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Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

Active microchannel heat exchanger  

DOE Patents [OSTI]

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.

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

2001-01-01T23:59:59.000Z

2

Microchannel Heat Exchangers with Carbon Dioxide  

SciTech Connect (OSTI)

The objective of the present study was to determine the performance of CO{sub 2} microchannel evaporators and gas coolers in operational conditions representing those of residential heat pumps. A set of breadboard prototype microchannel evaporators and gas coolers was developed and tested. The refrigerant in the heat exchangers followed a counter cross-flow path with respect to the airflow direction. The test conditions corresponded to the typical operating conditions of residential heat pumps. In addition, a second set of commercial microchannel evaporators and gas coolers was tested for a less comprehensive range of operating conditions. The test results were reduced and a comprehensive data analysis, including comparison with the previous studies in this field, was performed. Capacity and pressure drop of the evaporator and gas cooler for the range of parameters studied were analyzed and are documented in this report. A gas cooler performance prediction model based on non-dimensional parameters was also developed and results are discussed as well. In addition, in the present study, experiments were conducted to evaluate capacities and pressure drops for sub-critical CO{sub 2} flow boiling and transcritical CO{sub 2} gas cooling in microchannel heat exchangers. An extensive review of the literature failed to indicate any previous systematic study in this area, suggesting a lack of fundamental understanding of the phenomena and a lack of comprehensive data that would quantify the performance potential of CO{sub 2} microchannel heat exchangers for the application at hand. All experimental tests were successfully conducted with an energy balance within {+-}3%. The only exceptions to this were experiments at very low saturation temperatures (-23 C), where energy balances were as high as 10%. In the case of evaporators, it was found that a lower saturation temperature (especially when moisture condensation occurs) improves the overall heat transfer coefficient significantly. However, under such conditions, air side pressure drop also increases when moisture condensation occurs. An increase in airflow rate also increases the overall heat transfer coefficient. Air side pressure drop mainly depends on airflow rate. For the gas cooler, a significant portion of the heat transfer occurred in the first heat exchanger module on the refrigerant inlet side. The temperature and pressure of CO{sub 2} significantly affect the heat transfer and fluid flow characteristics due to some important properties (such as specific heat, density, and viscosity). In the transcritical region, performance of CO{sub 2} strongly depends on the operating temperature and pressure. Semi-empirical models were developed for predictions of CO{sub 2} evaporator and gas cooler system capacities. The evaporator model introduced two new factors to account for the effects of air-side moisture condensate and refrigerant outlet superheat. The model agreed with the experimental results within {+-}13%. The gas cooler model, based on non-dimensional parameters, successfully predicted the experimental results within {+-}20%. Recommendations for future work on this project include redesigning headers and/or introducing flow mixers to avoid flow mal-distribution problems, devising new defrosting techniques, and improving numerical models. These recommendations are described in more detail at the end of this report.

Zhao, Y.; Ohadi, M.M.; Radermacher, R.

2001-09-15T23:59:59.000Z

3

Diffusion-Welded Microchannel Heat Exchanger for Industrial Processes  

SciTech Connect (OSTI)

The goal of next generation reactors is to increase energy ef?ciency in the production of electricity and provide high-temperature heat for industrial processes. The ef?cient 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. The need for ef?ciency, compactness, and safety challenge the boundaries of existing heat exchanger technology. 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 ef?cient industrial processes. Modern compact heat exchangers can provide high compactness, a measure of the ratio of surface area-to-volume of a heat exchange. The microchannel heat exchanger studied here is a plate-type, robust heat exchanger that combines compactness, low pressure drop, high effectiveness, and the ability to operate with a very large pressure differential between hot and cold sides. The plates are etched and thereafter joined by diffusion welding, resulting in extremely strong all-metal heat exchanger cores. After bonding, any number of core blocks can be welded together to provide the required ?ow capacity. This study explores the microchannel heat exchanger and draws conclusions about diffusion welding/bonding for joining heat exchanger plates, with both experimental and computational modeling, along with existing challenges and gaps. Also, presented is a thermal design method for determining overall design speci?cations for a microchannel printed circuit heat exchanger for both supercritical (24 MPa) and subcritical (17 MPa) Rankine power cycles.

Piyush Sabharwall; Denis E. Clark; Michael V. Glazoff; Michael G. McKellar; Ronald E. Mizia

2013-03-01T23:59:59.000Z

4

Microchannel crossflow fluid heat exchanger and method for its fabrication  

DOE Patents [OSTI]

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.

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

1985-05-14T23:59:59.000Z

5

Microchannel crossflow fluid heat exchanger and method for its fabrication  

DOE Patents [OSTI]

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.

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

1982-08-31T23:59:59.000Z

6

Low-Cost Microchannel Heat Exchanger  

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

psi pressure capability High effectiveness > 90% 80% lower estimated external heat loss 60% estimated lower cost Complete remaining tests and refine cost...

7

Experimentally validated models of refrigerant distribution in microchannel heat exchangers used to evaluate charge reduction of various working fluids.  

E-Print Network [OSTI]

??This thesis presents experimentally validated simulation models developed to obtain accurate prediction of microchannel heat exchanger performance and charge. Effects of using various correlations are (more)

Padilla, Yadira

2012-01-01T23:59:59.000Z

8

Microchannel heat sink assembly  

DOE Patents [OSTI]

The present invention provides a microchannel heat sink with a thermal range from cryogenic temperatures to several hundred degrees centigrade. The heat sink can be used with a variety of fluids, such as cryogenic or corrosive fluids, and can be operated at a high pressure. The heat sink comprises a microchannel layer preferably formed of silicon, and a manifold layer preferably formed of glass. The manifold layer comprises an inlet groove and outlet groove which define an inlet manifold and an outlet manifold. The inlet manifold delivers coolant to the inlet section of the microchannels, and the outlet manifold receives coolant from the outlet section of the microchannels. In one embodiment, the manifold layer comprises an inlet hole extending through the manifold layer to the inlet manifold, and an outlet hole extending through the manifold layer to the outlet manifold. Coolant is supplied to the heat sink through a conduit assembly connected to the heat sink. A resilient seal, such as a gasket or an O-ring, is disposed between the conduit and the hole in the heat sink in order to provide a watertight seal. In other embodiments, the conduit assembly may comprise a metal tube which is connected to the heat sink by a soft solder. In still other embodiments, the heat sink may comprise inlet and outlet nipples. The present invention has application in supercomputers, integrated circuits and other electronic devices, and is suitable for cooling materials to superconducting temperatures. 13 figs.

Bonde, W.L.; Contolini, R.J.

1992-03-24T23:59:59.000Z

9

DEVELOPMENT OF A UHT WATER PASTEURIZATION SYSTEM USING MICROCHANNEL HEAT EXCHANGER TECHNOLOGY  

E-Print Network [OSTI]

stages of proposal development for DaVita, leveraging the OSU Venture Fund money for a small-scale system+ that a small-scale system is feasible with microchannel technology. These past activities, as footnoted below, significant interest exists in a stand-alone water purification system in the 1000 ml

Escher, Christine

10

Modeling and optimization of a combined cycle Stirling-ORC system and design of an integrated microchannel Stirling heat rejector.  

E-Print Network [OSTI]

??The performance of a combined Stirling-ORC power cycle is evaluated, and an integrated microchannel heat exchanger is designed as an annular cold-side heat rejector for (more)

Ingram-Goble, Robbie

2010-01-01T23:59:59.000Z

11

Hydrodynamics and heat transfer during flow boiling instabilities in a single microchannel  

E-Print Network [OSTI]

Hydrodynamics and heat transfer during flow boiling instabilities in a single microchannel July 2008 Keywords: Boiling Microchannels Visualisation Flow boiling instabilities Heat transfer a b intensification heat removal. Flow boiling heat transfer in microchannel geometry and the associated flow

Aussillous, Pascale

12

Innovative heat removal structure for power devices -the drift region integrated microchannel cooler  

E-Print Network [OSTI]

Innovative heat removal structure for power devices - the drift region integrated microchannel is approved to be a compact and high-performance solution to deal with the thermal requirements of power devices and modules. This is due to the large heat exchange surface, the high heat transfer coefficient

Boyer, Edmond

13

Heat exchanger  

DOE Patents [OSTI]

A heat exchanger comparising a shell attached at its open end to one side of a tube sheet and a detachable head connected to the other side of said tube sheet. The head is divided into a first and second chamber in fluid communication with a nozzle inlet and nozzle outlet, respectively, formed in said tube sheet. A tube bundle is mounted within said shell and is provided with inlets and outlets formed in said tube sheet in communication with said first and second chambers, respectively.

Brackenbury, Phillip J. (Richland, WA)

1986-01-01T23:59:59.000Z

14

Heat exchanger  

DOE Patents [OSTI]

A heat exchanger comparising a shell attached at its open end to one side of a tube sheet and a detachable head connected to the other side of said tube sheet. The head is divided into a first and second chamber in fluid communication with a nozzle inlet and nozzle outlet, respectively, formed in said tube sheet. A tube bundle is mounted within said shell and is provided with inlets and outlets formed in said tube sheet in communication with said first and second chambers, respectively.

Brackenbury, P.J.

1983-12-08T23:59:59.000Z

15

Segmented heat exchanger  

DOE Patents [OSTI]

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

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

2010-12-14T23:59:59.000Z

16

Hydrodynamics, heat transfer and flow boiling instabilities in microchannels  

E-Print Network [OSTI]

Boiling in microchannels is a very efficient mode of heat transfer with high heat and mass transfer coefficients achieved. Less pumping power is required for two-phase flows than for single-phase liquid flows to achieve ...

Barber, Jacqueline Claire

2010-01-01T23:59:59.000Z

17

Woven heat exchanger  

DOE Patents [OSTI]

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.

Piscitella, R.R.

1984-07-16T23:59:59.000Z

18

Analysis of three-dimensional heat transfer in micro-channel heat sinks  

E-Print Network [OSTI]

, the three-dimensional fluid flow and heat transfer in a rectangular micro-channel heat sink are ana- lyzedAnalysis of three-dimensional heat transfer in micro-channel heat sinks Weilin Qu, Issam Mudawar numerically using water as the cooling fluid. The heat sink consists of a 1-cm2 silicon wafer. The micro

Qu, Weilin

19

Heat Integrated Distillation through Use of Microchannel Technology  

Broader source: Energy.gov [DOE]

This factsheet describes a research project whose goal is to develop a breakthrough distillation process using Microchannel Process Technology to integrate heat transfer and separation into a single unit operation.

20

A numerica1 study of fluid flow and heat transfer in different microchannel heat sinks for electronic chip cooling  

Science Journals Connector (OSTI)

Four different microchannel heat sinks are designed to study the effects of structures in microchannel heat sinks for electronic chips cooling. Based on the theoretic analysis and numerical computation of flow...

Shanglong Xu; Guangxin Hu; Jie Qin

2012-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Wound tube heat exchanger  

DOE Patents [OSTI]

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.

Ecker, Amir L. (Duncanville, TX)

1983-01-01T23:59:59.000Z

22

Experimental study of fluid flow and heat transfer in tortuous microchannels.  

E-Print Network [OSTI]

??Tortuous microchannels have attracted increasing interest due to great potential to enhance fluid mixing and heat transfer. While the fluid flow and heat transfer in (more)

Dai, Zhenhui

2014-01-01T23:59:59.000Z

23

Thermoelectric heat exchange element  

DOE Patents [OSTI]

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.

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

2007-08-14T23:59:59.000Z

24

Heat transfer and heat exchangers reference handbook  

SciTech Connect (OSTI)

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.

Not Available

1991-01-15T23:59:59.000Z

25

Microchannel devices  

SciTech Connect (OSTI)

The fabrication of stainless steel microchannel heat exchangers was examined through microlamination, the process of diffusion bonding precision machined metallic foils. The influence of diffusion bonding parameters, as well as the device geometry on the strength of the bond between the foils and embedded channel integrity, was investigated. During diffusion bonding, high temperatures and/or pressures result in well bonded foils, but these conditions cause the embedded channels to deform, which will degrade the efficiency of fluid flow through the channels. Alternatively, low temperatures and/or pressures result in undeformed channels but weakly bonded foils. This causes failure of the device due to fluid leakage. Thus, a processing envelope exists for producing a sound device with no fluid leakage and no degradation of fluid flow properties. The theoretical limit on aspect ratio within two-fluid counter-flow microchannel heat exchangers was also investigated. A counter-flow device is comprised of alternating layers of microchannels, which allow the two fluids to flow in opposite directions separated by fins. A theoretical model for interpreting the span of the fin as a function of the fin thickness was established. The model was verified experimentally by fabricating specimens to simulate the counter-flow device. The results of these investigations were used to aid in the design and processing of prototype microchannel devices.

Alman, David E.; Wilson, Rick D.

2001-09-01T23:59:59.000Z

26

Heat exchanger-accumulator  

DOE Patents [OSTI]

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.

Ecker, Amir L. (Dallas, TX)

1980-01-01T23:59:59.000Z

27

Experimental Investigation of Forced Convection Heat Transfer of Nanofluids in a Microchannel using Temperature Nanosensors  

E-Print Network [OSTI]

Experiments were performed to study forced convective heat transfer of de-ionized water (DI water) and aqueous nanofluids flowing in a microchannel. An array of temperature nanosensors, called Thin Film Thermocouples (TFT), was utilized...

Yu, Jiwon 1982-

2012-12-03T23:59:59.000Z

28

SINGLE-PHASE LIQUID HEAT TRANSFER IN PLAIN AND ENHANCED MICROCHANNELS Mark E. Steinke  

E-Print Network [OSTI]

SINGLE-PHASE LIQUID HEAT TRANSFER IN PLAIN AND ENHANCED MICROCHANNELS Mark E. Steinke Systems upon the understanding of the fundamental heat transfer processes that occur in these systems. There have been great advancements in our understanding of the heat transfer and fluid flow mechanisms

Kandlikar, Satish

29

Modular heat exchanger  

DOE Patents [OSTI]

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.

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

1981-03-03T23:59:59.000Z

30

Heat Exchangers for Solar Water Heating Systems | Department of Energy  

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

Heat Exchangers for Solar Water Heating Systems Heat Exchangers for Solar Water Heating Systems Heat Exchangers for Solar Water Heating Systems May 30, 2012 - 3:40pm Addthis Image of a heat exchanger. | Photo 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 collectors to the liquid or 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 it is a good thermal conductor and has greater resistance to corrosion. Types of Heat Exchangers Solar water heating systems use three types of heat exchangers: Liquid-to-liquid A liquid-to-liquid heat exchanger uses a heat-transfer fluid that

31

Heat exchanger with ceramic elements  

DOE Patents [OSTI]

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.

Corey, John A. (North Troy, NY)

1986-01-01T23:59:59.000Z

32

Materials - Micro heat exchangers ... | ornl.gov  

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

Materials - Micro heat exchangers ... Heat exchanger components fabricated with 3-D printing and analyzed with neutron imaging create a world of opportunities for electronic...

33

Integrated Module Heat Exchanger | Department of Energy  

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

Module Heat Exchanger Integrated Module Heat Exchanger 2012 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting...

34

Ceramic heat exchanger  

DOE Patents [OSTI]

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.

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

1998-06-16T23:59:59.000Z

35

Ceramic heat exchanger  

DOE Patents [OSTI]

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.

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

1998-01-01T23:59:59.000Z

36

Three-dimensional analysis of fluid flow and heat transfer in single- and two-layered micro-channel heat sinks  

Science Journals Connector (OSTI)

A three-dimensional numerical analysis of laminar fluid flow and conjugate heat transfer has been conducted for single- and two-layered micro-channel heat sinks. The validity of the numerical model ... power, the...

M. L.-J. Levac; H. M. Soliman; S. J. Ormiston

2011-11-01T23:59:59.000Z

37

Heat Exchanger Fouling- Prediction, Measurement and Mitigation  

E-Print Network [OSTI]

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

Peterson, G. R.

38

"Heat Exchange Enhancing Insert" Inventors .--.. Andrei Khodak...  

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

Heat Exchange Enhancing Insert" Inventors .--.. Andrei Khodak, Michael A. Jaworski A new shape of the heat enhancing insert is proposed. This device creates an impinging jet...

39

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

SciTech Connect (OSTI)

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

Culver, G.

