National Library of Energy BETA

Sample records for heat exchanger surface

  1. Corrosive resistant heat exchanger

    DOE Patents [OSTI]

    Richlen, Scott L. (Annandale, VA)

    1989-01-01

    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 Sensible heat flux Shortwave radiation Surface wind fields 2 #12;Sea surface exchanges of momentum, heat and the atmosphere communicate through the interfacial exchanges of heat, freshwater, and momentum. While

  3. A corrosive resistant heat exchanger

    DOE Patents [OSTI]

    Richlen, S.L.

    1987-08-10

    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.

  4. SMALL PARTICLE HEAT EXCHANGERS

    E-Print Network [OSTI]

    Hunt, A.J.

    2011-01-01

    The Small Particle Heat Exchange Receiver (SPHER) for Solarof the small particle heat exchange receiver (or SPHER), asabsorption process, the heat exchange to the gas, the choice

  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)

    2011-06-28

    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)

    2007-09-18

    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

    2010-10-01

    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. SMALL PARTICLE HEAT EXCHANGERS

    E-Print Network [OSTI]

    Hunt, A.J.

    2011-01-01

    heat exchangers. These types of heat exchangers have limitedheat exchanger to solar collection systems that utilize linear trough- typenon-solar heat exchangers. These may be of the type used to

  9. Heat pipe array heat exchanger

    DOE Patents [OSTI]

    Reimann, Robert C. (Lafayette, NY)

    1987-08-25

    A heat pipe arrangement for exchanging heat between two different temperature fluids. The heat pipe arrangement is in a ounterflow relationship to increase the efficiency of the coupling of the heat from a heat source to a heat sink.

  10. Optimization of Heat Exchanger Cleaning 

    E-Print Network [OSTI]

    Siegell, J. H.

    1986-01-01

    EXCHANGER CLEANING Jeffrey H. Siegell Exxon Research and Engineering Company Florham Park, New Jersey ABSTRACT 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, economic incentives for heat exchanger cleaning are evaluated using linear, exponential, and exponential finite decrease models of the heat...

  11. Woven heat exchanger

    DOE Patents [OSTI]

    Piscitella, R.R.

    1984-07-16

    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. Woven heat exchanger

    DOE Patents [OSTI]

    Piscitella, Roger R. (Idaho Falls, ID)

    1987-01-01

    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.

  13. Heat exchange apparatus

    DOE Patents [OSTI]

    Degtiarenko, Pavel V.

    2003-08-12

    A heat exchange apparatus comprising a coolant conduit or heat sink having attached to its surface a first radial array of spaced-apart parallel plate fins or needles and a second radial array of spaced-apart parallel plate fins or needles thermally coupled to a body to be cooled and meshed with, but not contacting the first radial array of spaced-apart parallel plate fins or needles.

  14. Direct fired heat exchanger

    DOE Patents [OSTI]

    Reimann, Robert C. (Lafayette, NY); Root, Richard A. (Spokane, WA)

    1986-01-01

    A gas-to-liquid heat exchanger system which transfers heat from a gas, generally the combustion gas of a direct-fired generator of an absorption machine, to a liquid, generally an absorbent solution. The heat exchanger system is in a counterflow fluid arrangement which creates a more efficient heat transfer.

  15. Wound tube heat exchanger

    DOE Patents [OSTI]

    Ecker, Amir L. (Duncanville, TX)

    1983-01-01

    What is disclosed is a wound tube heat exchanger in which a plurality of tubes having flattened areas are held contiguous adjacent flattened areas of tubes by a plurality of windings to give a double walled heat exchanger. The plurality of windings serve as a plurality of effective force vectors holding the conduits contiguous heat conducting walls of another conduit and result in highly efficient heat transfer. The resulting heat exchange bundle is economical and can be coiled into the desired shape. Also disclosed are specific embodiments such as the one in which the tubes are expanded against their windings after being coiled to insure highly efficient heat transfer.

  16. Modeling Free Convection Flow of Liquid Hydrogen within a Cylindrical Heat Exchanger Cooled to 14 K

    E-Print Network [OSTI]

    Yang, S.W.; Oxford U.

    2004-01-01

    is to put part of the heat exchange surface inside thewall as well as added heat exchange surface. This study

  17. 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

    2001-01-01

    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.

  18. Thermoelectric heat exchange element

    DOE Patents [OSTI]

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

    2007-08-14

    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.

  19. Greywater heat exchanger

    SciTech Connect (OSTI)

    Holmberg, D.

    1983-11-21

    A kilowatt meter and water meter were installed to monitor pregreywater usage. The design considerations, the heat exchanger construction and installation, and the monitoring of usage levels are described.

  20. Radial flow heat exchanger

    DOE Patents [OSTI]

    Valenzuela, Javier (Hanover, NH)

    2001-01-01

    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.

  1. Heat transfer and heat exchangers reference handbook

    SciTech Connect (OSTI)

    Not Available

    1991-01-15

    The purpose of this handbook is to provide Rocky Flats personnel with an understanding of the basic concepts of heat transfer and the operation of heat exchangers.

  2. Heat Exchangers for Solar Water Heating Systems | Department...

    Energy Savers [EERE]

    Heat Exchangers for Solar Water Heating Systems Heat Exchangers for Solar Water Heating Systems Image of a heat exchanger. | Photo from iStockphoto.com Image of a heat exchanger. |...

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

    SciTech Connect (OSTI)

    Piyush Sabharwall; Mike Patterson; Vivek Utgikar; Fred Gunnerson

    2008-09-01

    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.

  4. Heat exchanger-accumulator

    DOE Patents [OSTI]

    Ecker, Amir L. (Dallas, TX)

    1980-01-01

    What is disclosed is a heat exchanger-accumulator for vaporizing a refrigerant or the like, characterized by an upright pressure vessel having a top, bottom and side walls; an inlet conduit eccentrically and sealingly penetrating through the top; a tubular overflow chamber disposed within the vessel and sealingly connected with the bottom so as to define an annular outer volumetric chamber for receiving refrigerant; a heat transfer coil disposed in the outer volumetric chamber for vaporizing the liquid refrigerant that accumulates there; the heat transfer coil defining a passageway for circulating an externally supplied heat exchange fluid; transferring heat efficiently from the fluid; and freely allowing vaporized refrigerant to escape upwardly from the liquid refrigerant; and a refrigerant discharge conduit penetrating sealingly through the top and traversing substantially the length of the pressurized vessel downwardly and upwardly such that its inlet is near the top of the pressurized vessel so as to provide a means for transporting refrigerant vapor from the vessel. The refrigerant discharge conduit has metering orifices, or passageways, penetrating laterally through its walls near the bottom, communicating respectively interiorly and exteriorly of the overflow chamber for controllably carrying small amounts of liquid refrigerant and oil to the effluent stream of refrigerant gas.

  5. Heat exchanger for power generation equipment

    DOE Patents [OSTI]

    Nirmalan, Nirm Velumylm; Bowman, Michael John

    2005-06-14

    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.

  6. Heat exchanger with transpired, highly porous fins

    DOE Patents [OSTI]

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

    2002-01-01

    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.

  7. Heat exchange assembly

    DOE Patents [OSTI]

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

    2004-06-08

    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.

  8. Approach to the surface characteristics of the H and H -LaT forms of cation-exchange resins by measurement of the heat of immersion

    SciTech Connect (OSTI)

    Suzuki, T.; Uematsu, T.

    1985-11-07

    Surface characteristics of H and its multivalent cation-exchanged resins, which have been used as catalysts, were probed by measurement of the heats of immersion in 1-nitropropane, n-hexane, and water. It was found that the electrostatic field strengths (F) calculated from the heats of immersion in 1-nitropropane and n-hexane increased with increasing ratios of the exchanged multivalent cation (LaT ) in the univalent form (H ) cation-exchange resin. This tendency was also observed in the differences in F between the LaT exchanged resins and H form of the resin by using the calorimetric data obtained from the heats of immersion in water. These results suggest that the exchanged LaT ion does not homogeneously interact with three univalent anionic sites (SO3 ) of the cation-exchange resin, but interacts with only two SO3 ions, that is, the LaT ion is localized on the surface of the resin. The difference in F obtained from the heats of immersion into water was found to be useful as a simple and rapid criterion of the surface characteristics of the cation-exchange resins. 18 references, 4 figures, 1 table.

  9. 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.

    2015-04-04

    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. Helium–helium 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 optimummore »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.« less

  10. Modular heat exchanger

    DOE Patents [OSTI]

    Giardina, A.R.

    1981-03-03

    A shell and tube heat exchanger is described having a plurality of individually removable tube bundle modules. A lattice of structural steel forming rectangular openings therein is placed at each end of a cylindrical shell. Longitudinal structural members are placed in the shell between corners of the rectangular openings situated on opposite ends of the shell. Intermediate support members interconnect the longitudinal supports so as to increase the longitudinal supports rigidity. Rectangular parallelepiped tube bundle modules occupy the space defined by the longitudinal supports and end supports and each include a rectangular tube sheet situated on each end of a plurality of tubes extending there through, a plurality of rectangular tube supports located between the tube sheets, and a tube bundle module stiffening structure disposed about the bundle's periphery and being attached to the tube sheets and tube supports. The corners of each tube bundle module have longitudinal framework members which are mateable with and supported by the longitudinal support members. Intermediate support members constitute several lattices, each of which is situated in a plane between the end support members. The intermediate support members constituting the several lattices extend horizontally and vertically between longitudinal supports of adjacent tube module voids. An alternative embodiment for intermediate support members constitute a series of structural plates situated at the corners of the module voids and having recesses therein for receiving the respective longitudinal support members adjacent thereto, protrusions separating the recesses, and a plurality of struts situated between protrusions of adjacent structural plates. 12 figs.

  11. Modular heat exchanger

    DOE Patents [OSTI]

    Giardina, Angelo R. [Marple Township, Delaware County, PA

    1981-03-03

    A shell and tube heat exchanger having a plurality of individually removable tube bundle modules. A lattice of structural steel forming rectangular openings therein is placed at each end of a cylindrical shell. Longitudinal structural members are placed in the shell between corners of the rectangular openings situated on opposite ends of the shell. Intermediate support members interconnect the longitudinal supports so as to increase the longitudinal supports rigidity. Rectangular parallelpiped tube bundle moldules occupy the space defined by the longitudinal supports and end supports and each include a rectangular tube sheet situated on each end of a plurality of tubes extending therethrough, a plurality of rectangular tube supports located between the tube sheets, and a tube bundle module stiffening structure disposed about the bundle's periphery and being attached to the tube sheets and tube supports. The corners of each tube bundle module have longitudinal framework members which are mateable with and supported by the longitudinal support members. Intermediate support members constitute several lattice, each of which is situate d in a plane between the end support members. The intermediate support members constituting the several lattice extend horizontally and vertically between longitudinal supports of adjacent tube module voids. An alternative embodiment for intermediate support members constitute a series of structural plates situated at the corners of the module voids and having recesses therein for receiving the respective longitudinal support members adjacent thereto, protrusions separating the recesses, and a plurality of struts situated between protrusions of adjacent structural plates.

  12. Introduction to Heat Exchangers

    E-Print Network [OSTI]

    Heller, Barbara

    . Since, the effectiveness can be written in terms of heat capacitance rate [W/K], C, and change in temperature [K], . The heat capacitance rate is defined in terms of mass flow rate [kg/s], , and specific heat: ! ! ! " # = ! ! "# ! ! ! - ! ! ! ! ! ! = ! !! ! ! ! ! = ! ! ! ! ! - ! ! ! ! ! "# ! ! ! - ! ! ! ! ! ! = ! ! ! ! ! - ! ! ! ! ! "# ! ! ! - ! ! ! ! ! Heat%Capacitance%Rate % ! = ! !! ! ! Heat%Capacitance%Rate%[W % ! = ! ! ! ! ! ! ! = ! ! !! ! ! ! max

  13. Bayonet heat exchangers in heat-assisted Stirling heat pump

    SciTech Connect (OSTI)

    Yagyu, S.; Fukuyama, Y.; Morikawa, T.; Isshiki, N.; Satoh, I.; Corey, J.; Fellows, C.

    1998-07-01

    The Multi-Temperature Heat Supply System is a research project creating a city energy system with lower environmental load. This system consists of a gas-fueled internal combustion engine and a heat-assisted Stirling heat pump utilizing shaft power and thermal power in a combination of several cylinders. The heat pump is mainly driven by engine shaft power and is partially assisted by thermal power from engine exhaust heat source. Since this heat pump is operated by proportioning the two energy sources to match the characteristics of the driving engine, the system is expected to produce cooling and heating water at high COP. This paper describes heat exchanger development in the project to develop a heat-assisted Stirling heat pump. The heat pump employs the Bayonet type heat exchangers (BHX Type I) for supplying cold and hot water and (BHX Type II) for absorbing exhaust heat from the driving engine. The heat exchanger design concepts are presented and their heat transfer and flow loss characteristics in oscillating gas flow are investigated. The main concern in the BHX Type I is an improvement of gas side heat transfer and the spirally finned tubes were applied to gas side of the heat exchanger. For the BHX Type II, internal heat transfer characteristics are the main concern. Shell-and-tube type heat exchangers are widely used in Stirling machines. However, since brazing is applied to the many tubes for their manufacturing processes, it is very difficult to change flow passages to optimize heat transfer and loss characteristics once they have been made. The challenge was to enhance heat transfer on the gas side to make a highly efficient heat exchanger with fewer parts. It is shown that the Bayonet type heat exchanger can have good performance comparable to conventional heat exchangers.

  14. Ceramic heat exchanger

    DOE Patents [OSTI]

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

    1998-06-16

    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.

  15. Ceramic heat exchanger

    DOE Patents [OSTI]

    LaHaye, Paul G. (Kennebunk, ME); Rahman, Faress H. (Portland, ME); Lebeau, Thomas P. E. (Portland, ME); Severin, Barbara K. (Biddeford, ME)

    1998-01-01

    A tube containment system. 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.

  16. Heat exchanger with ceramic elements

    DOE Patents [OSTI]

    Corey, John A. (North Troy, NY)

    1986-01-01

    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.

  17. Heat exchanger using graphite foam

    DOE Patents [OSTI]

    Campagna, Michael Joseph; Callas, James John

    2012-09-25

    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.

  18. Sabdia's Radial Flow Air Bearing Heat Exchanger

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

    Sandia's Radial Flow ir Bearing Heat Exchanger 2014 Building Technologies Office Peer Review Sandia's TRL 5 Air Bearing Heat exchanger technology (a. k. a. The Sandia Cooler)...

  19. Sandia Energy - Heat-Exchanger Development

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

    Heat-Exchanger Development Home Stationary Power Nuclear Fuel Cycle Advanced Nuclear Energy Nuclear Energy Systems Laboratory (NESL) Brayton Lab Heat-Exchanger Development...

  20. 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

    2008-11-01

    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.

  1. SMALL PARTICLE HEAT EXCHANGERS

    E-Print Network [OSTI]

    Hunt, A.J.

    2011-01-01

    by half, the solar collection efficiency will still be insolar thermal electric power program rests on the efficiency,efficiency heat storage systems. This type of hybrid, solar-

  2. Heat exchanger and related methods

    DOE Patents [OSTI]

    Turner, Terry D.; McKellar, Michael G.

    2015-12-22

    Heat exchangers include a housing having an inlet and an outlet and forming a portion of a transition chamber. A heating member may form another portion of the transition chamber. The heating member includes a first end having a first opening and a second end having a second opening larger than the first opening. Methods of conveying a fluid include supplying a first fluid into a transition chamber of a heat exchanger, supplying a second fluid into the transition chamber, and altering a state of a portion of the first fluid with the second fluid. Methods of sublimating solid particles include conveying a first fluid comprising a material in a solid state into a transition chamber, heating the material to a gaseous state by directing a second fluid through a heating member and mixing the first fluid and the second fluid.

  3. Modeling particle deposition on HVAC heat exchangers

    SciTech Connect (OSTI)

    Siegel, J.A.; Nazaroff, W.W.

    2002-01-01

    Fouling of fin-and-tube heat exchangers by particle deposition leads to diminished effectiveness in supplying ventilation and air conditioning. This paper explores mechanisms that cause particle deposition on heat exchanger surfaces. We present a model that accounts for impaction, diffusion, gravitational settling, and turbulence. Simulation results suggest that some submicron particles deposit in the heat exchanger core, but do not cause significant performance impacts. Particles between 1 and 10 {micro}m deposit with probabilities ranging from 1-20% with fin edge impaction representing the dominant mechanism. Particles larger than 10 {micro}m deposit by impaction on refrigerant tubes, gravitational settling on fin corrugations, and mechanisms associated with turbulent airflow. The model results agree reasonably well with experimental data, but the deposition of larger particles at high velocities is underpredicted. Geometric factors, such as discontinuities in the fins, are hypothesized to be responsible for the discrepancy.

  4. Heat Exchangers for Solar Water Heating Systems | Department...

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

    from iStockphoto.com Image of a heat exchanger. | Photo from iStockphoto.com Solar water heating systems use heat exchangers to transfer solar energy absorbed in solar...

  5. 4. Heat exchangers; Steam, steam processes

    E-Print Network [OSTI]

    Zevenhoven, Ron

    to transfer a certain heat rate Q (J/s = W) For a small section dx of the tube (with diameter D), the heat With average temperature difference = for the heat exchanger length, the heat rate can1/74 4. Heat exchangers; Steam, steam processes Ron Zevenhoven Åbo Akademi University Thermal

  6. Miniaturized Air-to-Refrigerant Heat Exchangers

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

    kW air-to-water and air-to- refrigerant heat exchangers Investigate conventional and additive manufacturing techniques Analyze system level performance of novel heat...

  7. Industrial Plate Exchangers Heat Recovery and Fouling 

    E-Print Network [OSTI]

    Cross, P. H.

    1981-01-01

    Plate and Frame Heat Exchangers have special characteristics for both fouling and heat recovery. These are discussed in general then related to two industrial examples....

  8. Integrated Approach to Revamping Heat Exchangers Networks 

    E-Print Network [OSTI]

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

    2002-01-01

    A heat exchanger network constitutes the core of the plant energy systems interlinking the core process operation and the utility systems. This paper will illustrate an integrated approach for the revamp of a heat exchanger network by bringing...

  9. Synergistic diffuser/heat-exchanger design

    E-Print Network [OSTI]

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

    2004-01-01

    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 ...

  10. Second Law Optimization of Heat Exchangers 

    E-Print Network [OSTI]

    Witte, L. C.

    1985-01-01

    A new method for optimizing heat exchangers is developed in this paper. It is based on second law efficiency relationships rather than on the traditional heat exchanger effectiveness concept. The cost of energy is based on its availability level...

  11. Helically coiled tube heat exchanger

    SciTech Connect (OSTI)

    Harris, A.M.

    1981-08-18

    In a heat exchanger such as a steam generator for a nuclear reactor, two or more bundles of helically coiled tubes are arranged in series with the tubes in each bundle integrally continuing through the tube bundles arranged in series therewith. Pitch values for the tubing in any pair of tube bundles, taken transverse to the path of the reactor coolant flow about the tubes, are selected as a ratio of two unequal integers to permit efficient operation of each tube bundle while maintaining the various tube bundles of the heat exchanger within a compact envelope. Preferably, the helix angle and tube pitch parallel to the path of coolant flow are constant for all tubes in a single bundle so that the tubes are of approximately the same length within each bundle.

  12. 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

    2011-04-01

    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.

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

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

    Light weight and economical exhaust heat exchanger for waste heat recovery using mixed radiant and convective heat transfer Light weight and economical exhaust heat exchanger for...

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

    E-Print Network [OSTI]

    Thole, Karen A.

    acceptable increases in pressure losses. Increases in efficiency allow for louvered fin heat exchang- ersHeat transfer augmentation along the tube wall of a louvered fin heat exchanger using practical surface of louvered fin heat exchangers. It is shown that delta winglets placed on louvered fins produce

  15. Heat exchanger for a Stirling engine

    SciTech Connect (OSTI)

    Fujiwara, M.; Nomaguchi, T.; Kazumoto, Y.; Tsuchino, K.; Kawajiri, K.; Hisamori, Y.

    1987-05-05

    A heat exchanger is described for a Stirling engine comprising: a domed cylinder having a domed portion and a cylindrical portion. The domed cylinder serves as a high-temperature cylinder and a regenerator housing of the Stirling engine; a cylindrical inner liner which is coaxially disposed inside the domed cylinder and which divides the inside of the domed cylinder into an expansion space inside of the inner liner and a regenerator space between the outer surface of the inner liner and the inner surface of the cylindrical portion of the domed cylinder.

  16. Heat Exchangers for Solar Water Heating Systems | Department...

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

    air used to heat water or a space. Heat exchangers can be made of steel, copper, bronze, stainless steel, aluminum, or cast iron. Solar heating systems usually use copper, because...

  17. Thermodynamic Efficiency of Heat Exchange Devices 

    E-Print Network [OSTI]

    Witte, L. C.; Shamsundar, N.

    1982-01-01

    inlet temperatures, the efficiency and effectiveness for particular heat exchange configurations are related. Conclusions regarding the effect of stream temperatures on the efficiency of various types of exchangers are made. The concept is applied...

  18. Silver Sinter Heat Exchangers Construction of a sinter press and a BET-system to measure

    E-Print Network [OSTI]

    Zumbühl, Dominik

    Silver Sinter Heat Exchangers Construction of a sinter press and a BET-system to measure specific, efficient heat exchangers are of special importance. As the thermal boundary resistance, called Kapitza­resistance, is inversely proportional to the interface area, heat exchangers with large surface areas are used for the heat

  19. 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...

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

    E-Print Network [OSTI]

    Singh, K. P.

    1979-01-01

    CHARACTERISTICS OF A GENERALIZED DIVIDED FLrnJ HEAT EXCHANGER KRISHNA P. SINGH, CHIEF ENGINEER JOSEPH OAT CORPORATION 2500 Broadway, Camden, New Jersey 08104 ,l\\bstract The concept of a "Di vi ded-fl O~I" heat exchanger is general i zed by 1oca t i n...-Pass Split-Flow Shell Trans. of the ASME, Journal of Heat Transfer, pp 408-416, Aug. 1964. (4) Singh, K. P. and Holtz, ~I.J., "Generalization of the Split Flow Heat Exchanger - Geometry for Enhanced Heat Transfer", 18th National ASME/AICHE Heat Transfer...

  1. Simultaneous Synthesis of Heat Exchanger Networks with Operability Considerations

    E-Print Network [OSTI]

    Grossmann, Ignacio E.

