Z

    The cabin cooling system includes a cooling duct positioned proximate and above upper edges of one or more windows of a vehicle to exhaust hot air as the air is heated by inner surfaces of the windows and forms thin boundary layers of heated air adjacent the heated windows. The cabin cooling system includes at least one fan to draw the hot air into the cooling duct at a flow rate that captures the hot air in the boundary layer without capturing a significant portion of the cooler cabin interior air and to discharge the hot air at a point outside the vehicle cabin, such as the vehicle trunk. In a preferred embodiment, the cooling duct has a cross-sectional area that gradually increases from a distal point to a proximal point to the fan inlet to develop a substantially uniform pressure drop along the length of the cooling duct. Correspondingly, this cross-sectional configuration develops a uniform suction pressure and uniform flow rate at the upper edge of the window to capture the hot air in the boundary layer adjacent each window.

  6. Single Channel Testing for Characterization of the Direct Gas Cooled Reactor and the SAFE-100 Heat Exchanger

    SciTech Connect (OSTI)

    Bragg-Sitton, S.M. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Propulsion Research Center, NASA Marshall Space Flight Center, Huntsville, AL 35812 (United States); Kapernick, R. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Godfroy, T.J. [Propulsion Research Center, NASA Marshall Space Flight Center, Huntsville, AL 35812 (United States)

    2004-02-04T23:59:59.000Z

    Experiments have been designed to characterize the coolant gas flow in two space reactor concepts that are currently under investigation by NASA Marshall Space Flight Center and Los Alamos National Laboratory: the direct-drive gas-cooled reactor (DDG) and the SAFE-100 heatpipe-cooled reactor (HPR). For the DDG concept, initial tests have been completed to measure pressure drop versus flow rate for a prototypic core flow channel, with gas exiting to atmospheric pressure conditions. The experimental results of the completed DDG tests presented in this paper validate the predicted results to within a reasonable margin of error. These tests have resulted in a re-design of the flow annulus to reduce the pressure drop. Subsequent tests will be conducted with the re-designed flow channel and with the outlet pressure held at 150 psi (1 MPa). Design of a similar test for a nominal flow channel in the HPR heat exchanger (HPR-HX) has been completed and hardware is currently being assembled for testing this channel at 150 psi. When completed, these test programs will provide the data necessary to validate calculated flow performance for these reactor concepts (pressure drop and film temperature rise)

  7. Development of a coal-fueled Internal Manifold Heat Exchanger (IMHEX reg sign ) molten carbonate fuel cell

    SciTech Connect (OSTI)

    Not Available

    1991-09-01T23:59:59.000Z

    The design of a CGMCFC electric generation plant that will provide a cost of eletricity (COE) which is lower than that of current electric generation technologies and which is competitive with other long-range electric generating systems is presented. This effort is based upon the Internal Manifold Heat Exchanger (IMHEX) technology as developed by the Institute of Gas Technology (IGT). The project was executed by selecting economic and performance objectives for alternative plant arrangements while considering process constraints identified during IMHEX fuel cell development activities at ICT. The four major subsystems of a coal-based MCFC power plant are coal gasification, gas purification, fuel cell power generation and the bottoming cycle. The design and method of operation of each subsystem can be varied, and, depending upon design choices, can have major impact on both the design of other subsystems and the resulting cost of electricity. The challenge of this project was to select, from a range of design parameters, those operating conditions that result in a preferred plant design. Computer modelling was thus used to perform sensitivity analyses of as many system variables as program resources and schedules would permit. In any systems analysis, it is imperative that the evaluation methodology be verifiable and comparable. The TAG Class I develops comparable (if imprecise) data on performance and costs for the alternative cases being studied. It identifies, from a range of options, those which merit more exacting scrutiny to be undertaken at the second level, TAG class II analysis.

  8. Heat pump with freeze-up prevention

    DOE Patents [OSTI]

    Ecker, Amir L. (Dallas, TX)

    1981-01-01T23:59:59.000Z

    What is disclosed is a heat pump apparatus for conditioning a fluid characterized by a fluid handler and path for circulating the fluid in heat exchange relationship with a refrigerant fluid; at least two refrigerant heat exchangers, one for effecting heat exchange with the fluid and a second for effecting heat exchange between refrigerant and a heat exchange fluid and the ambient air; a compressor for efficiently compressing the refrigerant; at least one throttling valve for throttling liquid refrigerant; a refrigerant circuit; refrigerant; a source of heat exchange fluid; heat exchange fluid circulating device and heat exchange fluid circuit for circulating the heat exchange fluid in heat exchange relationship with the refrigerant; and valves or switches for selecting the heat exchangers and direction of flow of the refrigerant therethrough for selecting a particular mode of operation. The heat exchange fluid prevents freeze up of the second heat exchanger by keeping the temperature above the dew point; and, optionally, provides heat for efficient operation.

  9. Absorption heat pump system

    DOE Patents [OSTI]

    Grossman, Gershon (Oak Ridge, TN)

    1984-01-01T23:59:59.000Z

    The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.

  10. Absorption heat pump system

    DOE Patents [OSTI]

    Grossman, G.

    1982-06-16T23:59:59.000Z

    The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.

  11. Effect of ocean surface currents on wind stress, heat flux, and wind power input to the ocean

    E-Print Network [OSTI]

    Thompson, LuAnne

    Effect of ocean surface currents on wind stress, heat flux, and wind power input to the ocean, J. T., and L. Thompson (2006), Effect of ocean surface currents on wind stress, heat flux, and wind power input to the ocean, Geophys. Res. Lett., 33, L09604, doi:10.1029/2006GL025784. 1. Introduction [2

  12. Driving Oxygen Coordinated Ligand Exchange at Nanocrystal Surfaces using Trialkylsilylated Chalcogenides

    SciTech Connect (OSTI)

    Caldwell, Marissa A.; Albers, Aaron E.; Levy, Seth C.; Pick, Teresa E.; Cohen, Bruce E.; Helms, Brett A.; Milliron, Delia J.

    2010-11-11T23:59:59.000Z

    A general, efficient method is demonstrated for exchanging native oxyanionic ligands on inorganic nanocrystals with functional trimethylsilylated (TMS) chalcogenido ligands. In addition, newly synthesized TMS mixed chalcogenides leverage preferential reactivity of TMS-S bonds over TMS-O bonds, enabling efficient transfer of luminescent nanocrystals into aqueous media with retention of their optical properties.

  13. Interannual variability of surface energy exchange depends on stand age in a boreal forest fire chronosequence

    E-Print Network [OSTI]

    Liu, Heping; Randerson, James T

    2008-01-01T23:59:59.000Z

    15 ] Half-hourly data of net radiation and sensible andhour time series data of net radiation, sensible heat flux,data in March of 2002. b K # : incoming shortwave radiation (

  14. Regeneration Heat Exchange

    SciTech Connect (OSTI)

    J. Lin

    2003-07-30T23:59:59.000Z

    The original project goals were to establish the viability of the proposed gas turbine regenerator concept by performing the following tasks: (1) Perform detailed design of a working model of the regenerator concept. (2) Construct a ''bench-top'' model of the regenerator concept based upon the detail design. (3) Test the bench-top model and gather data to support the concept's viability. The project funding was used to acquire the tools and material to perform the aforementioned tasks.

  15. SMALL PARTICLE HEAT EXCHANGERS

    E-Print Network [OSTI]

    Hunt, A.J.