1990-11-01T23:59:59.000Z

40

2.13 HEAT TRANSFER & FLUID FLOW IN MICROCHANNELS 2.13.7-1 Molecular dynamics methods in  

E-Print Network [OSTI]

2.13 HEAT TRANSFER & FLUID FLOW IN MICROCHANNELS 2.13.7-1 2.13.7 Molecular dynamics methods in microscale heat transfer Shigeo Maruyama A. Introduction In normal heat transfer and fluid flow calculations of molecules. This situation is approached in microscale heat transfer and fluid flow. Molecular level

Maruyama, Shigeo

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Thermohydraulic Simulation of Heat Exchanger Networks  

Science Journals Connector (OSTI)

The determination of network temperatures is carried out together with the evaluation of flow rates and pressures along the network, considering head losses in heat exchangers and associated piping. ... The HEN responsible to distribute cooling water in an industrial unit is composed by three heat exchangers in parallel. ... However, the cooling water distribution among the three exchangers presents a considerable unbalance, where heat exchanger E-101 receives much less cooling water than the design specification. ...

Viviane B. G. Tavares; Eduardo M. Queiroz; Andre? L. H. Costa

2010-04-26T23:59:59.000Z

42

Boiling heat transfer in a vertical microchannel: Local estimation during flow boiling with a non intrusive method  

E-Print Network [OSTI]

Boiling heat transfer in a vertical microchannel: Local estimation during flow boiling with a non the results of experimental and numerical studies concerning boiling heat transfer inside vertical in minichannels for several gravity levels (µg, 1g, 2g). To fully understand the high heat transfer potential

43

COMPACT HEAT EXCHANGERS FOR CONDENSATION APPLICATIONS: YESTERDAY...  

Office of Scientific and Technical Information (OSTI)

or allow other to do so, for U. S. Government purposes, i I ABSTRACT Compact heat exchangers are being increasinglyconsidered for condensationapplications in the...

44

Modeling of Heat Transfer in Geothermal Heat Exchangers  

E-Print Network [OSTI]

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...

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

2006-01-01T23:59:59.000Z

45

Cryogenic Fluid Flow Heat Transfer in a Porous Heat Exchanger  

Science Journals Connector (OSTI)

The recent utilization of porous heat exchangers in various key industries has aroused considerable interest in the heat transfer and fluid dynamics processes in channel flows involving suction...1], suction with...

L. L. Vasiliev; G. I. Bobrova; S. K. Vinokurov

1978-01-01T23:59:59.000Z

46

Convective Heat Transfer and Fluid Dynamics in Heat Exchanger Applications  

Science Journals Connector (OSTI)

This article concerns the local structure of flow and temperature fields as well as overall heat transfer coefficients and pressure drops in flow passages of relevance for heat exchangers. Results from investi...

Bengt Sundn

1999-01-01T23:59:59.000Z

47

Cryogenic heat exchanger with turbulent flows  

Science Journals Connector (OSTI)

An evaporator-type cryogenic heat exchanger is designed and built for introducing fluidsolid heat exchange phenomena to undergraduates in a practical and efficient way. The heat exchanger functions at liquid nitrogen temperature and enables cooling of N2and He gases from room temperatures. We present first the experimental results of various parameters which characterize the heat exchanger (efficiency, number of transfer units, heat exchange coefficient, etc) as a function of the mass flow rate of the gas to be cooled. An analysis of the NuRe diagram is also presented. All experiments were conducted with N2gas. The scope of this tool is readily extended to research purposes.

Jay Amrit; Christelle Douay; Francis Dubois; Grard Defresne

2012-01-01T23:59:59.000Z

48

A model for improvement of water heating heat exchanger designs for residential heat pump water heaters.  

E-Print Network [OSTI]

??Heat pump water heaters are a promising technology to reduce energy use and greenhouse gas emissions. A key component is the water heating heat exchanger. (more)

Weerawoot, Arunwattana

2010-01-01T23:59:59.000Z

49

Definition: Heat exchanger | Open Energy Information  

Open Energy Info (EERE)

Definition Definition Edit with form History Facebook icon Twitter icon » Definition: Heat exchanger Jump to: navigation, search Dictionary.png Heat exchanger A device for transferring thermal energy (heat) from one fluid (liquid or gas) to another, when the two fluids are physically separated; such as a radiator.[1][2] View on Wikipedia Wikipedia Definition A heat exchanger is a piece of equipment built for efficient heat transfer from one medium to another. The media may be separated by a solid wall to prevent mixing or they may be in direct contact. They are widely used in space heating, refrigeration, air conditioning, power plants, chemical plants, petrochemical plants, petroleum refineries [bp, shell, sasol], natural gas processing, and sewage treatment. The classic example

50

Heat Exchanger Design for Solar Gas-Turbine Power Plant.  

E-Print Network [OSTI]

?? The aim of this project is to select appropriate heat exchangers out of available gas-gas heat exchangers for used in a proposed power plant. (more)

Yakah, Noah

2012-01-01T23:59:59.000Z

51

Condensing Heat Exchangers Optimize Steam Boilers  

E-Print Network [OSTI]

The development of fluorocarbon resin covered tubes has advanced to the point where full scale marketing in connection with condensing heat exchangers has begun. Field installations show simple paybacks of one to one and a half years with resulting...

Sullivan, B.; Sullivan, P. A.

1983-01-01T23:59:59.000Z

52

Building Technologies Office: HVAC Optimized Heat Exchangers Research  

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

Optimized Heat Optimized Heat Exchangers Research Project to someone by E-mail Share Building Technologies Office: HVAC Optimized Heat Exchangers Research Project on Facebook Tweet about Building Technologies Office: HVAC Optimized Heat Exchangers Research Project on Twitter Bookmark Building Technologies Office: HVAC Optimized Heat Exchangers Research Project on Google Bookmark Building Technologies Office: HVAC Optimized Heat Exchangers Research Project on Delicious Rank Building Technologies Office: HVAC Optimized Heat Exchangers Research Project on Digg Find More places to share Building Technologies Office: HVAC Optimized Heat Exchangers Research Project on AddThis.com... About Take Action to Save Energy Partner with DOE Activities Appliances Research Building Envelope Research

53

MODELING PARTICLE DEPOSITION ON HVAC HEAT EXCHANGERS  

E-Print Network [OSTI]

LBNL-49339 MODELING PARTICLE DEPOSITION ON HVAC HEAT EXCHANGERS J.A. Siegel1,3 * and W.W. Nazaroff2 Department of Energy under contract DE-AC03-76SF00098. #12;MODELING PARTICLE DEPOSITION ON HVAC HEAT, such as discontinuities in the fins, are hypothesized to be responsible for the discrepancy. INDEX TERMS HVAC, Fouling

54

Saturated critical heat flux in a multi-microchannel heat sink fed by a split flow system  

SciTech Connect (OSTI)

An extensive experimental campaign has been carried out for the measurement of saturated critical heat flux in a multi-microchannel copper heat sink. The heat sink was formed by 29 parallel channels that were 199 {mu}m wide and 756 {mu}m deep. In order to increase the critical heat flux and reduce the two-phase pressure drop, a split flow system was implemented with one central inlet at the middle of the channels and two outlets at either end. The base critical heat flux was measured using three HFC Refrigerants (R134a, R236fa and R245fa) for mass fluxes ranging from 250 to 1500 kg/m{sup 2} s, inlet subcoolings from -25 to -5 K and saturation temperatures from 20 to 50 C. The parametric effects of mass velocity, saturation temperature and inlet subcooling were investigated. The analysis showed that significantly higher CHF was obtainable with the split flow system (one inlet-two outlets) compared to the single inlet-single outlet system, providing also a much lower pressure drop. Notably several existing predictive methods matched the experimental data quite well and quantitatively predicted the benefit of higher CHF of the split flow. (author)

Mauro, A.W.; Toto, D. [Department of Energetics, Applied Thermofluidynamics and Air Conditioning Systems, FEDERICO II University, p.le Tecchio 80, 80125 Napoli (Italy); Thome, J.R. [Laboratory of Heat and Mass Transfer (LTCM), Faculty of Engineering (STI), Ecole Polytechnique Federale de Lausanne (EPFL), Station 9, Lausanne CH-1015 (Switzerland); Vanoli, G.P. [Engineering Department, Sannio University, Corso Garibaldi 107, Palazzo dell'Aquila Bosco Lucarelli, 82100 Benevento (Italy)

2010-01-15T23:59:59.000Z

55

Heat exchanger with auxiliary cooling system  

DOE Patents [OSTI]

A heat exchanger with an auxiliary cooling system capable of cooling a nuclear reactor should the normal cooling mechanism become inoperable. A cooling coil is disposed around vertical heat transfer tubes that carry secondary coolant therethrough and is located in a downward flow of primary coolant that passes in heat transfer relationship with both the cooling coil and the vertical heat transfer tubes. A third coolant is pumped through the cooling coil which absorbs heat from the primary coolant which increases the downward flow of the primary coolant thereby increasing the natural circulation of the primary coolant through the nuclear reactor.

Coleman, John H. (Salem Township, Westmoreland County, PA)

1980-01-01T23:59:59.000Z

56

HEAT RECOVERY FROM WASTE WATER BY MEANS OF A RECUPERATIVE HEAT EXCHANGER AND A HEAT PUMP  

Science Journals Connector (OSTI)

ABSTRACT The useful heat of warm waste water is generally transferred to cold water using a recuperative heat exchanger. Depending on its design, the heat exchanger is able to utilise up to 90% of the waste heat potential available. The electric energy needed to operate such a system is more than compensated for by an approximately 50-fold gain of useful heat. To increase substantially the waste heat potential available and the amount of heat recovered, the system for recuperative heat exchange can be complemented by a heat pump. Such a heat recovery system on the basis of waste water is being operated in a public indoor swimming pool. Here the recuperative heat exchanger accounts for about 60%, the heat pump for about 40% of the toal heat reclaimed. The system consumes only 1 kWh of electric energy to supply 8 kWh of useful heat. In this way the useful heat of 8 kWh is compensated for by the low consumption of primary energy of 2.8 kWh. Due to the installation of an automatic cleaning device, the heat transfer surfaces on the waste water side avoid deposits so that the troublesome maintenance work required in other cases on the heat exchangers is not required. KEYWORDS Shower drain water, recuperative heat recovery, heat recovery by means of a heat pump, combination of both types of heat recovery, automatic cleaning device for the heat exchangers, ratio of useful heat supply vs. electric energy consumption, economic consideration.

K. Biasin; F.D. Heidt

1988-01-01T23:59:59.000Z

57

Demonstration and Performance Monitoring of Foundation Heat Exchangers...  

Energy Savers [EERE]

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

58

Heat Transfer Characteristics of a Generalized Divided Flow Heat Exchanger  

E-Print Network [OSTI]

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

Singh, K. P.

1979-01-01T23:59:59.000Z

59

A New Type Heat Exchanger for Coal Burning Boilers  

Science Journals Connector (OSTI)

To make the best of heat energy in the flue gas exhausted from a coal burning boiler, the design proposal for a new type of heat exchanger was put forward in the paper. Via the new type of heat exchanger, temperature of the flue gas can be decreased ... Keywords: waste heat utilization, energy conservation, special heat exchanger, economizer

Bingwen Zhang; Yingjin Zhang

2010-06-01T23:59:59.000Z

60

Modeling particle deposition on HVAC heat exchangers  

SciTech Connect (OSTI)

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.

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

2002-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Heat exchanger for coal gasification process  

DOE Patents [OSTI]

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.

Blasiole, George A. (Greensburg, PA)

1984-06-19T23:59:59.000Z

62

Sandwhiched Orb/Grid Heat Exchanger | Princeton Plasma Physics...  

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

Sandwhiched OrbGrid Heat Exchanger The design basis of the heat exchanger is that the most efficient geometrical shape to thermally stabilize during exposure to heat or to neutron...

63

Industrial Plate Exchangers Heat Recovery and Fouling  

E-Print Network [OSTI]

by choosing a more suitable material of construction. Plate exchangers being economic on surface area are able to use materials such as stainless steels, titanium,hastelloy,incolloy etc.without excessive cost. Normally the more e~pensive the material... it to the plate exchanger which is easy to open and clean. During the late sixties the first plate heat exchangers were used for acid cooling direct. These had plates of Hastelloy C and gaskets of Viton rubber. These were generally restricted to an acid...

Cross, P. H.

1981-01-01T23:59:59.000Z

64

Heat exchanger containing a component capable of discontinuous movement  

DOE Patents [OSTI]

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.

Wilson, David Gordon (Winchester, MA)

2002-01-01T23:59:59.000Z

65

Heat exchanger containing a component capable of discontinuous movement  

DOE Patents [OSTI]

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. 11 figures.

Wilson, D.G.

1993-11-09T23:59:59.000Z

66

Multidimensional numerical modeling of heat exchangers. [LMFBR  

SciTech Connect (OSTI)

A comprehensive, multidimensional, thermal-hydraulic model is developed for the analysis of shell-and-tube heat exchangers for liquid-metal services. For the shellside fluid, the conservation equations of mass, momentum, and energy for continuum fluids are modified using the concept of porosity, surface permeability and distributed resistance to account for the blockage effects due to the presence of heat-transfer tubes, flow baffles/shrouds, the support plates, etc. On the tubeside, the heat-transfer tubes are connected in parallel between the inlet and outlet plenums, and tubeside flow distribution is calculated based on the plenum-to-plenum pressure difference being equal for all tubes. It is assumed that the fluid remains single-phase on the shell side and may undergo phase-change on the tube side, thereby simulating the conditions of Liquid Metal Fast Breeder Reactor (LMFBR) intermediate heat exchangers (IHX) and steam generators (SG).

Sha, W.T.; Yang, C.I.; Kao, T.T.; Cho, S.M.

1982-01-01T23:59:59.000Z

67

Simulation of three-dimensional laminar flow and heat transfer in an array of parallel microchannels  

E-Print Network [OSTI]

and incorrect reporting of experimental uncertainty. Agostini et al. [16] detailed the importance of obtaining a very low uncertainty when measuring the dimensions of mini and microchannels. An example illustrated that a 3% uncertainty on channel width...

Mlcak, Justin Dale

2009-05-15T23:59:59.000Z

68

HVAC Radial Air Bearing Heat Exchangers Research Project | Department of  

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

Radial Air Bearing Heat Exchangers Radial Air Bearing Heat Exchangers Research Project HVAC Radial Air Bearing Heat Exchangers Research Project The U.S. Department of Energy is currently conducting research into heating, ventilation, and air conditioning (HVAC) radial air bearing heat exchangers. Rotary air bearing heat exchanger technology simultaneously solves four long standing problems of conventional "fan-plus-finned-heat-sink" heat exchangers. Project Description This project seeks to design, fabricate, and test successive generations of prototype radial air bearing heat exchanger devices based on lessons learned and further insights into device optimization, computational fluid dynamic studies for parametric optimization and determination of scaling laws, and laboratory measurement of flow field and heat transfer

69

Dealing with Uncertainties During Heat Exchanger Design  

E-Print Network [OSTI]

Technology Conference, Houston, TX, May 1-4, 2001 E2 Area = 100 m 2 cp= 35 kW/K El Area = 300 m 2 Figure 1. Simple Heat Exchanger Network CP = 30 kW/K CP= 55 kWIK Assume that exchangers EI (of heat transfer area 100 m 2 ) and E2 (of 300 m 2... .) are perfectly sized. Consequently, the cold stream leaving E I has a temperature of 277?C and that leaving E2 a temperature of 212?C. If a ten percent design margin had been added to each of these units (i.e. El now has 110 m 2 and E2 has 330 m 2...

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

70

Optimizing PT Arun LNG main heat exchanger  

SciTech Connect (OSTI)

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.

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

1995-12-01T23:59:59.000Z

71

Heat exchanger support apparatus in a fluidized bed  

DOE Patents [OSTI]

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.