    Simultaneous Synthesis of Heat Exchanger Networks with Operability Considerations: Flexibility for the synthesis of flexible and controllable Heat Exchanger Networks. The synthesis is projected to operate over: heat integration, heat exchanger network synthesis, operability, flexibility, controllability

  2. Modeling of Heat Transfer in Geothermal Heat Exchangers 

    E-Print Network [OSTI]

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

    2006-01-01

    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. Microchannel crossflow fluid heat exchanger and method for its fabrication

    DOE Patents [OSTI]

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

    1982-08-31

    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.

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

    DOE Patents [OSTI]

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

    1985-05-14

    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.

  5. 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)

    1985-01-01

    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.

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

    E-Print Network [OSTI]

    of double-tube heat exchangers #12;Company Logo Experimental apparatus Metal Type Ti SUS304 Al Cu Al 15m AlDesign and Test of Tube & Shell Heat Exchangers for Potential OTEC Application Jeong-Tae Kwon1 exchanger #12;Company Logo Cross-Counter -1 heat exchanger Cross-Counter -2 heat exchanger Double tube heat

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

    DOE Patents [OSTI]

    Koplow, Jeffrey P. (San Ramon, CA)

    2012-07-24

    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.

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

    DOE Patents [OSTI]

    Koplow, Jeffrey P.

    2015-12-08

    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.

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

    DOE Patents [OSTI]

    Koplow, Jeffrey P

    2013-12-10

    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.

  10. Hierarchical Modeling for Population-Based Heat Exchanger Design

    E-Print Network [OSTI]

    Geb, David

    2013-01-01

    Figure 3.3: Heat exchanger core pressure drop. Adapted fromFigure 3.3: Heat exchanger core pressure drop. Adapted fromtotal pressure drop through a compact heat exchanger as ? P

  11. Low Cost Polymer heat Exchangers for Condensing Boilers

    SciTech Connect (OSTI)

    Butcher, Thomas; Trojanowski, Rebecca; Wei, George; Worek, Michael

    2015-09-30

    Work in this project sought to develop a suitable design for a low cost, corrosion resistant heat exchanger as part of a high efficiency condensing boiler. Based upon the design parameters and cost analysis several geometries and material options were explored. The project also quantified and demonstrated the durability of the selected polymer/filler composite under expected operating conditions. The core material idea included a polymer matrix with fillers for thermal conductivity improvement. While the work focused on conventional heating oil, this concept could also be applicable to natural gas, low sulfur heating oil, and biodiesel- although these are considered to be less challenging environments. An extruded polymer composite heat exchanger was designed, built, and tested during this project, demonstrating technical feasibility of this corrosion-resistant material approach. In such flue gas-to-air heat exchangers, the controlling resistance to heat transfer is in the gas-side convective layer and not in the tube material. For this reason, the lower thermal conductivity polymer composite heat exchanger can achieve overall heat transfer performance comparable to a metal heat exchanger. However, with the polymer composite, the surface temperature on the gas side will be higher, leading to a lower water vapor condensation rate.

  12. Heat Exchanger Support Bracket Design Calculations

    SciTech Connect (OSTI)

    Rucinski, Russ; /Fermilab

    1995-01-12

    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.

  13. Measuring important parameters for air-sea heat exchange Christoph S. Garbeab, Uwe Schimpfab and Bernd Jhneab

    E-Print Network [OSTI]

    Garbe, Christoph S.

    Measuring important parameters for air-sea heat exchange Christoph S. Garbeab, Uwe Schimpfab Exchange, Heat flux, Digital Image Processing, Surface Renewal 1. INTRODUCTION Thermographic techniques-water heat exchange. A driving force in air sea interactions is the net sea surface heat flux. It is a vital

  14. Advanced Heat/Mass Exchanger Technology for Geothermal and solar...

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

    HeatMass Exchanger Technology for Geothermal and solar Renewable Energy Systems Advanced HeatMass Exchanger Technology for Geothermal and solar Renewable Energy Systems Advanced...

  15. Predicting particle deposition on HVAC heat exchangers

    E-Print Network [OSTI]

    Siegel, J A; Nazaroff, William W

    2003-01-01

    Processing 75 (1), 121-127. Muyshondt, A. , Nutter, D. ,Bott and Bemrose, 1983; Muyshondt et al. , 1998). However,HVAC heat exchanger fouling (Muyshondt et al. , 1998). It is

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

    SciTech Connect (OSTI)

    Koplow, Jeffrey P.

    2010-01-01

    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.

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

    E-Print Network [OSTI]

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

    2009-01-01

    . Before the design process can begin, product specifications, such as steam or water pressures and temperatures, and equipment, such as absorption chillers and heat exchangers, need to be identified and defined. The Energy Engineering Laboratory...

  18. Dealing with Uncertainties During Heat Exchanger Design 

    E-Print Network [OSTI]

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

    2001-01-01

    Over the last thirty years much progress has been made in heat exchanger design methodology. Even so, the design engineer still has to deal with a great deal of uncertainty. Whilst the methods used to predict heat transfer coefficients are now quite...

  19. Heat Exchanger With Internal Pin Elements

    DOE Patents [OSTI]

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

    2004-01-13

    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.

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

    SciTech Connect (OSTI)

    Rosner, D.E.

    1988-12-01

    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.

  1. Heat exchanger for coal gasification process

    DOE Patents [OSTI]

    Blasiole, George A. (Greensburg, PA)

    1984-06-19

    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.

  2. Heat exchanger containing a component capable of discontinuous movement

    DOE Patents [OSTI]

    Wilson, David Gordon (Winchester, MA)

    2002-01-01

    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.

  3. Heat exchanger containing a component capable of discontinuous movement

    DOE Patents [OSTI]

    Wilson, David G. (Winchester, MA)

    1993-01-01

    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.

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

    E-Print Network [OSTI]

    Fisk, William J.

    2013-01-01

    effectiveness of a heat exchanger rates due to the decreasesthrough volumetric flow the rate heat of exchanger. the twothe heat exchanger. The rate of heat transfer "Q" between

  5. Carbon nanotube heat-exchange systems

    DOE Patents [OSTI]

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

    2008-11-11

    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).

  6. 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

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

    E-Print Network [OSTI]

    Thole, Karen A.

    Abstract The louvered fin heat exchanger, a type of compact heat exchanger, has been used heavilyEffects 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

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

    E-Print Network [OSTI]

    . Feasibility of foundation heat exchangers in ground source heat pump systems in the United States. ASHRAE 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

  9. Triple loop heat exchanger for an absorption refrigeration system

    DOE Patents [OSTI]

    Reimann, Robert C. (Lafayette, NY)

    1984-01-01

    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.

  10. 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 pump systems. For detailed analysis and accurate simulation of the transient heat transfer in vertical

  11. Preliminary SP-100/Stirling heat exchanger designs

    SciTech Connect (OSTI)

    Schmitz, P.; Tower, L.; Dawson, R.; Blue, B.; Dunn, P.

    1994-09-01

    Analytic modeling of several heat exchanger concepts to couple the SP-100 nuclear reactor lithium loop and the Space Stirling Power Convertor (SSPC) was performed. Four 25 kWe SSPC`s are used to produce the required 100 kW of electrical power. This design work focused on the interface between a single SSPC and the primary lithium loop. Manifolding to separate and collect the four channel flow was not modeled. This work modeled two separate types of heat exchanger interfaces (conductive coupling and radiative coupling) to explore their relative advantages and disadvantages. The minimum mass design of the conductively coupled concepts was 18 kg or 0.73 kg/kWe for a single 25 kWe convertor. The minimum mass radiatively coupled concept was 41 kg or 1.64 kg/kWe. The direct conduction heat exchanger provides a lighter weight system because of its ability to operate the Stirling convertor evaporator at higher heat fluxes than those attainable by the radiatively coupled systems. Additionally the conductively coupled concepts had relatively small volumes and provide potentially simpler assembly. Their disadvantages were the tight tolerances and material joining problems associated with this refractory to superalloy interface. The advantages of the radiatively coupled designs were the minimal material interface problems.

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

    E-Print Network [OSTI]

    exchanger model is crucial for analysis of hybrid ground source heat pump systems. Ground source heat pumps in a hybrid ground source heat pump application under different climate conditions. An actual office buildingMODELING OF VERTICAL GROUND LOOP HEAT EXCHANGERS FOR GROUND SOURCE HEAT PUMP SYSTEMS By CENK

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

    Energy Savers [EERE]

    Demonstration and Performance Monitoring of Foundation Heat Exchangers in Low Load, High Performance Research Homes Demonstration and Performance Monitoring of Foundation Heat...

  14. Using Plate Heat Exchangers to Increase Energy Efficiency 

    E-Print Network [OSTI]

    Bailey, K.

    1999-01-01

    "In recent years, there has been an increasing awareness of Plate Heat Exchangers (PHE's) in industrial processes around the world. While PHE's have historically been classified as compact heat exchangers, compactness is often a secondary advantage...

  15. Hierarchical Modeling for Population-Based Heat Exchanger Design

    E-Print Network [OSTI]

    Geb, David

    2013-01-01

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

  16. A laboratory exercise using a physical model for demonstrating countercurrent heat exchange

    E-Print Network [OSTI]

    Loudon, Catherine; Davis-Berg, Elizabeth C; Botz, Jason T

    2012-01-01

    demonstrating countercurrent heat exchange Catherine Loudon,demonstrating countercurrent heat exchange. Adv Physiol Educ23). Countercurrent heat exchange may be physically modeled

  17. A NEW SOLAR THERMAL RECEIVER UTILIZING A SMALL PARTICLE HEAT EXCHANGER

    E-Print Network [OSTI]

    Hunt, Arlon J.

    2011-01-01

    a Small Particle Heat Exchange Receiver (SPHER) operates byof the Small Particle Heat Exchange Receiver (or SPHER), asabsorption process, the heat exchange to the gas, the their

  18. INTEGRATED DESIGN AND CONTROL OF HEAT EXCHANGER NETWORKS

    E-Print Network [OSTI]

    Skogestad, Sigurd

    INTEGRATED DESIGN AND CONTROL OF HEAT EXCHANGER NETWORKS #12; by Knut Wiig Mathisen A Thesis examples in their research attitudes. Truls also introduced me to heat exchanger networks, and has been have worked closely together with John Ulvøy on a paper on heat exchanger network synthesis

  19. ISHED1: Applying the LEM Methodology to Heat Exchanger Design

    E-Print Network [OSTI]

    Michalski, Ryszard S.

    ISHED1: Applying the LEM Methodology to Heat Exchanger Design Kenneth A. Kaufman Ryszard S. Michalski MLI 00-2 #12;2 ISHED1: APPLYING THE LEM METHODOLOGY TO HEAT EXCHANGER DESIGN Kenneth A. Kaufman-2 January 2000 #12;ISHED1: APPLYING THE LEM METHODOLOGY TO HEAT EXCHANGER DESIGN Abstract Evolutionary

  20. Heat exchanger support apparatus in a fluidized bed

    DOE Patents [OSTI]

    Lawton, Carl W. (West Hartford, CT)

    1982-01-01

    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. The Neural Heat Exchanger ``Invited Talk'' at ICONIP'96

    E-Print Network [OSTI]

    Schmidhuber, Juergen

    The Neural Heat Exchanger ``Invited Talk'' at ICONIP'96 J¨urgen Schmidhuber IDSIA, Corso Elvezia 36 by the physical heat exchanger. Unlike backprop, it is entirely local. This makes its parallel implementation in written form. To fully understand the Neural Heat Exchanger's advantages and limitations, however, much

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

    E-Print Network [OSTI]

    Boyer, Edmond

    Boundary geometric control of a counter-current heat exchanger Ahmed MAIDIa , Moussa DIAFb , Jean control of a counter-current heat exchanger whose control is designed considering a model based on two. The objective consists in controlling the internal fluid temperature, at the heat exchanger outlet

  3. Optimizing PT Arun LNG main heat exchanger

    SciTech Connect (OSTI)

    Irawan, B.

    1995-12-01

    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.

  4. Technology Solutions Case Study: Foundation Heat Exchanger, Oak Ridge, Tennessee

    SciTech Connect (OSTI)

    2014-03-01

    The foundation heat exchanger, developed by Oak Ridge National Laboratory, is a new concept for a cost-effective horizontal ground heat exchanger that can be connected to water-to-water or water-to-air heat pump systems for space conditioning as well as domestic water heating.

  5. Expanded microchannel heat exchanger: design, fabrication and preliminary experimental test

    E-Print Network [OSTI]

    Denkenberger, David C; Pearce, Joshua M; Zhai, John; 10.1177/0957650912442781

    2012-01-01

    This paper first reviews non-traditional heat exchanger geometry, laser welding, practical issues with microchannel heat exchangers, and high effectiveness heat exchangers. Existing microchannel heat exchangers have low material costs, but high manufacturing costs. This paper presents a new expanded microchannel heat exchanger design and accompanying continuous manufacturing technique for potential low-cost production. Polymer heat exchangers have the potential for high effectiveness. The paper discusses one possible joining method - a new type of laser welding named "forward conduction welding," used to fabricate the prototype. The expanded heat exchanger has the potential to have counter-flow, cross-flow, or parallel-flow configurations, be used for all types of fluids, and be made of polymers, metals, or polymer-ceramic precursors. The cost and ineffectiveness reduction may be an order of magnitude or more, saving a large fraction of primary energy. The measured effectiveness of the prototype with 28 micro...

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

    E-Print Network [OSTI]

    Fisk, William J.

    2013-01-01

    another. Another type of heat exchanger is a heat wheel (ferent for each type of heat exchanger. exchanger may heatopposite directions. A heat similar type of exchanger 1s the

  7. GEA Heat Exchangers GEA Searle Cooler and Condensing Unit Ranges

    E-Print Network [OSTI]

    Frandsen, Søren

    process cooling, combined heat and power installations and air-conditioning equip- ment for hospitalsGEA Heat Exchangers GEA Searle Cooler and Condensing Unit Ranges Top-level engineering solutions,Eurovent verification and many more. GEA is one of the longest established and principal manufacturers of heat exchange

  8. Limitations of Using Uniform Heat Flux Assumptions in Sizing Vertical Borehole Heat Exchanger Fields

    E-Print Network [OSTI]

    of ground heat exchangers (GHE) used with ground source heat pump (GSHP) systems. These models can account approach with a parametric study. Keywords - Ground Source Heat Pumps; Borehole Heat Exchangers; Finite Line Source Theory; g-functions 1. Introduction Ground source heat pump (GSHP) systems are a widely

  9. 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

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

    E-Print Network [OSTI]

    Chen, Y.; Zhao, J.

    2006-01-01

    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 ...

  11. Automatic Tube Cleaning Systems for Condensers and Heat Exchangers 

    E-Print Network [OSTI]

    Someah, K.

    1991-01-01

    The on-line Automatic Tube Cleaning Systems (ATCS) for condensers and heat exchangers provide a positive means for automatic cleaning on a continuous basis, while the exchanger or condenser remains "on stream" and at ...

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

    E-Print Network [OSTI]

    Fisk, William J.

    2013-01-01

    effectiveness and low pressure exchanger would drop of thisAluminum Flanges Pressure Tap Heat Exchanger Transition,therefore the pressure in the heat exchanger was slightly

  13. 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)

    1988-01-01

    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.

  14. Heat extraction from salinity-gradient solar ponds using heat pipe heat exchangers

    SciTech Connect (OSTI)

    Tundee, Sura; Terdtoon, Pradit; Sakulchangsatjatai, Phrut; Singh, Randeep; Akbarzadeh, Aliakbar

    2010-09-15

    This paper presents the results of experimental and theoretical analysis on the heat extraction process from solar pond by using the heat pipe heat exchanger. In order to conduct research work, a small scale experimental solar pond with an area of 7.0 m{sup 2} and a depth of 1.5 m was built at Khon Kaen in North-Eastern Thailand (16 27'N102 E). Heat was successfully extracted from the lower convective zone (LCZ) of the solar pond by using a heat pipe heat exchanger made from 60 copper tubes with 21 mm inside diameter and 22 mm outside diameter. The length of the evaporator and condenser section was 800 mm and 200 mm respectively. R134a was used as the heat transfer fluid in the experiment. The theoretical model was formulated for the solar pond heat extraction on the basis of the energy conservation equations and by using the solar radiation data for the above location. Numerical methods were used to solve the modeling equations. In the analysis, the performance of heat exchanger is investigated by varying the velocity of inlet air used to extract heat from the condenser end of the heat pipe heat exchanger (HPHE). Air velocity was found to have a significant influence on the effectiveness of heat pipe heat exchanger. In the present investigation, there was an increase in effectiveness by 43% as the air velocity was decreased from 5 m/s to 1 m/s. The results obtained from the theoretical model showed good agreement with the experimental data. (author)

  15. Negative Joule Heating in Ion-Exchange Membranes

    E-Print Network [OSTI]

    P. M. Biesheuvel; D. Brogioli; H. V. M. Hamelers

    2014-02-06

    In ion-exchange membrane processes, ions and water flow under the influence of gradients in hydrostatic pressure, ion chemical potential, and electrical potential (voltage), leading to solvent flow, ionic fluxes and ionic current. At the outer surfaces of the membranes, electrical double layers (EDLs) are formed (Donnan layers). When a current flows through the membrane, we argue that besides the positive Joule heating in the bulk of the membrane and in the electrolyte outside the membrane, there is also negative Joule heating in one of the EDLs. We define Joule heating as the inner product of the two vectors current and field strength. Also when fluid flows through a charged membrane, at one side of the membrane there is pressure-related cooling, due to the osmotic and hydrostatic pressure differences across the EDLs.

  16. Negative Joule Heating in Ion-Exchange Membranes

    E-Print Network [OSTI]

    Biesheuvel, P M; Hamelers, H V M

    2014-01-01

    In ion-exchange membrane processes, ions and water flow under the influence of gradients in hydrostatic pressure, ion chemical potential, and electrical potential (voltage), leading to solvent flow, ionic fluxes and ionic current. At the outer surfaces of the membranes, electrical double layers (EDLs) are formed (Donnan layers). When a current flows through the membrane, we argue that besides the positive Joule heating in the bulk of the membrane and in the electrolyte outside the membrane, there is also negative Joule heating in one of the EDLs. We define Joule heating as the inner product of the two vectors current and field strength. Also when fluid flows through a charged membrane, at one side of the membrane there is pressure-related cooling, due to the osmotic and hydrostatic pressure differences across the EDLs.

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

    DOE Patents [OSTI]

    Gillett, James E. (Greensburg, PA); Johnson, F. Thomas (Baldwin Boro, PA); Orr, Richard S. (Pittsburgh, PA); Schulz, Terry L. (Murrysville Boro, PA)

    1993-01-01

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

  18. High-Performance Refrigerator Using Novel Rotating Heat Exchanger...

    Energy Savers [EERE]

    Cooler relative to current heat exchanger technology are additional refrigerated space, noise reduction, and fouling reduction. Additional refrigerated volume realized by the more...

  19. Urban Surfaces and Heat Island Mitigation Potentials

    E-Print Network [OSTI]

    Akbari, Hashem

    2008-01-01

    Finster. 2000. “The Urban Heat Island, Photochemical Smog,2001. “EPA/NASA Urban Heat Island Pilot Project,” GlobalSystem Urban Surfaces and Heat Island Mitigation Potentials

  20. 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

    2014-12-01

    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 materialmore »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 « less

  1. Automatic Tube Cleaning Systems for Condensers & Heat Exchangers 

    E-Print Network [OSTI]

    Someah, K.

    1993-01-01

    Condenser tube fouling contributes up to 50% of the total condenser tube heat transfer resistance. This fouling results in reduced heat exchanger performance, reduced production, increased operational cost, increased back pressure, increased tube...

  2. MEE 452: Example 3-2 ShellShell--andand--Tube Heat Exchanger Analysis:Tube Heat Exchanger Analysis

    E-Print Network [OSTI]

    Kostic, Milivoje M.

    MEE 452: Example 3-2 ShellShell--andand--Tube Heat Exchanger Analysis:Tube Heat Exchanger Analysis-butyl alcohol @150oF. Two-tube-pass for illustration only COUNTER FLOW T PARALLEL FLOW T Heat Exchanger/c,out or 16/Re otherwise Tube-side Pressure drop ... MathCAD S&T HX analysis 7 of 7 Tube-side Pressure drop

  3. Advanced heat exchanger development for molten salts

    SciTech Connect (OSTI)

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

    2014-12-01

    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.

  4. Thermal behavior of spiral fin-and-tube heat exchanger having fly ash deposit

    SciTech Connect (OSTI)

    Nuntaphan, Atipoang; Kiatsiriroat, Tanongkiat

    2007-08-15

    This research investigates the effect of fly-ash deposit on thermal performance of a cross-flow heat exchanger having a set of spiral finned-tubes as a heat transfer surface. A stream of warm air having high content of fly-ash is exchanging heat with a cool water stream in the tubes. In this study, the temperature of the heat exchanger surface is lower than the dew point temperature of air, thus there is condensation of moisture in the air stream on the heat exchanger surface. The affecting parameters such as the fin spacing, the air mass flow rate, the fly-ash mass flow rate and the inlet temperature of warm air are varied while the volume flow rate and the inlet temperature of the cold water stream are kept constant at 10 l/min and 5 C, respectively. From the experiment, it is found that as the testing period is shorter than 8 h the thermal resistance due to the fouling increases with time. Moreover, the deposit of fly-ash on the heat transfer surface is directly proportional to the dust-air ratio and the amount of condensate on heat exchange surface. However, the deposit of fly-ash is inversely proportional to the fin spacing. The empirical model for evaluating the thermal resistance is also developed in this work and the simulated results agree well with those of the measured data. (author)

  5. An Investigation and Characterization of Metal Foam Filled Double-Pipe Heat Exchangers

    E-Print Network [OSTI]

    Chen, Xi

    2014-01-01

    a metal foam filled double-pipe heat exchanger: a) Pressurein a metal foam filled double-pipe heat exchanger witha plain double-pipe heat exchanger: a) Total heat transfer

  6. Steps for design of Heat Exchanger Dr. Reyad Shawabkeh

    E-Print Network [OSTI]

    Shawabkeh, Reyad A.

    Steps for design of Heat Exchanger By Dr. Reyad Shawabkeh Department of Chemical Engineering King to cold and hot streams. Then obtain the heat duty, q. 5. Based on the type of flow, calculate Log Mean/Assume the type of floating head of the exchanger and obtain the bundle diameter clearance, BDC . Use the chart

  7. Circulating heat exchangers for oscillating wave engines and refrigerators

    DOE Patents [OSTI]

    Swift, Gregory W.; Backhaus, Scott N.