    2011-01-01T23:59:59.000Z

    of advanced concept solar power plants. For conditions ofThe size for a solar-hybrid power plant incorporating aplant has the additional advantage of not' requiring cooling water, an important feature since arid areas are the best solar

  16. Determining the quality and quantity of heat produced by proton exchange membrane fuel cells with application to air-cooled stacks for combined heat and power

    E-Print Network [OSTI]

    Victoria, University of

    cells as a heat and electrical power source for residential combined heat and power (CHP characterization provided data to assess the CHP potential of the Nexa and validate the model used ambient temperature. #12;iv To improve performance as a CHP heat engine, the Nexa and other air-cooled PEM

  17. SU(3) Latent Heat and Surface Tension from Tree Level and Tadpole Improved Actions

    E-Print Network [OSTI]

    B. Beinlich; F. Karsch; A. Peikert

    1996-08-27T23:59:59.000Z

    We analyze the latent heat and surface tension at the SU(3) deconfinement phase transition with tree level and tadpole improved Symanzik actions on lattices with temporal extent $N_\\tau = 3$ and 4 and spatial extent $N_\\sigma/ N_\\tau = 4$, 6 and 8. In comparison to the standard Wilson action we do find a drastic reduction of cut-off effects already with tree level improved actions. On lattices with temporal extent $N_\\tau=4$ results for the surface tension and latent heat obtained with a tree level improved action agree well with those obtained with a tadpole improved action. A comparison with $N_\\tau=3$ calculations, however, shows that results obtained with tadpole action remain unaffected by cut-off effects even on this coarse lattice, while the tree level action becomes sensitive to the cut-off. For the surface tension and latent heat we find $\\sigma_I/ T_c^3 = 0.0155~(16)$ and $\\Delta\\epsilon/T_c^4 = 1.40~(9)$, respectively.

  18. SU(3) Latent Heat and Surface Tension from Tree Level and Tadpole Improved Actions

    E-Print Network [OSTI]

    Beinlich, B; Peikert, A

    1996-01-01T23:59:59.000Z

    We analyze the latent heat and surface tension at the SU(3) deconfinement phase transition with tree level and tadpole improved Symanzik actions on lattices with temporal extent $N_\\tau = 3$ and 4 and spatial extent $N_\\sigma/ N_\\tau = 4$, 6 and 8. In comparison to the standard Wilson action we do find a drastic reduction of cut-off effects already with tree level improved actions. On lattices with temporal extent $N_\\tau=4$ results for the surface tension and latent heat obtained with a tree level improved action agree well with those obtained with a tadpole improved action. A comparison with $N_\\tau=3$ calculations, however, shows that results obtained with tadpole action remain unaffected by cut-off effects even on this coarse lattice, while the tree level action becomes sensitive to the cut-off. For the surface tension and latent heat we find $\\sigma_I/ T_c^3 = 0.0155~(16)$ and $\\Delta\\epsilon/T_c^4 = 1.40~(9)$, respectively.

  19. Silica gel as a model surface for adsorption calorimetry of enhanced-oil-recovery systems. [Heat of immersion

    SciTech Connect (OSTI)

    Noll, L.A.; Burchfield, T.E.

    1982-06-01T23:59:59.000Z

    This report describes a method for studying interaction of fluids with surfaces by measuring the heat of immersion and then measuring simultaneously the surface excess and enthalpy of replacement for a series of binary solutions. The method of calculating surface excess is described. These techniques are applied to silica gel which has had different activation temperatures. Heating overnight to 400/sup 0/C results in a reproducible surface. The adsorption of n-butyl alcohol from toluene and from water upon these surfaces is compared.

  20. Observations of Stratocumulus Clouds and Their Effect on the Eastern Pacific Surface Heat Budget along 208S

    E-Print Network [OSTI]

    Yuter, Sandra

    of cloud properties and drizzle statistics, and the effect of stratocumulus clouds on surface radiationObservations of Stratocumulus Clouds and Their Effect on the Eastern Pacific Surface Heat Budget gradients in boundary layer and cloud vertical structure, surface radiation and cloud radiative forcing

  1. Effects of surface enhancement, film-feed supply rate, and bundle geometry on spray evaporation heat transfer performance

    SciTech Connect (OSTI)

    Moeykens, S.A. [Trane Co., La Crosse, WI (United States); Newton, B.J. [Univ. of Wisconsin, Madison, WI (United States). Mechanical Engineering Dept.; Pate, M.B. [Iowa State Univ., Ames, IA (United States). Mechanical Engineering Dept.

    1995-12-31T23:59:59.000Z

    Testing was conducted with R-134a through an overfeed ratio range of 1.4 to 7.9 in order to evaluate the effects of Reynolds number on shell-side heat transfer performance in the spray evaporation environment. The overfeed ratio is defined as the ratio of the refrigerant flow rate supplied to the tube bundle to the refrigerant flow rate that vaporizes. Data were taken with a fixed refrigerant supply rate while varying the shell-side heat flux from 40 kW/m{sup 2} (12,688 Btu/[h{center_dot}ft{sup 2}]) to 19 kW/m{sup 2} (6,027 Btu/[h{center_dot}ft{sup 2}]). Both triangular and square-pitch tube bundles were tested to determine the effects of bundle geometry on heat transfer performance. Two enhanced condensation surfaces, one enhanced boiling surface, and one low-finned surface tube were used in this study. Plain-surface bundle testing was conducted in parallel with the enhanced surface testing to determine the degree of improvement obtained with the different surface enhancements relative to that of a smooth tube. In addition, the effect of bundle depth on heat transfer performance was evaluated. Refrigerant was introduced into the test section with wide-angle, solid-cone nozzles. To determine the amount of refrigerant contacting the tube bundle, collector testing was performed in parallel with the heat transfer analysis experiments. Using results form the collector tests, bundle overfeed ratios were calculated and are reported. Heat transfer performance showed dependence on film-feed supply rate (i.e., overfeed ratio) to varying degrees, depending on the type of surface enhancement. Those surfaces that limited axial flow of the liquid film yielded poor heat transfer performance in lower rows of the bundle. The spray evaporation heat transfer performance for one of the enhanced condensation surfaces was better than the flooded evaporator performance for the enhanced boiling surface.

  2. The Economic and Environmental Aspects of Heat Exchanger Cleaning -- How FP&L Has Used the Newly Patented MCC Process to Clean Turbine Lube Oil Coolers to Maximize Efficiency and Minimize Waste

    E-Print Network [OSTI]

    Wood, H. A. T.

    of efficient and timely cleaning of heat exchangers. There are great differences in the cleaning processes that are used to clean exchanger bundles in industry today. The cleaning of turbine lube oil coolers is a specialized case in point. A newly patented...

  3. Enhancement of Heat Transfer with Pool and Spray Impingement Boiling on Microporous and Nanowire Surface Coatings

    SciTech Connect (OSTI)

    Thiagarajan, S. J.; Wang, W.; Yang, R.; Narumanchi, S.; King, C.

    2010-09-01T23:59:59.000Z

    The DOE National Renewable Energy Laboratory (NREL) is leading a national effort to develop next-generation cooling technologies for hybrid vehicle electronics. The goal is to reduce the size, weight, and cost of power electronic modules that convert direct current from batteries to alternating current for the motor, and vice versa. Aggressive thermal management techniques help to increase power density and reduce weight and volume, while keeping chip temperatures within acceptable limits. The viability of aggressive cooling schemes such as spray and jet impingement in conjunction with enhanced surfaces is being explored. Here, we present results from a series of experiments with pool and spray boiling on enhanced surfaces, such as a microporous layer of copper and copper nanowires, using HFE-7100 as the working fluid. Spray impingement on the microporous coated surface showed an enhancement of 100%-300% in the heat transfer coefficient at a given wall superheat with respect to spray impingement on a plain surface under similar operating conditions. Critical heat flux also increased by 7%-20%, depending on flow rates.

  4. On the Surface Heating of Synchronously-Spinning Short-Period Jovian Planets

    E-Print Network [OSTI]

    Andreas Burkert; Douglas Lin; Peter Bodenheimer; Chris Jones; Harold Yorke

    2003-12-18T23:59:59.000Z

    We consider the atmospheric flow on short-period extra-solar planets through two-dimensional numerical simulations of hydrodynamics with radiation transfer. One side is always exposed to the irradiation from the host star. The other is always in shadow. The temperature of the day side is determined by the equilibrium which the planetary atmosphere establishes with stellar radiation. Part of the thermal energy deposited on the day side is advected to the night side by a current. The radiation transfer, the night-side temperature distribution and by this the spectroscopic signature of the planet are sensitive functions of the atmospheric opacity. If the atmosphere contains grains with an abundanceand size distribution comparable to that of the interstellar medium, shallow heating occurs on the day side and the night side cools well below the day side. The temperature difference decreases as the abundance of grains is reduced. A simple analytic model of the dissipation of the circulation flow and associated kinetic heating is considered. This heating effect occurs mostly near the photosphere, not deep enough to significantly affect the size of planets. We show that the surface irradiation suppresses convection near the photospheric region on the day side. In some cases convection zones appear near the surface on the night side. This structural modification may influence the response and dissipation of tidal disturbances and alter the circularization and synchronization time scales.