Lawton, Carl W. (West Hartford, CT)

1982-01-01T23:59:59.000Z

72

Effect of Channel Configurations for Tritium Transfer in Printed Circuit Heat Exchangers  

SciTech Connect (OSTI)

The Next Generation Nuclear Plant (NGNP), a very High temperature Gas-Cooled Reactor (VHTR) concept, will provide the first demonstration of a closed-loop Brayton cycle at a commercial scale of a few hundred megawatts electric and hydrogen production. The power conversion system (PCS) for the NGNP will take advantage of the significantly higher reactor outlet temperatures of the VHTR to provide higher efficiencies than can be achieved in the current generation of light water reactors. Besides demonstrating a system design that can be used directly for subsequent commercial deployment, the NGNP will demonstrate key technology elements that can be used in subsequent advanced power conversion systems for other Generation IV reactors. In anticipation of the design, development and procurement of an advanced power conversion system for the NGNP, the system integration of the NGNP and hydrogen plant was initiated to identify the important design and technology options that must be considered in evaluating the performance of the proposed NGNP. In the VHTR system, an intermediate heat exchanger (IHX), which transfers heat from the reactor core to the electricity or hydrogen production system is one key component, and its effectiveness is directly related to the system overall efficiency. In the VHTRs, the gas fluids used for coolant generally have poor heat transfer capability, so it requires very large surface area for a given condition. For this reason, a compact heat exchanger (CHE), which is widely used in industry especially for gasto-gas or gas-to-liquid heat exchange is considered as a potential candidate for an IHX replacing the classical shell and tube type heat exchanger. A compact heat exchanger is arbitrary referred to be a heat exchanger having a surface area density greater than 700 m2/m3. The compactness is usually achieved by fins and micro-channels, and leads to the enormous heat transfer enhancement and size reduction. The surface area density is the total heat transfer area divided by the volume of the heat exchanger. In the case of PCHE units, the heat transfer surface area density may be as high as 2,500 m2/m3. This high compactness implies an appreciable reduction in material reducing cost. In this study, heat transfer and tritium penetration analyses have been performed for two different channel configurations of the PCHE; (1) standard and (2) off-set. One of the goals of this study was to determine whether offsetting the hot and cold streams would significantly reduce the tritium flux, and whether or not it would affect the heat transfer significantly.

Chang Oh; Eung Kim; Robert Shrake; Mike Patterson

2009-05-01T23:59:59.000Z

73

Hydrotreater feed/effluent heat exchange  

SciTech Connect (OSTI)

This patent describes a hydrotreating process for catalytically hydrogenating a hydrocarbon stock. It comprises dividing the hydrocarbon stock into two portions comprising a major portion and a minor portion, mixing the major portion with hydrogen to form a major portion mixture at a first temperature, and passing the major portion mixture through a multiple pass tube furnace to yield a heated major portion mixture at a first reactor inlet temperature, passing the heated major portion mixture to a hydrogenation catalyst containing reactor, thereby hydrogenating and heating the major portion mixture by heat of reaction to a reactor outlet temperature, withdrawing a hot hydrogenated stock from the reactor at the reactor outlet temperature wherein the hot hydrogenated stock comprises the entire reactor effluent, mixing the minor portion with hydrogen to form a minor portion mixture at about the first temperature, heating the minor portion mixture by indirect heat exchange with the hot hydrogenated stock to a second reactor inlet temperature approximately equal to the first reactor inlet temperature and then passing the minor portion to the first hydrogenation catalyst containing reactor in the absence of additional heating, the minor portion in an amount sufficient to quench the hot hydrogenated stock to a third temperature approximately equal to the first reactor inlet temperature.

Steinberg, R.M.; Deshpande, V.A.

1991-08-13T23:59:59.000Z

74

Heat transfer effectiveness of three-fluid separated heat pipe exchanger  

Science Journals Connector (OSTI)

A heat transfer model for three-fluid separated heat pipe exchanger was analyzed, and the temperature transfer matrix for general three-fluid separated heat exchanger working in parallel-flow or counter- ... It w...

Chengming Shi; Yang Wang; Ying Yang; Quan Liao

2011-02-01T23:59:59.000Z

75

Heat Pump Cycle with Solution Circuit and Internal Heat Exchange  

E-Print Network [OSTI]

-stage cycle, the heat transfer area required on the refrigerant side will increase by 10~ compared to the ammonia cycl e. CONCLUSIONS The hea t p1llllp cycl e employ ing one sol ut ion circuit and absorber/de sorber heat exchange has a more sophisticated... when a two-stage version fed into the same compressor. While ammonia of this cycl e is used. In this paper. another evaporate s out of an ammonia-water sol ution on C version of such cycles will be discussed which the composition. X. of this solution...

Radermacher, R.

76

Building Technologies Office: HVAC Radial Air Bearing Heat Exchanger  

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

Radial Air Bearing Radial Air Bearing Heat Exchanger Research Project to someone by E-mail Share Building Technologies Office: HVAC Radial Air Bearing Heat Exchanger Research Project on Facebook Tweet about Building Technologies Office: HVAC Radial Air Bearing Heat Exchanger Research Project on Twitter Bookmark Building Technologies Office: HVAC Radial Air Bearing Heat Exchanger Research Project on Google Bookmark Building Technologies Office: HVAC Radial Air Bearing Heat Exchanger Research Project on Delicious Rank Building Technologies Office: HVAC Radial Air Bearing Heat Exchanger Research Project on Digg Find More places to share Building Technologies Office: HVAC Radial Air Bearing Heat Exchanger Research Project on AddThis.com... About Take Action to Save Energy Partner with DOE

77

Design and Development of a Plastic Film Heat Exchanger  

E-Print Network [OSTI]

of the PFHX technology in olving heat. exchange at any pressure other than'atmo pheric pressure. Atmospheric applications could ope ate with a simple remote level control basin. There are also many other potential appl ca tions of the PFHX technology...DESIGN AND DEVELOPMENT OF A PLASTIC FILM HEAT EXCHANGER Eric C. Guyer, Sc.D., David L. Brownell, and Martin K. Gollin Dynatech RID Company Cambridge, Massachusetts ABSTRACT A plastic film heat exchang.er (PFHX) utilizes the low cost...

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

78

Condensation in horizontal heat exchanger tubes  

SciTech Connect (OSTI)

Many innovative reactor concepts for Generation III nuclear power plants use passive safety equipment for residual heat removal. These systems use two phase natural circulation. Heat transfer to the coolant results in a density difference providing the driving head for the required mass flow. By balancing the pressure drop the system finds its operational mode. Therefore the systems depend on a strong link between heat transfer and pressure drop determining the mass flow through the system. In order to be able to analyze these kind of systems with the help of state of the art computer codes the implemented numerical models for heat transfer, pressure drop or two phase flow structure must be able to predict the system performance in a wide parameter range. Goal of the program is to optimize the numerical models and therefore the performance of computer codes analyzing passive systems. Within the project the heat transfer capacity of a heat exchanger tube will be investigated. Therefore the tube will be equipped with detectors, both temperature and pressure, in several directions perpendicular to the tube axis to be able to resolve the angular heat transfer. In parallel the flow structure of a two phase flow inside and along the tube will be detected with the help of x-ray tomography. The water cooling outside of the tube will be realized by forced convection. It will be possible to combine the flow structure measurement with an angular resolved heat transfer for a wide parameter range. The test rig is set up at the TOPLFOW facility at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), so that it will be possible to vary the pressure between 5 and 70 bar. The steam mass content will be varied between 0 and 100 percent. The results will be compared to the large scaled Emergency Condenser Tests performed at the INKA test facility in Karlstein (Germany). The paper will explain the test setup and the status of the project will be presented. (authors)

Leyer, S.; Zacharias, T.; Maisberger, F.; Lamm, M. [AREVA NP GmbH, Paul-Gossen-Strasse 100, Erlangen, 91052 (Germany); Vallee, C.; Beyer, M.; Hampel, U. [Helmholtz-Zentrum Dresden-Rossendorf e.V., Bautzner Landstrasse 400, Dresden, 01328 (Germany)

2012-07-01T23:59:59.000Z

79

HVAC Optimized Heat Exchangers Research Project | Department of Energy  

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

Optimized Heat Exchangers Research Optimized Heat Exchangers Research Project HVAC Optimized Heat Exchangers Research Project The U.S. Department of Energy is currently conducting research into heating, ventilation, and air conditioning (HVAC) optimized heat exchangers. The information generated in this study will demonstrate performance improvements that can be achieved through optimization of refrigerant circuitry for non-uniform inlet air distribution. The tubing circuitry on fin-tube heat exchangers used in residential space-conditioning systems is typically designed assuming uniform airflow through the finned passageways. However, the air flow in installed systems is highly non-uniform, resulting in mismatched refrigerant-air heat transfer that reduces the capacity of the heat exchanger and efficiency of

80

Heat exchanger for a Stirling engine  

SciTech Connect (OSTI)

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.

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

1987-05-05T23:59:59.000Z

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

The developing heat transfer and fluid flow in micro-channel heat sink with viscous heating effect  

Science Journals Connector (OSTI)

The numerical modeling of the conjugate heat transfer and fluid flow through the micro-heat sink was presented in the paper, considering the viscous dissipation effect. Three different fluids with temperature dep...

Dorin Lelea; Adrian Eugen Cioabla

2011-07-01T23:59:59.000Z

82

Design of a microbreather for two-phase microchannel devices  

E-Print Network [OSTI]

Multiphase flows in microchannels are encountered in a variety of microfluidic applications. Two-phase microchannel heat sinks leverage the latent heat of vaporization to offer an efficient method of dissipating large heat ...

Alexander, Brentan R

2008-01-01T23:59:59.000Z

83

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

E-Print Network [OSTI]

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

Kandlikar, Satish

84

Characteristics of fluid flow and heat transfer in a fluidized heat exchanger with circulating solid particles  

Science Journals Connector (OSTI)

The commercial viability of heat exchanger is mainly dependent on its long- ... loss and degrades the thermal performance of a heat exchanger. An experimental study was performed to investigate the characteristic...

Soo Whan Ahn; ByungChang Lee; WonCheol Kim; Myung- Whan Bae

2002-09-01T23:59:59.000Z

85

Heat exchanger for fuel cell power plant reformer  

DOE Patents [OSTI]

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.

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

1988-01-01T23:59:59.000Z

86

Control Dewar Subcooler Heat Exchanger Calculations  

SciTech Connect (OSTI)

The calculations done to size the control dewar subcooler were done to obtain a sufficient subcooler size based on some conservative assumptions. The final subcooler design proposed in the design report will work even better because (1) It has more tubing length, and (2) will have already subcooled liquid at the inlet due to the transfer line design. The subcooler design described in the 'Design Report of the 2 Tesla Superconducting Solenoid for the Fermilab D0 Detector Upgrade' is the final design proposed. A short description of this design follows. The subcooler is constructed of 0.50-inch OD copper tubing with 1.0-inch diameter fins. It has ten and one half spirals at a 11.375-inch centerline diameter to provide 31 feet of tubing length. The liquid helium supply for the solenoid flows through the subcooler and then is expanded through a J-T valve. The subcooler spirals are immersed in the return two phase helium process stream. The return stream is directed over the finned tubing by an annulus created by a 10-inch pipe inside a 12-inch pipe. The transfer line from the refrigerator to the control dewar is constructed such that the liquid helium supply tube is in the refrigerator return stream, thereby subcooling the liquid up to the point where the u-tubes connect the transfer line to the control dewar. The subcooler within the control dewar will remove the heat picked up in the helium supply u-tube/bayonets. The attached subcooler/heat exchanger calculations were done neglecting any subcooling in the transfer line. All heat picked up in the transfer line from the refrigerator storage dewar to the control dewar is absorbed by the supply stream. The subcooler was sized such that the two phase supply fluid is subcooled at 1.7 atm pressure and when expanded through a JT valve to 1.45 atm pressure it is at a saturated liquid state. The calculations apply during steady state operation and at a flow rate of 16 g/s. The analysis of the heat exchanger was broken into two parts relating to the heat transfer mode taking place. The first part is considered the condensing part in which the helium supply stream is changed from two phase fluid to one phase liquid. The second part is the subcooling part where the liquid temperature is lowered, i.e.. subcooled. A summary of the calculations and results appears on the next page. The raw calculations follow the summary.

Rucinski, R.; /Fermilab

1993-10-04T23:59:59.000Z

87

Heat exchanger and water tank arrangement for passive cooling system  

DOE Patents [OSTI]

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.

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

1993-01-01T23:59:59.000Z

88

NEI Corporation Technology Promotes Efficiency in Heat Exchangers...  

Office of Science (SC) Website

More Information January 2013 NEI Corporation Technology Promotes Efficiency in Heat Exchangers NEI's SuperCondenser(tm) technology increases the energy efficiency of a...

89

Heat exchanger optimization for geothermal district heating systems: A fuel saving approach  

Science Journals Connector (OSTI)

One of the most commonly used heating devices in geothermal systems is the heat exchanger. The output conditions of heat exchangers are based on several parameters. The heat transfer area is one of the most important parameters for heat exchangers in terms of economics. Although there are a lot of methods to optimize heat exchangers, the method described here is a fairly easy approach. In this paper, a counter flow heat exchanger of geothermal district heating system is considered and optimum design values, which provide maximum annual net profit, for the considered heating system are found according to fuel savings. Performance of the heat exchanger is also calculated. In the analysis, since some values are affected by local conditions, Turkey's conditions are considered.

Ahmet Dagdas

2007-01-01T23:59:59.000Z

90

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

E-Print Network [OSTI]

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

Thole, Karen A.

91

Deposition of Biological Aerosols on HVAC Heat Exchangers  

E-Print Network [OSTI]

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

92

Application of heat exchangers in BWR nuclear power stations  

SciTech Connect (OSTI)

Applications of heat exchangers, in typical BWR Nuclear Power Plant fluid systems, are described from a process standpoint. System schematics and lists of heat exchanger parameters are presented to aid in understanding the influence of the process on specific applications. These exchangers are constructed to meet special code, seismic, and quality assurance criteria. They have a variety of configurations, including both vertical and horizontal, and are of ''U'' tube or once-through design.

Hess, F.L.; Patti, F.J.

1982-01-01T23:59:59.000Z

93

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

SciTech Connect (OSTI)

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.

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

1993-04-01T23:59:59.000Z

94

Heat transfer and fluid flow characteristics of microchannels with internal longitudinal fins.  

E-Print Network [OSTI]

??Electronic components generate large amount of heat during their operation, which requires to be dissipated. Over the past decade, internal heat generation levels have exponentially (more)

Foong, Andrew Jun Li

2009-01-01T23:59:59.000Z

95

THERMOSIPHON WATER HEATERS WITH HEAT EXCHANGERS  

E-Print Network [OSTI]

communications). Heat transfer fluid is 60% o-o1vco1 bycharacteristics, heat transfer fluids, flow resistances,of a non- freezing heat transfer fluid circulating in a loop

Mertol, Atila

2012-01-01T23:59:59.000Z

96

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

E-Print Network [OSTI]

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...

Chen, Y.; Zhang, J.

2006-01-01T23:59:59.000Z

97

Measurement of flow field and local heat transfer distribution on a scraped heat exchanger crystalliser surface  

E-Print Network [OSTI]

Measurement of flow field and local heat transfer distribution on a scraped heat exchanger geometry the flow field influence on the local heat transfer distribution on an evenly cooled scraped heat loss heat loss to the surroundings stst stainless steel plate lc thermo-chromic liquid crystal

Boyer, Edmond

98

Heat exchanger and water tank arrangement for passive cooling system  

DOE Patents [OSTI]

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.

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

1993-11-30T23:59:59.000Z

99

Laminar Flow Forced Convection Heat Transfer Behavior of Phase Change Material Fluid in Straight and Staggered Pin Microchannels  

E-Print Network [OSTI]

numerical results of circular, square, straight rectangular microchannels with various aspect ratios (1:2, 1:4 and 1:8), and rectangular microchannels with two characteristic staggered pins (square and circular, fixed height with no variation in aspect ratio...

Kondle, Satyanarayana

2011-10-21T23:59:59.000Z

100

SILICON CARBIDE CERAMICS FOR COMPACT HEAT EXCHANGERS  

SciTech Connect (OSTI)

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

DR. DENNIS NAGLE; DR. DAJIE ZHANG

2009-03-26T23:59:59.000Z

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Heat exchanger for reactor core and the like  

DOE Patents [OSTI]

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.

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

1986-01-01T23:59:59.000Z

102

Multi-period design of heat exchanger networks  

Science Journals Connector (OSTI)

Heat exchanger networks are an integral part of chemical processes as they recover available heat and reduce utility consumption, thereby improving the overall economics of an industrial plant. This paper focuses on heat exchanger network design for multi-period operation wherein the operating conditions of a process may vary with time. A typical example is the hydrotreating process in petroleum refineries where the operators increase reactor temperature to compensate for catalyst deactivation. Superstructure based multi-period models for heat exchanger network design have been proposed previously employing deterministic optimisation algorithms, e.g. (Aaltola, 2002; Verheyen and Zhang, 2006). Stochastic optimisation algorithms have also been applied for the design of flexible heat exchanger networks recently (Ma et al., 2007, 2008). The present work develops an optimisation approach using simulated annealing for design of heat exchanger networks for multi-period operation. A comparison of the new optimisation approach with previous deterministic optimisation based design approaches is presented to illustrate the utilisation of simulated annealing in design of optimal heat exchanger network configurations for multi-period operation.