    2003-10-28

    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.

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

    DOE Patents [OSTI]

    Drake, Richard L. (Delmar, NY)

    1993-01-01

    A heat exchanger 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.

  9. Test results of a Stirling engine utilizing heat exchanger modules with an integral heat pipe

    SciTech Connect (OSTI)

    Skupinski, R.C.; Tower, L.K.; Madi, F.J.; Brusk, K.D.

    1993-04-01

    The Heat Pipe Stirling Engine (HP-1000), a free-piston Stirling engine incorporating three heat exchanger modules, each having a sodium filled heat pipe, has been tested at the NASA-Lewis Research Center as part of the Civil Space Technology Initiative (CSTI). The heat exchanger modules were designed to reduce the number of potential flow leak paths in the heat exchanger assembly and incorporate a heat pipe as the link between the heat source and the engine. An existing RE-1000 free-piston Stirling engine was modified to operate using the heat exchanger modules. This paper describes heat exchanger module and engine performance during baseline testing. Condenser temperature profiles, brake power, and efficiency are presented and discussed.

  10. 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

    2011-12-01

    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

  11. 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)

    1994-11-29

    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.

  12. 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.

    2002-01-01

    -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...

  13. Error Analysis of Heat Transfer for Finned-Tube Heat-Exchanger Text-Board 

    E-Print Network [OSTI]

    Chen, Y.; Zhang, J.

    2006-01-01

    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...

  14. Low-Cost Microchannel Heat Exchanger

    Office of Environmental Management (EM)

    corrosion resistant alloys construction Oil and gas platform processes, separators, LNG processing, chillers, heat pumps, fuels reforming, waste heat power systems and...

  15. 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.

    1993-11-30

    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.

  16. A simplified model for heat transfer in heat exchangers and stack plates for thermoacoustic devices

    SciTech Connect (OSTI)

    Chen, Y.; Herman, C.

    1999-07-01

    A simplified model of heat transfer in heat exchangers and stack plates of thermoacoustic devices was developed. The model took advantage of previous results regarding the thermal behavior of the thermoacoustic core for investigations of the performance of heat exchangers attached to the core. Geometrical and operational parameters as well as thermophysical properties of the heat exchangers, the plate, and the working medium were organized into dimensionless groups that allowed to account for their impact on the performance of the heat exchangers. Numerical simulations with the model were carried out. Nonlinear temperature distributions and heat fluxes near the edge of the stack plate were observed. Effects of different parameters on the thermal performance of the heat exchangers were investigated.

  17. Acoustically enhanced heat exchange and drying apparatus

    DOE Patents [OSTI]

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

    1987-07-10

    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.

  18. SILICON CARBIDE CERAMICS FOR COMPACT HEAT EXCHANGERS

    SciTech Connect (OSTI)

    DR. DENNIS NAGLE; DR. DAJIE ZHANG

    2009-03-26

    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

  19. Heat exchanger for reactor core and the like

    DOE Patents [OSTI]

    Kaufman, Jay S. (Del Mar, CA); Kissinger, John A. (Del Mar, CA)

    1986-01-01

    A compact bayonet tube type heat exchanger which finds particular application as an auxiliary heat exchanger for transfer of heat from a reactor gas coolant to a secondary fluid medium. The heat exchanger is supported within a vertical cavity in a reactor vessel intersected by a reactor coolant passage at its upper end and having a reactor coolant return duct spaced below the inlet passage. The heat exchanger includes a plurality of relatively short length bayonet type heat exchange tube assemblies adapted to pass a secondary fluid medium therethrough and supported by primary and secondary tube sheets which are releasibly supported in a manner to facilitate removal and inspection of the bayonet tube assemblies from an access area below the heat exchanger. Inner and outer shrouds extend circumferentially of the tube assemblies and cause the reactor coolant to flow downwardly internally of the shrouds over the tube bundle and exit through the lower end of the inner shroud for passage to the return duct in the reactor vessel.

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

    E-Print Network [OSTI]

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

    1988-01-01

    , would be those relatively few cases where heat has been recovered from pyrolysis furnace gases (in ethylene 78712 manufacture) via a quench liquid that provides intennedia level heat for process purposes. In the present paper we shall concentrate... pyrolysis furnace are cooled in oil- and water-quench towers, and higher-boiling oils are condensed from the gases. While not always used for heat recovery, the exit process water stream is hot enough for process heat exchange. For the examples shown...

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

    SciTech Connect (OSTI)

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

    2011-06-01

    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.

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

    SciTech Connect (OSTI)

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

    2011-04-01

    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.

  3. 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.

    1994-01-01

    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...

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

    E-Print Network [OSTI]

    Gaskill, Travis

    2012-02-14

    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...

  5. Energy effectiveness of simultaneous heat and mass exchange devices

    E-Print Network [OSTI]

    Narayan, G. Prakash

    2010-01-01

    Simultaneous heat and mass exchange devices such as cooling towers, humidifiers and dehumidifiers are widely used in the power generation, desalination, air conditioning, and refrigeration industries. For design and rating ...

  6. Oscillating side-branch enhancements of thermoacoustic heat exchangers

    SciTech Connect (OSTI)

    Swift, Gregory W.

    2003-05-13

    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.

  7. Building Integrated Heat and Moisture Exchange | Department of...

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

    1 of 2 Building-integrated heat and moisture exchanger, the AirFlow(tm) Panel, installed for evaluation at Lawrence Berkeley National Lab. Image: Architectural Applications 2 of 2...

  8. Internal combustion engine system with fog injection and heat exchange

    SciTech Connect (OSTI)

    Munk, M.

    1987-10-27

    An improved turbine apparatus is described comprising: a turbine power generator, including a source of input air, and a source of fuel, a compressor which receives the input air, a combustion chamber which receives air from the output of the compressor and fuel from the source of fuel, a turbine which receives exhaust gases from the combustion chamber; and an electrical generator mechanically coupled with the turbine; a fogging device communicating with the input air. The fogging device is adapted to receive a fogger air supply and a fogger water supply, and to generate a fog in the input air, an adjustable heat exchanger for exchanging heat from the exhaust of the turbine to the input air to be fogged; and means for adjusting the level of heat exchange of the heat exchanger in accordance with properties of the input air and the level of fog being generated.

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

    E-Print Network [OSTI]

    Lazaridis, A.; Rafailidis, E.

    1995-01-01

    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...

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

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

    of a High Efficiency Hot Gas Turbo-expander and Low Cost Heat Exchangers for Optimized CSP Supercritical CO2 Operation 10-Megawatt Supercritical Carbon Dioxide Turbine - FY13 Q2...

  11. Pressure drop across spined heat exchangers in crossflow 

    E-Print Network [OSTI]

    Carranza, Richard Guy

    1987-01-01

    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...

  12. Heat Exchanger Fouling- Prediction, Measurement and Mitigation 

    E-Print Network [OSTI]

    Peterson, G. R.

    1989-01-01

    of an industrial gas stream and to derive the fouling thermal resistance. The probe is a hollow metal cylinder capable of measuring the average heat flux along the length of the tube. The local heat flux is also measured by a heat flux meter embedded in the probe...

  13. Design issues of a thermoacoustic refrigerator and its heat exchangers

    SciTech Connect (OSTI)

    Wetzel, M.; Herman, C.

    1996-12-31

    Thermoacoustic refrigeration is a fast advancing new refrigeration technology. Performance calculations indicate remarkable values for the thermoacoustic core of a thermoacoustic refrigerator. The thermoacoustic core is responsible for pumping heat from a cold to a hot temperature reservoir. However, the systems necessary to support the thermoacoustic core, such as heat exchangers and acoustic drivers are the weak points of this refrigeration technology. Particularly, heat exchangers were designed so far without any optimization. A reason for this is the lack of knowledge of the flow structures and heat transfer phenomena at the interface between the thermoacoustic core and the heat exchangers. For the purpose of gaining better insight, the authors built a thermoacoustic refrigerator model and applied visualization techniques, such as smoke injection and holographic interferometry, to visualize the flow and temperature fields at the interface.

  14. Acoustically enhanced heat exchange and drying apparatus

    DOE Patents [OSTI]

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

    1989-01-01

    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.

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

    E-Print Network [OSTI]

    Parker, Brandon DeWayne

    1995-01-01

    The effects of outdoor heat exchanger hydrophobic treatment on the performance of an air source heat pump were investigated. The base case tests used a bare aluminum outdoor heat exchanger in the experimental setup. The base case test results were...

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

    DOE Patents [OSTI]

    Drake, R.L.

    1993-12-28

    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.

  17. Temperature control system for a J-module heat exchanger

    DOE Patents [OSTI]

    Basdekas, Demetrios L. (Rockville, PA); Macrae, George (Murrysville, PA); Walsh, Joseph M. (Pittsburgh, PA)

    1978-01-01

    The level of primary fluid is controlled to change the effective heat transfer area of a heat exchanger utilized in a liquid metal nuclear power plant to eliminate the need for liquid metal control valves to regulate the flow of primary fluid and the temperature of the effluent secondary fluid.

  18. MODELING PARTICLE DEPOSITION ON HVAC HEAT EXCHANGERS

    E-Print Network [OSTI]

    in supplying ventilation and air conditioning. This paper explores mechanisms that cause particle deposition energy and indoor air quality degradation for heating, ventilating, and air conditioning (HVAC) systems

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

    DOE Patents [OSTI]

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

    1984-08-30

    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.

  20. 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)

    1985-01-01

    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.

  1. Online optimization and choice of optimization variables for control of heat exchanger networks

    E-Print Network [OSTI]

    Skogestad, Sigurd

    On­line optimization and choice of optimization variables for control of heat exchanger networks B operation of a general heat exchanger network with given structure, heat exchanger areas and stream data to any heat exchanger network. Using this model periodically for optimization, the operating conditions

  2. On-line optimization and choice of optimization variables for control of heat exchanger networks

    E-Print Network [OSTI]

    Skogestad, Sigurd

    On-line optimization and choice of optimization variables for control of heat exchanger networks B operation of a general heat exchanger network with given structure, heat exchanger areas and stream data to any heat exchanger network. Using this model periodically for optimization, the operating conditions

  3. 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 oil in the heat exchanger network. The steady state mass and energy balance of the 20 heat exchangers

  4. 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

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

    E-Print Network [OSTI]

    Fisk, William J.

    2013-01-01

    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

  6. 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)

    1996-12-03

    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.

  7. THERMOSIPHON WATER HEATERS WITH HEAT EXCHANGERS

    E-Print Network [OSTI]

    Mertol, Atila

    2012-01-01

    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

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

    E-Print Network [OSTI]

    Gonzalez, Jose Antonio

    1993-01-01

    produced a ground coupled heat pump simulation (GSIM) which modeled ground coupled systems using soil properties, weather data, building load and ground coil properties. This model has been validated in cooling [Dobson, 1991] and heating [Margo, 1992... U-tube ground coupled heat pump heat exchangers for Texas climates is presented. Weather and soil data for Texas were gathered and presented using topographical charts. GSIM, the ground coupled heat pump simulation model, was utilized to provide...

  9. Liquid Salt Heat Exchanger Technology for VHTR Based Applications

    SciTech Connect (OSTI)

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

    2012-10-11

    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.

  10. SIMULATION OF COMPACT HEAT EXCHANGERS USING GLOBAL REGRESSION AND SOFT COMPUTING

    E-Print Network [OSTI]

    Sen, Mihir

    SIMULATION OF COMPACT HEAT EXCHANGERS USING GLOBAL REGRESSION AND SOFT COMPUTING A Dissertation investigates enhancement in accuracy of heat rate predictions in compact fin-tube heat exchangers. The sources determined and later applied to heat exchanger data. The direct heat-rate estimations are more accurate. #12

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

    SciTech Connect (OSTI)

    Anderson, Mark; Nellis, Greg; Corradini, Michael

    2012-10-19

    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.

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

    SciTech Connect (OSTI)

    Edward Levy; Harun Bilirgen; John DuPoint

    2011-03-31

    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.

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

    SciTech Connect (OSTI)

    Levy, Edward; Bilirgen, Harun; DuPont, John

    2011-03-31

    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: • 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. • 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. • 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. • 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. • Data on effectiveness of acid traps in reducing sulfuric acid concentrations in a heat exchanger tube bundle. • Condensed flue gas water treatment needs and costs. • 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. • Results of cost-benefit studies of condensing heat exchangers.

  14. Diffusion Welding of Compact Heat Exchangers for Nuclear Applications

    SciTech Connect (OSTI)

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

    2012-06-01

    The next-­-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-­-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.

  15. Design and Development of a Plastic Film Heat Exchanger 

    E-Print Network [OSTI]

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

    1986-01-01

    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... with the design of elements and manifolds are described together with an analysis of the thermal and hydraulic factors affecting the operation of the unit. INTRODUCTION The concept for the plastic film heat exchanger (PFHX) is that of individual heat...

  16. Heat exchanger module for stirling engines

    SciTech Connect (OSTI)

    Darche, M. J. P.; Carlquist, S.

    1985-02-12

    The invention relates to Stirling engines and provides a modular assembly composed of a cylinder head, a heater, a regenerator, a cooler and a cold duct, and making it possible by mounting a plurality of identical modules on an engine assembly to construct a multi-cylinder double acting Stirling engine of the indirect heating type.

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

    SciTech Connect (OSTI)

    Mittereder, N.; Poerschke, A.

    2013-11-01

    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.

  18. Supercritical Carbon Dioxide Turbo-Expander and Heat Exchangers

    Broader source: Energy.gov [DOE]

    This fact sheet describes a supercritical carbon dioxide turbo-expander and heat exchangers project awarded under the DOE's 2012 SunShot Concentrating Solar Power R&D award program. The team, led by the Southwest Research Institute, is working to develop a megawatt-scale s-CO2 hot-gas turbo-expander optimized for the highly transient solar power plant profile. The team is also working to optimize novel printed circuit heat exchangers for s-CO2 applications to drastically reduce their manufacturing costs.

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

    E-Print Network [OSTI]

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

    1987-01-01

    stream_source_info ESL-IE-87-09-07.pdf.txt stream_content_type text/plain stream_size 30705 Content-Encoding ISO-8859-1 stream_name ESL-IE-87-09-07.pdf.txt Content-Type text/plain; charset=ISO-8859-1 HEAT EXCHANGER... of heat exchanger networks (HENs) has focused on the production of powerful, user-friendly software. Advanced optimization techniques, such as mixed integer non linear programming, have been added to established pinch procedures to increase...

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

    E-Print Network [OSTI]

    Witte, L. C.

    1987-01-01

    OF AVAILABILITY COSTS ON OPTIMAL H~ EXCHANGER SIZE Larry C. Witte Professor of Mechanical Engineering University of Houston Houston, TX 77004 examples of such a process. I I Optimizing heat exchangers based on se cond law rather than first law co... ) we can make the plot in Figure 5 of heat duty vs. ~gt. Figures 4 and 5 contain the required inrormation for the selection of an appropri.te optimally sized condensing heater for a p.rticular he.t duty. 300 () 0 I Q) ... n; ~ ... Q...

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

    E-Print Network [OSTI]

    Radermacher, R.

    1986-01-01

    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 ...

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

    E-Print Network [OSTI]

    Fernández de Córdoba, 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

  3. ASME code considerations for the compact heat exchanger

    SciTech Connect (OSTI)

    Nestell, James; Sham, Sam

    2015-08-31

    The mission of the U.S. Department of Energy (DOE), Office of Nuclear Energy is to advance nuclear power in order to meet the nation's energy, environmental, and energy security needs. Advanced high temperature reactor systems such as sodium fast reactors and high and very high temperature gas-cooled reactors are being considered for the next generation of nuclear reactor plant designs. The coolants for these high temperature reactor systems include liquid sodium and helium gas. Supercritical carbon dioxide (sCO?), a fluid at a temperature and pressure above the supercritical point of CO?, is currently being investigated by DOE as a working fluid for a nuclear or fossil-heated recompression closed Brayton cycle energy conversion system that operates at 550°C (1022°F) at 200 bar (2900 psi). Higher operating temperatures are envisioned in future developments. All of these design concepts require a highly effective heat exchanger that transfers heat from the nuclear or chemical reactor to the chemical process fluid or the to the power cycle. In the nuclear designs described above, heat is transferred from the primary to the secondary loop via an intermediate heat exchanger (IHX) and then from the intermediate loop to either a working process or a power cycle via a secondary heat exchanger (SHX). The IHX is a component in the primary coolant loop which will be classified as "safety related." The intermediate loop will likely be classified as "not safety related but important to safety." These safety classifications have a direct bearing on heat exchanger design approaches for the IHX and SHX. The very high temperatures being considered for the VHTR will require the use of very high temperature alloys for the IHX and SHX. Material cost considerations alone will dictate that the IHX and SHX be highly effective; that is, provide high heat transfer area in a small volume. This feature must be accompanied by low pressure drop and mechanical reliability and robustness. Classic shell and tube designs will be large and costly, and may only be appropriate in steam generator service in the SHX where boiling inside the tubes occurs. For other energy conversion systems, all of these features can be met in a compact heat exchanger design. This report will examine some of the ASME Code issues that will need to be addressed to allow use of a Code-qualified compact heat exchanger in IHX or SHX nuclear service. Most effort will focus on the IHX, since the safety-related (Class A) design rules are more extensive than those for important-to-safety (Class B) or commercial rules that are relevant to the SHX.

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

    E-Print Network [OSTI]

    Al-Shayea, Naser Abdul-Rahman

    response test of a ground heat exchanger. In this study, a vertical U-shaped ground heat exchanger with 80 understanding of the overall performance of vertical ground heat exchangers, verifies the thermal response test from the hydraulic section #12;3 1. Introduction Geothermal energy (geo-exchange) systems have been

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

    E-Print Network [OSTI]

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

    1981-01-01

    exchangers and distillation trays permits additional energy savings by lower reboiler temperature differences, and reduced reflux requirements for a fixed column height, due to closer tray spacings. This paper surveys the heat pump systems currently...

  6. 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

    2011-03-04

    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.

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

    SciTech Connect (OSTI)

    Sabharwall, P.; Kim, E. S.; Siahpush, A.; McKellar, M.; Patterson, M.

    2012-07-01

    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)

  8. 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)

    1998-07-21

    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.

  9. 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.

    1998-07-21

    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.

  10. Heat Exchanger Technologies for Distillation Columns 

    E-Print Network [OSTI]

    Polley, G. T.

    2002-01-01

    '" Surface " i i i i I Vapour Flow I IDowncomcr , ICoolanlFCtXl I ('oolAnl Rcll1nJ I Figure 3. Integral Intermediate Condenser The mass flow of liquid coming down the column will generally be similar to that of the vapour flowing up the column...

  11. Finned Tube With Vortex Generators For A Heat Exchanger.

    DOE Patents [OSTI]

    Sohal, Manohar S. (Idaho Falls, ID); O'Brien, James E. (Idaho Falls, ID)

    2005-12-20

    A system for and method of manufacturing a finned tube for a heat exchanger is disclosed herein. A continuous fin strip is provided with at one pair of vortex generators. A tube is rotated and linearly displaced while the continuous fin strip with vortex generators is spirally wrapped around the tube.

  12. Finned Tube With Vortex Generators For A Heat Exchanger.

    DOE Patents [OSTI]

    Sohal, Monohar S. (Idaho Falls, ID); O'Brien, James E. (Idaho Falls, ID)

    2004-09-14

    A system for and method of manufacturing a finned tube for a heat exchanger is disclosed herein. A continuous fin strip is provided with at least one pair of vortex generators. A tube is rotated and linearly displaced while the continuous fin strip with vortex generators is spirally wrapped around the tube.

  13. Integral collector storage system with heat exchange apparatus

    DOE Patents [OSTI]

    Rhodes, Richard O.

    2004-04-20

    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.

  14. Condensing Heat Exchanger for Optimization of Energy Efficiency 

    E-Print Network [OSTI]

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

    1995-01-01

    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...

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

    SciTech Connect (OSTI)

    Mittereder, Nick; Poerschke, Andrew

    2013-11-01

    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.

  16. 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 the column . We have previously shown (Jimenez et al. 2003) that optimaloperation of serial heat exchangers total heat exchanger area in different trays and calculate the optimal allocation of a given heat

  17. A Semi-Empirical Model for Porous Media Heat Exchanger Design Richard A. Wirtz1

    E-Print Network [OSTI]

    Wirtz, Richard A.

    A Semi-Empirical Model for Porous Media Heat Exchanger Design Richard A. Wirtz1 Mechanical-dimensional temperature Introduction Compact heat exchangers invariably incorporate heat transfer augmentation technology matrix at the fluid-solid interface of a compact heat exchanger will also enhance performance

  18. Heat exchanger efficiently operable alternatively as evaporator or condenser

    DOE Patents [OSTI]

    Ecker, Amir L. (Dallas, TX)

    1981-01-01

    A heat exchanger adapted for efficient operation alternatively as evaporator or condenser and characterized by flexible outer tube having a plurality of inner conduits and check valves sealingly disposed within the outer tube and connected with respective inlet and outlet master flow conduits and configured so as to define a parallel flow path for a first fluid such as a refrigerant when flowed in one direction and to define a serpentine and series flow path for the first fluid when flowed in the opposite direction. The flexible outer tube has a heat exchange fluid, such as water, flowed therethrough by way of suitable inlet and outlet connections. The inner conduits and check valves form a package that is twistable so as to define a spiral annular flow path within the flexible outer tube for the heat exchange fluid. The inner conduits have thin walls of highly efficient heat transfer material for transferring heat between the first and second fluids. Also disclosed are specific materials and configurations.

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

    SciTech Connect (OSTI)

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

    2014-08-01

    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.

  20. 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

    2012-06-01

    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 exchangers—helical coiled heat exchanger and printed circuit heat exchanger—as 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.

  1. Light weight and economical exhaust heat exchanger for waste heat recovery using mixed radiant and convective heat transfer

    Broader source: Energy.gov [DOE]

    A hybrid heat exchanger is designed to keep highly stressed materials around the working fluid at a moderate temperature so that it can operate at higher working fluid pressure.

  2. 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

    2011-01-01

    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.

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

    DOE Patents [OSTI]

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

    2012-08-07

    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.

  4. 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

    2013-07-02

    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.

  5. A self-circulating heat exchanger for use in stirling andthermoacoust...

    Office of Scientific and Technical Information (OSTI)

    Conference: A self-circulating heat exchanger for use in stirling and thermoacoustic-stirling engines Citation Details In-Document Search Title: A self-circulating heat exchanger...