  5. Clean Firetube Boiler Waterside Heat Transfer Surfaces, Energy Tips: STEAM, Steam Tip Sheet #7 (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2012-04-01T23:59:59.000Z

    A steam energy tip sheet for the Advanced Manufacturing Office (AMO). The prevention of scale formation in firetube boilers can result in substantial energy savings. Scale deposits occur when calcium, magnesium, and silica, commonly found in most water supplies, react to form a continuous layer of material on the waterside of the boiler heat exchange tubes. Scale creates a problem because it typically possesses a thermal conductivity, an order of magnitude less than the corresponding value for bare steel. Even thin layers of scale serve as an effective insulator and retard heat transfer. The result is overheating of boiler tube metal, tube failures, and loss of energy efficiency. Fuel consumption may increase by up to 5% in firetube boilers because of scale. The boilers steam production may be reduced if the firing rate cannot be increased to compensate for the decrease in combustion efficiency. Energy losses as a function of scale thickness and composition are given. Any scale in a boiler is undesirable. The best way to deal with scale is not to let it form in the first place. Prevent scale formation by: (1) Pretreating of boiler makeup water (using water softeners, demineralizers, and reverse osmosis to remove scale-forming minerals); (2) Injecting chemicals into the boiler feedwater; and (3) Adopting proper boiler blowdown practices.

  6. Problems with Specifying Tmin in the Design of Processes with Heat Exchangers Jrgen Bauck Jensen and Sigurd Skogestad*

    E-Print Network [OSTI]

    Skogestad, Sigurd

    and Sigurd Skogestad* Department of Chemical Engineering, Norwegian UniVersity of Science and Technology is the individual exchanger minimum approach temperature (EMAT). This should not be confused with the "pinch

  7. The radiative heat transfer between a rotating nanoparticle and a plane surface

    E-Print Network [OSTI]

    Vahid Ameri; Mehdi Shafei Aporvari; Fardin Kheirandish

    2015-06-03T23:59:59.000Z

    Based on a microscopic approach, we propose a Lagrangian for the combined system of a rotating dielectric nanoparticle above a plane surface in the presence of electromagnetic vacuum fluctuations. In the framework of canonical quantization, the electromagnetic vacuum field is quantized in the presence of dielectric fields describing the nanoparticle and a semi-infinite dielectric with planar interface. The radiative heat power absorbed by the rotating nanoparticle is obtained and the result is in agreement with previous results when the the rotational frequency of the nanoparticle is zero or much smaller than the relaxation frequency of the dielectrics. The well known near field effect is reexamined and discussed in terms of the rotational frequency. The radiative heat power absorbed by the nanoparticle for well-known peak frequencies, is plotted in terms of the rotational frequency showing an interesting effect resembling a phase transition around a critical frequency, determined by the relaxation frequency of the dielectrics.

  8. Theoretical Studies of Energy and Momentum Exchange in Atomic and Molecular Scattering from Surfaces

    SciTech Connect (OSTI)

    Joseph R. Manson

    2005-06-30T23:59:59.000Z

    The contributions that we have made during the grant period of DE-FG02-98ER45704 can be placed into six different categories: (1) advances in the Theory of Molecule-Surface Scattering, (2) advances in the Theory of Atom-Surface Scattering, (3) utilization of scattering theory to Extract Physical Information about Surfaces, (4) Gas-Surface Interactions, (5) Ion Scattering from surfaces and (6) Scanning Tunneling Microscopy (STM). These six topics are discussed below as individual listings under the title 'IV. Detailed description of research accomplishments'. These advances show that we have made significant progress on several scientific problems in atomic and molecular surface scattering during the course of this grant as well as contributions to other areas. It is also noted that this work, although fundamentally theoretical, is marked by its strong motivation to explain current experimental measurements. This was an important secondary goal in the proposed work. We have developed theory that is useful to experimentalists in the explanation and analysis of their experimental data.

  9. Measurement of residual radioactive surface contamination by 2-D laser heated TLD

    SciTech Connect (OSTI)

    Jones, S.C.

    1997-06-01T23:59:59.000Z

    The feasibility of applying and adapting a two-dimensional laser heated thermoluminescence dosimetry system to the problem of surveying for radioactive surface contamination was studied. The system consists of a CO{sub 2} laser-based reader and monolithic arrays of thin dosimeter elements. The arrays consist of 10,201 thermoluminescent phosphor elements of 40 micron thickness, covering a 900 cm{sup 2} area. Array substrates are 125 micron thick polyimide sheets, enabling them to easily conform to regular surface shapes, especially for survey of surfaces that are inaccessible for standard survey instruments. The passive, integrating radiation detectors are sensitive to alpha and beta radiation at contamination levels below release guideline limits. Required contact times with potentially contaminated surfaces are under one hour to achieve detection of transuranic alpha emission at 100 dpm/100 cm{sup 2}. Positional information obtained from array evaluation is useful for locating contamination zones. Unique capabilities of this system for survey of sites, facilities and material include measurement inside pipes and other geometrical configurations that prevent standard surveys, and below-surface measurement of alpha and beta emitters in contaminated soils. These applications imply a reduction of material that must be classified as radioactive waste by virtue of its possibility of contamination, and cost savings in soil sampling at contaminated sites.

  10. Surface Contribution to Electronic Density of States, Heat-Capacity, and Spin Susceptibility

    E-Print Network [OSTI]

    KENNER, VE; Allen, Roland E.

    1975-01-01T23:59:59.000Z

    by 1/p(E~), where p(E) is the density of states and Er is the Fermi energy, For particles which are about 100 A in each dimension, 5/ks 1 K~ where ks ls the Boltzmann constant. Their results indicate that if 0 7 ?,5, where T is the temperature...?843 (Received 22 April 1974) The surface contributions to the electronic heat capacity C,'? and spin susceptibility g' are, respectively, C', ? ?(l/3)A Iy(k ?)?m/4]k ~ T and g' = (p,~/m )A [y(k F) ?m/4] for any semi-infinite free-electron model, where y(k...

  11. ARM - Field Campaign - Surface Heat Budget of the Arctic Ocean (SHEBA)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006Datastreamstwrcam40m DocumentationJanuary 9, 2009 [Events, Feature StoriesgovCampaignsSurface Heat Budget of

  12. Process for oil shale retorting using gravity-driven solids flow and solid-solid heat exchange

    DOE Patents [OSTI]

    Lewis, Arthur E. (Los Altos, CA); Braun, Robert L. (Livermore, CA); Mallon, Richard G. (Livermore, CA); Walton, Otis R. (Livermore, CA)

    1986-01-01T23:59:59.000Z

    A cascading bed retorting process and apparatus in which cold raw crushed shale enters at the middle of a retort column into a mixer stage where it is rapidly mixed with hot recycled shale and thereby heated to pyrolysis temperature. The heated mixture then passes through a pyrolyzer stage where it resides for a sufficient time for complete pyrolysis to occur. The spent shale from the pyrolyzer is recirculated through a burner stage where the residual char is burned to heat the shale which then enters the mixer stage.

  13. Process for oil shale retorting using gravity-driven solids flow and solid-solid heat exchange

    DOE Patents [OSTI]

    Lewis, A.E.; Braun, R.L.; Mallon, R.G.; Walton, O.R.

    1983-09-21T23:59:59.000Z

    A cascading bed retorting process and apparatus are disclosed in which cold raw crushed shale enters at the middle of a retort column into a mixer stage where it is rapidly mixed with hot recycled shale and thereby heated to pyrolysis temperature. The heated mixture then passes through a pyrolyzer stage where it resides for a sufficient time for complete pyrolysis to occur. The spent shale from the pyrolyzer is recirculated through a burner stage where the residual char is burned to heat the shale which then enters the mixer stage.