Muhammad Imran Ahmad; Nan Zhang; Megan Jobson; Lu Chen

2012-01-01T23:59:59.000Z

103

Experimental and numerical study of pressure drop and heat transfer in a single-phase micro-channel heat sink  

E-Print Network [OSTI]

Experimental and numerical study of pressure drop and heat transfer in a single-phase micro Received 6 July 2001; received in revised form 26 October 2001 Abstract The pressure drop and heat transfer-dimensional heat transfer characteristics of the heat sink were analyzed numerically by solving the conjugate heat

Qu, Weilin

104

Evaluation of fluid bed heat exchanger optimization parameters. Final report  

SciTech Connect (OSTI)

Uncertainty in the relationship of specific bed material properties to gas-side heat transfer in fluidized beds has inhibited the search for optimum bed materials and has led to over-conservative assumptions in the design of fluid bed heat exchangers. An experimental program was carried out to isolate the effects of particle density, thermal conductivity, and heat capacitance upon fluid bed heat transfer. A total of 31 tests were run with 18 different bed material loads on 12 material types; particle size variations were tested on several material types. The conceptual design of a fluidized bed evaporator unit was completed for a diesel exhaust heat recovery system. The evaporator heat transfer surface area was substantially reduced while the physical dimensions of the unit increased. Despite the overall increase in unit size, the overall cost was reduced. A study of relative economics associated with bed material selection was conducted. For the fluidized bed evaporator, it was found that zircon sand was the best choice among materials tested in this program, and that the selection of bed material substantially influences the overall system costs. The optimized fluid bed heat exchanger has an estimated cost 19% below a fin augmented tubular heat exchanger; 31% below a commercial design fluid bed heat exchanger; and 50% below a conventional plain tube heat exchanger. The comparisons being made for a 9.6 x 10/sup 6/ Btu/h waste heat boiler. The fluidized bed approach potentially has other advantages such as resistance to fouling. It is recommended that a study be conducted to develop a systematic selection of bed materials for fluidized bed heat exchanger applications, based upon findings of the study reported herein.

Not Available

1980-03-01T23:59:59.000Z

105

Process Heat Exchanger Options for Fluoride Salt High Temperature Reactor  

SciTech Connect (OSTI)

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.

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

2011-04-01T23:59:59.000Z

106

Exergy Effectiveness Analysis of Three-Fluid Heat Exchanger  

Science Journals Connector (OSTI)

In this paper, exergy effectiveness is defined to describe the thermodynamic ... ratio of the inlet temperature of fluids on exergy effectiveness of three-fluid heat exchangers. Furthermore, the exergy effectiven...

Deng-Fang Ruan; Xiao-Feng Yuan

2010-08-01T23:59:59.000Z

107

Condensing Heat Exchanger for Optimization of Energy Efficiency  

E-Print Network [OSTI]

out, rapid deterioration, due to acid corrosion, of the outlet duct and stack would result. With the development of the condensing heat exchanger, boiler efficiency can now exceed 90%. Approximately 1% gain in boiler efficiency can be expected...

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

108

Analysis of conjugate heat transfer in tube-in-block heat exchangers for some engineering applications.  

E-Print Network [OSTI]

??This project studied the effect of different parameters on the conjugate heat transfer in tube-in-block heat exchangers for various engineering applications. These included magnetic coolers (more)

Gari, Abdullatif Abdulhadi

2006-01-01T23:59:59.000Z

109

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

E-Print Network [OSTI]

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...

Gaskill, Travis

2012-02-14T23:59:59.000Z

110

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

E-Print Network [OSTI]

HEAT EXCHANGER NETWORK TARGETING, DESIGN AND ANALYSIS: THE MIDAS PACKAGE I. BARTON, D.H. JONES AND G.J. SMITH TENSA Services, Houston, Texas ICI PLC, Wilton England ABSTRACT Recent work to consolidate pinch-based procedures for targeting... was reduced to industrial practice by the U.K. major, ICI PLC. A wide range of pinch-based procedures have been developed for process energy efficiency applications. These incl~de heat exchanger network (HEN) design [2,3], distillation system...

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

111

Automatic Tube Cleaning Systems for Condensers & Heat Exchangers  

E-Print Network [OSTI]

than 36 in. in diameter. Thus, mos of the ball systems are in fossil fuel, nuclear) cogeneration, and geothermal power plants. The temperature (maximum 220 0 F) and process limitations of the rubber ball material restrict the use of ball systems... of Heat Exchangers," Hydrocarbon Processing, pp. 25-27 (Jan. 1983) 7. Grande. M?? and K. SCIEah. "Automatic On-Line Mechanical Cleaning System for Condensers and Heat Exchangers," in EPRI Geothermal Conference and Yorkshop, Seminar Yorkbook (June 23...

Someah, K.

112

Fouling of carbon steel heat exchanger caused by iron bacteria  

SciTech Connect (OSTI)

A carbon steel heat exchanger installed in a reverse osmosis unit failed after 1 1/2 years from start-up as a result of tubes, lids, tube sheets, and connection pipes clogging from rust deposits. Chemical analysis of cooling water and scraped precipitates, as well laboratory screening of the deposits for bacteria, revealed that activity of iron-oxidizing bacteria present in cooling water could lead to heat exchanger blockage.

Starosvetsky, J.; Armon, R.; Starosvetsky, D. (Technion-Israel Inst. of Tech. (Israel)); Groysman, A.

1999-01-01T23:59:59.000Z

113

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

E-Print Network [OSTI]

A SIMPLIFIED METHODOLOGY FOR SIZING GROUND COUPLED HEAT PUMP HEAT EXCHANGERS IN COOLING DOMINATED CLIMATES A Thesis by JOSE ANTONIO GONZALEZ Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE August 1993 Major Subject: Mechanical Engineering A SIMPLIFIED METHODOLOGY FOR SIZING GROUND COUPLED HEAT PUMP HEAT EXCHANGERS IN COOLING DOMINATED CLIMATES A Thesis by JOSE ANTONIO GONZALEZ Approved...

Gonzalez, Jose Antonio

2012-06-07T23:59:59.000Z

114

Heat transfer and fluid flow in microchannels and nanochannels at high Knudsen number using thermal lattice-Boltzmann method  

Science Journals Connector (OSTI)

The present paper deals with the two-dimensional numerical simulation of gaseous flow and heat transfer in planar microchannel and nanochannel with different wall temperatures in transitional regime 0.1?Kn?1. An atomistic molecular simulation method is used known as thermal lattice-Boltzmann method. The results of simulation are presented in four cases corresponding to the Fourier flow, shear-driven flow (Couette flow), pressure-driven flow (Poiseuille flow), and mixed shearpressure-driven flow in the developing and fully developed regions. The mixed shearpressure-driven flow is divided into two subcases with shear stress and pressure gradient acting in the same and the opposite directions. Normalized temperature and velocity profiles across the channel, distribution of local wall Nusselt number, and friction coefficient are illustrated. Using this method, nonlinear pressure distribution in the streamwise direction, reduction in mass flow rate, Cf?Re, and Nu by increasing the Knudsen number are studied. It is seen that for Couette flow, Nu over the hotter plate is greater than the cooler plate, but for the pressure-driven flow with stationary wall temperature dependency of viscosity and thermal conductivity causes this trend to be reversed. The reversed flow appearance in the velocity profile is captured in the case of opposite shearpressure-driven flow.

J. Ghazanfarian and A. Abbassi

2010-08-13T23:59:59.000Z

115

Miniaturized Air to Refrigerant Heat Exchangers | Department...  

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

- Grenada, MS -- International Copper Association - New York, NY -- Wieland - Ulm, Germany -- Heat Transfer Technologies - Abington, PA DOE Funding: 1,500,000 Cost Share: NA...

116

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

E-Print Network [OSTI]

when it was located in the downstream, which also weakened heat exchange[5-8], (4)pulse flow might enhance or weaken heat exchange that lied on flow parameter[9-11]. This article made use of FLUENT software to numerical Simulate round... exchange[12]. When adapted FLUENT software, we considered the model was slender tube which had a large gap between length and scale, so we could use double precision solver; In the numerical simulation, the pressure interpolation selected standard...

Chen, Y.; Zhao, J.

2006-01-01T23:59:59.000Z

117

Fast reactor power plant design having heat pipe heat exchanger  

DOE Patents [OSTI]

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.

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

1984-08-30T23:59:59.000Z

118

Fast reactor power plant design having heat pipe heat exchanger  

DOE Patents [OSTI]

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.

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

1985-01-01T23:59:59.000Z

119

Direct-contact closed-loop heat exchanger  

DOE Patents [OSTI]

A high temperature heat exchanger is disclosed which has a closed loop and a heat transfer liquid within the loop, the closed loop having a first horizontal channel with inlet and outlet means for providing direct contact of a first fluid at a first temperature with the heat transfer liquid, a second horizontal channel with inlet and outlet means for providing direct contact of a second fluid at a second temperature with the heat transfer liquid, and means for circulating the heat transfer liquid.

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

1981-11-02T23:59:59.000Z

120

Electricity Consumption of Pumps in Heat Exchanging Stations of DH Systems in China  

Science Journals Connector (OSTI)

This study analyzed the current electricity consumption of heating exchanging stations in China. By...

Lei Dong; JianJun Xia; Yi Jiang

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

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

E-Print Network [OSTI]

Model based methodology development for energy recovery in flash heat exchange systems Problem of energy efficiency in process operations. Where heat exchange is required between two streams and where with a condensing heat exchanger can be used when heat exchange is required between two streams and where at least

McCarthy, John E.

122

STUDY OF FROST GROWTH ON HEAT EXCHANGERS USED AS OUTDOOR COILS IN AIR SOURCE HEAT PUMP SYSTEMS  

E-Print Network [OSTI]

STUDY OF FROST GROWTH ON HEAT EXCHANGERS USED AS OUTDOOR COILS IN AIR SOURCE HEAT PUMP SYSTEMS OF FROST GROWTH ON HEAT EXCHANGERS USED AS OUTDOOR COILS IN AIR SOURCE HEAT PUMP SYSTEMS Dissertation . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 3.5.3 Air Side Heat Transfer Rates . . . . . . . . . . . . . . . . . . 43 3.5.4 Fluid Side Heat

123

Liquid Salt Heat Exchanger Technology for VHTR Based Applications  

SciTech Connect (OSTI)

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.

Mark Anderson; Kumar Sridhara; Todd Allen; Per Peterson

2012-10-11T23:59:59.000Z

124

Solar Assisted Heat Pump Systems with Ground Heat Exchanger Simulation Studies  

Science Journals Connector (OSTI)

Abstract Different concepts of solar assisted heat pump systems with ground heat exchanger are simulated according to IEA SHC Task44/HPP Annex38 reference conditions. Two aspects of the concepts are investigated using TRNSYS simulations. First, the solar impact on system efficiency is assessed by the seasonal performance factor. Second, the solar impact on the possible shortening of the ground heat exchanger is evaluated by the minimum temperature at the ground heat exchanger inlet. The simulation results reveal diverging optimums for the concepts. The direct use of solar energy clearly achieves the best effect on the efficiency improvement. A simple domestic hot water system reaches a seasonal performance factor of 4.5 and solar combi-systems seasonal performance factors up to 6. In contrast, the use of solar energy on the cold side of the heat pump achieves the best effects on the shortening of the ground heat exchanger of up to 20%. Two highly sensitive influences are investigated with the developed transient system model. First, the minimum allowed heat source temperature is varied. Here 1K equals a variation of 0.25 in the seasonal performance or of around 10% ground heat exchanger length. Second, the ground heat exchanger model is simulated without and with a pre-pipe that improves the transient model behavior. The influence of this pre-pipe on the SPF is small for conventionally designed ground heat exchangers, but of around 2K for the minimum inlet temperature. Therefore, the dynamic model quality reveals potential to reduce the size of the ground heat exchanger corresponding to investment costs.

Erik Bertram

2014-01-01T23:59:59.000Z

125

Scale effects on flow boiling heat transfer in microchannels: A fundamental perspective  

E-Print Network [OSTI]

pattern transitions and stability for flow boiling of water and FC-77 are evaluated. From the insight between heat transfer around a nucleating bubble in pool boiling and in the elongated bubble/slug flow on the high-speed visualization and localized thermal measurements made at the base of a nucleating bubble

Kandlikar, Satish

126

Design of Heat Exchanger for Heat Recovery in CHP Systems  

E-Print Network [OSTI]

The objective of this research is to review issues related to the design of heat recovery unit in Combined Heat and Power (CHP) systems. To meet specific needs of CHP systems, configurations can be altered to affect different factors of the design...

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

127

Materials, Turbomachinery and Heat Exchangers for Supercritical CO2 Systems  

SciTech Connect (OSTI)

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 650C. 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 40C 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.

Mark Anderson; Greg Nellis; Michael Corradini

2012-10-19T23:59:59.000Z

128

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

E-Print Network [OSTI]

A simplified technique for the sizing of vertical U-tube ground coupled heat pump (GCHP) heat exchangers for Texas climates was developed utilizing a transient simulation model of a ground coupled heat pump and weather and soil data for Texas...

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

1994-01-01T23:59:59.000Z

129

Heat-Exchanger Network Synthesis Involving Organic Rankine Cycle for Waste Heat Recovery  

Science Journals Connector (OSTI)

This article aims to present a mathematical model for the synthesis of a heat-exchanger network (HEN) which can be integrated with an organic Rankine cycle (ORC) for the recovery of low-grade waste heat from the heat surplus zone of the background ...

Cheng-Liang Chen; Feng-Yi Chang; Tzu-Hsiang Chao; Hui-Chu Chen; Jui-Yuan Lee

2014-04-23T23:59:59.000Z

130

Heat energy Q: -energy exchanged between systems if they have a different temperature  

E-Print Network [OSTI]

About heat Heat energy Q: - energy exchanged between systems if they have a different temperature - heat flows from higher to lower temperature - without temperature difference, no heat is exchanged If a system is receiving or releasing heat, then this heat is called a) Sensible heat, if the system changes

Boyd, Sylke

131

Flow-induced vibration of component cooling water heat exchangers  

SciTech Connect (OSTI)

This paper presents an evaluation of flow-induced vibration problems of component cooling water heat exchangers in one of Taipower's nuclear power stations. Specifically, it describes flow-induced vibration phenomena, tests to identify the excitation mechanisms, measurement of response characteristics, analyses to predict tube response and wear, various design alterations, and modifications of the original design. Several unique features associated with the heat exchangers are demonstrated, including energy-trapping modes, existence of tube-support-plate (TSP)-inactive modes, and fluidelastic instability of TSP-active and -inactive modes. On the basis of this evaluation, the difficulties and future research needs for the evaluation of heat exchangers are identified. 11 refs., 19 figs., 3 tabs.

Yeh, Y.S.; Chen, S.S. (Taiwan Power Co., Taipei (Taiwan). Nuclear Engineering Dept.; Argonne National Lab., IL (USA))

1990-01-01T23:59:59.000Z

132

Sludge, fuel degradation and reducing fouling on heat exchangers  

SciTech Connect (OSTI)

Brookhaven National Laboratory, under contract to the US Department of Energy, operates an oil heat research primarily to lower energy consumption in the 12 million oil heated homes in the US. The program objectives include: Improve steady state efficiency of oil heating equipment, Improve seasonal efficiencies, Eliminate or minimize factors which tend to degrade system performance. This paper provides an overview of the status of three specific projects which fall under the above objectives. This includes our fuel quality project, oil appliance venting and a project addressing efficiency degradation due to soot fouling of heat exchangers.

Butcher, T.; Litzke, Wai Lin; Krajewski, R.; Celebi, Y.

1992-02-01T23:59:59.000Z

133

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.

134

DOE/ANL/HTRI heat exchanger tube vibration data bank  

SciTech Connect (OSTI)

Development of a new heat exchanger tube vibration data bank at Argonne National Laboratory is described. Comprehensive case histories on heat exchangers that have experienced tube-vibration problems and units that have been trouble-free are accumulated and this information is rendered available for evaluation, improvement, and development of vibration-prediction methods and design guidelines. Discussions include difficulties in generating a data bank, data form development, and solicitation efforts. Also included are 15 case histories upon which the data bank will be built. As new case histories are received, they will be assembled and published as addenda to this report.

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

1980-02-01T23:59:59.000Z

135

Oscillating flow in a stirling engine heat exchanger  

Science Journals Connector (OSTI)

Three heat exchangers exist in modern Stirling engines: a heater, a cooler, and a regenerator. Here a study that deals principally with tubular heaters and coolers is carried out. The calculation procedure for the oscillating flow heat transfer is presented. Literature sources are studied to find the most suitable correlations by comparing them to each other and to the classical turbulent flow correlations encountered in the literature. The enhancement of heat transfer by means of a few circumferential slots inside the tubes and the pressure losses of oscillatory flow are discussed. Non-circular cross-section conduits with rectangular and triangular cross-sections are investigated and compared to the smooth circular tubes. The increment of the performance of an idealised Stirling engine with slotted heat exchanger tubes is compared to the case with smooth ones. The ratio of the gain in the shaft power and pumping losses is 2.22. The Carnot efficiency increment is 2.7%.