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

    E-Print Network [OSTI]

    Gezelius, Knut, 1978-

    2004-01-01

    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 ...

  7. Data Center Economizer Cooling with Tower Water; Demonstration of a Dual Heat Exchanger Rack Cooling Device

    E-Print Network [OSTI]

    Greenberg, Steve

    2014-01-01

    rates of each fluid (water and air) to be known for eachcontained two separate air-to-water heat exchangers, rathercontained two, larger air-to-water heat exchangers, compared

  8. 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)

    1981-11-24

    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.

  9. 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

    2009-01-01

    for Compact Plate-Type Heat Exchangers. ” American Institutethese conditions, plate-type heat exchangers with small flowHeatric plate-type compact heat exchanger showing multiple

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

    SciTech Connect (OSTI)

    Vierow, Karen

    2005-08-29

    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.

  11. Optimum Design of Micro Bare-Tube Heat Exchanger Tomohisa OKU, Nobuhide KASAGI and Yuji SUZUKI

    E-Print Network [OSTI]

    Tokyo, University of

    , optimum design is made for three types of micro bare-tube heat exchangers, i.e., heater core and radiator2313 Optimum Design of Micro Bare-Tube Heat Exchanger Tomohisa OKU, Nobuhide KASAGI and Yuji SUZUKI@thtlab.t.u-tokyo.ac.jp Micro bare-tube heat exchangers can accomplish high performance and compactness with their simple

  12. Thesis proposal CSF Brazil 2014 Earth-Air Heat Exchangers at DISTRICT scale

    E-Print Network [OSTI]

    Bordenave, Charles

    Thesis proposal CSF Brazil 2014 Title: Earth-Air Heat Exchangers at DISTRICT scale Thesis. The objective of the work is to design new classes of Earth-Air Heat Exchangers at district scale in the context: This proposal is part of a more global research project dedicated to the study of Earth-Air Heat Exchangers

  13. PERFORMANCE OF A SINGLE-ROW HEAT EXCHANGER AT LOW IN-TUBE FLOW RATES

    E-Print Network [OSTI]

    Sen, Mihir

    PERFORMANCE OF A SINGLE-ROW HEAT EXCHANGER AT LOW IN-TUBE FLOW RATES A Thesis Submitted April 1995 #12;PERFORMANCE OF A SINGLE-ROW HEAT EXCHANGER AT LOW IN-TUBE FLOW RATES by Xiangwei Zhao Abstract The steady and time-dependentbehavior of a single-row heat exchanger with water and air in the in

  14. Computational Strategies for Large-Scale MILP Transshipment Models for Heat Exchanger Network Synthesis

    E-Print Network [OSTI]

    Grossmann, Ignacio E.

    1 Computational Strategies for Large-Scale MILP Transshipment Models for Heat Exchanger Network Determining the minimum number of units is an important step in heat exchanger network synthesis (HENS Words heat exchanger network synthesis (HENS), transshipment model, mixed-integer linear programming

  15. A Simple Control Scheme for Near-optimal Operation of Parallel Heat Exchanger Systems

    E-Print Network [OSTI]

    Skogestad, Sigurd

    A Simple Control Scheme for Near-optimal Operation of Parallel Heat Exchanger Systems Johannes J) N-7491 Trondheim, Norway Abstract For heat exchanger networks with stream splits, we present for systems with logarithmic mean temperature difference as driving force. Keywords: Heat exchanger networks

  16. Control Structure Selection for Optimal Operation of a Heat Exchanger Network

    E-Print Network [OSTI]

    Skogestad, Sigurd

    Control Structure Selection for Optimal Operation of a Heat Exchanger Network Johannes J--We consider the control structure design for a heat exchanger network (HEN), where a stream is split of temperature measurements. Index Terms--Control structure selection, Self-optimizing con- trol, Heat exchanger

  17. Fouling of HVAC Fin and Tube Heat Exchangers Jeffrey Siegel and Van P. Carey

    E-Print Network [OSTI]

    LBNL-47668 Fouling of HVAC Fin and Tube Heat Exchangers Jeffrey Siegel and Van P. Carey FIN AND TUBE HEAT EXCHANGERS Jeffrey Siegel1,2 and Van P. Carey2 1 Lawrence Berkeley National, USA; E-mail: vcarey@euler.me.berkeley.edu ABSTRACT Fin and tube heat exchangers are used widely

  18. A Simple Strategy for Optimal Operation of Heat Exchanger V. LERSBAMRUNGSUK1

    E-Print Network [OSTI]

    Skogestad, Sigurd

    A Simple Strategy for Optimal Operation of Heat Exchanger Networks V. LERSBAMRUNGSUK1 , S for optimal operation of heat exchanger networks. Optimal operation in this context requires that 1) all of heat exchanger networks are analyzed and used to identify if the operation is structurally feasible

  19. Problems with specifying Tmin in design of processes with heat exchangers

    E-Print Network [OSTI]

    Skogestad, Sigurd

    Problems with specifying Tmin in design of processes with heat exchangers Jørgen Bauck Jensen case studies. Keywords: Tmin, vapour compression cycle, heat exchanger, design. 1 Introduction simple and common approach for design of processes with heat exchangers, especially at an early design

  20. Heat exchanger bypass system for an absorption refrigeration system

    DOE Patents [OSTI]

    Reimann, Robert C. (Lafayette, NY)

    1984-01-01

    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.

  1. Fouling of HVAC fin and tube heat exchangers

    SciTech Connect (OSTI)

    Siegel, Jeffrey; Carey, Van P.

    2001-07-01

    Fin and tube heat exchangers are used widely in residential, commercial and industrial HVAC applications. Invariably, indoor and outdoor air contaminants foul these heat exchangers. This fouling can cause decreased capacity and efficiency of the HVAC equipment as well as indoor air quality problems related to microbiological growth. This paper describes laboratory studies to investigate the mechanisms that cause fouling. The laboratory experiments involve subjecting a 4.7 fins/cm (12 fins/inch) fin and tube heat exchanger to an air stream that contains monodisperse particles. Air velocities ranging from 1.5-5.2 m/s (295 ft/min-1024 ft/min) and particle sizes from 1--8.6 {micro}m are used. The measured fraction of particles that deposit as well as information about the location of the deposited material indicate that particles greater than about 1 {micro}m contribute to fouling. These experimental results are used to validate a scaling analysis that describes the relative importance of several deposition mechanisms including impaction, Brownian diffusion, turbophoresis, thermophoresis, diffusiophoresis, and gravitational settling. The analysis is extended to apply to different fin spacings and particle sizes typical of those found in indoor air.

  2. 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))

    1991-01-01

    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.

  3. Industrial Waste Heat Recovery Using Heat Pipes 

    E-Print Network [OSTI]

    Ruch, M. A.

    1981-01-01

    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...

  4. Experimental study of mixed convection heat transfer in vertical helically coiled tube heat exchangers

    SciTech Connect (OSTI)

    Ghorbani, N. [School of Mechanical Engineering, University of Leeds, Leeds, England (United Kingdom); Taherian, H. [Department of Engineering Technology and Industrial Distribution, Texas A and M University, College Station, TX (United States); Gorji, M. [Department of Mechanical Engineering, Babol Noushirvani University of Technology, Babol (Iran); Mirgolbabaei, H. [Department of Mechanical Engineering, Islamic Azad University, Jouybar branch, Jouybar (Iran)

    2010-10-15

    In this study the mixed convection heat transfer in a coil-in-shell heat exchanger for various Reynolds numbers, various tube-to-coil diameter ratios and different dimensionless coil pitch was experimentally investigated. The experiments were conducted for both laminar and turbulent flow inside coil. Effects of coil pitch and tube diameters on shell-side heat transfer coefficient of the heat exchanger were studied. Different characteristic lengths were used in various Nusselt number calculations to determine which length best fits the data and several equations were proposed. The particular difference in this study in comparison with the other similar studies was the boundary conditions for the helical coils. The results indicate that the equivalent diameter of shell is the best characteristic length. (author)

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

    E-Print Network [OSTI]

    Oak Ridge National Laboratory

    vertical heat exchanger. Bose et al [2-4] described a geothermal well used for heat pump application#12;Vertical Concentric Tube Ground Couoled Heat Exchangers V. C. Mei and S. K. Fischer* Abstract An experimental and analytical project to study the design of vertical, concentric-tube ground-coupled heat

  6. 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

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

    E-Print Network [OSTI]

    Yu, Kun

    2014-05-08

    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...

  8. Heat-exchange statistics in driven open quantum systems

    E-Print Network [OSTI]

    S. Gasparinetti; P. Solinas; A. Braggio; M. Sassetti

    2014-07-29

    As the dimensions of physical systems approach the nanoscale, the laws of thermodynamics must be reconsidered due to the increased importance of fluctuations and quantum effects. While the statistical mechanics of small classical systems is relatively well understood, the quantum case still poses challenges. Here we set up a formalism that allows to calculate the full probability distribution of energy exchanges between a periodically driven quantum system and a thermalized heat reservoir. The formalism combines Floquet theory with a generalized master equation approach. For a driven two-level system and in the long-time limit, we obtain a universal expression for the distribution, providing clear physical insight into the exchanged energy quanta. We illustrate our approach in two analytically solvable cases and discuss the differences in the corresponding distributions. Our predictions could be directly tested in a variety of systems, including optical cavities and solid-state devices.

  9. 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 been

  10. Permeation Barrier Coatings for the Helical Heat Exchanger

    SciTech Connect (OSTI)

    Korinko, P.S.

    1999-05-26

    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.

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

    SciTech Connect (OSTI)

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

    1994-06-01

    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.

  12. Thermal self-oscillations in radiative heat exchange

    E-Print Network [OSTI]

    Dyakov, Sergey; Yan, Min; Qiu, Min

    2014-01-01

    We report the effect of relaxation-type self-induced temperature oscillations in the system of two parallel plates of SiO$_2$ and VO$_2$ which exchange heat by thermal radiation in vacuum. The nonlinear feedback in the self-oscillating system is provided by metal-insulator transition in VO$_2$. Using the method of fluctuational electrodynamics we show that under the action of external laser of a constant power, the temperature of VO$_2$ plate oscillates around its phase transition value.

  13. Nonballistic heat conduction in an integrable random-exchange Ising chain studied with quantum master equations

    E-Print Network [OSTI]

    Li, Baowen

    Nonballistic heat conduction in an integrable random-exchange Ising chain studied with quantum numerically investigate the heat conduction in a random-exchange Ising spin chain by using the quantum master equation. The chain is subject to a uniform transverse field h, while the exchange couplings Qn between

  14. Optimization of heat exchanger design in a thermoacoustic engine using a second law analysis

    SciTech Connect (OSTI)

    Ishikawa, H.; Hobson, P.A.

    1996-05-01

    An analysis for the time averaged entropy generation due to both flow and heat transfer losses in the heat exchangers of a thermoacoustic engine has been developed. An expression for the optimum dimensionless heat exchanger area corresponding to minimum entropy generation has been determined in terms of three other dimensionless parameters. Optimum heat exchanger areas were calculated for three thermoacoustic devices. For the prime mover components of the thermoacoustic devices investigated where the temperature differences across the regenerator stacks were high, the analysis developed indicated that the heat exchanger at the hot end of the regenerator stack should be smaller than that at the cold end.

  15. Integrated heat exchanger design for a cryogenic storage tank

    SciTech Connect (OSTI)

    Fesmire, J. E.; Bonner, T.; Oliveira, J. M.; Johnson, W. L.; Notardonato, W. U.; Tomsik, T. M.; Conyers, H. J.

    2014-01-29

    Field demonstrations of liquid hydrogen technology will be undertaken for the proliferation of advanced methods and applications in the use of cryofuels. Advancements in the use of cryofuels for transportation on Earth, from Earth, or in space are envisioned for automobiles, aircraft, rockets, and spacecraft. These advancements rely on practical ways of storage, transfer, and handling of liquid hydrogen. Focusing on storage, an integrated heat exchanger system has been designed for incorporation with an existing storage tank and a reverse Brayton cycle helium refrigerator of capacity 850 watts at 20 K. The storage tank is a 125,000-liter capacity horizontal cylindrical tank, with vacuum jacket and multilayer insulation, and a small 0.6-meter diameter manway opening. Addressed are the specific design challenges associated with the small opening, complete modularity, pressure systems re-certification for lower temperature and pressure service associated with hydrogen densification, and a large 8:1 length-to-diameter ratio for distribution of the cryogenic refrigeration. The approach, problem solving, and system design and analysis for integrated heat exchanger are detailed and discussed. Implications for future space launch facilities are also identified. The objective of the field demonstration will be to test various zero-loss and densified cryofuel handling concepts for future transportation applications.

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

    SciTech Connect (OSTI)

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

    2013-09-01

    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.

  17. 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.

    2012-11-30

    Ground-source heat pump (GSHP) systems are perhaps the most widely used “sustainable” 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.

  18. 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

    1998-10-01

    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.

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

    E-Print Network [OSTI]

    Latcham, Jacob G. (Jacob Greco)

    2009-01-01

    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 ...

  20. Problems with Specifying Tmin in the Design of Processes with Heat Exchangers Jrgen Bauck Jensen and Sigurd Skogestad*

    E-Print Network [OSTI]

    Skogestad, Sigurd

    Problems with Specifying Tmin in the Design of Processes with Heat Exchangers Jørgen Bauck Jensen exchangers may lead to wrong decisions and should be used with care when designing heat exchanger systems the resulting areas are installed. In addition, different U values for the heat exchangers are not easily

  1. 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...

  2. Deposition of biological aerosols on HVAC heat exchangers

    SciTech Connect (OSTI)

    Siegel, Jeffrey; Walker, Ian

    2001-09-01

    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.

  3. TEMPERATURE CONTROLLABILITY IN CROSS-FLOW HEAT EXCHANGERS AND LONG DUCTS

    E-Print Network [OSTI]

    Sen, Mihir

    TEMPERATURE CONTROLLABILITY IN CROSS-FLOW HEAT EXCHANGERS AND LONG DUCTS A Dissertation Submitted-FLOW HEAT EXCHANGERS AND LONG DUCTS Abstract by Sorour Abdulhadi Alotaibi The performance of thermal control and long ducts, are investigated, and the following issues are addressed. (a) The first is controllability

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

    E-Print Network [OSTI]

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

    1988-01-01

    by using a fouling factor in the design which results in additional capital cost of the heat exchanger. As fouling deposits build up in a heat exchanger, its performance will start to deteriorate and less energy will be transferred through the unit. A plot...

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

    SciTech Connect (OSTI)

    Piyush Sabharwall

    2011-09-01

    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.

  6. Effects of hydrophilic surface treatment on evaporation heat transfer at the outside wall of horizontal tubes

    E-Print Network [OSTI]

    Kim, Ho-Young

    transfer between fluids, and many types of heat exchangers are used to enhance the heat transfer efficiency.elsevier.com/locate/apthermeng #12;shell-and-tube heat exchanger is generally used for its relatively low pressure drop in the system far, to promote the heat transfer in heat exchangers of the system, either the heat transfer area

  7. 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

  8. Numerical Study of Convective Heat Transfer in Flat Tube Heat Exchangers Operating in Self-Sustained Oscillatory Flow Regimes 

    E-Print Network [OSTI]

    Fullerton, Tracy

    2012-02-14

    Laminar, two-dimensional, constant-property numerical simulations of flat tube heat exchanger devices operating in flow regimes in which self-sustained oscillations occur were performed. The unsteady flow regimes were ...

  9. State of technology of direct contact heat exchanging

    SciTech Connect (OSTI)

    Vallario, R.W.; DeBellis, D.E.

    1984-05-01

    Specific objectives of this study were to assess the state of technology development and to identify and evaluate the constraints to wider use of direct contact heat exchanger (DCHE) technology in the U.S. The scope of this study is relatively broad; it includes many types of generic systems and end-use applications, both current and future. Domestic and foreign experience with DCHE technology are compared, although the primary focus is on domestic experience. Twenty-two distinct applications of DCHE technology were identified in this study and are examined in this report. The general format is to describe each system, explore its potential applications, discuss current and past research activities and identify major implementation barriers. Finally, as a result of discussions with principal users of DCHE systems and with other knowledgeable sources, generic and specific R and D needs to overcome specific implementation barriers have been identified. The following list of DCHE systems/concepts has been classified into four major end-uses; there is also a category for specialized (other) applications.

  10. 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)

    1996-11-05

    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.

  11. OPTIMALDESIGN OF MICRO BARE-TUBE HEAT EXCHANGER Sawat Paitoonsurikarn, Nobuhide Kasagi, and Yuji Suzuki

    E-Print Network [OSTI]

    Kasagi, Nobuhide

    design offers a significant degree of improvement in terms of the pumping power, the heat transmissionW) In-line Staggered deal of industrial effort with this sort of sophisticated extended heat transferOPTIMALDESIGN OF MICRO BARE-TUBE HEAT EXCHANGER Sawat Paitoonsurikarn, Nobuhide Kasagi, and Yuji

  12. 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.

    1988-01-01

    ., "Review of Various Types of Flow Maldistribution in Heat Exchangers," in Maldistribu tion of I;low and Its Effect on Heat Exchan~erPerformance, 1. B. Kitto, Jr., and J. M. Robertson, Eds., ASME Heat Transfer Division, Vol. 75, pp. 3-16 (1987). Palen...

  13. DIRECT CONTACT HEAT EXCHANGER 10 kW POWER LOOP. SECTION 1: EXECUTIVE SUMMARY. SECTION 2: TEST SERIES NO. 1. SECTION 3; TEST SERIES NO. 2

    E-Print Network [OSTI]

    Engineering, Barber-Nicholas

    2011-01-01

    high pressure brine to a direct contact heat exchanger whichPRESSURE RATIO Figure ,11. Pure IC4 calibration test (using hairpin heat exchanger).exchanger where heat was extracted from it to isobutane. The high pressure

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

    E-Print Network [OSTI]

    Phillips, Bren Andrew

    2011-01-01

    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 ...

  15. FORMALDEHYDE AND TRACER GAS TRANSFER BETWEEN AIRSTREAMS IN ENTHALPY-TYPE AIR-TO-AIR HEAT EXCHANGERS

    E-Print Network [OSTI]

    Fisk, W.J.

    2014-01-01

    air- by this type of heat exchanger and, thus, returned toIN ENTHALPY-TYPE AIR-TO-AIR HEAT EXCHANGERS AIRSTRE&~S W.J.IN ENTHALPY-TYPE AIR-TQ-AIR HEAT EXCHANGERS William J. Fisk,

  16. Predicting yearly energy savings using BIN weather data with heat-pipe heat exchangers

    SciTech Connect (OSTI)

    Mathur, G.D. [Zexel USA Corp., Decatur, IL (United States)

    1997-12-31

    In an earlier paper, the author had investigated the impact that a heat pipe heat exchanger (HPHE) has on the energy consumption and the peak demand on an existing air conditioning system. A detailed performance investigation was carried out for a number of cities for year round operation of the HVAC system with HPHE. Heating degree days and cooling hours were used for predicting the energy savings with the HPHE. In order to calculate the true energy savings, a more realistic approach is to use the BIN weather data. The author has developed a simulation program that can predict the energy savings by using the BIN weather data. The investigation has been carried out for 33 US cities with widely different climactic conditions and the results are presented in this paper. Economic analysis reveals that a simple retrofit on an existing HVAC system can pay for itself in less than a year. Based on this investigation, it is recommended that electric utilities use this technology as a demand side management strategy for reducing energy and peak demand.

  17. 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.

    2006-01-01

    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...

  18. Surface heat flow, crustal temperatures and mantle heat flow in the Proterozoic

    E-Print Network [OSTI]

    Rolandone, Frederique

    ) and an ancient island arc (Lynn Lake Belt) made of depleted juvenile rocks. Higher heat flow values foundSurface heat flow, crustal temperatures and mantle heat flow in the Proterozoic Trans-Hudson Orogen report on new measurements of heat flow and radiogenic heat production in 30 boreholes at 17 locations

  19. Predicting yearly energy savings using BIN weather data with heat-pipe heat exchangers with indirect evaporative cooling

    SciTech Connect (OSTI)

    Mathur, G.D.

    1998-07-01

    Heat-Pipe Heat-Exchangers (HPHE) are passive systems that have recently seen application in energy recovery (Mathur, 1997). A HPHE consists of individual closed end heat pipe tubes that are charged with a suitable working fluid. In these systems, the working fluid evaporates on one side of the heat exchanger and condenses over the other end of the heat exchanger. The condensed fluid returns back to the evaporator section through the capillary action of the wick. The performance of a HPHE system can be improved by the raising the condenser portion of the heat exchanger which facilitates effective return of the condensate back to the evaporator. HPHE can be used with air conditioning systems as retrofits and in new applications. For retrofit applications, the operating costs are reduced because of the reduction in the energy (kWh) and peak demand (kW) consumptions. For new installations, the heating and cooling equipment can be of smaller capacity which will result in lower equipment and operating costs. During the summer season, indirect evaporative cooling can also be used to further enhance the performance of the air conditioning system. When operated during both the heating and cooling seasons, a HPHE yields four types of savings: (i) Heating equipment savings (ii) Cooling equipment savings (iii) Heating operating savings (iv) Cooling operating savings. Savings in the energy consumption for both heating and cooling were calculated with the HPHE for 30 cities with widely different climactic conditions. The payback periods for most of the cities were less than 1 year. If indirect evaporative cooling is used during the summer season, more energy savings would be realized on an yearly basis along with further reductions in the peak demand. In this paper, the author has simulated the performance of a HPHE with indirect evaporative cooling using the BIN weather data.

  20. The Effects of Frost Growth on Finned Tube Heat Exchangers under Laminar Flow 

    E-Print Network [OSTI]

    Kondepudi, Sekhar

    1988-01-01

    A study on the effects of frost growth on the performance of finned tube heat exchangers under laminar flow has been conducted. The study was both experimental and analytical. The experimental part of the investigation ...

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

    E-Print Network [OSTI]

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

    1983-01-01

    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...

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

    E-Print Network [OSTI]

    Mertol, A.

    2013-01-01

    Combined Collector and Storage Type, 11 Solar Vo1.15, 1973,Effects Low Solar Input and Amount Storage on Thermosyphonsolar thermosiphon water heaters with heat exchangers in storage

  3. Numerical simulation of gas dynamics and heat exchange tasks in fuel assemblies of the nuclear reactors

    SciTech Connect (OSTI)

    Zhuchenko, S. V.