  14. Improved Formulations for Air-Surface Exchanges Related to National Security Needs: Dry Deposition Models

    SciTech Connect (OSTI)

    Droppo, James G.

    2006-07-01T23:59:59.000Z

    The Department of Homeland Security and others rely on results from atmospheric dispersion models for threat evaluation, event management, and post-event analyses. The ability to simulate dry deposition rates is a crucial part of our emergency preparedness capabilities. Deposited materials pose potential hazards from radioactive shine, inhalation, and ingestion pathways. A reliable characterization of these potential exposures is critical for management and mitigation of these hazards. A review of the current status of dry deposition formulations used in these atmospheric dispersion models was conducted. The formulations for dry deposition of particulate materials from am event such as a radiological attack involving a Radiological Detonation Device (RDD) is considered. The results of this effort are applicable to current emergency preparedness capabilities such as are deployed in the Interagency Modeling and Atmospheric Assessment Center (IMAAC), other similar national/regional emergency response systems, and standalone emergency response models. The review concludes that dry deposition formulations need to consider the full range of particle sizes including: 1) the accumulation mode range (0.1 to 1 micron diameter) and its minimum in deposition velocity, 2) smaller particles (less than .01 micron diameter) deposited mainly by molecular diffusion, 3) 10 to 50 micron diameter particles deposited mainly by impaction and gravitational settling, and 4) larger particles (greater than 100 micron diameter) deposited mainly by gravitational settling. The effects of the local turbulence intensity, particle characteristics, and surface element properties must also be addressed in the formulations. Specific areas for improvements in the dry deposition formulations are 1) capability of simulating near-field dry deposition patterns, 2) capability of addressing the full range of potential particle properties, 3) incorporation of particle surface retention/rebound processes, and. 4) development of dry deposition formulations applicable to urban areas. Also to improve dry deposition modeling capabilities, atmospheric dispersion models in which the dry deposition formulations are imbedded need better source-term plume initialization and improved in-plume treatment of particle growth processes. Dry deposition formulations used in current models are largely inapplicable to the complex urban environment. An improved capability is urgently needed to provide surface-specific information to assess local exposure hazard levels in both urban and non-urban areas on roads, buildings, crops, rivers, etc. A model improvement plan is developed with a near-term and far-term component. Despite some conceptual limitations, the current formulations for particle deposition based on a resistance approach have proven to provide reasonable dry deposition simulations. For many models with inadequate dry deposition formulations, adding or improving a resistance approach will be the desirable near-term update. Resistance models however are inapplicable aerodynamically very rough surfaces such as urban areas. In the longer term an improved parameterization of dry deposition needs to be developed that will be applicable to all surfaces, and in particular urban surfaces.

  15. International Lige Colloquium on Ocean Dynamics, GAS TRANSFER AT WATER SURFACES, May 2 -6 2005 Estimation of air-sea gas and heat fluxes from infrared imagery and

    E-Print Network [OSTI]

    Jaehne, Bernd

    2005 Estimation of air-sea gas and heat fluxes from infrared imagery and surface wave measurements and much higher heat fluxes. In addition, the infrared imagery analysis reveals potentially significant the infrared images. It is also shown that the difference in the surface boundary conditions for heat and gas

  16. A novel approach to heat transfer enhancement using trapezoid shaped spiral strips to promote tumble and swirl in a slot shaped channel used in heat exchangersá

    E-Print Network [OSTI]

    Segura, D.; Acharya, S.

    2012-01-01T23:59:59.000Z

    Heat transfer results for a given slot shaped channel with a 3:1 aspect ratio are presented using various configurations of a trapezoid shaped spiral wound strips to enhance swirl and tumble motion in the channel. The Reynolds numbers investigated...

  17. Temperature inversion on the surface of externally heated optically thick multigrain dust clouds

    E-Print Network [OSTI]

    Dejan Vinkovic

    2006-12-01T23:59:59.000Z

    It was recently discovered that the temperature in the surface layer of externally heated optically thick gray dust clouds increases with the optical depth for some distance from the surface, as opposed to the normal decrease in temperature with distance in the rest of the cloud. This temperature inversion is a result of efficient absorption of diffuse flux from the cloud interior by the surface dust exposed to the external radiation. A micron or bigger size grains experience this effect when the external flux is of stellar spectrum. We explore what happens to the effect when dust is a mixture of grain sizes (multigrain). Two possible boundary conditions are considered: i) a constant external flux without constrains on the dust temperature, and ii) the maximum dust temperature set to the sublimation temperature. We find that the first condition allows small grains to completely suppress the temperature inversion of big grains if the overall opacity is dominated by small grains. The second condition enables big grains to maintain the inversion even when they are a minor contributor to the opacity. In reality, the choice of boundary condition depends on the dust dynamics. When applied to the physics of protoplanetary disks, the temperature inversion leads to a previously unrecognized disk structure where optically thin dust can exist inside the dust destruction radius of an optically thick disk. We conclude that the transition between the dusty disk and the gaseous inner clearing is not a sharp edge, but rather a large optically thin region.

  18. Oxygen diffusion, surface exchange and oxygen semi-permeation performances of Ln2NiO4+ membranes (Ln = La, Pr and Nd)

    E-Print Network [OSTI]

    Paris-Sud XI, UniversitÚ de

    Oxygen diffusion, surface exchange and oxygen semi-permeation performances of Ln2NiO4+ membranes the rate determining step (rds) in oxygen semi-permeation of dense Ln2NiO4+ membranes (with Ln = La, Pr and Nd), a specific setup has been designed, which allowed measuring the oxygen semi-permeation flux

  19. Enhanced heat transfer through filler-polymer interface by surface-coupling agent in heat-dissipation material: A non-equilibrium molecular dynamics study

    SciTech Connect (OSTI)

    Tanaka, Kouichi [DENSO CORPORATION, Kariya, Aichi 448-8661 (Japan); Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555 (Japan); Ogata, Shuji; Kobayashi, Ryo; Tamura, Tomoyuki [Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555 (Japan); Kitsunezuka, Masashi; Shinma, Atsushi [DENSO CORPORATION, Kariya, Aichi 448-8661 (Japan)

    2013-11-21T23:59:59.000Z

    Developing a composite material of polymers and micrometer-sized fillers with higher heat conductance is crucial to realize modular packaging of electronic components at higher densities. Enhancement mechanisms of the heat conductance of the polymer-filler interfaces by adding the surface-coupling agent in such a polymer composite material are investigated through the non-equilibrium molecular dynamics (MD) simulation. A simulation system is composed of ?-alumina as the filler, bisphenol-A epoxy molecules as the polymers, and model molecules for the surface-coupling agent. The inter-atomic potential between the ?-alumina and surface-coupling molecule, which is essential in the present MD simulation, is constructed to reproduce the calculated energies with the electronic density-functional theory. Through the non-equilibrium MD simulation runs, we find that the thermal resistance at the interface decreases significantly by increasing either number or lengths of the surface-coupling molecules and that the effective thermal conductivity of the system approaches to the theoretical value corresponding to zero thermal-resistance at the interface. Detailed analyses about the atomic configurations and local temperatures around the interface are performed to identify heat-transfer routes through the interface.

  20. Analysis Of Post-Wet-Chemistry Heat Treatment Effects On Nb SRF Surface Resistance

    SciTech Connect (OSTI)

    Dhakal, Pashupati; Ciovati, Gianluigi; Kneisel, Peter K.; Myneni, Ganapati Rao

    2014-02-01T23:59:59.000Z

    Most of the current research in superconducting radio frequency (SRF) cavities is focused on ways to reduce the construction and operating cost of SRF-based accelerators as well as on the development of new or improved cavity processing techniques. The increase in quality factors is the result of the reduction of the surface resistance of the materials. A recent test on a 1.5 GHz single cell cavity made from ingot niobium of medium purity and heat treated at 1400 deg C in a ultra-high vacuum induction furnace resulted in a residual resistance of ~ 1n{Omega} and a quality factor at 2.0 K increasing with field up to ~ 5Î10{sup 10} at a peak magnetic field of 90 mT. In this contribution, we present some results on the investigation of the origin of the extended Q{sub 0}-increase, obtained by multiple HF rinses, oxypolishing and heat treatment of ?all Nb? cavities.