M. Kuosa; K. Saari; A. Kankkunen; T.-M. Tveit

2012-01-01T23:59:59.000Z

136

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

E-Print Network [OSTI]

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

Fernández de Córdoba, Pedro

137

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

E-Print Network [OSTI]

??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 (more)

Parker, Brandon DeWayne

2012-01-01T23:59:59.000Z

138

A Zero Emission Mechanical Seal with Integral Micro Heat Exchanger  

E-Print Network [OSTI]

/689,406) with an internal heat exchanger within the body of the mating ring that channels a coolant toward the interface to effectively cool the seal faces. The coolant may be either liquid or gas, such as instrument air. This research is in part supported by a...An Industrial Zero 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...

Khonsari, M.

2005-01-01T23:59:59.000Z

139

Design of Coil Heat Exchanger for Remote-Storage Solar Water Heating System  

Science Journals Connector (OSTI)

A coil heat exchanger for hot water thermal storage was presented including the choice of the ... calculation of flow resistance. In this design, solar collector contour aperture area is 4.26...2, the volume of w...

Lv Cuiping; He Duanlian; Dou Jianqing

2009-01-01T23:59:59.000Z

140

Secondary heat exchanger design and comparison for advanced high temperature reactor  

SciTech Connect (OSTI)

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)

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

2012-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

GEA Heat Exchangers GEA Searle Cooler and Condensing Unit Ranges  

E-Print Network [OSTI]

have high efficiency EC fans as standard across the range. All our commercial unit coolers have whiteUnits GEA Searle Condensing Units are supplied as standard to a high specification with a complete controlGEA Heat Exchangers GEA Searle Cooler and Condensing Unit Ranges Top-level engineering solutions

Frandsen, Søren

142

Finned Tube With Vortex Generators For A Heat Exchanger.  

DOE Patents [OSTI]

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.

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

2004-09-14T23:59:59.000Z

143

Novel Power Electronics Three-Dimensional Heat Exchanger: Preprint  

SciTech Connect (OSTI)

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.

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

2014-08-01T23:59:59.000Z

144

Secondary Heat Exchanger Design and Comparison for Advanced High Temperature Reactor  

SciTech Connect (OSTI)

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 exchangershelical coiled heat exchanger and printed circuit heat exchangeras 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.

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

2012-06-01T23:59:59.000Z

145

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.

146

Flexible, reusable fiberglass insulation tailored to fit valves, heat exchangers  

SciTech Connect (OSTI)

About 120,000 bbl/day of crude oil are refined into gasoline at the Marathon Petroleum refinery in Robinson, IL. Built in the early part of the century, the Robinson refinery has been continually updated and modernized in response to improving technology. To control heat loss on some of the unusually shaped and previously uninsulated process equipment, Marathon engineering personnel initiated a program to systematically evaluate and insulate these pieces of equipment. Primarily, over 500 valves and heat exchanger heads were losing heat which had been estimated to cost hundreds of thousands of dollars per year. The plant performed on-site evaluations of several types of removable insulation covers. The primary differences and deciding factors were in construction detail - particularly in the fasteners. Marathon chose lace-up fastening insulation covers because plant evaluation found them to be the best. Also the manufacturer agreed to provide tailor-made covers for all of the valves and heat exchanger heads. Service from the manufacturer through an insulation contractor located in Robinson was also a plus. The local contractor, working in conjunction with the manufacturer, conducted an in-plant survey that confirmed the already mentioned heat loss cost in the $100,000s range. It was also determined that an equipment temperature somewhere between 150 and 200/sup 0/F was the lowest temperature at which to economically install insulation. Marathon has been pleased with the performance of the insulation covers which reduce heat loss and, as an incidental benefit, provide personnel safety from hot surfaces. An important benefit has been the removability and reusability of the insulation, particularly advantageous on valves and heat exchangers the require frequent access.

Gockenbach, L.G.; Singleton, D.; Toy, D.A.

1986-06-01T23:59:59.000Z

147

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

SciTech Connect (OSTI)

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.

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

2011-01-01T23:59:59.000Z

148

A review of different heat exchangers designs for increasing the diesel exhaust waste heat recovery  

Science Journals Connector (OSTI)

Abstract In this paper, after a short review of waste heat recovery technologies from diesel engines, the heat exchangers (HEXs) used in exhaust of engines is introduced as the most common way. So, a short review of the technologies that increase the heat transfer in \\{HEXs\\} is introduced and the availability of using them in the exhaust of engines is evaluated and finally a complete review of different \\{HEXs\\} which previously were designed for increasing the exhaust waste heat recovery is presented. Also, future view points for next \\{HEXs\\} designs are proposed to increase heat recovery from the exhaust of diesel engines.

M. Hatami; D.D. Ganji; M. Gorji-Bandpy

2014-01-01T23:59:59.000Z

149

Heat Exchanger Monitoring and Its Application to Cleaning and Antifoulant Use  

E-Print Network [OSTI]

of heat exchanger monitoring, the development of an optimum cleaning strategy and the use of antifoulants. This paper presents a brief overview of the heat exchanger monitoring procedure, and through examples, it shows the incentives of monitoring...

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

1983-01-01T23:59:59.000Z

150

Reducing Ventilation Energy Demand by Using Air-to-Earth Heat Exchangers  

Science Journals Connector (OSTI)

Air-to-Earth heat exchangers (earth tubes) utilize the fact that the temperature in the ground is relatively constant during the year. By letting the air travel through an air-to-earth heat exchanger before re...

Hans Havtun; Caroline Trnqvist

2013-01-01T23:59:59.000Z

151

Building America Technology Solutions for New and Existing Homes: Foundation Heat Exchanger, Oak Ridge, Tennessee  

Broader source: Energy.gov [DOE]

This case study introduces the foundation heat exchanger that can significantly reduce the cost of the ground source heat pump (GHSP).

152

Heat efficiency of translucent cover-radiation absorbing heat-exchange panel system of flat solar collectors  

Science Journals Connector (OSTI)

An analytic expression is proposed for determining the heat efficiency of the translucent cover-radiation absorbing heat-exchange panel system of flat solar collectors, and on its base the heat efficiency of th...

R. R. Avezov; N. R. Avezova

2008-09-01T23:59:59.000Z

153

Experimental study on heat transfer characteristics of internal heat exchangers for CO2 system under cooling condition  

Science Journals Connector (OSTI)

This paper presents the heat transfer characteristics of the internal heat exchanger (IHX) for CO2 heat pump system. The influence on the IHX length, the mass flow rate, the shape of IHX, the operating condition,...

Young Chul Kwon; Dae Hoon Kim; Jae Heon Lee

2009-03-01T23:59:59.000Z

154

A Plastic-Core Compact Heat Exchanger for Energy Conservation  

E-Print Network [OSTI]

is 10 er cost compared to one with a metallic core, but it as the potential of contamination from mOisfre contained in air. All of these heat exchangers su fer from fouling by dust and particulates wile condensation of moisture leads to corrosion... maximum temperature does not exceed 340 K (150?F) while polypropylene is recommended for use up to 370 K (200?F). Fouling of the transfer surfaces has the negative effect of increasing the resistance to heat flow that leads to deterioration...

Lazaridis, A.; Rafailidis, E.

155

Fouling of HVAC fin and tube heat exchangers  

SciTech Connect (OSTI)

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.

Siegel, Jeffrey; Carey, Van P.

2001-07-01T23:59:59.000Z

156

Project Profile: High-Flux Microchannel Solar Receiver | Department...  

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

of a rectangle shape. The research team seeks to reduce the size, weight, and thermal loss from high-temperature solar receivers by applying microchannel heat-transfer...

157

High Performance Catalytic Heat Exchanger for SOFC Systems - FuelCell Energy  

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

Catalytic Heat Catalytic Heat Exchanger for SOFC Systems-FuelCell Energy Background In a typical solid oxide fuel cell (SOFC) power generation system, hot (~900 °C) effluent gas from a catalytic combustor serves as the heat source within a high-temperature heat exchanger, preheating incoming fresh air for the SOFC's cathode. The catalytic combustor and the cathode air heat exchanger together represent the largest opportunity for cost

158

Natural convection heat exchangers for solar water heating systems. Technical progress report, November 15, 1996--January 14, 1997  

SciTech Connect (OSTI)

The goals of this project are: (1) to develop guidelines for the design and use of thermosypohon side-arm heat exchangers in solar domestic water heating systems, and (2) to establish appropriate modeling and testing criteria for evaluating the performance of systems using this type of heat exchanger.

Davidson, J.H.

1998-06-01T23:59:59.000Z

159

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

E-Print Network [OSTI]

Fouling of heat exchangers used in heating, ventilating, and air conditioning (HVAC) systems is important contributor to overall energy use and peak electric demand. Furthermore, the location of heat exchangers in HVAC systems means that if bioaerosols containing bacteria, fungi, and viruses deposit on heat

160

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

E-Print Network [OSTI]

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

Yu, Lisan

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

MULTIPLE POLLUTANT REMOVAL USING THE CONDENSING HEAT EXCHANGER  

SciTech Connect (OSTI)

The Integrated Flue Gas Treatment (IFGT) system is a new concept whereby a Teflon covered condensing heat exchanger is adapted to remove certain flue gas constituents, both particulate and gaseous, while recovering low level heat. The pollutant removal performance and durability of this device is the subject of a USDOE sponsored program to develop this technology. The program was conducted under contract to the United States Department of Energy?s Fossil Energy Technology Center (DOE-FETC) and was supported by the Ohio Coal Development Office (OCDO) within the Ohio Department of Development, the Electric Power Research Institute?s Environmental Control Technology Center (EPRI-ECTC) and Babcock and Wilcox - a McDermott Company (B&W). This report covers the results of the first phase of this program. This Phase I project has been a two year effort. Phase I includes two experimental tasks. One task dealt principally with the pollutant removal capabilities of the IFGT at a scale of about 1.2MWt. The other task studied the durability of the Teflon 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. Although soda ash was shown to be the most effective reagent for acid gas absorption, comparative cost analyses suggested that magnesium enhanced lime was the most promising avenue for future study. The durability of the Teflon covered heat exchanger tubes was studied on a pilot-scale single- stage condensing heat exchanger (CHX ). This device was operated under typical coal-fired flue gas conditions on a continuous basis for a period of approximately 10 months. Data from the test indicate that virtually no decrease in Teflon 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.

B.J. JANKURA; G.A. KUDLAC; R.T. BAILEY

1998-06-01T23:59:59.000Z

162

Heat transfer characteristics of fluidized bed heat exchanger in a 300MW CFB boiler  

Science Journals Connector (OSTI)

In order to investigate the heat transfer characteristics of fluidized bed heat exchanger (FBHE), a series of experiments was carried out in a commercial 300MW circulating fluidized bed (CFB) boiler with FBHE. The parameters of steam, solids and air in FBHE were measured at different boiler loads, based on which the absorbed heat and heat transfer coefficient were calculated. Further study indicates that when the calculated results are applied to the design of large-scale CFB boilers, the bed side heat transfer coefficient in FBHE can be simplified as the function of solids temperature and flow. Therefore, the empirical model of heat transfer coefficient at bed side is put forward. The deviation between calculated results and measured values is acceptable in engineering application. This model provides strong support for the FBHE design in 600MW supercritical CFB boilers.

Man Zhang; Haibo Wu; Qinggang Lu; Yunkai Sun; Guoliang Song

2012-01-01T23:59:59.000Z

163

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

E-Print Network [OSTI]

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...

Yu, Kun

2014-05-08T23:59:59.000Z

164

Comment on Heat transfer and fluid flow in microchannels and nanochannels at high Knudsen number using thermal lattice-Boltzmann method  

Science Journals Connector (OSTI)

In this Comment we reveal the falsehood of the claim that the lattice Bhatnagar-Gross-Krook (BGK) model is capable of modeling shear-driven, pressure-driven, and mixed shear-pressure-driven rarified [sic] flows and heat transfer up to Kn=1 in the transitional regime made in a recent paper [Ghazanfarian and Abbassi, Phys. Rev. E 82, 026307 (2010)]. In particular, we demonstrate that the so-called Knudsen effects described are merely numerical artifacts of the lattice BGK model and they are unphysical. Specifically, we show that the erroneous results for the pressure-driven flow in a microchannel imply the false and unphysical condition that 6?Kn

Li-Shi Luo

2011-10-25T23:59:59.000Z

165

Engineering Analysis of Intermediate Loop and Process Heat Exchanger Requirements to Include Configuration Analysis and Materials Needs  

SciTech Connect (OSTI)

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.

T.M. Lillo; R.L. Williamson; T.R. Reed; C.B. Davis; D.M. Ginosar

2005-09-01T23:59:59.000Z

166

Retrofit of a Heat-Exchanger Network by Considering Heat-Transfer Enhancement and Fouling  

Science Journals Connector (OSTI)

Besides, for network-topology modifications the capital cost associated with the related pipe and civil work is high, and the negative financial impact of production losses resulting from plant shut down during the lengthy periods of a retrofit is also a concern. ... One way is to add heat-transfer enhancement to the cold side in a heat exchanger to increase the cold-side heat-transfer coefficients, and the other is to change the network structure to reassign the temperature distribution in the network. ... An existing industrial PHT network is simulated using a dynamic, distributed math. ...

Yufei Wang; Robin Smith

2013-06-07T23:59:59.000Z

167

Aging management guideline for commercial nuclear power plants - heat exchangers  

SciTech Connect (OSTI)

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.

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

1994-06-01T23:59:59.000Z

168

Thermal self-oscillations in radiative heat exchange  

E-Print Network [OSTI]

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.

Dyakov, Sergey; Yan, Min; Qiu, Min

2014-01-01T23:59:59.000Z

169

Experimental investigation of plastic finned-tube heat exchangers, with emphasis on material thermal conductivity  

SciTech Connect (OSTI)

In this paper, two modified types of polypropylene (PP) with high thermal conductivity up to 2.3 W/m K and 16.5 W/m K are used to manufacture the finned-tube heat exchangers, which are prospected to be used in liquid desiccant air conditioning, heat recovery, water source heat pump, sea water desalination, etc. A third plastic heat exchanger is also manufactured with ordinary PP for validation and comparison. Experiments are carried out to determine the thermal performance of the plastic heat exchangers. It is found that the plastic finned-tube heat exchanger with thermal conductivity of 16.5 W/m K can achieve overall heat transfer coefficient of 34 W/m{sup 2} K. The experimental results are compared with calculation and they agree well with each other. Finally, the effect of material thermal conductivity on heat exchanger thermal performance is studied in detail. The results show that there is a threshold value of material thermal conductivity. Below this value improving thermal conductivity can considerably improve the heat exchanger performance while over this value improving thermal conductivity contributes very little to performance enhancement. For the finned-tube heat exchanger designed in this paper, when the plastic thermal conductivity can reach over 15 W/m K, it can achieve more than 95% of the titanium heat exchanger performance and 84% of the aluminum or copper heat exchanger performance with the same dimension. (author)

Chen, Lin; Li, Zhen; Guo, Zeng-Yuan [Department of Engineering Mechanics, Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Tsinghua University, Beijing 100084 (China)

2009-07-15T23:59:59.000Z

170

3D numerical simulation on fluid flow and heat transfer characteristics in multistage heat exchanger with slit fins  

Science Journals Connector (OSTI)

In this paper, a numerical investigation is performed for three-stage heat exchangers with plain plate fins and slit ... are arranged in a staggered way, and heat conduction in fins is considered. In order ... av...

W. Q. Tao; Y. P. Cheng; T. S. Lee

2007-11-01T23:59:59.000Z

171

Effect of alumina nanoparticles in the fluid on heat transfer in double-pipe heat exchanger system  

Science Journals Connector (OSTI)

This study was performed to investigate the convective heat transfer coefficient of nanofluids made of several alumina ... transformer oil which flow through a double pipe heat exchanger system in the laminar flo...

Byung-Hee Chun; Hyun Uk Kang; Sung Hyun Kim

2008-09-01T23:59:59.000Z

172

3D Numerical heat transfer and fluid flow analysis in plate-fin and tube heat exchangers with electrohydrodynamic enhancement  

Science Journals Connector (OSTI)

Three-dimensional laminar fluid flow and heat transfer over a four-row plate-fin and tube heat exchanger with electrohydrodynamic (EHD) wire electrodes...V E...=016kV) are investigated in detail...