    2014-11-12

    This report presents a PC-based program for solution gas dynamics and heat exchange mathematical tasks in fuel assemblies of the fast-neutron nuclear reactors. A fuel assembly consisting of bulk heat-generating elements, which are integrated together by the system of supply and pressure manifolds, is examined. Spherical heat-generating microelements, which contain nuclear fuel, are pulled into the heat-generating elements. Gaseous coolant proceed from supply manifolds to heat-generating elements, where it withdraws the nuclear reaction heat and assembles in pressure manifolds.

  4. 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

    1998-12-31

    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.

  5. Controlling bubble motion over heated surface through evaporation momentum force to enhance pool boiling heat transfer

    E-Print Network [OSTI]

    Kandlikar, Satish

    Controlling bubble motion over heated surface through evaporation momentum force to enhance pool://apl.aip.org/about/rights_and_permissions #12;Controlling bubble motion over heated surface through evaporation momentum force to enhance pool on the basis of this hypothesis to control the bubble trajectory for (i) enhancing the heat transfer

  6. A Zero Emission Mechanical Seal with Integral Micro Heat Exchanger 

    E-Print Network [OSTI]

    Khonsari, M.

    2005-01-01

    Emission Seal with Improved Heat Transfer Characteristics Michael Khonsari Dow Chemical Endowed Chair in Rotating Machinery and Professor Center for Rotating Machinery Department of Mechanical Engineering Louisiana State University Baton Rouge, LA... 70803 Khonsari@me.lsu.edu Mechanical seals are susceptible to premature failure due to intense heat generation at the interface between the rotating and stationary seal faces. Heat checking, blistering, and hot spotting are all manifestations...

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

    E-Print Network [OSTI]

    Adames, Adrian A

    2010-01-01

    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 ...

  8. Clean Firetube Boiler Waterside Heat Transfer Surfaces, Energy...

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

    7 Clean Firetube Boiler Waterside Heat Transfer Surfaces The prevention of scale formation in firetube boilers can result in substantial energy savings. Scale deposits occur when...

  9. 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...

  10. Evaluation Methodology for Advance Heat Exchanger Concepts Using Analytical Hierarchy Process

    SciTech Connect (OSTI)

    Piyush Sabharwall; Eung Soo Kim

    2012-07-01

    The primary purpose of this study is to aid in the development and selection of the secondary/process heat exchanger (SHX) for power production and process heat application for a Next Generation Nuclear Reactors (NGNR). The potential options for use as an SHX are explored such as shell and tube, printed circuit heat exchanger. A shell and tube (helical coiled) heat exchanger is a recommended for a demonstration reactor because of its reliability while the reactor design is being further developed. The basic setup for the selection of the SHX has been established with evaluation goals, alternatives, and criteria. This study describes how these criteria and the alternatives are evaluated using the analytical hierarchy process (AHP).

  11. Measuring Edinburgh’s Surface Urban Heat Island 

    E-Print Network [OSTI]

    Mackinnon, Kerr A H

    2013-10-27

    This project investigated Edinburgh’s surface urban heat island (SUHI) in relation to land cover and land use. Thermal channels of Landsat TM, Landsat ETM+ and ASTER imagery captured between 1999 and 2011 provide land surface temperatures (LST...

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

    SciTech Connect (OSTI)

    Hughes, Patrick [ORNL; Im, Piljae [ORNL

    2012-01-01

    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

  13. Modeling of Vertical Ground Loop Heat Exchangers with Variable Convective Resistance and Thermal Mass of the Fluid

    E-Print Network [OSTI]

    Modeling of Vertical Ground Loop Heat Exchangers with Variable Convective Resistance and Thermal-term behavior of ground loop heat exchangers (GLHE) is critical to the design and energy analysis of ground in the tube to guarantee a low convective heat transfer resistance. However, for some antifreeze types

  14. Modeling of Vertical Ground Loop Heat Exchangers with Variable Convective Resistance and Thermal Mass of the Fluid

    E-Print Network [OSTI]

    source heat pump (GSHP) systems. Thermal load profiles vary significantly from building to buildingModeling of Vertical Ground Loop Heat Exchangers with Variable Convective Resistance and Thermal-term behavior of ground loop heat exchangers (GLHE) is critical to the design and energy analysis of ground

  15. Heat and freshwater exchange on the Antarctic continental1 shelf in a regional coupled climate model2

    E-Print Network [OSTI]

    Holland, David

    Heat and freshwater exchange on the Antarctic continental1 shelf in a regional coupled climate exchange with the atmosphere and sea ice dominates the annual cycle in heat29 and freshwater content;2 Abstract23 Understanding heat and freshwater content change in the Antarctic shelf seas is important

  16. Global Heat Exchangers Market to be driven by Rapidly Expanding...

    Open Energy Info (EERE)

    by Rapidly Expanding End-user Industries Home > Groups > Renewable Energy RFPs Wayne31jan's picture Submitted by Wayne31jan(150) Contributor 2 July, 2015 - 00:43 Heat...

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

    SciTech Connect (OSTI)

    Duane Spencer; Kevin McCoy

    2010-02-02

    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.

  18. Standard Test Method for Measuring Heat Flux Using Surface-Mounted One-Dimensional Flat Gages

    E-Print Network [OSTI]

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This test method describes the measurement of the net heat flux normal to a surface using flat gages mounted onto the surface. Conduction heat flux is not the focus of this standard. Conduction applications related to insulation materials are covered by Test Method C 518 and Practices C 1041 and C 1046. The sensors covered by this test method all use a measurement of the temperature difference between two parallel planes normal to the surface to determine the heat that is exchanged to or from the surface in keeping with Fourier’s Law. The gages operate by the same principles for heat transfer in either direction. 1.2 This test method is quite broad in its field of application, size and construction. Different sensor types are described in detail in later sections as examples of the general method for measuring heat flux from the temperature gradient normal to a surface (1). Applications include both radiation and convection heat transfer. The gages have broad application from aerospace to biomedical en...

  19. 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

    2009-01-01

    intermediate heat exchanger used high pressure helium not asexchanger performance: predictive model for heat transfer and pressurePressure Drop Correlations for the Rectangular Offset Strip Fin Compact Heat Exchanger. ”

  20. 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)

    2002-01-01

    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.

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

    E-Print Network [OSTI]

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

    2011-01-01

    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...

  2. 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.

    1988-12-01

    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.

  3. 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

    Determining the quality and quantity of heat produced by proton exchange membrane fuel cells Determining the quality and quantity of heat produced by proton exchange membrane fuel cells with application). The experiments and simulations focused on the air-cooled Ballard Nexa fuel cell. The experimental

  4. Numerical studies of an eccentric tube-in-tube helically coiled heat exchanger for IHEP-ADS helium purification system

    E-Print Network [OSTI]

    Zhang, Jianqin

    2014-01-01

    The tube-in-tube helically coiled (TTHC) heat exchanger is preferred in the purifier of IHEP-ADS helium purification system. The position of an internal tube is usually eccentric in a TTHC heat exchanger in practice, while most TTHC heat exchangers in the literature studied are concentric. In this paper, TTHC heat exchangers with different eccentricity ratios are numerically studied for turbulent flow and heat transfer characteristics under different flow rates. The fluid considered is helium at the pressure of 20Mpa, with temperature dependent thermo-physical properties for the inner tube and the annulus. The inner Nusselt number between the concentric and eccentric TTHC heat exchangers are compared, so is the annulus Nusselt number. The results show that with the eccentricity increasing, the annulus Nusselt number increases substantially. According to the numerical data, new empirical correlations of Nusselt number as a function of Reynolds number and eccentricity for the inner tube and the annulus are pres...

  5. Condensation heat transfer on nanoengineered surfaces

    E-Print Network [OSTI]

    Paxson, Adam Taylor

    2011-01-01

    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 ...

  6. 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)

    2001-01-01

    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.

  7. Rapid infrared heating of a surface

    DOE Patents [OSTI]

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

    2003-12-23

    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.

  8. 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)

    2002-01-01

    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.

  9. Compact Ceramic Heat Exchangers for Corrosive Waste Gas Applications 

    E-Print Network [OSTI]

    Laws, W. R.; Reed, G. R.

    1982-01-01

    gas temperatures. It was noted that ~ degree of self-cleaning had occurred and L particularly all carbon deposits had OXidiSrd away. I 2. Aluminium I Silicon carbide and mullite tubes have been~ evaluated in the waste gas streams of natur 1 gas... fired aluminium reverberator:r furnaces. aving waste gas temperatures cycling from 800 to 1200 deg. C. The application of metallic : convective heat exchar~ers for this duty ha$ proved ur~uitable for ir~tallations partic~arly where the injection...

  10. Optimum Temperature Difference and Pressure Drop in Heat Exchangers 

    E-Print Network [OSTI]

    Steinmeyer, D.

    1991-01-01

    ontv nne'" nllld lo\\'olves sensible heat transfer. ie. a temperature chan,ge: tbe jf'ecl-ejjluenl exchanJ;cr, in which hoth nuid~ involve sensihle heal transfer and are roughly halanced. ie. underg-o e5~entilllly the same tempertlture chang:e.../yr: and~Th..,i:iTl!t Ii :; 1.20, ESL-IE-91-06-04 Proceedings from the 13th National Industrial Energy Technology Conference, Houston, TX, June 12-13, 1991 The ieboiler. The csse shown is common lor rf'boilers and CtlluJenst'r:-i Thf' hest a...

  11. Building Integrated Heat and Moisture Exchange | 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirley Ann JacksonDepartment of EnergyResearchers atDayWhenBethanyOnAristideson theofintegrated heat

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

    E-Print Network [OSTI]

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

    1980-01-01

    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...

  13. OTEC HEAT EXCHANGER PROGRAM ULTRASONIC SCANNING FOR CORROSION

    E-Print Network [OSTI]

    6061 sample surfaces were covered by corrosion product; the extent of coverage would alter the flow 5086 in flowing seawater. In all corroding samples, the ultrasonic scans revealed crevice corrosion. The corrosion product encases the immediate area and changes the local environment which acts to accelerate

  14. Heat transfer between elastic solids with randomly rough surfaces

    E-Print Network [OSTI]

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

    2009-08-27

    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.

  15. Global heat transfer analysis in Czochralski silicon furnace with radiation on curved specular surfaces

    E-Print Network [OSTI]

    Guo, Zhixiong "James"

    Global heat transfer analysis in Czochralski silicon furnace with radiation on curved specular method are adopted to solve the global heat transfer and the radiative heat exchange, respectively rate QJ diffuse radiation heat transfer rate QX net rate of radiative heat loss QT heat generation rate

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

    E-Print Network [OSTI]

    Paris-Sud XI, Université 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 Nôtre, F49045 Angers France Keywords: green roof roofs increases in Western European and North American cities. It is estimated that 12% of all flat

  17. Thesis proposal CSF Brazil 2014 Earth-Air Heat exchangers at BUILDING scale

    E-Print Network [OSTI]

    Bordenave, Charles

    Thesis proposal CSF Brazil 2014 Title: Earth-Air Heat exchangers at BUILDING scale Thesis (Brazil) and continental (France) areas. Subject description: This proposal is part of a more global and Mass Transfer, 55 7832-7837, 2012. Expected collaboration in Brazil: Federal University of Rio Grande

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

    E-Print Network [OSTI]

    Field, J. E.

    2002-01-01

    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...

  19. Critical heat flux maxima during boiling crisis on textured surfaces

    E-Print Network [OSTI]

    Dhillon, Navdeep Singh

    Enhancing the critical heat flux (CHF) of industrial boilers by surface texturing can lead to substantial energy savings and global reduction in greenhouse gas emissions, but fundamentally this phenomenon is not well ...

  20. The Role of Interocean Exchanges on Decadal Variations of the Meridional Heat Transport in the South Atlantic

    E-Print Network [OSTI]

    The Role of Interocean Exchanges on Decadal Variations of the Meridional Heat Transport 2010, in final form 19 April 2011) ABSTRACT The interocean exchange of water from the South Atlantic the role of the interocean exchanges in the variability of the Atlantic meridional overturning circulation

  1. ORIGINAL PAPER Transient Heat Conduction Between Rough Sliding Surfaces

    E-Print Network [OSTI]

    Awtar, Shorya

    , and the results are combined with the height distributions to determine the mean heat flux and the mean normal increases with the square root of the sliding speed and decreases with the 3/4 power of the combined RMSORIGINAL PAPER Transient Heat Conduction Between Rough Sliding Surfaces Yuwei Liu · J. R. Barber

  2. An enhanced version of the heat exchange algorithm with excellent energy conservation properties

    E-Print Network [OSTI]

    Wirnsberger, P; Dellago, C

    2015-01-01

    We propose a new algorithm for non-equilibrium molecular dynamics simulations of thermal gradients. The algorithm is an extension of the heat exchange algorithm developed by Hafskjold and co-workers [Mol. Phys. 80, 1389 (1993); Mol. Phys. 81, 251 (1994)], in which a certain amount of heat is added to one region and removed from another by rescaling velocities appropriately. Since the amount of added and removed heat is the same and the dynamics between velocity rescaling steps is Hamiltonian, the heat exchange algorithm is expected to conserve the energy. However, it has been reported previously that the original version of the heat exchange algorithm exhibits a pronounced drift in the total energy, the exact cause of which remained hitherto unclear. Here, we show that the energy drift is due to the truncation error arising from the operator splitting and suggest an additional coordinate integration step as a remedy. The new algorithm retains all the advantages of the original one whilst exhibiting excellent ...

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

    SciTech Connect (OSTI)

    Gross, Andrew John

    2014-01-01

    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.

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

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield Municipal Gas &SCE-Sessions | Department ofVP of TransmissionIT Tools JOHNandonSankar Sambasivan

  5. 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

  6. 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

    2012-09-01

    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

  7. 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

    2012-06-12

    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.

  8. Measuring the heat exchange of a quantum process

    E-Print Network [OSTI]

    John Goold; Ulrich Poschinger; Kavan Modi

    2014-08-19

    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. 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

    2014-04-01

    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 (750–800 °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/1.0–2.7 MPa for the cold side and 208–790 °C/1.0–2.7 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.

  10. Urban Surfaces and Heat Island Mitigation Potentials

    SciTech Connect (OSTI)

    Akbari, Hashem; Akbari, Hashem; Shea Rose, Leanna

    2007-06-14

    Data on materials and surface types that comprise a city, i.e. urban fabric, are needed in order to estimate the effects of light-colored surfaces (roofs and pavements) and urban vegetation (trees, grass, shrubs) on the meteorology and air quality of a city. We discuss the results of a semi-automatic statistical approach used to develop data on surface-type distribution and urban-fabric makeup using aerial color orthophotography, for four metropolitan areas of Chicago, IL, Houston, TX, Sacramento, CA, and Salt Lake City, UT. The digital high resolution (0.3 to 0.5-m) aerial photographs for each of these metropolitan areas covers representative urban areas ranging from 30 km{sup 2} to 52 km{sup 2}. Major land-use types examined included: commercial, residential, industrial, educational, and transportation. On average, for the metropolitan areas studied, vegetation covers about 29-41% of the area, roofs 19-25%, and paved surfaces 29-39%. For the most part, trees shade streets, parking lots, grass, and sidewalks. At ground level, i.e., view from below the tree canopies, vegetation covers about 20-37% of the area, roofs 20-25%, and paved surfaces 29-36%.

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

    SciTech Connect (OSTI)

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

    2014-04-01

    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.

  12. An analytical oscillating-flow thermal analysis of the heat exchangers and regenerator in Stirling machines

    SciTech Connect (OSTI)

    Monte, F. de; Galli, G.; Marcotullio, F.

    1996-12-31

    A closed form-expression for the effectiveness of the heat exchangers and regenerator of a Stirling cycle machine is given. This result may be used in a simple way in order to evaluate their effect on the machine performance. The proposed method, indeed, allows the actual cycle gas temperatures in the heater and cooler to be obtained readily, once the geometry of the heater, cooler and regenerator is known and some quantities characterizing the engine dynamics (strokes, frequency and phase angle of the moving elements) and its heat-exchange processes (inlet temperatures of the heating and cooling fluids, and their volumetric flow rates) are measured. Thus, an immediate indication about the effectiveness of the heat exchangers and regenerator as well as about the machine thermal efficiency may be obtained. The availability of a closed-form expression for the heater, regenerator and cooler effectiveness is useful especially for those engines, like the free-piston Stirling engines, whose design requires the application of analytically based optimization criteria.

  13. 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.

    1998-06-01

    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.

  14. 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.

    2006-01-01

    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...

  15. 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)

    1988-01-01

    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.

  16. 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.

    1981-11-02

    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.

  17. 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

    2010-02-23

    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.

  18. Calculation of Protein Heat Capacity from Replica-Exchange Molecular Dynamics Simulations with Different Implicit Solvent Models

    E-Print Network [OSTI]

    Calculation of Protein Heat Capacity from Replica-Exchange Molecular Dynamics Simulations The heat capacity has played a major role in relating microscopic and macroscopic properties of proteins, and configurational averaging. To better understand these factors on calculating a protein heat capacity, we provide

  19. Heat and freshwater exchange on the Antarctic continental1" shelf in a regional coupled climate model2"

    E-Print Network [OSTI]

    Gerber, Edwin

    Heat and freshwater exchange on the Antarctic continental1" shelf in a regional coupled climate, South Korea 120-749. Email:21" cyoo@cims.nyu.edu.22" #12;2" Abstract23" Understanding heat. This study analyzes the heat and freshwater budget using a regional25" coupled climate model, which has been

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

    SciTech Connect (OSTI)

    Ibrahim, M.B.; Tew, R.C.; Dudenhoefer, J.E.

    1994-09-01

    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.

  1. 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)

    1997-01-01

    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.

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

    DOE Patents [OSTI]

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

    1997-04-22

    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.

  3. arXiv:1211.0829v2[cond-mat.stat-mech]8Jan2013 Heat exchanges in a quenched ferromagnet

    E-Print Network [OSTI]

    Zannetti, Marco

    arXiv:1211.0829v2[cond-mat.stat-mech]8Jan2013 Heat exchanges in a quenched ferromagnet Federico-equilibrium probability distribution of the heat exchanged by a ferromag- net in a time interval after a quench below responsible of the order parameter condensation in the equilibrium low temperature phase. The heat exchanged

  4. Research for Advanced Heat Exchangers- The U.S. DOE Program 

    E-Print Network [OSTI]

    Richlen, S. L.

    1986-01-01

    technical problem areas have been identified (see Figure 2). From these problem areas the technology deficiencies or R&D categories tend to group into three major areas: o Configurations o Materials o Support Technologies Industry's Heat Exchanger R... of Sciences, and outside reviewers to be sure that they fit within the DOE guidelines and meet industry's needs. The Office of Industrial Programs has considerable interaction with various technical societies, trade associations, industry working groups...

  5. 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)

    1994-01-01

    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.

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

    DOE Patents [OSTI]

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

    1994-10-18

    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.

  7. 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

    2013-05-05

    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.

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

    DOE Patents [OSTI]

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

    2005-11-22

    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.

  9. 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

  10. 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

    2008-01-01

    LIU AND RANDERSON: BOREAL FOREST FIRE AND ENERGY EXCHANGE2006), The impact of boreal forest fire on climate warming,pathways by which boreal forest fire influences the surface

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

    SciTech Connect (OSTI)

    Gupta, Prabhat Kumar; Rabehl, Roger

    2014-07-01

    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.

  12. 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.

    2006-01-01

    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 ...

  13. Scale Resistant Heat Exchanger for Low Temperature Geothermal Binary Cycle Power Plant

    SciTech Connect (OSTI)

    Hays, Lance G.

    2014-11-18

    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 ºF. 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 ºF, 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 ºF 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 “piggyback” 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.

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

    E-Print Network [OSTI]

    Bateni, Sayed Mohyeddin

    2011-01-01

    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. ...

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

    SciTech Connect (OSTI)

    Mylavarapu, Sai K.; Sun, Xiaodong; Christensen, Richard N.; Glosup, Richard E.; Unocic, Raymond R

    2012-01-01

    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.

  16. been conducted to analyze the exchanger experimentally (Bose and Parker 1983; Bose et al. 1980, 1982). An analytical study of such heat exchangers, which uses a detailed mathematical model to describe their

    E-Print Network [OSTI]

    Oak Ridge National Laboratory

    , 1982). An analytical study of such heat exchangers, which uses a detailed mathematical model-tube heat exchangers. Six 6-in (152-mm) wells were drilled at depths of 53, 60, 70, 80, 90, and 100 ft (16#12;been conducted to analyze the exchanger experimentally (Bose and Parker 1983; Bose et al. 1980

  17. 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)

    2012-07-01

    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)

  18. ME 360N Intermediate Heat Transfer ABET EC2000 syllabus

    E-Print Network [OSTI]

    Ben-Yakar, Adela

    and Internal), Heat Exchangers (1) 3. Heat Exchanger Analysis (1) 4. Radiation (Intro) (Properties, Surface (1) 22. Nat'l. Conv. (1) 23. Intro Heat Exchangers & Energy Balances (1) 24. Overall H.T. Coeff ­ Intermediate Heat Transfer Page 2 ABET EC2000 syllabus Class/Laboratory Schedule (Type, number and duration

  19. Method for braze-joining spirally wound tapes to inner walls of heat exchanger tubes

    DOE Patents [OSTI]

    Garrison, M.E.

    1982-09-03

    The present invention is directed to a method of fabricating heat exchanger tubes in which twisted tapes are utilized for promoting turbulence and heat transfer. The method of the present invention provides for the brazing of the tapes to the inner walls of the tubes for enhancing heat transfer between the fluid within the conduit and a fluid medium outside of the conduit by conduction through the tape. The braze joint of the present invention is coextensive with the tape over the entire length thereof within the conduit. The practice of the present invention is achieved by placing a filler wire of brazing metal along the tape at a location removed from the side walls and then heating the conduit and tape sufficiently to effect the displacement of the filler metal by wicking to the contact point between the tape and the conduit wall to form a braze joint coextensive with the length of the tape within the conduit. This arrangement provides maximum heat transfer and assures that the tape is in contact with the conduit over the entire common length thereof.

  20. Method for braze-joining spirally wound tapes to inner walls of heat exchanger tubes

    DOE Patents [OSTI]

    Garrison, Melton E. (Powell, TN)

    1984-01-01

    The present invention is directed to a method of fabricating heat exchanger tubes in which twisted tapes are utilized for promoting turbulence and heat transfer. The method of the present invention provides for the brazing of the tapes to the inner walls of the tubes for enhancing heat transfer between the fluid within the conduit and a fluid medium outside of the conduit by conduction through the tape. The braze joint of the present invention is coextensive with the tape over the entire length thereof within the conduit. The practice of the present invention is achieved by placing a filler wire of brazing metal along the tape at a location removed from the side walls and then heating the conduit and tape sufficiently to effect the displacement of the filler metal by wicking to the contact point between the tape and the conduit wall to form a braze joint coextensive with the length of the tape within the conduit. This arrangement provides maximum heat transfer and assures that the tape is in contact with the conduit over the entire common length thereof.