  1. SIZE AND SURFACE AREA OF ICY DUST AGGREGATES AFTER A HEATING EVENT AT A PROTOPLANETARY NEBULA

    SciTech Connect (OSTI)

    Sirono, Sin-iti [Earth and Environmental Sciences, Graduate School of Environmental Studies, Nagoya University, Nagoya 464-8601 (Japan)] [Earth and Environmental Sciences, Graduate School of Environmental Studies, Nagoya University, Nagoya 464-8601 (Japan)

    2013-03-01T23:59:59.000Z

    The activity of a young star rises abruptly during an FU Orionis outburst. This event causes a temporary temperature increase in the protoplanetary nebula. H{sub 2}O icy grains are sublimated by this event, and silicate cores embedded inside the ice are ejected. During the high-temperature phase, the silicate grains coagulate to form silicate core aggregates. After the heating event, the temperature drops, and the ice recondenses onto the aggregates. I determined numerically the size distribution of the ice-covered aggregates. The size of the aggregates exceeds 10 {mu}m around the snow line. Because of the migration of the ice to large aggregates, only a small fraction of the silicate core aggregate is covered with H{sub 2}O ice. After the heating event, the surface of an ice-covered aggregate is totally covered by silicate core aggregates. This might reduce the fragmentation velocity of aggregates when they collide. It is possible that the covering silicate cores shield the UV radiation field which induces photodissociation of H{sub 2}O ice. This effect may cause the shortage of cold H{sub 2}O vapor observed by Herschel.

  2. Heat pump having improved defrost system

    DOE Patents [OSTI]

    Chen, Fang C. (Knoxville, TN); Mei, Viung C. (Oak Ridge, TN); Murphy, Richard W. (Knoxville, TN)

    1998-01-01T23:59:59.000Z

    A heat pump system includes, in an operable relationship for transferring heat between an exterior atmosphere and an interior atmosphere via a fluid refrigerant: a compressor; an interior heat exchanger; an exterior heat exchanger; an accumulator; and means for heating the accumulator in order to defrost the exterior heat exchanger.

  3. Heat pump having improved defrost system

    DOE Patents [OSTI]

    Chen, F.C.; Mei, V.C.; Murphy, R.W.

    1998-12-08T23:59:59.000Z

    A heat pump system includes, in an operable relationship for transferring heat between an exterior atmosphere and an interior atmosphere via a fluid refrigerant: a compressor; an interior heat exchanger; an exterior heat exchanger; an accumulator; and means for heating the accumulator in order to defrost the exterior heat exchanger. 2 figs.

  4. Rotary magnetic heat pump

    DOE Patents [OSTI]

    Kirol, Lance D. (Shelly, ID)

    1988-01-01T23:59:59.000Z

    A rotary magnetic heat pump constructed without flow seals or segmented rotor accomplishes recuperation and regeneration by using split flow paths. Heat exchange fluid pumped through heat exchangers and returned to the heat pump splits into two flow components: one flowing counter to the rotor rotation and one flowing with the rotation.

  5. Rotary magnetic heat pump

    DOE Patents [OSTI]

    Kirol, L.D.

    1987-02-11T23:59:59.000Z

    A rotary magnetic heat pump constructed without flow seals or segmented rotor accomplishes recuperation and regeneration by using split flow paths. Heat exchange fluid pumped through heat exchangers and returned to the heat pump splits into two flow components: one flowing counter to the rotor rotation and one flowing with the rotation. 5 figs.

  6. Mass and Heat Recoveryá

    E-Print Network [OSTI]

    Hindawai, S. M.

    2010-01-01T23:59:59.000Z

    In the last few years heat recovery was under spot and in air conditioning fields usually we use heat recovery by different types of heat exchangers. The heat exchanging between the exhaust air from the building with the fresh air to the building...

  7. Heat extraction for the CSPonD thermal storage unit

    E-Print Network [OSTI]

    Rojas, Folkers Eduardo

    2011-01-01T23:59:59.000Z

    Three coiled tube heat exchanger prototypes were designed to extract heat from containers holding 0.5 kg, 2.3 kg, and 10.5 kg of Sodium Nitrate-Potassium Nitrate salt. All of the prototypes were left with an open surface ...

  8. Midtemperature Solar Systems Test Facility predictions for thermal performance of the Suntec solar collector with heat-formed glass reflector surface

    SciTech Connect (OSTI)

    Harrison, T.D.

    1980-11-01T23:59:59.000Z

    Thermal performance predictions are presented for the Suntec solar collector, with heat-formed glass reflector surface, for three output temperatures at five cities in the United States.

  9. "Nanotechnology Enabled Advanced Industrial Heat Transfer Fluids"

    SciTech Connect (OSTI)

    Dr. Ganesh Skandan; Dr. Amit Singhal; Mr. Kenneth Eberts; Mr. Damian Sobrevilla; Prof. Jerry Shan; Stephen Tse; Toby Rossmann

    2008-06-12T23:59:59.000Z

    ABSTRACT Nanotechnology Enabled Advanced industrial Heat Transfer Fluidsö Improving the efficiency of Industrial Heat Exchangers offers a great opportunity to improve overall process efficiencies in diverse industries such as pharmaceutical, materials manufacturing and food processing. The higher efficiencies can come in part from improved heat transfer during both cooling and heating of the material being processed. Additionally, there is great interest in enhancing the performance and reducing the weight of heat exchangers used in automotives in order to increase fuel efficiency. The goal of the Phase I program was to develop nanoparticle containing heat transfer fluids (e.g., antifreeze, water, silicone and hydrocarbon-based oils) that are used in transportation and in the chemical industry for heating, cooling and recovering waste heat. Much work has been done to date at investigating the potential use of nanoparticle-enhanced thermal fluids to improve heat transfer in heat exchangers. In most cases the effect in a commercial heat transfer fluid has been marginal at best. In the Phase I work, we demonstrated that the thermal conductivity, and hence heat transfer, of a fluid containing nanoparticles can be dramatically increased when subjected to an external influence. The increase in thermal conductivity was significantly larger than what is predicted by commonly used thermal models for two-phase materials. Additionally, the surface of the nanoparticles was engineered so as to have a minimal influence on the viscosity of the fluid. As a result, a nanoparticle-laden fluid was successfully developed that can lead to enhanced heat transfer in both industrial and automotive heat exchangers

  10. Turbine vanes experience high convective surface heat transfer as a consequence of the turbulent flow exiting the combustor. Before im-

    E-Print Network [OSTI]

    Thole, Karen A.

    1 Abstract Turbine vanes experience high convective surface heat transfer as a consequence region of the passage reacts as it passes between two adjacent turbine vanes. In this study, a scaled-up turbine vane geometry was used in a low-speed wind tunnel simulation. The test section included a cen

  11. Surface energy budget over the South Pole and turbulent heat fluxes as a function of an empirical bulk Richardson number

    E-Print Network [OSTI]

    Walden, Von P.

    as a residual of the energy budget, temperature inversion strength, and wind shear as a function of the bulkSurface energy budget over the South Pole and turbulent heat fluxes as a function of an empirical 2009; accepted 12 August 2009; published 26 November 2009. [1] Routine radiation and meteorological

  12. Variation of corrosion behavior of candidate heat exchanger alloys with local oxygen partial pressure in a 0. 6 meter diameter AFBC

    SciTech Connect (OSTI)

    Not Available

    1983-08-01T23:59:59.000Z

    The research reviewed here is in support of a program in which a coal-fired atmospheric fluidized-bed combustor (AFBC) is being designed to supply heat to a closed-cycle gas turbine co-generation system. The objective is to develop a system which could utilize high-sulfur coal. The major technical challenge is the design and development of the in-bed primary heat exchanger, which is required to operate near the bed temperature (1172 K, 1650 F). The purpose of this research was to characterize the types of corrosive environments encountered in the AFBC by monitoring the oxygen partial pressure at the exposure locations and to correlate the corrosion behavior of the exposed alloys to the local oxygen partial pressure measurements. Results were given for Incoloy 800, FeCr A/Y cladding, and nickel-base alloys. The relationships between the observed corrosion products and measured oxygen partial pressures suggest that the deposits formed in the AFBC had porosity sufficient such that intimate gas-metal contact was possible. 3 figures. (DP)