Chia-Wen Lin; Jiin-Yuh Jang

2005-05-01T23:59:59.000Z

173

Analysis of a high-temperature heat exchanger for an externally-fired micro gas turbine  

Science Journals Connector (OSTI)

Abstract The externally-fired gas turbine (EFGT) can convert fuels such as coal, biomass, biomass gasification gas and solar energy into electricity and heat. The combination of this technology with biomass gasification gas represents an interesting option for gasification, for which it has been difficult to find a conversion technology. In this system, the heat exchanger deals with the contaminants of biomass derived gas instead of the turbine itself. However, these contaminants can build a deposit layer in the heat exchanger that can affect its performance. The heat exchanger is important in externally fired gas turbines since the turbine inlet temperature is directly dependent on its performance. Several studies on heat exchangers for externally fired gas turbines have been carried out. However, very few detailed studies were found comparing the performance of heat exchangers for externally fired gas turbines considering the effect of deposit materials on the surfaces. In this regard, this work compares the performance of a corrugated plate heat exchanger and a two-tube-passes shell and tube heat exchanger considering the effect of thickness of deposit material with different thermal conductivities on pressure drop and effectiveness. The results show that the effectiveness of the corrugated plate heat exchanger is more influenced at larger thicknesses of deposit materials than the two-tube-passes shell and tube heat exchanger. There is an exponential increase in the pressure drop of the plate heat exchanger while a monotonic increase of pressure drop is seen for the shell and tube heat exchanger. The increase in the thickness of the deposit material has two effects. On one hand, it increases the resistance to heat transfer and on the other hand, it reduces the through flow area increasing the velocity and hence the heat transfer coefficient. Additionally, the effectiveness of the heat exchangers had a stronger influence on the power output than the pressure drop.

Fabiola Baina; Anders Malmquist; Lucio Alejo; Bjrn Palm; Torsten H. Fransson

2015-01-01T23:59:59.000Z

174

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

E-Print Network [OSTI]

THE EFFECTS OF OUTDOOR HEAT EXCHANGER HYDROPHOBIC TREATMENT ON THE PERFORMANCE OF AN AIR SOURCE HEAT PUMP A Thesis by BRANDON DEWAYNE PARKER Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE May 1995 Major Subject: Mechanical Engineering THE EFFECTS OF OUTDOOR HEAT EXCHANGER HYDROPHOBIC TREATMENT ON THE PERFORMANCE OF AN AIR SOURCE HEAT PUMP A Thesis by BRANDON DEWAYNE PARKER Submitted...

Parker, Brandon DeWayne

2012-06-07T23:59:59.000Z

175

Integrated heat exchanger design for a cryogenic storage tank  

SciTech Connect (OSTI)

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.

Fesmire, J. E.; Bonner, T.; Oliveira, J. M.; Johnson, W. L.; Notardonato, W. U. [NASA Kennedy Space Center, Cryogenics Test Laboratory, NE-F6, KSC, FL 32899 (United States); Tomsik, T. M. [NASA Glenn Research Center, 21000 Brookpark Road, Cleveland, OH 44135 (United States); Conyers, H. J. [NASA Stennis Space Center, Building 3225, SSC, MS 39529 (United States)

2014-01-29T23:59:59.000Z

176

Integrated heat exchanger design for a cryogenic storage tank  

Science Journals Connector (OSTI)

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.

2014-01-01T23:59:59.000Z

177

Development of high-temperature heat exchanger for hydrogen combustion turbine system  

SciTech Connect (OSTI)

New Rankine Cycle and Topping Regenerative Cycle are representative 500MW power generation systems for a hydrogen combustion turbine (HCT). The energy efficiency based on HHV of these is expected to be over 60% because the inlet temperature of turbine can be increased to 1,970K. These systems comprise various heat exchangers. Especially, the development of high temperature heat exchanger dealing with the high temperature and pressure steam is very important to realize the hydrogen combustion turbine system. The high-temperature heat exchanger of New Rankine Cycle is a supercritical heat recovery steam generator operating at pressure of 36MPa. This heat exchanger is heated by steam at temperature of 1,390K. On the other hand, Topping Regenerative Cycle has two high-temperature heat exchangers. One is a regenerator operating at pressure of 37MPa. The other is a regenerator operating at pressure of 5MPa. Both regenerators are heated by steam at temperature of 1,030K. The following are the principal development subject of high-temperature heat exchanger: (1) Improving the heat transfer characteristics to achieve the compact heat exchanger, and (2) Planning the heat exchanger structure suitable for the high thermal stress. To improve a heat transfer characteristic of the high-temperature heat exchangers, a parameter survey is conducted to optimize a tube arrangement and a fin configuration on tube outside and/or inside. The heat transfer areas are minimized through using the tubes with an extended heat transfer surface on both sides of a tube. Structural integrity is also estimated by conducting a structural analysis for the critical parts of the high-temperature heat exchangers.

Takakuwa, Akihiro; Mochida, Yoshio

1999-07-01T23:59:59.000Z

178

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

E-Print Network [OSTI]

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

Thole, Karen A.

179

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

E-Print Network [OSTI]

Heat transfer augmentation along the tube wall of a louvered fin heat exchanger using practical the formation of streamwise vortices and increase heat transfer between a working fluid and the surface on which the winglets are placed. This study investigates the use of delta winglets to augment heat transfer on the tube

Thole, Karen A.

180

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

E-Print Network [OSTI]

#12;AN OPTIMIZED TWO-CAPACITY ADVANCED ELECTRIC HEAT PUMP S. E. Veyo S. E. Veyo, Manager, Heat Exchange Systems Research Westinghouse Electric Corporation, R&D Center 1310 Beulah Road Pittsburgh, PA 15235 KEYWORDS: heat pump, air conditioner, electric, residential, energy, compressor, fan, blower, heat

Oak Ridge National Laboratory

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Numerical computation of 3D heat transfer in complex parallel convective exchangers using generalized Graetz modes  

E-Print Network [OSTI]

Numerical computation of 3D heat transfer in complex parallel convective exchangers using insights into the most con- tributing structure to exchanges and transfers. Several examples of heat, whilst many other can be found in a recent review [12]. As quoted in [12] conjugate heat transfer

Paris-Sud XI, Université de

182

Condensing heat exchanger systems for residential/commercial furnaces and boilers. Phase IV  

SciTech Connect (OSTI)

The development of condensing heat exchanger systems is studied. In the work reported here, the focus is on the corrosion resistance of materials to condensate produced by gas-fired heating equipment, and the characterization of the spatial variation of condensation corrosivity in condensing heat exchangers.

Razgaitis, R.; Payer, J.H.; Talbert, S.G.; Hindin, B.; White, E.L.; Locklin, D.W.; Cudnik, R.A.; Stickford, G.H.

1985-10-01T23:59:59.000Z

183

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

E-Print Network [OSTI]

. In the chemical and process industries, large amounts of energy can be saved by using heat recovery in heat exchanger networks, which transfer energy in form of heat Corresponding author: email: skoge@ntnu.no, phone exchanger networks for saving energy and costs has led to a large body of research, and most

Skogestad, Sigurd

184

Continuation of Studies on Development of ODS Heat Exchanger Tubing  

SciTech Connect (OSTI)

The Department of Energy (DOE), National Energy Technology Center (NETL), has initiated a strategic plan for the development of advanced technologies needed to design and build fossil fuel plants with very high efficiency and environmental performance. These plants, referred to as 'Vision 21' and FutureGen programs by DOE, will produce electricity, chemicals, fuels, or a combination of these products, and possibly secondary products such as steam/heat for industrial use. MA956 is a prime candidate material being considered for a high temperature heat exchanger in the 'Vision 21' and FutureGen programs. This material is an oxide dispersion strengthened (ODS) alloy; however, there are some gaps in the data required to commit to the use of these alloys in a full-size plant. To fill the technology gaps for commercial production and use of the material for 'Advanced Power Generation Systems' this project has performed development activity to significant increase in circumferential strength of MA956 as compared to currently available material, investigated bonding technologies for bonding tube-to-tube joints through joining development, and performed tensile, creep and fire-side corrosion tests to validate the use and fabrication processes of MA956 to heat exchanger tubing applications. Development activities within this projected has demonstrated increased circumferential strength of MA956 tubes through flow form processing. Of the six fabrication technologies for bonding tube-to-tube joints, inertia friction welding (IFW) and flash butt welding (FBW) were identified as processes for joining MA956 tubes. Tensile, creep, and fire-side corrosion test data were generated for both base metal and weld joints. The data can be used for design of future systems employing MA956. Based upon the positive development activities, two test probes were designed and fabricated for field exposure testing at 1204 C ({approx}2200 F) flue gas. The probes contained tube portions with FBW and IFW welded MA956. Field testing of the probes and remaining heat exchanger design activity will be performed by Oak Ridge National Laboratory under DOE Contract DE-AC05-00OR22725.

Lawrence Brown; David Workman; Bimal Kad; Gaylord Smith; Archie Robertson; Ian Wright

2008-04-15T23:59:59.000Z

185

Erosion of heat exchanger tubes in fluidized beds  

SciTech Connect (OSTI)

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

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

1991-01-01T23:59:59.000Z

186

Heat transfer and combustion characteristics of a burner with a rotary regenerative heat exchanger  

SciTech Connect (OSTI)

The authors have developed a Rotary Regenerative Combustion (RRX) System, which is coupled with a compact high efficiency regenerative air heat exchanger and a combustion burner. This system contributes to saving energy of fuel firing industrial furnaces and decreases NO{sub x} emission. This technology can be considered as a solution of greenhouse problem. This paper, discusses a compact high efficiency regenerative air heat exchanger in comparison with the existing types of regenerative burners and reverse firing with high momentum fuel jet (with motive fluid) in the furnace. This burner is compact in size, with high fuel efficiency, low NOx emission, easy to operate, and reliable, based on the results of field tests and commercial operations. The authors can say that the RRX system is a regenerative burner of the second generation.

Hirose, Yasuo; Kaji, Hitoshi; Arai, Norio

1998-07-01T23:59:59.000Z

187

Technical Information Exchange on Pyrolysis Oil: Potential for a renewable heating oil substitution  

Broader source: Energy.gov [DOE]

Two-day agenda from the workshop: Technical Information Exchange on Pyrolysis Oil: Potential for a renewable heating oil substitution fuel in New England.

188

E-Print Network 3.0 - active heat exchange Sample Search Results  

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

typical of those sold before 1978, at 8C outdoor air temperature... .2, an additional 43% loss. Heat losses observed at the compressorheat exchangers, a necessary condition... COP...

189

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

E-Print Network [OSTI]

??The effect of using metal foams in double-pipe heat exchangers is investigated in this work. The advantages and drawbacks of using metal foams in these (more)

Chen, Xi

2014-01-01T23:59:59.000Z

190

Advanced Heat/Mass Exchanger Technology for Geothermal and solar Renewable Energy Systems  

Broader source: Energy.gov [DOE]

Advanced Heat/Mass Exchanger Technology for Geothermal and solar Renewable Energy Systems presentation at the April 2013 peer review meeting held in Denver, Colorado.

191

Development of Design Criteria for Fluid Induced Structural Vibrations in Steam Generators and Heat Exchangers  

SciTech Connect (OSTI)

Flow-induced vibration in heat exchangers has been a major cause of concern in the nuclear industry for several decades. Many incidents of failure of heat exchangers due to apparent flow-induced vibration have been reported through the USNRC incident reporting system. Almost all heat exchangers have to deal with this problem during their operation. The phenomenon has been studied since the 1970s and the database of experimental studies on flow-induced vibration is constantly updated with new findings and improved design criteria for heat exchangers.

Uvan Catton; Vijay K. Dhir; Deepanjan Mitra; Omar Alquaddoomi; Pierangelo Adinolfi

2004-04-06T23:59:59.000Z

192

Heat Transfer Enhancement for Finned-tube Heat Exchangers with Winglets  

SciTech Connect (OSTI)

This paper presents the results of an experimental study of forced convection heat transfer in a narrow rectangular duct fitted with a circular tube and/or a delta-winglet pair. The duct was designed to simulate a single passage in a fin-tube heat exchanger. Heat transfer measurements were obtained using a transient technique in which a heated airflow is suddenly introduced to the test section. High-resolution local fin-surface temperature distributions were obtained at several times after initiation of the transient using an imaging infrared camera. Corresponding local fin-surface heat transfer coefficient distributions were then calculated from a locally applied one-dimensional semi-infinite inverse heat conduction model. Heat transfer results were obtained over an airflow rate ranging from 1.51 x 10-3 to 14.0 x 10-3 kg/s. These flow rates correspond to a duct-height Reynolds number range of 670 6300 with a duct height of 1.106 cm and a duct width-toheight ratio, W/H, of 11.25. The test cylinder was sized such that the diameter-to-duct height ratio, D/H is 5. Results presented in this paper reveal visual and quantitative details of local fin-surface heat transfer distributions in the vicinity of a circular tube, a delta-winglet pair, and a combination of a circular tube and a delta-winglet pair. Comparisons of local and average heat transfer distributions for the circular tube with and without winglets are provided. Overall mean finsurface Nusselt-number results indicate a significant level of heat transfer enhancement associated with the deployment of the winglets with the circular cylinder. At the lowest Reynolds numbers (which correspond to the laminar operating conditions of existing geothermal air-cooled condensers), the enhancement level is nearly a factor of two. At higher Reynolds numbers, the enhancement level is close to 50%.

O'Brien, James Edward; Sohal, Manohar Singh

2000-11-01T23:59:59.000Z

193

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

SciTech Connect (OSTI)

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

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

2002-08-01T23:59:59.000Z

194

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

E-Print Network [OSTI]

??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 (more)

Latcham, Jacob G. (Jacob Greco)

2009-01-01T23:59:59.000Z

195

PHYSICAL REVIEW E 84, 048302 (2011) Reply to "Comment on `Heat transfer and fluid flow in microchannels and nanochannels  

E-Print Network [OSTI]

PHYSICAL REVIEW E 84, 048302 (2011) Reply to "Comment on `Heat transfer and fluid flow) model for high-Knudsen-number (Kn) flow and heat transfer, in the range of Kn 1. We present various studies employing the LBGK model for high-Kn flow and heat transfer simulations. It is concluded that

Luo, Li-Shi

196

Cooling characteristics of ground source heat pump with heat exchange methods  

Science Journals Connector (OSTI)

Abstract The objective of this study is to investigate the influence of the cooling performance for a water-to-water ground source heat pump (GSHP) by using the counter flow and parallel flow methods. The GSHP uses R-410A as a refrigerant, and its main components are a scroll compressor, plate heat exchangers as a condenser, an evaporator, a thermostatic expansion valve, a receiver, and an inverter. Based on our modeling results, the heat transfer rate of the counter flow evaporator is higher than that of the parallel flow evaporator for a heat exchanger length greater than 0.42m. The evaporator length of the GSHP used in this study was set to over 0.5m. The performance of the water-to-water GSHP was measured by varying the compressor speed and source-side entering water temperature (EWT). The cooling capacity of the GSHP increased with increased compressor \\{RPMs\\} and source side EWT. Also, using the counter flow method, compared to the parallel flow method, improves the COP by approximately 5.9% for an ISO 13256-2 rated condition.

Ohkyung Kwon; KyungJin Bae; Chasik Park

2014-01-01T23:59:59.000Z

197

Deposition of biological aerosols on HVAC heat exchangers  

SciTech Connect (OSTI)

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.

Siegel, Jeffrey; Walker, Ian

2001-09-01T23:59:59.000Z

198

45 (2008-5) Adjoint-Based Shape Optimization of a Heat-Exchanger Passage  

E-Print Network [OSTI]

conduction is employed. The cost function is defined as a sum of pressure loss and heat transfer, Distribution of non-dimensional heat flux : (c) Initial shape, (d) 6th shape, (e) Cross section of the bottomF244 45 (2008-5) - 623 - Adjoint-Based Shape Optimization of a Heat-Exchanger Passage with Heat

Kasagi, Nobuhide

199

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

E-Print Network [OSTI]

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...

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

200

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

SciTech Connect (OSTI)

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.