  1. 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.

  2. 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

    = Q34 = h4 ­ h3 = 2173,3 kJ/kg d. Heat input = Q15 = h1 ­ h5 = h1 ­ h4 + 4 (pump power) = 2831,0 kPTG exam 9 April 2014 short answers 123. Heat given off = surface * heat transfer coefficient * temperature = A * h * T Heat transfer coefficient from Nunumber, which for natural convection

  3. 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

    2014-01-01

    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.

  4. Penetrative turbulence associated with mesoscale surface heat flux variations

    E-Print Network [OSTI]

    Alam, Jahrul M

    2015-01-01

    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.

  5. Impact inducted surface heating by planetesimals on early Mars

    E-Print Network [OSTI]

    Maindl, T I; Lammer, H; Güdel, M; Schäfer, C; Speith, R; Odert, P; Erkaev, N V; Kislyakova, K G; Pilat-Lohinger, E

    2014-01-01

    We investigate the influence of impacts of large planetesimals and small planetary embryos on the early Martian surface on the hydrodynamic escape of an early steam atmosphere that is exposed to the high soft X-ray and EUV flux of the young Sun. Impact statistics in terms of number, masses, velocities, and angles of asteroid impacts onto the early Mars are determined via n-body integrations. Based on these statistics, smoothed particle hydrodynamics (SPH) simulations result in estimates of energy transfer into the planetary surface material and according surface heating. For the estimation of the atmospheric escape rates we applied a soft X-ray and EUV absorption model and a 1-D upper atmosphere hydrodynamic model to a magma ocean-related catastrophically outgassed steam atmosphere with surface pressure values of 52 bar H2O and 11 bar CO2. The estimated impact rates and energy deposition onto an early Martian surface can account for substantial heating. The energy influx and conversion rate into internal ener...

  6. Diesel particulate filter regeneration via resistive surface heating

    DOE Patents [OSTI]

    Gonze, Eugene V; Ament, Frank

    2013-10-08

    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.

  7. Characterization of Elevated Temperature Properties of Heat Exchanger and Steam Generator Alloys

    SciTech Connect (OSTI)

    J.K. Wright; L.J. Carroll; J.K. Benz; J.A. Simpson; R.N. Wright; W.R. Lloyd; J.A. Chapman

    2010-10-01

    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. In general dynamic strain aging is observed to begin at higher temperatures and serrated flow persists to higher temperatures in Alloy 617 compared to Alloy 800H. Dynamic strain aging is a concern for these materials since it is observed to result in reduced ductility for many solid solution alloys. The role of dynamic strain aging in the creep-fatigue behavior of Alloy 617 at temperatures of 800°C and above has also been examined in detail. Serrated flow is found to persist in cyclic stress-strain curves up to nearly the cycle to failure in some temperature and strain regimes. Results of those experiments and implications for creep-fatigue testing protocols will be described.

  8. 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

    2012-10-01

    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.

  9. Effect of residential air-to-air heat and moisture exchangers on indoor humidity

    SciTech Connect (OSTI)

    Barringer, C.G.; McGugan, C.A. )

    1989-01-01

    A project was undertaken to develop guidelines for the selection of residential heat and moisture recovery ventilation systems (HRVs) in order to maintain an acceptable indoor humidity for various climatic conditions. These guidelines were developed from reviews on ventilation requirements, HRV performance specifications, and from computer modeling. Space conditions within three house/occupancy models for several types of HRV were simulated for three climatic conditions (Lake Charles, LA; Seattle, WA; and Winnipeg, MB) in order to determine the impact of the HRVs on indoor relative humidity and space-conditioning loads. Results show that when reduction of cooling cost is the main consideration, exchangers with moisture recovery are preferable to sensible HRVs. For reduction of heating costs, moisture recovery should be done for ventilation rates greater than about 15 L/s and average winter temperatures less than about (minus) 10{degrees}C if internal moisture generation rates are low. For houses with higher ventilation rates and colder average winter temperatures, exchangers with moisture recovery should be used.

  10. Cross flow heat exchange of textile cellular metal core sandwich panels , T.J. Lu b,*, H.P. Hodson a

    E-Print Network [OSTI]

    Wadley, Haydn

    Cross flow heat exchange of textile cellular metal core sandwich panels J. Tian a , T.J. Lu b,*, H. Finally, the thermal performance of brazed woven tex- tiles is compared with other heat exchanger media flow resistance and heat transfer rate were measured. The flow friction factor is found to depend

  11. Demonstration and Performance Monitoring of Foundation Heat Exchangers (FHX) in Ultra-High Energy Efficient Research Homes

    SciTech Connect (OSTI)

    Im, Piljae; Hughes, Patrick; Liu, Xiaobing

    2012-01-01

    The more widespread use of Ground Source Heat Pump (GSHP) systems has been hindered by their high first cost, which is mainly driven by the cost of the drilling and excavation for installation of ground heat exchangers (GHXs). A new foundation heat exchanger (FHX) technology was proposed to reduce first cost by placing the heat exchanger into the excavations made during the course of construction (e.g., the overcut for the basement and/or foundation and run-outs for water supply and the septic field). Since they reduce or eliminate the need for additional drilling or excavation, foundation heat exchangers have the potential to significantly reduce or eliminate the first cost premium associated with GSHPs. Since December 2009, this FHX technology has been demonstrated in two ultra-high energy efficient new research houses in the Tennessee Valley, and the performance data has been closely monitored as well. This paper introduces the FHX technology with the design, construction and demonstration of the FHX and presents performance monitoring results of the FHX after one year of monitoring. The performance monitoring includes hourly maximum and minimum entering water temperature (EWT) in the FHX compared with the typical design range, temperature difference (i.e., T) across the FHX, and hourly heat transfer rate to/from the surrounding soil.

  12. Characterization of the effect of Froude number on surface waves and heat transfer in inclined turbulent

    E-Print Network [OSTI]

    Abdou, Mohamed

    Characterization of the effect of Froude number on surface waves and heat transfer in inclined describes wave/heat transfer phenomena in inclined turbulent open surface water flows. The experiments were. These changes lead to a heat transfer improvement, enough to double the heat transfer coefficient

  13. EXPERIMENTAL INVESTIGATIONS AND DESIGN TOOL DEVELOPMENT FOR SURFACE WATER HEAT PUMP

    E-Print Network [OSTI]

    EXPERIMENTAL INVESTIGATIONS AND DESIGN TOOL DEVELOPMENT FOR SURFACE WATER HEAT PUMP SYSTEMS By MATT AND DESIGN TOOL DEVELOPMENT FOR SURFACE WATER HEAT PUMP SYSTEMS Thesis Approved: Jeffrey D. Spitler Thesis Title of Study: EXPERIMENTAL INVESTIGATION AND DESIGN TOOL DE- VELOPMENT FOR SURFACE WATER HEAT PUMP

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

    E-Print Network [OSTI]

    Paris-Sud XI, Université 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

  15. 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

    2011-01-01

    heat exchanger, representative elementary volume Introduction Volume averaging theory (VAT) is an approach that can be applied to many different types

  16. Heat transfer via dropwise condensation on hydrophobic microstructured surfaces

    E-Print Network [OSTI]

    Ruleman, Karlen E. (Karlen Elizabeth)

    2009-01-01

    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 ...

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

    SciTech Connect (OSTI)

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

    1986-04-01

    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.

  18. 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

    2014-12-01

    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 materialmore »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 « less

  19. Analysis of heat transfer and pressure drop for fin-and-tube heat exchangers with rectangular winglet-type vortex generators

    E-Print Network [OSTI]

    Zhang, Yuwen

    , air-conditioning and refrigeration) systems, petrochemical industry, and electronics cooling impact. A high-efficiency compact heat exchanger is effective to achieve such goals as improving energy channel in the air flow direction. The effects of attack angle of RWPs, row-number of RWPs and placement

  20. 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 ...

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

    SciTech Connect (OSTI)

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

    2014-12-01

    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.

  2. 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.; Boag, Stephen

    2010-05-15

    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.

  3. 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.

    2011-07-14

    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.

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

    SciTech Connect (OSTI)

    J. K. Wright

    2010-09-01

    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. Today’s 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.

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

    SciTech Connect (OSTI)

    J. K. Wright

    2008-04-01

    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. Today’s 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.

  6. 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, Université 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

  7. VOL. 167 -NO. 12 HEATS OF EXCHANGE MEASURED BY FLOW CALORIMETRY 777 kaolinitic soil clay that he derived from the tem-

    E-Print Network [OSTI]

    Ma, Lena

    #12;#12;#12;#12;VOL. 167 -NO. 12 HEATS OF EXCHANGE MEASURED BY FLOW CALORIMETRY 777 kaolinitic soil any reported values for K/Ca exchange. After look- ing at Udo's data more carefully,however, we be,-', not the 54.5 kJ mol,-' orig- inallyreported. If our calculation is correct,Udo's enthalpy for K/Ca exchange

  8. Effect of Turbulence Fluctuations on Surface Heating Rate in Hypersonic Turbulent

    E-Print Network [OSTI]

    Martín, Pino

    Effect of Turbulence Fluctuations on Surface Heating Rate in Hypersonic Turbulent Boundary Layers the effect of turbulence fluctuations on surface heating rate by conducting direct numerical simulations (DNS subtle influence on the mean heating rate. We also find that the effect of turbulence

  9. Hardware Implementation of the Primary Mirror Surface Heating System for the Gemini 8 meter Telescopes

    E-Print Network [OSTI]

    ­meter primary mirror. Keywords: seeing, resistive heating, thermal control, primary mirror 2 as a resistive heating element; the control of current flow across the mirror surface results in a controlled Block Diagram for Gemini Surface Heating System 2.4 Primary Voltage Control Subsystem: This system

  10. Hardware Implementation of the Primary Mirror Surface Heating System for the Gemini 8 meter Telescopes

    E-Print Network [OSTI]

    -meter primary mirror. Keywords: seeing, resistive heating, thermal control, primary mirror 2 as a resistive heating element; the control of current flow across the mirror surface results in a controlled Block Diagram for Gemini Surface Heating System 2.4 Primary Voltage Control Subsystem: This system

  11. Geothermal Heat Pump Basics

    Broader source: Energy.gov [DOE]

    Geothermal heat pumps use the constant temperature of the earth as an exchange medium for heat. Although many parts of the country experience seasonal temperature extremes—from scorching heat in the summer to sub-zero cold in the winter—the ground a few feet below the earth's surface remains at a relatively constant temperature.

  12. Solid oxide fuel cell power plant having a fixed contact oxidation catalyzed section of a multi-section cathode air heat exchanger

    DOE Patents [OSTI]

    Saito, Kazuo; Lin, Yao

    2015-02-17

    The multi-section cathode air heat exchanger (102) includes at least a first heat exchanger section (104), and a fixed contact oxidation catalyzed section (126) secured adjacent each other in a stack association. Cool cathode inlet air flows through cool air channels (110) of the at least first (104) and oxidation catalyzed sections (126). Hot anode exhaust flows through hot air channels (124) of the oxidation catalyzed section (126) and is combusted therein. The combusted anode exhaust then flows through hot air channels (112) of the first section (104) of the cathode air heat exchanger (102). The cool and hot air channels (110, 112) are secured in direct heat exchange relationship with each other so that temperatures of the heat exchanger (102) do not exceed 800.degree. C. to minimize requirements for using expensive, high-temperature alloys.

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

    E-Print Network [OSTI]

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

    2013-01-01

    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, ...

  14. 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 ...

  15. Two-phase flow and pressure drop in flow passages of compact heat exchangers

    SciTech Connect (OSTI)

    Wambsganss, M.W.; Jendrzejczyk, J.A.; France, D.M.

    1992-01-01

    Two-phase flow experiments were performed with air/water mixtures in a small rectangular channel measuring 9.52 {times} 1.59 mm (aspects ratio equal to 6), for applications to compact heat exchangers. Pressure drop and flow pattern definition data were obtained over a large range of mass qualities (0.0002 to 1), and in the case of flow pattern data, a large range of mass fluxes (50 to 2,000 kg/m{sup 2}s). A flow pattern map, based on visual observations and photographs of the flow patterns, is presented and compared with a map developed for a rectangular channel of the same aspect ratio but with dimensions twice those of the test channel, and with a map developed for a circular tube with the same hydraulic diameter of 3 mm. Pressure drop data are presented as a function of both mass quality and Martinelli parameter and are compared with state-of-the-art correlations and a modified Chisholm correlation. 13 refs.

  16. Two-phase flow and pressure drop in flow passages of compact heat exchangers

    SciTech Connect (OSTI)

    Wambsganss, M.W.; Jendrzejczyk, J.A.; France, D.M.

    1992-02-01

    Two-phase flow experiments were performed with air/water mixtures in a small rectangular channel measuring 9.52 {times} 1.59 mm (aspects ratio equal to 6), for applications to compact heat exchangers. Pressure drop and flow pattern definition data were obtained over a large range of mass qualities (0.0002 to 1), and in the case of flow pattern data, a large range of mass fluxes (50 to 2,000 kg/m{sup 2}s). A flow pattern map, based on visual observations and photographs of the flow patterns, is presented and compared with a map developed for a rectangular channel of the same aspect ratio but with dimensions twice those of the test channel, and with a map developed for a circular tube with the same hydraulic diameter of 3 mm. Pressure drop data are presented as a function of both mass quality and Martinelli parameter and are compared with state-of-the-art correlations and a modified Chisholm correlation. 13 refs.

  17. Candidate alloys for cost-effective, high-efficiency, high-temperature compact/foil heat-exchangers

    SciTech Connect (OSTI)

    Evans, Neal D; Maziasz, Philip J; Shingledecker, John P; Pint, Bruce A; Yamamoto, Yukinori

    2007-01-01

    Solid oxide fuel cell (SOFC) and molten carbonate fuel cell (MCFC) systems operate at high temperatures (up to 1000 C and 650 C, respectively), which makes them especially attractive sources for combined heat and power (CHP) cogeneration. However, improvements in the efficiency of heat exchange in these fuel cells require both development and careful processing of advanced cost-effective alloys for use in such high-temperature service conditions. The high-temperature properties of both sheet and foil forms of several alloys being considered for use in compact heat-exchangers (recuperators) have been characterized. Mechanical and creep-rupture testing, oxidation studies, and microstructural studies have been performed on commercially available sheet and foil forms of alloy 347, alloys 625, HR230, HR120, and the new AL20-25+Nb. These studies have led to a mechanistic understanding of the responses of these alloys to anticipated service conditions, and suggest that these alloys developed for gas- and micro-turbine recuperator applications are also suitable for use in fuel cell heat-exchangers. Additional work is still required to achieve foil forms with creep life comparable to thicker-section wrought product forms of the same alloys.

  18. Evidence for thermalization of surface-desorbed molecules at heating rates of 108

    E-Print Network [OSTI]

    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.e., pulsed heating of the sapphire surface on the nanosecond time scale leads to thermal desorption and rapid

  19. Regional CO2 and latent heat surface fluxes in the Southern Great Plains: Measurements, modeling, and scaling

    SciTech Connect (OSTI)

    Riley, W. J.; Biraud, S.C.; Torn, M.S.; Fischer, M.L.; Billesbach, D.P.; Berry, J.A.

    2009-08-15

    Characterizing net ecosystem exchanges (NEE) of CO{sub 2} and sensible and latent heat fluxes in heterogeneous landscapes is difficult, yet critical given expected changes in climate and land use. We report here a measurement and modeling study designed to improve our understanding of surface to atmosphere gas exchanges under very heterogeneous land cover in the mostly agricultural U.S. Southern Great Plains (SGP). We combined three years of site-level, eddy covariance measurements in several of the dominant land cover types with regional-scale climate data from the distributed Mesonet stations and Next Generation Weather Radar precipitation measurements to calibrate a land surface model of trace gas and energy exchanges (isotope-enabled land surface model (ISOLSM)). Yearly variations in vegetation cover distributions were estimated from Moderate Resolution Imaging Spectroradiometer normalized difference vegetation index and compared to regional and subregional vegetation cover type estimates from the U.S. Department of Agriculture census. We first applied ISOLSM at a 250 m spatial scale to account for vegetation cover type and leaf area variations that occur on hundred meter scales. Because of computational constraints, we developed a subsampling scheme within 10 km 'macrocells' to perform these high-resolution simulations. We estimate that the Atmospheric Radiation Measurement Climate Research Facility SGP region net CO{sub 2} exchange with the local atmosphere was -240, -340, and -270 gC m{sup -2} yr{sup -1} (positive toward the atmosphere) in 2003, 2004, and 2005, respectively, with large seasonal variations. We also performed simulations using two scaling approaches at resolutions of 10, 30, 60, and 90 km. The scaling approach applied in current land surface models led to regional NEE biases of up to 50 and 20% in weekly and annual estimates, respectively. An important factor in causing these biases was the complex leaf area index (LAI) distribution within cover types. Biases in predicted weekly average regional latent heat fluxes were smaller than for NEE, but larger than for either ecosystem respiration or assimilation alone. However, spatial and diurnal variations of hundreds of W m{sup -2} in latent heat fluxes were common. We conclude that, in this heterogeneous system, characterizing vegetation cover type and LAI at the scale of spatial variation are necessary for accurate estimates of bottom-up, regional NEE and surface energy fluxes.

  20. Heat exchanger temperature response for duty-cycle transients in the NGNP/HTE.

    SciTech Connect (OSTI)

    Vilim, R. B.; Nuclear Engineering Division

    2009-03-12

    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

  1. Reduction of trapped ion anomalous heating by in situ surface plasma cleaning

    E-Print Network [OSTI]

    McConnell, Robert; Chiaverini, John; Sage, Jeremy

    2015-01-01

    Anomalous motional heating is a major obstacle to scalable quantum information processing with trapped ions. While the source of this heating is not yet understood, several previous studies suggest that surface contaminants may be largely responsible. We demonstrate an improvement by a factor of four in the room-temperature heating rate of a niobium surface electrode trap by in situ plasma cleaning of the trap surface. This surface treatment was performed with a simple homebuilt coil assembly and commercially-available matching network and is considerably gentler than other treatments, such as ion milling or laser cleaning, that have previously been shown to improve ion heating rates. We do not see an improvement in the heating rate when the trap is operated at cryogenic temperatures, pointing to a role of thermally-activated surface contaminants in motional heating whose activity may freeze out at low temperatures.

  2. Functional Integral approach to time-dependent heat exchange in open quantum systems: general method and applications

    E-Print Network [OSTI]

    M. Carrega; P. Solinas; A. Braggio; M. Sassetti; U. Weiss

    2014-12-22

    We establish the path integral approach for the time-dependent heat exchange of an externally driven quantum system coupled to a thermal reservoir. We derive the relevant influence functional and present an exact formal expression for the moment generating functional which carries all statistical properties of the heat exchange process for general linear dissipation. The general method is applied to the time-dependent average heat transfer in the dissipative two-state system. We show that the heat can be written as a convolution integral which involves the population and coherence correlation functions of the two-state system and additional correlations due to a polarization of the reservoir. The corresponding expression can be solved in the weak-damping limit both for white noise and for quantum mechanical coloured noise. The implications of pure quantum effects are discussed. Altogether a complete description of the dynamics of the average heat transfer ranging from the classical regime down to zero temperature is achieved.

  3. Comparison of practical vertical ground heat exchanger sizing methods to a Fort Polk data/model benchmark

    SciTech Connect (OSTI)

    Thornton, J.W.; McDowell, T.P.; Hughes, P.J.

    1997-09-01

    The results of five practical vertical ground heat exchanger sizing programs are compared against a detailed simulation model that has been calibrated to monitored data taken from one military family housing unit at Fort Polk, Louisiana. The calibration of the detailed model to data is described in a companion paper. The assertion that the data/detailed model is a useful benchmark for practical sizing methods is based on this calibration. The results from the comparisons demonstrate the current level of agreement between vertical ground heat exchanger sizing methods in common use. It is recommended that the calibration and comparison exercise be repeated with data sets from additional sites in order to build confidence in the practical sizing methods.

  4. 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

    2009-01-01

    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 ...

  5. Study of the Effects of Surface Morphology and Droplet Growth Dynamics on Condensation Heat Transfer 

    E-Print Network [OSTI]

    Yao, Chun-Wei

    2014-04-23

    Condensation heat transfer has recently received a lot of renewed attention due to the development and use of surfaces with micro- and nano-scale features. Most of the new surfaces tend to promote drop-wise condensation, ...

  6. Numerical simulation of intermediate heat exchanger of the liquid metal fast breeder reactor using COMMIX-1B 

    E-Print Network [OSTI]

    Saleh, Habeeb H.

    1990-01-01

    Structure Alignment CHAPTER III DESCRIPTION OF THE EXPERIMENTAL FACILITY III. I Description of FFTF The Fast Flux Test Facility (FFTF) is a 400-MWt, sodium-cooled, low-pressure, high-temperarure, fast neutron flux, nuclear fission reactor plant...NUMERICAL SIMULATION OF INTERMEDIATE HEAT EXCHANGER OF THE LIQUID METAL FAST BREEDER REACTOR USING COMMIX-1B A Thesis by HABEEB H. SALEH Submitted to the Office of Graduate Studies of Texas A@M University in partial fulfillment...

  7. Analysis of heat transfer in unlooped and looped pulsating

    E-Print Network [OSTI]

    Zhang, Yuwen

    to the exchange of sensible heat. Higher surface tension results in a slight increase in the total heat transfer into turns. There are two types of PHPs: the looped pulsating heat pipe and the unlooped pulsating heat pipeAnalysis of heat transfer in unlooped and looped pulsating heat pipes M.B. Sha®i and A. Faghri

  8. The (safety-related) heat exchangers aging management guideline for commercial nuclear power plants, and developments since 1994

    SciTech Connect (OSTI)

    Clauss, J.M.

    1998-08-01

    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. Dual source heat pump

    DOE Patents [OSTI]

    Ecker, Amir L. (Dallas, TX); Pietsch, Joseph A. (Dallas, TX)

    1982-01-01

    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.

  10. Impacts of landscape structure on surface urban heat islands: A case study of Shanghai, China

    E-Print Network [OSTI]

    Wu, Jianguo "Jingle"

    Impacts of landscape structure on surface urban heat islands: A case study of Shanghai, China in revised form 6 June 2011 Accepted 9 July 2011 Available online 5 August 2011 Keywords: Urban heat island of the ecological consequences of urbanization is the urban heat island (UHI) effect, which leads to higher

  11. Near-Field Radiative Heat Transfer between Macroscopic Planar Surfaces R. S. Ottens,1

    E-Print Network [OSTI]

    Tanner, David B.