  13. Analysis of radial fin assembly heat transfer with dehumidification

    SciTech Connect (OSTI)

    Rosario, L.; Rahman, M.M. [Univ. of South Florida, Tampa, FL (United States). Dept. of Mechanical Engineering

    1996-12-31T23:59:59.000Z

    The aim of this paper is the analysis of heat transfer in a radial fin assembly during the process of dehumidification. An individual finned tube geometry is a reasonable representation of heat exchangers used in air conditioning. The condensation process involves both heat and mass transfer and the cooling takes place by the removal of sensible as well as latent heat. The ratio of sensible to total heat is an important quantity that defines the heat transfer process during a dehumidifier operation. A one-dimensional model for heat transfer in the fin and the heat exchanger block is developed to study the effects of condensation on the fin surface. The combined heat and mass transfer process is modeled by incorporating the ratio of sensible to total heat in the formulation. The augmentation of heat transfer due to fin was established by comparing heat transfer rate with and without fins under the same operating conditions. Numerical calculations were carried out to study the effects of relative humidity and dry bulb temperature of the incoming air, and cold fluid temperature inside the coil on the performance of the heat exchanger. Results were compared to those published for rectangular fin under humid condition showed excellent agreement when the present model was used to compute that limiting condition. It was found that the heat transfer rate increased with increment in both dry bulb temperature and relative humidity of the air. The augmentation factor, however, decreased with increment in relative humidity and the dry bulb temperature.

  14. Heating system

    SciTech Connect (OSTI)

    Nishman, P.J.

    1983-03-08T23:59:59.000Z

    A heating system utilizing solar panels and buried ground conduits to collect and store heat which is delivered to a heatpump heat exchanger. A heat-distribution fluid continuously circulates through a ground circuit to transfer heat from the ground to the heat exchanger. The ground circuit includes a length of buried ground conduit, a pump, a check valve and the heat exchanger. A solar circuit, including a solar panel and a second pump, is connected in parallel with the check valve so that the distribution fluid transfers solar heat to the heat exchanger for utilization and to the ground conduit for storage when the second pump is energized. A thermostatically instrumented control system energizes the second pump only when the temperature differential between the solar panel inlet and outlet temperatures exceeds a predetermined value and the ground temperature is less than a predetermined value. Consequently, the distribution fluid flows through the solar panel only when the panel is capable of supplying significant heat to the remainder of the system without causing excessive drying of the ground.

  15. Micro- and Nanoscale Measurement Methods for Phase Change Heat Transfer on Planar and Structured Surfaces

    E-Print Network [OSTI]

    Buongiorno, Jacopo

    In this opinion piece, we discuss recent advances in experimental methods for characterizing phase change heat transfer. We begin with a survey of techniques for high-resolution measurements of temperature and heat flux ...

  16. The Synergism Between Heat and Mass Transfer Additive and Advanced Surfaces in Aqueous LiBr Horizontal Tube Absorbers

    SciTech Connect (OSTI)

    Miller, W.A.

    1999-03-24T23:59:59.000Z

    Experiments were conducted in a laboratory to investigate the absorption of water vapor into a falling-film of aqueous lithium bromide (LiBr). A mini-absorber test stand was used to test smooth tubes and a variety of advanced tube surfaces placed horizontally in a single-row bundle. The bundle had six copper tubes; each tube had an outside diameter of 15.9-mm and a length of 0.32-m. A unique feature of the stand is its ability to operate continuously and support testing of LiBr brine at mass fractions {ge} 0.62. The test stand can also support testing to study the effect of the failing film mass flow rate, the coolant mass flow rate, the coolant temperature, the absorber pressure and the tube spacing. Manufacturers of absorption chillers add small quantities of a heat and mass transfer additive to improve the performance of the absorbers. The additive causes surface stirring which enhances the transport of absorbate into the bulk of the film. Absorption may also be enhanced with advanced tube surfaces that mechanically induce secondary flows in the falling film without increasing the thickness of the film. Several tube geometry's were identified and tested with the intent of mixing the film and renewing the interface with fresh solution from the tube wall. Testing was completed on a smooth tube and several different externally enhanced tube surfaces. Experiments were conducted over the operating conditions of 6.5 mm Hg absorber pressure, coolant temperatures ranging from 20 to 35 C and LiBr mass fractions ranging from 0.60 through 0.62. Initially the effect of tube spacing was investigated for the smooth tube surface, tested with no heat and mass transfer additive. Test results showed the absorber load and the mass absorbed increased as the tube spacing increased because of the improved wetting of the tube bundle. However, tube spacing was not a critical factor if heat and mass transfer additive was active in the mini-absorber. The additive dramatically affected the hydrodynamics of the falling film and a droplet flow regime was evident for testing at all tube spacings. The mechanical mixing of the advanced surfaces increased the mass transfer to about 75% of that observed on a smooth tube bundle, tested with heat and mass transfer additive. Testing with heat and mass transfer additive and advanced surfaces demonstrated a synergistic effect which doubled the mass absorbed from that observed with only the advanced surface. The overall film-side heat transfer coefficient for the advanced tube bundles doubled with the addition of 500-wppm of 2-ethyl-1- hexanol.

  17. Transient Thermal, Hydraulic, and Mechanical Analysis of a Counter Flow Offset Strip Fin Intermediate Heat Exchanger using an Effective Porous Media Approach

    E-Print Network [OSTI]

    Urquiza, Eugenio

    2009-01-01T23:59:59.000Z

    low volumetric heat capacity (relative to liquid-cooledvolumetric heat capacity relative to the liquid salt. Thisvolumetric heat capacity (?*c p ) of the liquid salt permits

  18. Integrity assessment of the ferritic / austenitic dissimilar weld joint between intermediate heat exchanger and steam generator in fast reactor

    SciTech Connect (OSTI)

    Jayakumar, T.; Laha, K.; Chandravathi, K. S.; Parameswaran, P.; Goyal, S.; Kumar, J. G.; Mathew, M. D. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam- 603 102 (India)

    2012-07-01T23:59:59.000Z

    Integrity of the modified 9Cr-1Mo / alloy 800 dissimilar joint welded with Inconel 182 electrodes has been assessed under creep condition based on the detailed analysis of microstructure and stress distribution across the joint by finite element analysis. A hardness peak at the ferritic / austenitic weld interface and a hardness trough at the inter-critical heat affected zone (HAZ) in ferritic base metal developed. Un-tempered martensite was found at the ferritic / austenitic weld interface to impart high hardness in it; whereas annealing of martensitic structure of modified 9Cr-1Mo steel by inter-critical heating during welding thermal cycle resulted in hardness tough in the inter-critical HAZ. Creep tests were carried out on the joint and ferritic steel base metal at 823 K over a stress range of 160-320 MPa. The joint possessed lower creep rupture strength than its ferritic steel base metal. Failure of the joint at relatively lower stresses occurred at the ferritic / austenitic weld interface; whereas it occurred at inter-critical region of HAZ at moderate stresses. Cavity nucleation associated with the weld interface particles led to premature failure of the joint. Finite element analysis of stress distribution across the weld joint considering the micro-mechanical strength inhomogeneity across it revealed higher von-Mises and principal stresses at the weld interface. These stresses induced preferential creep cavitation at the weld interface. Role of precipitate in enhancing creep cavitation at the weld interface has been elucidated based on the FE analysis of stress distribution across it. (authors)

  19. Surface electric variations induced by deep hydraulic stimulation: An example from the Soultz HDR site

    E-Print Network [OSTI]

    Sailhac, Pascal

    Surface electric variations induced by deep hydraulic stimulation: An example from the Soultz HDR exchanger to heat up the water that activates turbines that generate electricity. It is therefore essential

  20. Effect of Droplet Morphology on Growth Dynamics and Heat Transfer during Condensation on Superhydrophobic Nanostructured Surfaces

    E-Print Network [OSTI]

    Miljkovic, Nenad

    Condensation on superhydrophobic nanostructured surfaces offers new opportunities for enhanced energy conversion, efficient water harvesting, and high performance thermal management. These surfaces are designed to be Cassie ...