Piyush Sabharwall

2011-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Local Heat Transfer for Finned-Tube Heat Exchangers using Oval Tubes  

SciTech Connect (OSTI)

This paper presents the results of an experimental study of forced convection heat transfer in a narrow rectangular duct fitted with either a circular tube or an elliptical tube in crossflow. The duct was designed to simulate a single passage in a fin-tube heat exchanger. Heat transfer measurements were obtained using a transient technique in which a heated airflow is suddenly introduced to the test section. High-resolution local fin-surface temperature distributions were obtained at several times after initiation of the transient using an imaging infrared camera. Corresponding local fin-surface heat transfer coefficient distributions were then calculated from a locally applied one-dimensional semi-infinite inverse heat conduction model. Heat transfer results were obtained over an airflow rate ranging from 1.56 x 10-3 to 15.6 x 10-3 kg/s. These flow rates correspond to a duct-height Reynolds number range of 630 6300 with a duct height of 1.106 cm and a duct width-toheight ratio, W/H, of 11.25. The test cylinder was sized such that the diameter-to-duct height ratio, D/H is 5. The elliptical tube had an aspect ratio of 3:1 and a/H equal to 4.33. Results presented in this paper reveal visual and quantitative details of local fin-surface heat transfer distributions in the vicinity of circular and oval tubes and their relationship to the complex horseshoe vortex system that forms in the flow stagnation region. Fin surface stagnation-region Nusselt numbers are shown to be proportional to the square-root of Reynolds number.

O'Brien, James Edward; Sohal, Manohar Singh

2000-08-01T23:59:59.000Z

202

Analyzing the efficiency of a heat pump assisted drain water heat recovery system that uses a vertical inline heat exchanger  

Science Journals Connector (OSTI)

Abstract The purpose of the present study is to accumulate knowledge on how a drain water heat recovery system using a vertical inline heat exchanger and a heat pump performs under different drain water flow profile scenarios. Investigating how the intermittent behavior of the drain water influences the performance for this type of system is important because it gives insight on how the system will perform in a real life situation. The scenarios investigated are two 24h drain water flow rate schedules and one shorter schedule representing a three minute shower. The results from the present paper add to the knowledge on how this type of heat recovery system performs in a setting similar to a multi-family building and how sizing influences the performance. The investigation shows that a heat recovery system of this type has the possibility to recover a large portion of the available heat if it has been sized to match the drain water profile. Sizing of the heat pump is important for the system performance; sizing of the storage tank is also important but not as critical.

Jrgen Wallin; Joachim Claesson

2014-01-01T23:59:59.000Z

203

Heat exchanger design considerations for high temperature gas-cooled reactor (HTGR) plants  

SciTech Connect (OSTI)

Various aspects of the high-temperature heat exchanger conceptual designs for the gas turbine (HTGR-GT) and process heat (HTGR-PH) plants are discussed. Topics include technology background, heat exchanger types, surface geometry, thermal sizing, performance, material selection, mechanical design, fabrication, and the systems-related impact of installation and integration of the units in the prestressed concrete reactor vessel. The impact of future technology developments, such as the utilization of nonmetallic materials and advanced heat exchanger surface geometries and methods of construction, is also discussed.

McDonald, C.F.; Vrable, D.L.; Van Hagan, T.H.; King, J.H.; Spring, A.H.

1980-02-01T23:59:59.000Z

204

An Experimental Study of Upward and Downward Flow of Supercritical Carbon Dioxide in a Straight Pipe Heat Exchanger with Constant Wall Heat Flux  

E-Print Network [OSTI]

An experimental analysis was conducted on a single circular tube heat exchanger using supercritical carbon dioxide as the working fluid. The heat exchanger was operated in two different orientations: vertically upward and downward. The experimental...

Umrigar, Eric Dara

2014-05-01T23:59:59.000Z

205

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

E-Print Network [OSTI]

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 transition flow regimes...

Fullerton, Tracy

2012-02-14T23:59:59.000Z

206

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

SciTech Connect (OSTI)

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

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

2014-03-01T23:59:59.000Z

207

OPTIMIZATION AND DESIGN GUIDELINES FOR HIGH FLUX MICRO-CHANNEL HEAT SINKS FOR LIQUID AND GASEOUS SINGLE-PHASE FLOW  

E-Print Network [OSTI]

orders of magnitude, especially for high heat flux devices. Using water and air as coolants, designs with the optimization tool are generalized and optimum configurations are illustrated on design charts. Physical trends

Müller, Norbert

208

Heat exchanger materials for fluidized bed coal combustors  

SciTech Connect (OSTI)

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

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

1980-01-01T23:59:59.000Z

209

Tracer dye transport from a well fitted with a downhole heat exchanger, Klamath Falls, Oregon  

SciTech Connect (OSTI)

Low or medium temperature geothermal resources are often used for space and domestic hot water heating. If the resource is located at reasonably shallow depths and adjacent to a major population centre large amounts of relatively cheap, clean heat can be provided. Geothermal fluid is often brought to the surface, either under natural artesian pressure or by pumping, to be used in surface heat exchangers (SHEs). This method generally requires a second well for disposal of the cooled fluid and a substantial capital outlay for pumps and heat exchangers. Large amounts of heat can be extracted from just one or two wells using surface heat exchangers and the method can prove very cost effective in areas with a high density of energy intensive users. For smaller heat loads surface heat exchangers can become expensive and in many instances a downhole heat exchanger (DHE) installed directly in the well bore is capable of supplying cheap heat to a smaller number of users. This report first describes the methods used to carry out the series of dye tests, from well selection to injection of the dye samples. It then discusses the results of these tests in terms of how much dye was recovered, where it was recovered from and how long it took to arrive. The results of the concurrent temperature monitoring work and DHE heat output performance are also presented. Some recommendations are made for any future testing. 13 refs., 42 figs.

Dunstall, M.G.

1990-02-01T23:59:59.000Z

210

The Role of Filtration in Maintaining Clean Heat Exchanger Coils  

SciTech Connect (OSTI)

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

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

2004-06-30T23:59:59.000Z

211

Liquid Metal Heat Exchanger for Geologic Deposits - Energy Innovation...  

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

heating apparatus that efficiently heats subterranean geological deposits, such as oil shale, to extract hydrocarbons for energy needs. The apparatus provides more efficient...

212

Ground heat exchanger design for direct geothermal energy systems .  

E-Print Network [OSTI]

??Direct geothermal energy systems use the ground to heat and cool buildings. Ground-source heat pump (GSHP) systems are the most widespread form of direct geothermal (more)

COLLS, STUART

2013-01-01T23:59:59.000Z

213

Multiple pollutant removal using the condensing heat exchanger. Task 3, Long term testing at the ECTC  

SciTech Connect (OSTI)

The objective of this task is to demonstrate long term operation of a condensing heat exchanger for coal-fired conditions. A small condensing heat exchanger will be installed at the Environmental Control Technology Center in Barker, New York. It will be installed downstream of the flue gas particulate removal system. The test will determine the amount of wear, if any, on the Teflon{trademark} covered internals of the heat exchanger. Visual inspection and measurements will be obtained for the Teflon{trademark} covered tubes during the test. The material wear study will conducted over a one year calendar period, and the CHX equipment will be operated to the fullest extent allowable.

Schulze, K.H.

1996-01-01T23:59:59.000Z

214

Derivation of equations describing a heat exchanger reactor and their solution using a computer  

E-Print Network [OSTI]

DERIVATION OF EQUATIONS DESCRIBING A HEAT EXCHANGER REACTOR AND THEIR SOLUTION USING A COMPUTER A Thesis By William Smith McLaughlin, Jr. i January 1956 DERIVATION OF EQUATIONS DESCRIBING A HEAT EXCHANGER REACTOR AND THEIR SOIUTION USING...]ect: Chemical Engineering DERIVATION OF EQUATIONS DESCRIBING A HEAT EXCHANGER REACTOR AND THEIR SOLUTION USING A COMPUTER A Thesis William Smith McLaughlin, Jr. Approved as to style and content by ha xnan o omm ee L)BRARY j A AA COLLEGE OF TEXAS...

McLaughlin, William Smith

2012-06-07T23:59:59.000Z

215

Drying and first heat up of a kiln unit with cyclone heat exchangers with a lining of refractory concretes  

SciTech Connect (OSTI)

This paper describes an accelerated drying and first heatup cycle developed for a kiln unit for dry production of clinker with a capacity of 3000 tons/day with cyclone heat exchangers of refractory concretes of high-alumina cement with a chamotte aggregate. The drying of the lining and the heating of the unit were done in 4 days. The results of the work indicate the desirability of use of refractory concretes for lining the cyclone heat exchangers of kiln units for dry production of clinker.

Petrov-Denisov, V.G.; Matveev, Y.V.; Pichkov, A.M.; Pozdnyakova, N.K.; Shakhov, I.I.

1985-11-01T23:59:59.000Z

216

Plate Fin Heat Exchanger Model with Axial Conduction and Variable Properties  

SciTech Connect (OSTI)

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

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

2011-06-10T23:59:59.000Z

217

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]

Heat Exchangers to Geothermal Power Production Cycles",Heat Exchanger to Geothermal Power Production Cycles",4057702. o m SUMMARY The geothermal power loop was modified

Engineering, Barber-Nicholas

2011-01-01T23:59:59.000Z

218

Heat transfer and pressure drop correlations for the rectangular offset strip fin compact heat exchanger  

Science Journals Connector (OSTI)

The development of thermal-hydraulic design tools for rectangular offset strip fin compact heat exchangers and the associated convection process are delineated. On the basis of current understanding of the physical phenomena and enhancement mechanisms, existing empirical f and j data for actual cores are reanalyzed. The asymptotic behavior of the data in the deep laminar and fully turbulent flow regimes is identified. The respective asymptotes for f and j are shown to be correlated by power law expressions in terms of Re and the dimensionless geometric parameters ?, ?, and ?. Finally, rational design equations for f and j are presented in the form of single continuous expressions covering the laminar, transition, and turbulent flow regimes.

Raj M. Manglik; Arthur E. Bergles

1995-01-01T23:59:59.000Z

219

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

E-Print Network [OSTI]

of a Dual Heat Exchanger Rack Cooling Device H.C. Coles, S.prototype computer equipment rack-level cooling device withIT equipment cooling, server rack cooling, server cooling,

Greenberg, Steve

2014-01-01T23:59:59.000Z

220

Investigation on the Integrated External Heat Exchanger for a New Type CFB Boiler Arrangement  

Science Journals Connector (OSTI)

Various external heat exchangers (EHE) are widely used with large-scale CFB boiler. The solid mass flow rate diverted ... EHE has been used in a new designed CFB boiler successfully.

Bin Xiong; Xiaofeng Lu; Hanzhou Liu

2007-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

E-Print Network 3.0 - absorption heat exchange Sample Search...  

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

on the initiation of flashover in a compartment fire Summary: to the wall Qw;r radiative heat loss from the hot layer to the wall gsx exchange factor between the hot layer... with...

222

Method for producing components with internal architectures, such as micro-channel reactors, via diffusion bonding sheets  

DOE Patents [OSTI]

This invention relates to a method for producing components with internal architectures, and more particularly, this invention relates to a method for producing structures with microchannels via the use of diffusion bonding of stacked laminates. Specifically, the method involves weakly bonding a stack of laminates forming internal voids and channels with a first generally low uniaxial pressure and first temperature such that bonding at least between the asperites of opposing laminates occurs and pores are isolated in interfacial contact areas, followed by a second generally higher isostatic pressure and second temperature for final bonding. The method thereby allows fabrication of micro-channel devices such as heat exchangers, recuperators, heat-pumps, chemical separators, chemical reactors, fuel processing units, and combustors without limitation on the fin aspect ratio.

Alman, David E. (Corvallis, OR); Wilson, Rick D. (Corvallis, OR); Davis, Daniel L. (Albany, OR)

2011-03-08T23:59:59.000Z

223

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

SciTech Connect (OSTI)

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)

Nuntaphan, Atipoang [Thermal Technology Research Laboratory, Mae Moh Training Center, Electricity Generating Authority of Thailand, Mae Moh, Lampang 52220 (Thailand); Kiatsiriroat, Tanongkiat [Department of Mechanical Engineering, Chiang Mai University, Chiang Mai 50200 (Thailand)

2007-08-15T23:59:59.000Z

224

Heat as a tracer to determine streambed water exchanges Jim Constantz1  

E-Print Network [OSTI]

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

225

Recovery of Water from Boiler Flue Gas Using Condensing Heat Exchangers  

SciTech Connect (OSTI)

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.

Edward Levy; Harun Bilirgen; John DuPoint

2011-03-31T23:59:59.000Z

226

Recovery of Water from Boiler Flue Gas Using Condensing Heat Exchangers  

SciTech Connect (OSTI)

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.

Levy, Edward; Bilirgen, Harun; DuPont, John

2011-03-31T23:59:59.000Z

227

Welding of dissimilar alloys for high temperature heat exchangers for SOFC  

SciTech Connect (OSTI)

Reduction in the cost of balance of plant applications is one of the top priority focus areas for the successful implementation of solid oxide fuel cell technology. High temperature heat exchangers are employed to heat cathode air utilizing either hot gases coming from the anode side of the stack or other hot gases generated by external processes. In order to reduce the cost of heat exchangers, it may be necessary to apply several different materials, each in a different temperature zone, for the construction of the heat exchanger. This technique would require the joining of dissimilar materials in the construction. In this work, welding of commercial candidate dissimilar materials is explored. Filler materials were identified using equilibrium phase diagrams and thermodynamic simulation software. Autogenous welding was performed and the welding defects were characterized. Finally, experimental weld microstructures were compared to phases predicted by the simulations.

Wilson, R.D.; Hatem, J.; Dogan, O.N.; King, P.E.

2006-10-01T23:59:59.000Z

228

Evaluation Methodology for Advance Heat Exchanger Concepts Using Analytical Hierarchy Process  

SciTech Connect (OSTI)

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).

Piyush Sabharwall; Eung Soo Kim

2012-07-01T23:59:59.000Z

229

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

SciTech Connect (OSTI)

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

Chang H. Oh; Eung S. Kim

2008-09-01T23:59:59.000Z

230

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

SciTech Connect (OSTI)

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

Hughes, Patrick [ORNL; Im, Piljae [ORNL

2012-01-01T23:59:59.000Z

231

Hierarchical Modeling for Population-Based Heat Exchanger Design  

E-Print Network [OSTI]

layer," Journal of Fluids Engineering, 117(1), pp. 181-journal. Ser. 2, Fluids engineering, heat transfer, power,Networks," Journal of Fluids Engineering, 125(6), pp. 1051-

Geb, David

2013-01-01T23:59:59.000Z

232

Design of chemical reactors of the heat exchanger type  

E-Print Network [OSTI]

Operating Profile - Example I 23 , 53 Heat Rate Comparison - Example I Operating Profile - Example 2 Operating Profile - Example 3 Operating Profile - Example 4 Equations (113) and (114) at 790 Reactor Profile - Exan piss 5 and 6 Heat of Reaction.... simple inathematical function of time. While his work was a step forward, it is not directly applicable to the problem of reactor design. Hougen and Watsor. (3), and recently Fair and Rase (4), illustra- ted an exact non-machine method of reactor...

McBeth, Lloyd Theodore

2012-06-07T23:59:59.000Z

233

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

SciTech Connect (OSTI)

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.

Duane Spencer; Kevin McCoy

2010-02-02T23:59:59.000Z

234

Recent development and application of several high-efficiency surface heat exchangers for energy conversion and utilization  

Science Journals Connector (OSTI)

Abstract In the present study, the recent research of three kinds of surface heat exchangers, i.e., shell-and-tube heat exchangers with helical baffles, air-cooled heat exchangers used in large air-cooled systems, and primary surface heat exchangers are reviewed. They are used in the energy conversion and utilization for liquid to liquid, gas to gas and liquid to gas heat exchange, respectively. It can be concluded that the helical baffled shell-and-tube heat exchangers (STHXs) should be used to replace the conventional segmental baffled \\{STHXs\\} in industries, despite there are a lot of research work have to be done, especially on the novel combined helical baffles. The primary surface gas to gas heat exchangers are developing towards to the more complex 3D CC primary surfaces, such as the double-wave CC primary surface, offset-bubble primary surface and 3D anti-phase secondary corrugation. The whole performance for the air-cooled heat exchangers in the air cooling system and the multi-objectives optimization for air-cooled heat exchangers should be paid more attention, considering the heat transfer, pumper power, space usage and other economic influence factors.