    Near-Field Radiative Heat Transfer between Macroscopic Planar Surfaces R. S. Ottens,1 V. Quetschke-field, blackbody radiation. Although heat transfer via near-field effects has been discussed for many years.014301 PACS numbers: 44.40.+a, 78.20.Ci Humans knew of radiative heat transfer at least as early

  12. Surface roughening by electron beam heating D. Grozea, E. Landree, and L. D. Marks

    E-Print Network [OSTI]

    Marks, Laurence D.

    Surface roughening by electron beam heating D. Grozea, E. Landree, and L. D. Marks Department 1997; accepted for publication 15 August 1997 The effect of electron beam heating during. The electron beam irradiation produced a disordered surface on the incident side of the sample and well

  13. Application Prospect Analysis of the Surface Water Source Heat-Pump in China 

    E-Print Network [OSTI]

    Zhang, C.; Zhuang, Z.; Huang, L.; Li, X.; Li, G.; Sun, D.

    2006-01-01

    Surface water resources in China are rather abundant and it can be use as the heat or cool source for heat pump. The winter surface water temperatures of 17 typical cities are investigated in December, and they are all distributed in the interval...

  14. Near-field heat transfer between a nanoparticle and a rough surface

    E-Print Network [OSTI]

    Svend-Age Biehs; Jean-Jacques Greffet

    2011-03-11

    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.

  15. Enhanced convective and film boiling heat transfer by surface gas injection

    SciTech Connect (OSTI)

    Duignan, M.R.; Greene, G.A. ); Irvine, T.F., Jr. . Dept. of Mechanical Engineering)

    1992-04-01

    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.

  16. Enhanced convective and film boiling heat transfer by surface gas injection

    SciTech Connect (OSTI)

    Duignan, M.R.; Greene, G.A.; Irvine, T.F., Jr.

    1992-04-01

    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.

  17. 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))

    1990-01-01

    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.

  18. Turbulent heat exchange between water and ice at an evolving ice-water interface

    E-Print Network [OSTI]

    Ramudu, Eshwan; Olson, Peter; Gnanadesikan, Anand

    2015-01-01

    We conduct laboratory experiments on the time evolution of an ice layer cooled from below and subjected to a turbulent shear flow of warm water from above. Our study is motivated by observations of warm water intrusion into the ocean cavity under Antarctic ice shelves, accelerating the melting of their basal surfaces. The strength of the applied turbulent shear flow in our experiments is represented in terms of its Reynolds number $\\textit{Re}$, which is varied over the range $2.0\\times10^3 \\le \\textit{Re} \\le 1.0\\times10^4$. Depending on the water temperature, partial transient melting of the ice occurs at the lower end of this range of $\\textit{Re}$ and complete transient melting of the ice occurs at the higher end. Following these episodes of transient melting, the ice reforms at a rate that is independent of $\\textit{Re}$. We fit our experimental measurements of ice thickness and temperature to a one-dimensional model for the evolution of the ice thickness in which the turbulent heat transfer is parameter...

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

    E-Print Network [OSTI]

    N. Daniilidis; S. Narayanan; S. A. Möller; R. Clark; T. E. Lee; P. J. Leek; A. Wallraff; St. Schulz; F. Schmidt-Kaler; H. Häffner

    2010-09-15

    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.

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

    E-Print Network [OSTI]

    Attinger, Daniel

    transport [1,2], prevents dropwise condensation or fogging [3,4], and facilitates boiling [5]. A surface

  1. Adsorption of Hydrofluorocarbons HFC-134 and HFC-134A on X and Y Zeolites: Effect of Ion-Exchange on Selectivity and Heat of Adsorption

    E-Print Network [OSTI]

    Siperstein, Flor R.

    Adsorption of Hydrofluorocarbons HFC-134 and HFC-134A on X and Y Zeolites: Effect of Ion-Exchange on Selectivity and Heat of Adsorption Scott Savitz, Flor R. Siperstein, Robert Huber, Stephen M. Tieri, Raymond J Adsorption isotherms and heats of adsorption were measured for HFC-134 (1,1,2,2-tetrafluoroethane) and HFC

  2. Mixed convection heat transfer from thermal sources mounted on horizontal and vertical surfaces

    SciTech Connect (OSTI)

    Tewari, S.S.; Jaluria, Y. )

    1990-11-01

    An experimental study is carried out on the fundamental aspects of the conjugate, mixed convective heat transfer from two finite width heat sources, which are of negligible thickness, have a uniform heat flux input at the surface, and are located on a flat plate in a horizontal or the vertical orientation. The heat sources are wide in the transverse direction and, therefore, a two-dimensional flow circumstance is simulated. The mixed convection parameter is varied over a fairly wide range to include the buoyancy-dominated and the mixed convection regimes. The circumstances of pure natural convection are also investigated. The convective mechanisms have been studied in detail by measuring the surface temperatures and determining the heat transfer coefficients for the two heated strips, which represent isolated thermal sources. Experimental results indicate that a stronger upstream heat source causes an increase in the surface temperature of a relatively weaker heat source, located downstream, by reducing it convective heat transfer coefficient. The influence of the upstream source is found to be strongly dependent on the surface orientation, especially in the pure natural convection and the buoyancy dominated regimes. The two heat sources are found to be essentially independent on the surface orientation, especially in the pure natural convection and the buoyancy dominated regimes. The two heat sources are found to be essentially independent of each other, in terms of thermal effects, at a separation distance of more than about three strip widths for both the orientations. The results obtained are relevant to many engineering applications, such as the cooling of electronic systems, positioning of heating elements in furnaces, and safety considerations in enclosure fires.

  3. Electricity-producing heating apparatus utilizing a turbine generator in a semi-closed brayton cycle

    DOE Patents [OSTI]

    Labinov, Solomon D.; Christian, Jeffrey E.

    2003-10-07

    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. Multiple source heat pump

    DOE Patents [OSTI]

    Ecker, Amir L. (Duncanville, TX)

    1983-01-01

    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.

  5. Experimental and numerical study of mixed convection with flow reversal in coaxial double-duct heat exchangers

    SciTech Connect (OSTI)

    Mare, Thierry; Voicu, Ionut; Miriel, Jacques [Laboratoire de Genie Civil et de Genie Mecanique (LGCGM), INSA de Rennes, IUT Saint Malo, 35043 Rennes (France); Galanis, Nicolas [Faculte de genie, Universite de Sherbrooke, Sherbrooke, QC (Canada); Sow, Ousmane [Laboratoire d'Energie Appliquee, Ecole superieure Polytechnique, Dakar (Senegal)

    2008-04-15

    Velocity vectors in a vertical coaxial double-duct heat exchanger for parallel ascending flow of water under conditions of laminar mixed convection have been determined experimentally using the particle image velocimetry technique. The measured velocity distributions for large annular flow rates, resulting in an essentially isothermal environment for the stream in the inner tube, are in very good agreement with corresponding numerical predictions. For flow rates of the same order of magnitude in the inner tube and the annulus, and corresponding temperature differences of about 20 C, experimental observations show that flow reversal occurs simultaneously in both streams over large axial distances for both heating and cooling of the flow in the inner tube. (author)

  6. 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. These refractory devices take advantage of high temperature operation with large delta-Ts to effectively handle helium flow loop at Sandia National Laboratories. The module survived a maximum absorbed heat flux of 34

  7. 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

    2005-09-01

    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.

  8. Prototype Testing of a Surface Heating System for the GEMINI 8m E. Hansen, D. Hagelbarger, E. Pearson

    E-Print Network [OSTI]

    to control the bulk temperature of the primary. The second, a surface heating system, will be used to adjustPrototype Testing of a Surface Heating System for the GEMINI 8­m Telescopes E. Hansen, D #12; Prototype Testing of a Surface Heating System for the GEMINI 8­m Telescopes Eric Hansen, David

  9. Prototype Testing of a Surface Heating System for the GEMINI 8-m E. Hansen, D. Hagelbarger, E. Pearson

    E-Print Network [OSTI]

    to control the bulk temperature of the primary. The second, a surface heating system, will be used to adjustPrototype Testing of a Surface Heating System for the GEMINI 8-m Telescopes E. Hansen, D #12;Prototype Testing of a Surface Heating System for the GEMINI 8-m Telescopes Eric Hansen, David

  10. Heat pump system

    DOE Patents [OSTI]

    Swenson, Paul F. (Cleveland, OH); Moore, Paul B. (Fedhaurn, FL)

    1982-01-01

    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. Forced-convection surface-boiling heat transfer and burnout in tubes of small diameters

    E-Print Network [OSTI]

    Bergles A. E.

    1962-01-01

    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. ...

  12. Clean Boiler Water-side Heat Transfer Surfaces - Steam Tip Sheet #7

    SciTech Connect (OSTI)

    2012-01-31

    This revised AMO 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.

  13. Enhanced flow boiling heat transfer in microchannels with structured surfaces at varied mass flow rates

    E-Print Network [OSTI]

    Bian, David (David Wei)

    2015-01-01

    This thesis investigates the role of mass flux on flow boiling heat transfer in microchannels with surface micropillar arrays. The motivation for this investigation was to determine the general trends of the optimal ...

  14. Anomalous Near-Field Heat Transfer between a Cylinder and a Perforated Surface

    E-Print Network [OSTI]

    Rodriguez-Wong, Alejandro

    We predict that the near-field radiative heat-transfer rate between a cylinder and a perforated surface depends nonmonotonically on their separation. This anomalous behavior, which arises due to evanescent-wave effects, ...

  15. Electric field noise above surfaces: a model for heating rate scaling law in ion traps

    E-Print Network [OSTI]

    Boyer, Edmond

    Electric field noise above surfaces: a model for heating rate scaling law in ion traps R. Dubessy try to account for this heating rate by considering typical electric noise sources in conductors, 2008) Abstract We present a model for the scaling laws of the electric field noise spectral density

  16. Aalborg Universitet Initial experiments with a Pt based heat exchanger methanol reformer for a HTPEM fuel

    E-Print Network [OSTI]

    Andreasen, Søren Juhl

    for a HTPEM fuel cell system Andreasen, Søren Juhl Publication date: 2007 Document Version Author final reformer for a HTPEM fuel cell system. Poster session presented at HyFC Seminar 2007, Svendborg, Denmark exchanger methanol reformer for a HTPEM fuel cell system Søren Juhl Andreasen* Institute of Energy

  17. On the Interaction between Marine Boundary Layer Cellular Cloudiness and Surface Heat Fluxes

    SciTech Connect (OSTI)

    Kazil, J.; Feingold, G.; Wang, Hailong; Yamaguchi, T.

    2014-01-02

    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.

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

    E-Print Network [OSTI]

    Westheimer, David Thomas

    2000-01-01

    poorly with an Earth based flow regime map; (ii) predicting that the maximum two-phase heat transfer coefficient would occur near the location the boiling fluid reached a saturated state, which also corresponded with the location of maximum nucleate...

  19. Numerical Investigation of Thermal Hydraulic Behavior of Supercritical Carbon Dioxide in Compact Heat Exchangers 

    E-Print Network [OSTI]

    Fatima, Roma

    2012-02-14

    The present work seeks to investigate the thermal hydraulic (heat transfer and fluid dynamics) behavior of supercritical (Sc) fluids at both the fundamental and applied levels. The thermal hydraulics of these fluids is not very well known although...

  20. Effects of surface parameters on boiling heat transfer phenomena

    E-Print Network [OSTI]

    Truong, Bao H. (Bao Hoai)

    2011-01-01

    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 ...

  1. Critical thickness of an optimum extended surface characterized by uniform heat transfer coefficient

    E-Print Network [OSTI]

    Leontiou, Theodoros

    2015-01-01

    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...

  2. 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

    2008-01-01

    stand age on the boreal forest energy balance, Agric. For.RANDERSON: BOREAL FOREST FIRE AND ENERGY EXCHANGE Johnstone,AND RANDERSON: BOREAL FOREST FIRE AND ENERGY EXCHANGE uous

  3. Integrated three-dimensional module heat exchanger for power electronics cooling

    DOE Patents [OSTI]

    Bennion, Kevin; Lustbader, Jason

    2013-09-24

    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.

  4. Aalborg Universitet Experimental Evaluation of a Pt-based Heat Exchanger Methanol Reformer for a

    E-Print Network [OSTI]

    Andreasen, Søren Juhl

    applications, stationary and mobile. Storage volume can be problem- atic for stationary fuel cell systems in power systems using electricity and heat. One of the great challenges of using the fuel cell technology for a HTPEM Fuel Cell Stack Andreasen, Søren Juhl; Kær, Søren Knudsen; Nielsen, Mads Pagh Published in: ECS

  5. September 15, 2003 / Vol. 28, No. 18 / OPTICS LETTERS 1665 Heat treatment for reduction of surface roughness

    E-Print Network [OSTI]

    Avrutsky, Ivan

    September 15, 2003 / Vol. 28, No. 18 / OPTICS LETTERS 1665 Heat treatment for reduction of surface postdevelopment heat treatment of the photoresist polymer used in the preparation of holographic gratings has been the postdevelopment heat treatment to reduce the surface roughness, the setup shown in Fig. 1 was used. The diffracted

  6. LOx breathing system with gas permeable-liquid impermeable heat exchange and delivery hose

    DOE Patents [OSTI]

    Hall, M.N.

    1996-04-30

    Life support apparatus is composed of: a garment for completely enclosing a wearer and constructed for preventing passage of gas from the environment surrounding the garment; a portable receptacle holding a quantity of an oxygen-containing fluid in liquid state, the fluid being in a breathable gaseous state when at standard temperature and pressure; a fluid flow member secured within the garment and coupled to the receptacle for conducting the fluid in liquid state from the receptacle to the interior of the garment; and a fluid flow control device connected for causing fluid to flow from the receptacle to the fluid flow member at a rate determined by the breathable air requirement of the wearer, wherein fluid in liquid state is conducted into the interior of the garment at a rate to be vaporized and heated to a breathable temperature by body heat produced by the wearer. 6 figs.

  7. Lox breathing system with gas permeable-liquid impermeable heat exchange and delivery hose

    DOE Patents [OSTI]

    Hall, Mark N. (Richland, WA)

    1996-01-01

    Life support apparatus composed of: a garment (2): for completely enclosing a wearer and constructed for preventing passage of gas from the environment surrounding the garment (2); a portable receptacle (6) holding a quantity of an oxygen-containing fluid in liquid state, the fluid being in a breathable gaseous; state when at standard temperature and pressure; a fluid flow member (16) secured within the garment (2) and coupled to the receptacle (6) for conducting the fluid in liquid state from the receptacle (6) to the interior of the garment (2); and a fluid flow control device (14) connected for causing fluid to flow from the receptacle (6) to the fluid flow member (16) at a rate determined by the breathable air requirement of the wearer, wherein fluid in liquid state is conducted into the interior of the garment (2) at a rate to be vaporized and heated to a breathable temperature by body heat produced by the wearer.

  8. A laboratory exercise using a physical model for demonstrating countercurrent heat exchange

    E-Print Network [OSTI]

    Loudon, Catherine; Davis-Berg, Elizabeth C; Botz, Jason T

    2012-01-01

    the system, collection in a styrofoam cup worked well,and we used styrofoam chips floating at the surface to limitin an ice bath in a styrofoam box with a stirbar mixing the

  9. Electron-muon heat conduction in neutron star cores via the exchange of transverse plasmons

    E-Print Network [OSTI]

    P. S. Shternin; D. G. Yakovlev

    2007-05-14

    We calculate the thermal conductivity of electrons and muons kappa_{e-mu} produced owing to electromagnetic interactions of charged particles in neutron star cores and show that these interactions are dominated by the exchange of transverse plasmons (via the Landau damping of these plasmons in nonsuperconducting matter and via a specific plasma screening in the presence of proton superconductivity). For normal protons, the Landau damping strongly reduces kappa_{e-mu} and makes it temperature independent. Proton superconductivity suppresses the reduction and restores the Fermi-liquid behavior kappa_{e-mu} ~ 1/T. Comparing with the thermal conductivity of neutrons kappa_n, we obtain kappa_{e-mu}> kappa_n for T>2 GK in normal matter and for any T in superconducting matter with proton critical temperatures T_c>3e9 K. The results are described by simple analytic formulae.

  10. Critical heat flux (CHF) phenomenon on a downward facing curved surface

    SciTech Connect (OSTI)

    Cheung, F.B.; Haddad, K.H.; Liu, Y.C. [Pennsylvania State Univ., University Park, PA (United States). Dept. of Mechanical Engineering

    1997-06-01

    This report describes a theoretical and experimental study of the boundary layer boiling and critical heat flux phenomena on a downward facing curved heating surface, including both hemispherical and toroidal surfaces. A subscale boundary layer boiling (SBLB) test facility was developed to measure the spatial variation of the critical heat flux and observe the underlying mechanisms. Transient quenching and steady-state boiling experiments were performed in the SBLB facility under both saturated and subcooled conditions to obtain a complete database on the critical heat flux. To complement the experimental effort, an advanced hydrodynamic CHF model was developed from the conservation laws along with sound physical arguments. The model provides a clear physical explanation for the spatial variation of the CHF observed in the SBLB experiments and for the weak dependence of the CHF data on the physical size of the vessel. Based upon the CHF model, a scaling law was established for estimating the local critical heat flux on the outer surface of a heated hemispherical vessel that is fully submerged in water. The scaling law, which compares favorably with all the available local CHF data obtained for various vessel sizes, can be used to predict the local CHF limits on large commercial-size vessels. This technical information represents one of the essential elements that is needed in assessing the efficacy of external cooling of core melt by cavity flooding as a severe accident management strategy. 83 figs., 3 tabs.

  11. A self-circulating heat exchanger for use in stirling and

    Office of Scientific and Technical Information (OSTI)

    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 Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield Municipal GasAdministrationTechnicalTechnicalScience.govWSRC-MS-g8-00318 Heat

  12. 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

    2004-09-27

    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.

  13. 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 tubes to that of the original tubes. b. (35 pts.) Determine the ratio of the pressure drop across of the flow through a single tube in the bundle. Is the flow laminar? D2. (10 pts.) Determine the pressure

  14. 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.

    2002-01-01

    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...

  15. 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)

    1995-01-01

    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.

  16. Modeling, Estimation, and Control of Waste Heat Recovery Systems

    E-Print Network [OSTI]

    Luong, David

    2013-01-01

    regulates heat exchanger pressures and ex- pander powerwhile regulating heat exchanger pressures. The pressure andworking fluid pressure in EGR heat exchanger Pegrin, in MPa

  17. Combined refrigeration system with a liquid pre-cooling heat exchanger

    DOE Patents [OSTI]

    Gaul, Christopher J.

    2003-07-01

    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.

  18. 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

  19. Insoluble coatings for Stirling engine heat pipe condenser surfaces. Final report

    SciTech Connect (OSTI)

    Dussinger, P.M.

    1993-09-01

    The work done by Thermacore, Inc., Lancaster, Pennsylvania, for the Phase 1, 1992 SBIR National Aeronautics and Space Administration Contract, Insoluble Coatings for Stirling Engine Heat Pipe Condenser Surfaces' is described. The work was performed between January 1992 and July 1992. Stirling heat engines are being developed for electrical power generation use on manned and unmanned earth orbital and planetary missions. Dish Stirling solar systems and nuclear reactor Stirling systems are two of the most promising applications of the Stirling engine electrical power generation technology. The sources of thermal energy used to drive the Stirling engine typically are non-uniform in temperature and heat flux. Liquid metal heat pipe receivers are used as thermal transformers and isothermalizers to deliver the thermal energy at a uniform high temperature to the heat input section of the Stirling engine. The use of a heat pipe receiver greatly enhances system efficiency and potential life span. One issue that is raised during the design phase of heat pipe receivers is the potential solubility corrosion of the Stirling engine heat input section by the liquid metal working fluid. This Phase 1 effort initiated a program to evaluate and demonstrate coatings, applied to nickel based Stirling engine heater head materials, that are practically 'insoluble' in sodium, potassium, and NaK. This program initiated a study of nickel aluminide as a coating and developed and demonstrated a heat pipe test vehicle that can be used to test candidate materials and coatings. Nickel 200 and nickel aluminide coated Nickel 200 were tested for 1000 hours at 800 C at a condensation heat flux of 25 W/sq cm. Subsequent analyses of the samples showed no visible sign of solubility corrosion of either coated or uncoated samples. The analysis technique, photomicrographs at 200X, has a resolution of better than 2.5 microns (.0001 in).

  20. 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)

    2001-01-01

    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.

  1. Measurements of instantaneous heat flux to metal and ceramic surfaces in a diesel engine

    SciTech Connect (OSTI)

    Huang, J.C.; Borman, G.L.

    1987-02-01

    The effects of surface materials and extent of insulation on the heat transfer to the head of an open-chamber diesel were studied. A large instrumentation plug designed to incorporate plates of various materials on the gas-side surface was utilized with a special research head. Instantaneous rates of heat transfer to the plate gas-side surface were measured. Measurement results obtained with a zirconia plate and an insulated metal plate are compared to data for an inunsulated metal plate. The insulation of the metal plate increased its gas-side surface temperature over the uninsulated case by about the same amount achieved with a 6.35-mm-thick zirconia plate. The magnitude of the surface temperature swing for zirconia is not as high as expected from conduction theory, but is substantially higher than that for the uninsulated metal. Significant reductions of steady-state heat fluxes were achieved with both the zirconia and the insulated metal compared to the uninsulated metal.

  2. Expansion of a radial jet from a guillotine tube breach in a shell-and-tube heat exchanger

    SciTech Connect (OSTI)

    Velasco, F.J.S.; del Pra, C. Lopez; Herranz, Luis E. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Nuclear fission division, Nuclear Safety Research Unit, Avda. Complutense, 22, P.O. Box 28040 Madrid (Spain)

    2008-02-15

    Aerodynamics of a particle-laden gas jet entering the secondary side of a shell-and-tube heat exchanger from a tube guillotine breach, determines to a large extent radioactive retention in the break stage of the steam generator (SG) during hypothetical SGTR accident sequences in pressurized nuclear water reactors (PWRs). These scenarios were shown to be risk-dominant in PWRs. The major insights gained from a set of experiments into such aerodynamics are summarized in this paper. A scaled-down mock-up with representative dimensions of a real SG was built. Two-dimensional (2D) PIV technique was used to characterize the flow field in the space between the breach and the neighbor tubes in the gas flow range investigated (Re{sub D} = 0.8-2.7 x 10{sup 5}). Pitot tube measurements and CFD simulations were used to discuss and complement PIV data. The results, reported mainly in terms of velocity and turbulent intensity profiles, show that jet penetration and gas entrainment are considerably enhanced when increasing Re{sub D}. The presence of tubes was observed to distort the jet shape and to foster gas entrainment with respect to a jet expansion free of tubes. Turbulence intensity level close to the breach increases linearly with Re{sub D}. Account of this information into aerosol modeling will enhance predictive capability of inertial impaction and turbulent deposition equations. (author)

  3. Development of a coal-fueled Internal Manifold Heat Exchanger (IMHEX reg sign ) molten carbonate fuel cell

    SciTech Connect (OSTI)

    Not Available

    1991-09-01

    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.