  1. Proposal for the Award of a Contract for the Heating, Ventilation and Cooling Installations for the LHC Surface Buildings

    E-Print Network [OSTI]

    1999-01-01T23:59:59.000Z

    This document concerns the award of a contract for the heating, ventilation and cooling installations for the LHC surface buildings. Following a market survey carried out among 80 firms in fifteen Member States, a call for tenders (IT-2524/ST/LHC) was sent on 14 January 1999 to four firms and five consortia, two consisting of three firms and three consisting of two firms, in five Member States. By the closing date, CERN had received five tenders. The Finance Committee is invited to agree to the negotiation of a contract for the heating, ventilation and cooling installations for the LHC surface buildings with the consortium DSD (DE), AIR ET CHALEUR (BE) and SPIE TRINDEL (FR) for a total amount not exceeding 14 500 000 Swiss francs, not subject to revision until 31 December 2001. The consortium has announced that the work will be distributed as follows: DSD (DE) 67% - Air et Chaleur (BE) 21% - Spie Trindel (FR) 12%.

  2. An Evaluation of the Impact of Surface Coatings on the Heat Transfer in High Temperature Ceramic Recuperators

    E-Print Network [OSTI]

    Guerrero, P. S.; Rebello, W. J.; Federer, J. I.

    AN EVALUATION OF THE IMPACT OF SURFACE COATINGS ON THE HEAT TRANSFER IN HIGH TEMPERATURE CERAMIC RECUPERATORS PABLO S. GUERRERO WILFRED J. REBELLO PAR Enterprises, Inc., Fairfax, VA and J. I. FEDERER Oak Ridge National Laboratory, Oak... these furnaces may contain sodium, potassium, halides, etc. that may attack SiC. protective coatings, such as alumina. zirconia and others, have been investigated as a means of increasing the life and reliability of these SiC recuperators. The objective...

  3. Heat pump system

    DOE Patents [OSTI]

    Swenson, Paul F.; Moore, Paul B.

    1983-06-21T23:59:59.000Z

    An air heating and cooling system for a building includes an expansion type refrigeration circuit and a vapor power circuit. The refrigeration circuit includes two heat exchangers, one of which is communicated with a source of indoor air from the building and the other of which is communicated with a source of air from outside the building. The vapor power circuit includes two heat exchangers, one of which is disposed in series air flow relationship with the indoor refrigeration circuit heat exchanger and the other of which is disposed in series air flow relationship with the outdoor refrigeration circuit heat exchanger. Fans powered by electricity generated by a vapor power circuit alternator circulate indoor air through the two indoor heat exchangers and circulate outside air through the two outdoor heat exchangers. The system is assembled as a single roof top unit, with a vapor power generator and turbine and compressor thermally insulated from the heat exchangers, and with the indoor heat exchangers thermally insulated from the outdoor heat exchangers.

  4. Heat pump system

    DOE Patents [OSTI]

    Swenson, Paul F. (Shaker Heights, OH); Moore, Paul B. (Fedhaven, FL)

    1983-01-01T23:59:59.000Z

    An air heating and cooling system for a building includes an expansion type refrigeration circuit and a vapor power circuit. The refrigeration circuit includes two heat exchangers, one of which is communicated with a source of indoor air from the building and the other of which is communicated with a source of air from outside the building. The vapor power circuit includes two heat exchangers, one of which is disposed in series air flow relationship with the indoor refrigeration circuit heat exchanger and the other of which is disposed in series air flow relationship with the outdoor refrigeration circuit heat exchanger. Fans powered by electricity generated by a vapor power circuit alternator circulate indoor air through the two indoor heat exchangers and circulate outside air through the two outdoor heat exchangers. The system is assembled as a single roof top unit, with a vapor power generator and turbine and compressor thermally insulated from the heat exchangers, and with the indoor heat exchangers thermally insulated from the outdoor heat exchangers.

  5. Development of a coal-fueled Internal Manifold Heat Exchanger (IMHEX{reg_sign}) molten carbonate fuel cell. Volumes 1--6, Final report

    SciTech Connect (OSTI)

    Not Available

    1991-09-01T23:59:59.000Z

    The design of a CGMCFC electric generation plant that will provide a cost of eletricity (COE) which is lower than that of current electric generation technologies and which is competitive with other long-range electric generating systems is presented. This effort is based upon the Internal Manifold Heat Exchanger (IMHEX) technology as developed by the Institute of Gas Technology (IGT). The project was executed by selecting economic and performance objectives for alternative plant arrangements while considering process constraints identified during IMHEX fuel cell development activities at ICT. The four major subsystems of a coal-based MCFC power plant are coal gasification, gas purification, fuel cell power generation and the bottoming cycle. The design and method of operation of each subsystem can be varied, and, depending upon design choices, can have major impact on both the design of other subsystems and the resulting cost of electricity. The challenge of this project was to select, from a range of design parameters, those operating conditions that result in a preferred plant design. Computer modelling was thus used to perform sensitivity analyses of as many system variables as program resources and schedules would permit. In any systems analysis, it is imperative that the evaluation methodology be verifiable and comparable. The TAG Class I develops comparable (if imprecise) data on performance and costs for the alternative cases being studied. It identifies, from a range of options, those which merit more exacting scrutiny to be undertaken at the second level, TAG class II analysis.

  6. Research on thermophoretic and inertial aspects of ash particle deposition on heat exchanger surfaces in coal-fired equipment

    SciTech Connect (OSTI)

    Rosner, D.E.

    1989-06-01T23:59:59.000Z

    Our results on photophoresis reveal significant transport effects, mainly for particles which are carbonaceous (char-like, soot-like) rather than ash-like. Figure 2 shows the predicted dimensionless transport coefficient (proportional to the ordinary Stanton number for mass transfer) as a function of radiation/convective flux ratio and carbonaceous particle radius for laminar boundary layer flow past a wall cooled to 70% of the mainstream temperature, subjected to a radiative energy spectrum appropriate to a black-body source at ca. 1800K. One sees that large effects on the particle deposition rate are produced if the radiative flux is comparable to or exceeds the ordinary (Fourier) energy flux. We are now extending this work to include the effects of inevitable particle asymmetries, including agglomerate (shape) effects, and the role that energy transfer (eg. radiative cooling of larger particles in a population) might play in the coagulation dynamics and deposition dynamics of such aerosol populations.

  7. The Surface Energy Balance System (SEBS) for estimation of turbulent heat fluxes Hydrology and Earth System Sciences, 6(1), 8599 (2002) EGS

    E-Print Network [OSTI]

    Paris-Sud XI, Universit├ę de

    The Surface Energy Balance System (SEBS) for estimation of turbulent heat fluxes 85 Hydrology and Earth System Sciences, 6(1), 85┬ş99 (2002) ┬ę EGS The Surface Energy Balance System (SEBS) for estimation, The Netherlands Email: B.su@Alterra.wag-ur.nl Abstract A Surface Energy Balance System (SEBS) is proposed

  8. Influence of surface heating on the boundary layer stability of flows with favorable pressure gradients

    E-Print Network [OSTI]

    Landrum, David Brian

    1986-01-01T23:59:59.000Z

    $ of its chord heated to about 1. 5 times the adiabatic temperature. Compared to the adiabatic case, the nose heating slightly delayed the initial amplification of disturbances and significantly incr eased the transition length. A vertical traverse... . . . . 10 Fig. 3 Neutral stability cur ve f' or a typical boundar y layer velocity profile 13 Fig. 4a Falkner-Skan velocity profiles with wall heating, 8 0. 0 18 Fig. 4b Falkner-Skan temperature profiles, B=O. O 19 Fig. 5a Falkner-Skan velocity prof...

  9. Immersion Condensation on Oil-Infused Heterogeneous Surfaces for Enhanced Heat Transfer

    E-Print Network [OSTI]

    Xiao, Rong

    Enhancing condensation heat transfer is important for broad applications from power generation to water harvesting systems. Significant efforts have focused on easy removal of the condensate, yet the other desired properties ...