  4. Heat pump with freeze-up prevention

    DOE Patents [OSTI]

    Ecker, Amir L. (Dallas, TX)

    1981-01-01

    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.

  5. Absorption heat pump system

    DOE Patents [OSTI]

    Grossman, G.

    1982-06-16

    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.

  6. Absorption heat pump system

    DOE Patents [OSTI]

    Grossman, Gershon (Oak Ridge, TN)

    1984-01-01

    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.

  7. Exchange of groundwater and surfacewater mediated by permafrost response to seasonal and long term air

    E-Print Network [OSTI]

    McKenzie, Jeffrey M.

    Exchange of groundwater and surfacewater mediated by permafrost response to seasonal and long term impact hydrologic cycle processes by promoting or impeding groundwater and surface water exchange. Under between groundwater and surface water. A coupled heat transport and groundwater flow model, SUTRA

  8. Please cite this article in press as: Jschke J, Skogestad S. Optimal operation of heat exchanger networks with stream split: Only tempera-ture measurements are required. Computers and Chemical Engineering (2014), http://dx.doi.org/10.1016/j.compchemeng.20

    E-Print Network [OSTI]

    Skogestad, Sigurd

    2014-01-01

    Please cite this article in press as: Jäschke J, Skogestad S. Optimal operation of heat exchanger of heat exchanger networks with stream split: Only temperature measurements are required Johannes Jäschke in revised form 20 March 2014 Accepted 27 March 2014 Available online xxx Keywords: Heat exchanger networks

  9. 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.

    2010-11-11

    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.

  10. Electric field noise above surfaces: a model for heating rate scaling law in ion traps

    E-Print Network [OSTI]

    Romain Dubessy; Thomas Coudreau; Luca Guidoni

    2008-12-17

    We present a model for the scaling laws of the electric field noise spectral density as a function of the distance, $d$, above a conducting surface. Our analytical approach models the patch potentials by introducing a correlation length, $\\zeta$, of the electric potential on the surface. The predicted scaling laws are in excellent agreement with two different classes of experiments (cold trapped ions and cantilevers), that span at least four orders of magnitude of $d$. According to this model, heating rate in miniature ion traps could be greatly reduced by proper material engineering.

  11. Optimal artificial neural network architecture selection for performance prediction of compact heat exchanger with the EBaLM-OTR technique

    SciTech Connect (OSTI)

    Dumidu Wijayasekara; Milos Manic; Piyush Sabharwall; Vivek Utgikar

    2011-07-01

    Artificial Neural Networks (ANN) have been used in the past to predict the performance of printed circuit heat exchangers (PCHE) with satisfactory accuracy. Typically published literature has focused on optimizing ANN using a training dataset to train the network and a testing dataset to evaluate it. Although this may produce outputs that agree with experimental results, there is a risk of over-training or overlearning the network rather than generalizing it, which should be the ultimate goal. An over-trained network is able to produce good results with the training dataset but fails when new datasets with subtle changes are introduced. In this paper we present EBaLM-OTR (error back propagation and Levenberg-Marquardt algorithms for over training resilience) technique, which is based on a previously discussed method of selecting neural network architecture that uses a separate validation set to evaluate different network architectures based on mean square error (MSE), and standard deviation of MSE. The method uses k-fold cross validation. Therefore in order to select the optimal architecture for the problem, the dataset is divided into three parts which are used to train, validate and test each network architecture. Then each architecture is evaluated according to their generalization capability and capability to conform to original data. The method proved to be a comprehensive tool in identifying the weaknesses and advantages of different network architectures. The method also highlighted the fact that the architecture with the lowest training error is not always the most generalized and therefore not the optimal. Using the method the testing error achieved was in the order of magnitude of within 10{sup -5} - 10{sup -3}. It was also show that the absolute error achieved by EBaLM-OTR was an order of magnitude better than the lowest error achieved by EBaLM-THP.

  12. SU(3) Latent Heat and Surface Tension from Tree Level and Tadpole Improved Actions

    E-Print Network [OSTI]

    Beinlich, B; Peikert, A

    1996-01-01

    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.

  13. SU(3) Latent Heat and Surface Tension from Tree Level and Tadpole Improved Actions

    E-Print Network [OSTI]

    B. Beinlich; F. Karsch; A. Peikert

    1996-08-27

    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.

  14. SMALL PARTICLE HEAT EXCHANGERS

    E-Print Network [OSTI]

    Hunt, A.J.

    2011-01-01

    of advanced concept solar power plants. For conditions ofThe size for a solar-hybrid power plant incorporating a

  15. Analytical and experimental study of a liquid desiccant heat and mass exchanger operating near water freezing temperature

    E-Print Network [OSTI]

    Pineda Vargas, Sergio Manuel

    2009-01-01

    exchanger operating near water freezing temperature A Thesisoperating near water freezing temperature Copyright © 2009operating near water freezing temperature Sergio M. Pineda

  16. Anomalous Near-Field Heat Transfer between a Cylinder and a Perforated Surface Alejandro W. Rodriguez,1,2

    E-Print Network [OSTI]

    Anomalous Near-Field Heat Transfer between a Cylinder and a Perforated Surface Alejandro W between a cylinder and a perforated surface depends nonmonotonically on their separation. This anomalous between a cylinder (or elongated object) and a perforated surface (e.g., a ring) can vary nonmonotonically

  17. 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.

    2010-09-01

    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.

  18. Clean Firetube Boiler Waterside Heat Transfer Surfaces, Energy Tips: STEAM, Steam Tip Sheet #7 (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2012-04-01

    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.

  19. The radiative heat transfer between a rotating nanoparticle and a plane surface

    E-Print Network [OSTI]

    Vahid Ameri; Mehdi Shafei Aporvari; Fardin Kheirandish

    2015-06-03

    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.

  20. 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 exchangers 

    E-Print Network [OSTI]

    Segura, D.; Acharya, S.

    2012-01-01

    and thermocouples were used to create a temperature vs. time map. Duhamel's superposition theorem was then used to determine the local heat transfer coefficients (h) and heat transfer enhancement factors (Nu/Nuo). In one series of testing a straight center inlet...

  1. Suppression of Heating Rates in Cryogenic Surface-Electrode Ion Traps

    E-Print Network [OSTI]

    Jaroslaw Labaziewicz; Yufei Ge; Paul Antohi; David Leibrandt; Kenneth R. Brown; Isaac L. Chuang

    2007-11-16

    Dense arrays of trapped ions provide one way of scaling up ion trap quantum information processing. However, miniaturization of ion traps is currently limited by sharply increasing motional state decoherence at sub-100 um ion-electrode distances. We characterize heating rates in cryogenically cooled surface-electrode traps, with characteristic sizes in 75 um to 150 um range. Upon cooling to 6 K, the measured rates are suppressed by 7 orders of magnitude, two orders of magnitude below previously published data of similarly sized traps operated at room temperature. The observed noise depends strongly on fabrication process, which suggests further improvements are possible.

  2. Heating rate and electrode charging measurements in a scalable, microfabricated, surface-electrode ion trap

    E-Print Network [OSTI]

    D. T. C. Allcock; T. P. Harty; H. A. Janacek; N. M. Linke; C. J. Ballance; A. M. Steane; D. M. Lucas; R. L. Jarecki Jr.; S. D. Habermehl; M. G. Blain; D. Stick; D. L. Moehring

    2011-05-24

    We characterise the performance of a surface-electrode ion "chip" trap fabricated using established semiconductor integrated circuit and micro-electro-mechanical-system (MEMS) microfabrication processes which are in principle scalable to much larger ion trap arrays, as proposed for implementing ion trap quantum information processing. We measure rf ion micromotion parallel and perpendicular to the plane of the trap electrodes, and find that on-package capacitors reduce this to heating rate for a single trapped ion. The performance of this trap is found to be comparable with others of the same size scale.

  3. Theoretical Studies of Energy and Momentum Exchange in Atomic and Molecular Scattering from Surfaces

    SciTech Connect (OSTI)

    Joseph R. Manson

    2005-06-30

    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.

  4. MATERIALS, FABRICATION, AND MANUFACTURING OF MICRO/NANOSTRUCTURED SURFACES FOR PHASE-CHANGE HEAT TRANSFER ENHANCEMENT

    SciTech Connect (OSTI)

    McCarthy, M; Gerasopoulos, K; Maroo, SC; Hart, AJ

    2014-07-23

    This article describes the most prominent materials, fabrication methods, and manufacturing schemes for micro- and nanostructured surfaces that can be employed to enhance phase-change heat transfer phenomena. The numerous processes include traditional microfabrication techniques such as thin-film deposition, lithography, and etching, as well as template-assisted and template-free nanofabrication techniques. The creation of complex, hierarchical, and heterogeneous surface structures using advanced techniques is also reviewed. Additionally, research needs in the field and future directions necessary to translate these approaches from the laboratory to high-performance applications are identified. Particular focus is placed on the extension of these techniques to the design of micro/nanostructures for increased performance, manufacturability, and reliability. The current research needs and goals are detailed, and potential pathways forward are suggested.

  5. Role of sea surface temperature, Arctic sea ice and Siberian snow in forcing the atmospheric circulation in winter of 2012–2013

    E-Print Network [OSTI]

    Peings, Y; Magnusdottir, G

    2015-01-01

    the atmosphere through heat flux exchanges (Bjerknes 1964).energy flux exchanges (radiative and turbulent heat fluxes).

  6. 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.

    1983-09-21

    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.

  7. 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)

    1986-01-01

    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.

  8. A Computational Study on the Thermal-Hydraulic Behavior of Supercritical Carbon Dioxide in Various Printed Circuit Heat Exchanger Designs 

    E-Print Network [OSTI]

    Matsuo, Bryce

    2013-02-04

    and concentrated solar power generation. Two main advantages of having supercritical carbon dioxide are the large property variations and component size associated with power cycle. Forced convection heat transfer of supercritical carbon dioxide in printed circuit...

  9. SIZE AND SURFACE AREA OF ICY DUST AGGREGATES AFTER A HEATING EVENT AT A PROTOPLANETARY NEBULA

    SciTech Connect (OSTI)

    Sirono, Sin-iti

    2013-03-01

    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.

  10. Measurements of net radiation, ground heat flux and surface temperature in an urban canyon

    SciTech Connect (OSTI)

    Gouveia, F J; Leach, M J; Shinn, J H

    2003-11-06

    The Joint Urban 2003 (JU2003) field study was conducted in Oklahoma City in July 2003 to collect data to increase our knowledge of dispersion in urban areas. Air motions in and around urban areas are very complicated due to the influence of urban structures on both mechanical and thermal forcing. During JU2003, meteorological instruments were deployed at various locations throughout the urban area to characterize the processes that influence dispersion. Some of the instruments were deployed to characterize urban phenomena, such as boundary layer development. In addition, particular sites were chosen for more concentrated measurements to investigate physical processes in more detail. One such site was an urban street canyon on Park Avenue between Broadway and Robinson Avenues in downtown Oklahoma City. The urban canyon study was designed to examine the processes that control dispersion within, into and out of the urban canyon. Several towers were deployed in the Park Avenue block, with multiple levels on each tower for observing the wind using sonic anemometers. Infrared thermometers, net radiometers and ground heat flux plates were deployed on two of the towers midway in the canyon to study the thermodynamic effects and to estimate the surface energy balance. We present results from the surface energy balance observations.

  11. Heat transfer of R-134a in single-tube spray evaporation including lubricant effects and enhanced surface results

    SciTech Connect (OSTI)

    Moeykens, S.A.; Huebsch, W.W.; Pate, M.B.

    1995-08-01

    Single-tube spray evaporation experimental tests were conducted in order to evaluate the average wall heat transfer coefficients for seven different commercially available tubes. Liquid film supply rates were held constant in order to evaluate the effects of the enhancement on shell-side heat transfer under similar conditions. Because the spray evaporation phenomenon is so different from pool boiling, both condensation-type and evaporation-type enhanced surfaces were evaluated. A comparison of the results for all of the tubes showed that the enhanced condensation surfaces performed better than the enhanced boiling surfaces. In addition, the 26-fpi surface tested marginally better than the 40-fpi surface. Small concentrations of a polyol-ester lubricant cause a foaming effect that increases the heat transfer performance. This tendency was seen with both 32-cs and 68-cs polyol-ester oils. The 68-cs lubricant was tested at concentrations of 0.0, 0.5, 1.0, 3.0, and 5.0 with the W-40 fpi and Tu-Cii surfaces. Results with this lubricant show the performance continues to increase through the 3% concentration for most of the heat flux range tested At the upper end of the range tested, the 1.0% mass fraction yielded the best performance. The 32-cs lubricant generated trends similar to those of the 68-cs lubricant. Lubricant concentrations of 1.0%, 2.0%, and 3.0% were evaluated with plain, W-40 fpi, and Tu-Cii surfaces. The 2.0% concentration, not the 1.0 %, generated the best performance at the highest heat flux tested. This difference must be attributed to the difference in the lubricant viscosity.

  12. Rotary magnetic heat pump

    DOE Patents [OSTI]

    Kirol, L.D.

    1987-02-11

    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.

  13. Rotary magnetic heat pump

    DOE Patents [OSTI]

    Kirol, Lance D. (Shelly, ID)

    1988-01-01

    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.

  14. Mass and Heat Recovery 

    E-Print Network [OSTI]

    Hindawai, S. M.

    2010-01-01

    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...

  15. Theoretical Design of a Thermosyphon for Efficient Process Heat Removal from Next Generation Nuclear Plant (NGNP) for Production of Hydrogen

    SciTech Connect (OSTI)

    Piyush Sabharwall; Fred Gunnerson; Akira Tokuhiro; Vivek Utgiker; Kevan Weaver; Steven Sherman

    2007-10-01

    The work reported here is the preliminary analysis of two-phase Thermosyphon heat transfer performance with various alkali metals. Thermosyphon is a device for transporting heat from one point to another with quite extraordinary properties. Heat transport occurs via evaporation and condensation, and the heat transport fluid is re-circulated by gravitational force. With this mode of heat transfer, the thermosyphon has the capability to transport heat at high rates over appreciable distances, virtually isothermally and without any requirement for external pumping devices. For process heat, intermediate heat exchangers (IHX) are required to transfer heat from the NGNP to the hydrogen plant in the most efficient way possible. The production of power at higher efficiency using Brayton Cycle, and hydrogen production requires both heat at higher temperatures (up to 1000oC) and high effectiveness compact heat exchangers to transfer heat to either the power or process cycle. The purpose for selecting a compact heat exchanger is to maximize the heat transfer surface area per volume of heat exchanger; this has the benefit of reducing heat exchanger size and heat losses. The IHX design requirements are governed by the allowable temperature drop between the outlet of the NGNP (900oC, based on the current capabilities of NGNP), and the temperatures in the hydrogen production plant. Spiral Heat Exchangers (SHE’s) have superior heat transfer characteristics, and are less susceptible to fouling. Further, heat losses to surroundings are minimized because of its compact configuration. SHEs have never been examined for phase-change heat transfer applications. The research presented provides useful information for thermosyphon design and Spiral Heat Exchanger.

  16. 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)

    1998-01-01

    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.

  17. Heat pump having improved defrost system

    DOE Patents [OSTI]

    Chen, F.C.; Mei, V.C.; Murphy, R.W.

    1998-12-08

    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.

  18. Heat extraction for the CSPonD thermal storage unit

    E-Print Network [OSTI]

    Rojas, Folkers Eduardo

    2011-01-01

    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 ...

  19. 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

  20. Integrated heat pump system

    SciTech Connect (OSTI)

    Reedy, W.R.

    1988-03-01

    An integrated heat pump and hot water system is described that includes: a heat pump having an indoor heat exchanger and an outdoor heat exchanger that are selectively connected to the suction line and the discharge line respectively of a compressor by a flow reversing means, and to each other by a liquid line having an expansion device mounted therein, whereby heating and cooling is provided to an indoor comfort zone by cycling the flow reversing means, a refrigerant to water heat exchanger having a hot water flow circuit in heat transfer relation with a first refrigerant condensing circuit and a second refrigerant evaporating circuit, a connection mounted in the liquid between the indoor heat exchanger and the expansion device, control means for regulating the flow of refrigerant through the refrigerant to water heat exchanger to selectively transfer heat into and out of the hot water flow circuit.

  1. 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 ...

  2. "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

    2008-06-12

    ABSTRACT Nanotechnology Enabled Advanced industrial Heat Transfer Fluids” 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

  3. Heat Transfer Fluids for Solar Water Heating Systems | Department...

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

    Illustration of a solar water heater. Illustration of a solar water heater. Heat-transfer fluids carry heat through solar collectors and a heat exchanger to the heat storage tanks...

  4. Integrated heat pump water heater

    SciTech Connect (OSTI)

    Robinson, G.P.; Blackshaw, A.L.

    1986-07-08

    An integrated heat pump water heater system is described for providing either heating or cooling of an interior space, and heating water in conjunction with either the heating or cooling cycle or independently, by means of a refrigerant flowing through the system. The system consists of: a compressor; a first heat exchanger means for providing heat to the interior space in the heating cycle and for removing heat during the cooling cycle by heat transfer with a refrigerant therein; a second heat exchanger means for transferring heat to or from a refrigerant therein by heat exchanger with an exterior medium; a third heat exchanger means for transferring heat from a refrigerant therein to water circulated therethrough; a first expansion device; a second expansion device; a third expansion device; refrigerant flow connection means connected between the compressor, the heat exchanger means, and the expansion devices which may be controllably connected in alternate configurations whereby. In a first configuration the refrigerant flow is sequentially from the compressor, through the third heat exchanger means, through the second heat exchanger means, through the first expansion device, through the first heat exchanger means, and back to the compressor. In a second configuration the refrigerant flow is sequentially from the compressor, through the third heat exchanger means, through the first heat exchanger means, through the second expansion device, through the second heat exchanger means, and back to the compressor. In a third configuration the refrigerant flow is sequentially from the compressor, through the third heat exchanger means, through the third expansion device, through the second heat exchanger means, and back to the compressor.

  5. Indirect evaporative coolers with enhanced heat transfer

    DOE Patents [OSTI]

    Kozubal, Eric; Woods, Jason; Judkoff, Ron

    2015-09-22

    A separator plate assembly for use in an indirect evaporative cooler (IEC) with an air-to-air heat exchanger. The assembly includes a separator plate with a first surface defining a dry channel and a second surface defining a wet channel. The assembly includes heat transfer enhancements provided on the first surface for increasing heat transfer rates. The heat transfer enhancements may include slit fins with bodies extending outward from the first surface of separator plate or may take other forms including vortex generators, offset strip fins, and wavy fins. In slit fin implementations, the separator plate has holes proximate to each of the slit fins, and the separator plate assembly may include a sealing layer applied to the second surface of the separator plate to block air flow through the holes. The sealing layer can be a thickness of adhesive, and a layer of wicking material is applied to the adhesive.

  6. 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.

    2012-07-01

    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)

  7. SENSIBLE HEAT STORAGE FOR A SOLAR THERMAL POWER PLANT

    E-Print Network [OSTI]

    Baldwin, Thomas F.

    2011-01-01

    for Pressure Drop Through the Heat Exchanger Tubing. MFa *Run Exchangers to~Heat~ Piping Run Total Pressure Drop, MPaPressure 51de g MFa Gas Temperature out of Heat Exchangers,

  8. 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 ...

  9. 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

    1991-09-01

    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.

  10. Heat pump system

    DOE Patents [OSTI]

    Swenson, Paul F. (Shaker Heights, OH); Moore, Paul B. (Fedhaven, FL)

    1983-01-01

    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.

  11. Heat pump system

    DOE Patents [OSTI]

    Swenson, Paul F.; Moore, Paul B.

    1983-06-21

    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.

  12. A method of correlating heat transfer data for surface boiling of liquids

    E-Print Network [OSTI]

    Rohsenow, Warren M.

    1951-01-01

    A method based an a logical uxplanation of the meani of beat transfer associated with the boiling process is presented for correlating heat transfer data for nucleate boiling of liquids for the case of pool boiling. Tbe ...

  13. Near-wall reaction effects on film-cooled surface heat transfer

    E-Print Network [OSTI]

    Kirk, Daniel Robert, 1975-

    2003-01-01

    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 ...

  14. Inferring surface heat flux distributions guided by a global seismic model: particular application to Antarctica

    E-Print Network [OSTI]

    Shapiro, Nikolai

    , the procedure generates a histogram of heat-flow values determined from existing measurements obtained from are strongly non-Gaussian, but are well approximated by the log-logistic distribution which is completely

  15. 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 ...

  16. The Impact of Heat Transfer Enhancement Techniques on Energy Savings in the U.S. Industry 

    E-Print Network [OSTI]

    Rebello, W. J.; Peterson, G. R.; Sohal, M.

    1988-01-01

    hydrocarbons in kettle reboilers in refineries. Finned tubing is now available in corrosion resistant materials, such as, titanium, Inconel, Hastelloy and stain less steel. In the past, finning techniques were developed for ductile, easy... and Internally Finned Tubes", J.of Heat Transfer vlOO, nl,Feb. 1978. 12. R. L. Webb, "Performance Evalu tion Criteria for Use of Enhanced Heat Transfer Surfaces in Heat Exchanger Design", International Journal of Heat and Mass Transfer, v24, n4, pp715, 1981...

  17. 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

    2015-01-01

    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...

  18. 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.

  19. 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.

    1996-12-01

    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.

  20. Fabrication and heating rate study of microscopic surface electrode ion traps This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-Print Network [OSTI]

    Wallraff, Andreas

    in the literature and the possible relation of anomalous heating to sources of noise and dissipation in otherFabrication and heating rate study of microscopic surface electrode ion traps This article has been of contents for this issue, or go to the journal homepage for more Home Search Collections Journals About