  10. Surface Reductive Capacity of Carbon Nanomaterials after Various Heating and Aging Processesá

    E-Print Network [OSTI]

    Lee, Chunghoon

    2012-10-19T23:59:59.000Z

    , commercially available carbon black, carbon nanotubes, standard reference materials, fullerenes, graphenes and acetylene soot generated in the lab were used. The carbon nanomaterials were subjected to heating at various temperatures in various atmospheres up...

  11. Near-wall reaction effects on film-cooled surface heat transfer

    E-Print Network [OSTI]

    Kirk, Daniel Robert, 1975-

    2003-01-01T23:59:59.000Z

    As commercial and military aircraft engines approach higher total temperatures and increasing overall fuel-to-air ratios, there exists a potential for significant heat release to occur in the turbine if energetic species ...

  12. Control of oligonucleotide conformation on nanoparticle surfaces for nanoscale heat transfer study

    E-Print Network [OSTI]

    Park, Sunho, 1976-

    2004-01-01T23:59:59.000Z

    Metal nanoparticles can be used as antennae covalently linked to biomolecules. External alternating magnetic field can turn on and off the biological activity of the molecules due to induction heating from the particles ...

  13. Analysis of fluid flow and heat transfer in a rib grit roughened surface solar air heater using CFD

    SciTech Connect (OSTI)

    Karmare, S.V. [Department of Mechanical Engineering, Government College Engineering, Karad 415 124, Maharashtra (India); Shivaji University, Kolhapur, Maharashtra (India); Tikekar, A.N. [Department of Mechanical Engineering, Walchand College of Engineering, Sangli (India); Shivaji University, Kolhapur, Maharashtra (India)

    2010-03-15T23:59:59.000Z

    This paper presents the study of fluid flow and heat transfer in a solar air heater by using Computational Fluid Dynamics (CFD) which reduces time and cost. Lower side of collector plate is made rough with metal ribs of circular, square and triangular cross-section, having 60 inclinations to the air flow. The grit rib elements are fixed on the surface in staggered manner to form defined grid. The system and operating parameters studied are: e/D{sub h} = 0.044, p/e = 17.5 and l/s = 1.72, for the Reynolds number range 3600-17,000. To validate CFD results, experimental investigations were carried out in the laboratory. It is found that experimental and CFD analysis results give the good agreement. The optimization of rib geometry and its angle of attack is also done. The square cross-section ribs with 58 angle of attack give maximum heat transfer. The percentage enhancement in the heat transfer for square plate over smooth surface is 30%. (author)

  14. Using Thermally-Degrading, Partitioning, and Nonreactive Tracers to Determine Temperature Distribution and Fracture/Heat Transfer Surface Area in Geothermal Reservoirs

    Broader source: Energy.gov [DOE]

    DOE Geothermal Peer Review 2010 - Project Summary. The goal of this project is to provide integrated tracer and tracer interpretation tools to facilitate quantitative characterization of temperature distributions and surface area available for heat transfer in EGS.

  15. Heat engines and heat pumps in a hydrostatic atmosphere: How surface pressure and temperature control wind power output and circulation cell size

    E-Print Network [OSTI]

    Makarieva, A M; Nefiodov, A V; Sheil, D; Nobre, A D; Shearman, P L; Li, B -L

    2015-01-01T23:59:59.000Z

    The gross spatial features of the atmospheric kinetic energy budget are analytically investigated. Kinetic energy generation is evaluated in a hydrostatic atmosphere where the axisymmetric circulation cells are represented by Carnot cycles. The condition that kinetic energy generation is positive in the lower atmosphere is shown to limit the poleward cell extension via a relationship between the meridional differences in surface pressure and temperature $\\Delta p_s$ and $\\Delta T_s$: an upper limit to cell size exists when $\\Delta p_s$ increases sublinearly with $\\Delta T_s$. This is the case for the Hadley cells as demonstrated here using data from MERRA re-analysis. The limited cell size necessitates the appearance of heat pumps -- circulation cells with negative work output where the low-level air moves towards colder areas. These cells consume the positive work output of heat engines -- cells where the low-level air moves towards the warmer areas -- and can in principle drive the global efficiency of atmo...

  16. Proceedings of US/Japan workshop, Q219 on high heat flux components and plasma surface interactions for next fusion devices

    SciTech Connect (OSTI)

    Ulrickson, M.A.; Stevens, P.L.; Hino, T.; Hirohata, Y. [eds.] [eds.

    1996-12-01T23:59:59.000Z

    This report contains the viewgraphs from the proceedings of US/Japan Workshop on High Heat Flux Components and Plasma Surface Interactions for Next Fusion Devices. Some of the general topics covered by this report are: PFC/PSI in tokamak and helical devices; development of high heat flux components; PSIS and plasma facing materials;tritium; and material damage.

  17. Refrigerant charge management in a heat pump water heater

    DOE Patents [OSTI]

    Chen, Jie; Hampton, Justin W.

    2014-06-24T23:59:59.000Z

    Heat pumps that heat or cool a space and that also heat water, refrigerant management systems for such heat pumps, methods of managing refrigerant charge, and methods for heating and cooling a space and heating water. Various embodiments deliver refrigerant gas to a heat exchanger that is not needed for transferring heat, drive liquid refrigerant out of that heat exchanger, isolate that heat exchanger against additional refrigerant flowing into it, and operate the heat pump while the heat exchanger is isolated. The heat exchanger can be isolated by closing an electronic expansion valve, actuating a refrigerant management valve, or both. Refrigerant charge can be controlled or adjusted by controlling how much liquid refrigerant is driven from the heat exchanger, by letting refrigerant back into the heat exchanger, or both. Heat pumps can be operated in different modes of operation, and segments of refrigerant conduit can be interconnected with various components.

  18. Experimental and Numerical Investigation of Pool Boiling Heat Transfer on Engineered Nano-Finned Surfaces

    E-Print Network [OSTI]

    Yang, Hongjoo

    2014-08-10T23:59:59.000Z

    ............................................................................... 69 3.3. Experimental Procedure ................................................................................... 70 3.3.1. Test Surface Assembly ............................................................................. 70 3.3.2. Leakage Test...

  19. Radiative heat transfer in porous uranium dioxide

    SciTech Connect (OSTI)

    Hayes, S.L. [Texas A and M Univ., College Station, TX (United States)] [Texas A and M Univ., College Station, TX (United States)

    1992-12-01T23:59:59.000Z

    Due to low thermal conductivity and high emissivity of UO{sub 2}, it has been suggested that radiative heat transfer may play a significant role in heat transfer through pores of UO{sub 2} fuel. This possibility was computationally investigated and contribution of radiative heat transfer within pores to overall heat transport in porous UO{sub 2} quantified. A repeating unit cell was developed to model approximately a porous UO{sub 2} fuel system, and the heat transfer through unit cells representing a wide variety of fuel conditions was calculated using a finite element computer program. Conduction through solid fuel matrix as wekk as pore gas, and radiative exchange at pore surface was incorporated. A variety of pore compositions were investigated: porosity, pore size, shape and orientation, temperature, and temperature gradient. Calculations were made in which pore surface radiation was both modeled and neglected. The difference between yielding the integral contribution of radiative heat transfer mechanism to overall heat transport. Results indicate that radiative component of heat transfer within pores is small for conditions representative of light water reactor fuel, typically less than 1% of total heat transport. It is much larger, however, for conditions present in liquid metal fast breeder reactor fuel; during restructuring of this fuel type early in life, the radiative heat transfer mode was shown to contribute as much as 10-20% of total heat transport in hottest regions of fuel.

  20. Direct contact heat exchanger performance

    SciTech Connect (OSTI)

    Wahl, E. F.

    1981-03-12T23:59:59.000Z

    Although the final performance result of a DCHE is the cost of the net electricity produced, the best performance cannot be achieved without optimizing the components of the system as well as the whole system. Thus collection and analysis of data on the internal performance of the column assists in optimizing the operation of the particular column as well as in suggesting ways for improving the operation and design of future columns.