Qiuwang Wang; Min Zeng; Ting Ma; Xueping Du; Jianfeng Yang

2014-01-01T23:59:59.000Z

235

Thermochemical Solar Energy Storage Via Redox Oxides: Materials and Reactor/Heat Exchanger Concepts  

Science Journals Connector (OSTI)

Abstract Thermochemical Storage of solar heat exploits the heat effects of reversible chemical reactions for the storage of solar energy. Among the possible reversible gas-solid chemical reactions, the utilization of a pair of redox reactions of multivalent solid oxides can be directly coupled to CSP plants employing air as the heat transfer fluid bypassing the need for a separate heat exchanger. The present work concerns the development of thermochemical storage systems based on such oxide-based redox materials and in particular on cobalt oxide; in the one hand by tailoring their heat storage/release capability and on the other hand via their incorporation in proper reactor/heat exchanger devices. In this respect the first stage of the work involved parametric testing of cobalt oxide compositions via Thermo-Gravimetric Analysis to comparatively investigate the temperature range for cyclic oxidation-reduction and optimize the cycle conditions for maximum reduction and re-oxidation extent. Subsequently, two reactor concepts for the coupling of solar energy to the redox reactions have been implemented and tested. These reactor concepts include in one hand structured ceramic reactors/heat exchangers based on redox-oxide-coated honeycombs and on the other hand powder-fed, solar-heated, rotary kiln reactors. The two reactor concepts were tested within non-solar-aided lab-scale and solar- aided campaigns, respectively. The feasibility of both concepts was shown and good chemical conversions were achieved. The experiments pointed out the challenging points related to the manufacture of pilot-scale reactors/heat exchangers with enhanced heat storage capacity. A numerical model using commercial CFD software is developed to define optimal geometrical characteristics and operating conditions and refine the pilot scale design in order to achieve efficient, long-term off-sun operation.

S. Tescari; C. Agrafiotis; S. Breuer; L. de Oliveira; M. Neises-von Puttkamer; M. Roeb; C. Sattler

2014-01-01T23:59:59.000Z

236

ADVANCED HEAT EXCHANGERS USING TUNABLE NANOSCALE-MOLECULAR ASSEMBLY  

SciTech Connect (OSTI)

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

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

2004-01-01T23:59:59.000Z

237

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

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

Demonstration and Performance Monitoring of Foundation Heat Exchangers (FHX) in Low Load, High Performance Research Homes Piljae Im, Ph.D. Oak Ridge National Laboratory Building America Technical Update Meeting April 29 - 30, Denver, Colorado ACKNOWLEDGEMENT * This project was sponsored by the Building Technologies Office of the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy and the Tennessee Valley Authority (TVA). Managed by UT-Battelle for the U.S. Department of Energy 2 PRESENTATION OVERVIEW * INTRODUCTION * FIELD TEST OF THE FOUNDATION HEAT EXCHANGER (FHX) CONCEPT * FOUNDATION HEAT EXCHANGER PERFORMANCE MEASUREMENTS * ADDITIONAL FINDINGS AND COST COMPARISON * SUMMARY Managed by UT-Battelle for the U.S. Department of Energy

238

Modelling the vertical heat exchanger in thermal basin  

Science Journals Connector (OSTI)

In geographical area characterize by specific geological conformations such as the Viterbo area which comprehend active volcanic basins, it is difficult to use conventional geothermal plants. In fact the area presents at shallow depths thermal falde ... Keywords: heat, thermal aquifer, thermal energy

Maurizio Carlini; Sonia Castellucci

2007-06-01T23:59:59.000Z

239

Producing microchannels using graduated diffusion bonding of...  

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

invention will have utility in micro-reactor design for heat exchangers, recuperators, heat-pumps, chemical separators, chemical reactors, fuel processing, and combustors....

240

HEAT exchanger design for hot air Ericsson-Brayton piston engine  

Science Journals Connector (OSTI)

One of the solutions without negative consequences for the increasing energy consumption in the world may be use of alternative energy sources in micro-cogeneration. Currently it is looking for different solutions and there are many possible ways. Cogeneration is known for long time and is widely used. But the installations are often large and the installed output is more suitable for cities or industry companies. When we will speak about decentralization the small machines have to be used. The article deals with the principle of hot-air engines their use in combined heat and electricity production from biomass and with heat exchangers as primary energy transforming element. In the article is hot air engine presented as a heat engine that allows the conversion of heat into mechanical energy while heat supply can be external. In the contribution are compared cycles of hot-air engine. Then are compared suitable heat exchangers for use with hot air Ericsson-Brayton engine. In the final part is proposal of heat exchanger for use in closed Ericsson-Brayton cycle.

Peter ?ur?ansk; Richard Lenhard; Jozef Janda?ka

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

A superconducting fault current limiter integrated in the cold heat exchanger of a  

Science Journals Connector (OSTI)

In this work we probe a compact superconducting fault current limiter (SFCL) integrated in the cold heat exchanger of a thermoacoustic refrigerator. A design for an SFCL device with a power of about 2.2kW is presented and described in detail. A thermoacoustic refrigerator is also proposed which, under fault conditions, must be able to remove around 50W at 80K. Asimulation routine is run to test the performance of the SFCL, based on YBCO films, in terms of both the limiting capacity and the energy to be dissipated and removed inside the heatexchanger.

M R Osorio; A Btrancourt; M X Franois; J A Veira; F Vidal

2008-01-01T23:59:59.000Z

242

Development of Design Criteria for Fluid Induced Structural Vibration in Steam Generators and Heat Exchangers  

SciTech Connect (OSTI)

OAK-B135 Flow-induced vibration in heat exchangers has been a major cause of concern in the nuclear industry for several decades. Many incidents of failure of heat exchangers due to apparent flow-induced vibration have been reported through the USNRC incident reporting system. Almost all heat exchangers have to deal with this problem during their operation. The phenomenon has been studied since the 1970s and the database of experimental studies on flow-induced vibration is constantly updated with new findings and improved design criteria for heat exchangers. In the nuclear industry, steam generators are often affected by this problem. However, flow-induced vibration is not limited to nuclear power plants, but to any type of heat exchanger used in many industrial applications such as chemical processing, refrigeration and air conditioning. Specifically, shell and tube type heat exchangers experience flow-induced vibration due to the high velocity flow over the tube banks. Flow-induced vibration in these heat exchangers leads to equipment breakdown and hence expensive repair and process shutdown. The goal of this research is to provide accurate measurements that can help modelers to validate their models using the measured experimental parameters and thereby develop better design criteria for avoiding fluid-elastic instability in heat exchangers. The research is divided between two primary experimental efforts, the first conducted using water alone (single phase) and the second using a mixture of air or steam and water as the working fluid (two phase). The outline of this report is as follows: After the introduction to fluid-elastic instability, the experimental apparatus constructed to conduct the experiments is described in Chapter 2 along with the measurement procedures. Chapter 3 presents results obtained on the tube array and the flow loop, as well as techniques used in data processing. The project performance is described and evaluated in Chapter 4 followed by a discussion of publications and presentations relevant to the project in Chapter 5, while the conclusions and recommendations for future work are presented in Chapter 6.

Catton, Ivan; Dhir, Vijay K.; Alquaddoomi, O.S.; Mitra, Deepanjan; Adinolfi, Pierangelo

2004-03-26T23:59:59.000Z

243

Geothermal helical heat exchangers: Comparison and use of two-dimensional axisymmetric models  

Science Journals Connector (OSTI)

Abstract This study concerns near-surface geothermic heat pumps applied to the heating or the cooling of buildings, and more especially the modeling of new helical heat exchangers buried in the subsoil between 1 and 4m depth. Two 2D axisymmetric models are considered for the exchangers: a horizontal rings model and an annular cylindrical conduit model. The models are described, and successfully compared with literature results applied to ground thermal energy storage. The 2 models give comparable results. The simulations run significantly faster when modeling the exchanger as an annular cylindrical conduit. The ability of the thermal model of the subsoil to simulate the earth freezing is validated by comparison to experimental results. The influence of the liquid fraction included into the ground on the thermal response of the geothermic heat pumps is analyzed. It has a significant impact on the return temperature from the geothermal heat exchangers because of the phase change phenomena and the increase of the conductivity due to the soil freezing.

Xavier Moch; Marc Palomares; Fabrice Claudon; Bernard Souyri; Benot Stutz

2014-01-01T23:59:59.000Z

244

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

E-Print Network [OSTI]

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...

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

2011-01-01T23:59:59.000Z

245

Test results of heat-exchanger cleaning in support of ocean thermal energy conversion  

SciTech Connect (OSTI)

These tests evaluated flow-driven brushes, recirculating sponge rubber balls, chlorination, and mechanical system/chlorination combinations for in-situ cleaning of two potential heat exchanger materials: titanium and aluminum alloy 5052. Tests were successful when fouling resistance was <3.0 x 10/sup -4/ ft/sup 2/ hr-/sup 0/F/Btu. Results indicated systems and cleaning techniques using brushes, soft sponge balls, and various concentrations of chlorine had some potential for maintaining heat transfer efficiency.

Lott, D F

1980-12-01T23:59:59.000Z

246

Monolithic microchannel heatsink  

DOE Patents [OSTI]

A silicon wafer has slots sawn in it that allow diode laser bars to be mounted in contact with the silicon. Microchannels are etched into the back of the wafer to provide cooling of the diode bars. To facilitate getting the channels close to the diode bars, the channels are rotated from an angle perpendicular to the diode bars which allows increased penetration between the mounted diode bars. This invention enables the fabrication of monolithic silicon microchannel heatsinks for laser diodes. The heatsinks have low thermal resistance because of the close proximity of the microchannels to the laser diode being cooled. This allows high average power operation of two-dimensional laser diode arrays that have a high density of laser diode bars and therefore high optical power density.

Benett, William J. (Livermore, CA); Beach, Raymond J. (Livermore, CA); Ciarlo, Dino R. (Livermore, CA)

1996-01-01T23:59:59.000Z

247

The design, construction, and calibration of a heat exchanger calorimeter  

E-Print Network [OSTI]

Laboratories, is described by Maxwell et al. ]2]. This paper is a general discussion of the different capabilities of the test system, which is intended for undergraduate teaching, along v ith graduate research. The discussion on coil studies and extended... consists of' four systems. The hot water system (I) provides continuously heated water to the test coil (2). The chilled water system (3) cools the water circulating through the auxiliary coil (4). The auxiliary coil is Auxi1i a r g Coi1 Blower Nozz1e...

Lovelady, Jeffery Paul

2012-06-07T23:59:59.000Z

248

Optimization of Heat Transfer Systems and Use of the Environmental Exergy Potential - Application to Compact Heat Exchangers and Heat Pumps.  

E-Print Network [OSTI]

??In this thesis, the optimization of forced convection heat sinks and groundwater-source heat pumps is addressed with the purpose of improving energy efficiency. Parallel ducts (more)

Canhoto, Paulo

2012-01-01T23:59:59.000Z

249

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

E-Print Network [OSTI]

level. Steam condensers are integral part of any nuclear and thermal power plant utilising steam A simulation model for a vertical U-tube steam condenser in which the condensate is stored at the bottom well and thus the bottom well acts as a heat exchanger. The storage of hydraulic and thermal energies

Paris-Sud XI, Université de

250

Seasonal thermal signatures of heat transfer by water exchange in an underground vault  

Science Journals Connector (OSTI)

......such a cavity, water phases do not need...place, and vertical water flow can be small...Aburatsubo, with a recovery time larger than...heat transfer by water exchange. This...evaporation and condensation process. If the...Monitoring the atmospheric temperature in a......

Frdric Perrier; Pierre Morat; Toshio Yoshino; Osam Sano; Hisashi Utada; Olivier Gensane; Jean-Louis Le Moul

2004-07-01T23:59:59.000Z

251

Long-term corrosion measurements in condensing heat exchangers. Topical report, September 1989-January 1993  

SciTech Connect (OSTI)

Corrosion of metals used in condensing heat exchangers for gas appliances has been correlated most strongly with the chloride content of the condensate. This study presents results of an experimental examination of the long-term corrosion in metals used in condensing heat exchangers. The objective of this work is to develop a rationale for predicting the performance and expected service life of metals in condensing heat exchangers. Long-term exposure tests were conducted using finned-tube condensing heat exchangers containing tubes of 304L, 3161L, 3171L, Sea-Cure, and 29-4C steel, and aluminum. The natural gas was spiked with R-11 to generate chloride ion levels in the condensate of 3 ppm, 26 ppm, and 225 ppm. The aluminum tubes experienced through-the-wall pitting after 1.5 months at 225 ppm chloride, and after 6 months at 26 ppm chloride. At 3 ppm, most of the tubes exhibited no corrosion. At 225 ppm and 26 ppm, the 300-series stainless steels experienced through-the-wall corrosion within 3 months, but at 3 ppm virtually no corrosion was found. Sea-Cure and 29-4C exhibited the best corrosion resistance with some pitting at 225 ppm but none at 26 ppm and 3 ppm.

Stickford, G.H.; Hindin, B.

1993-01-31T23:59:59.000Z

252

Particle loading rates for HVAC filters, heat exchangers, and ducts Nomenclature  

E-Print Network [OSTI]

Particle loading rates for HVAC filters, heat exchangers, and ducts Nomenclature Afl surface area of floor (m2 ) bf fraction of bypass flow around the filter (dimensionless) Cout outdoor concentration on the filter per volume of air (mg/lm m3 ) Mf,tot total mass deposited on the filter per month of operation (g

Siegel, Jeffrey

253

Experimental shellside flow visualization in a shell and tube heat exchanger  

E-Print Network [OSTI]

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

Fischer, Matthew Winslow

1998-01-01T23:59:59.000Z

254

Corrosion of heat-recovery exchangers in swimming-pool-hall ventilation systems. Research report  

SciTech Connect (OSTI)

The report concludes an investigation of the corrosion resistance of heat-recovery exchangers operating in swimming-pool-hall atmospheres. An interim report was published in August 1981. The trends detected then have been confirmed and it is concluded that exchangers using copper for both tubes and fins have adequate corrosion resistance and can be expected to remain efficient and structurally sound for more than ten years. Aluminium is shown to be unsuitable as a fin material because of its susceptibility to localized dissimilar metal corrosion when in contact with the copper tubes. Some of the steel components in the heat recovery chamber are apt to corrode badly and need to be protected, or else made out of non-corrodible materials. It is also important to filter the incoming air to prevent the exchangers becoming contaminated by airborne detritus.

Bird, T.L.

1985-09-01T23:59:59.000Z

255

Hybrid heat exchange for the compression capture of CO2 from recirculated flue gas  

SciTech Connect (OSTI)

An approach proposed for removal of CO2 from flue gas cools and compresses a portion of a recirculated flue-gas stream, condensing its volatile materials for capture. Recirculating the flue gas concentrates SOx, H2O and CO2 while dramatically reducing N2 and NOx, enabling this approach, which uses readily available industrial components. A hybrid system of indirect and direct-contact heat exchange performs heat and mass transfer for pollutant removal and energy recovery. Computer modeling and experimentation combine to investigate the thermodynamics, heat and mass transfer, chemistry and engineering design of this integrated pollutant removal (IPR) system.

Oryshchyn, Danylo B.; Ochs, Thomas L.; Summers, Cathy A.

2004-01-01T23:59:59.000Z

256

Criteria for the selection and design of efficient heat exchange bed media for RTO/RCO  

SciTech Connect (OSTI)

Regenerative thermal and catalytic oxidizers are used to treat VOC (volatile organic compound) contaminated waste gases. This paper describes how regenerative heat exchangers can be modeled and designed. Both, a detailed and a condensed model are discussed. Simulated results based on these models are used to investigate the performance of regenerative heat exchangers together with the influence of the relevant process parameters. The results show that for a given configuration systems with equal space velocity give identical thermal efficiencies (neglecting heat losses to the surroundings). Short cycle times are favorable for the thermal behavior without influencing the pressure drop. It is also shown, that the mass of the heat exchanging medium has a much lower impact than one would think initially. The key parameter, determining the thermal performance, is the product of the heat transfer coefficient and the specific surface area. Besides their much lower pressure drop this is the main reason for the superior thermal performance of ceramic cellular monoliths. At a required thermal efficiency, this allows for a significantly smaller design and a more economical operation of units with cellular monoliths.

Lambert, D.; Fu, X. [Corning Inc., NY (United States); Boger, T. [Corning GmbH, Wiesbaden (Germany)

1998-12-31T23:59:59.000Z

257

Interface Exchange as an Indicator for Eddy Heat Transport  

SciTech Connect (OSTI)

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.

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

2012-06-12T23:59:59.000Z

258

Design and optimization of a downhole coaxial heat exchanger for an enhanced geothermal system (EGS)  

Science Journals Connector (OSTI)

The present study considers the design, performance analysis and optimization of a downhole coaxial heat exchanger for an enhanced geothermal system (EGS). The optimum mass flow rate of the geothermal fluid for minimum pumping power and maximum extracted heat energy was determined. In addition, the coaxial pipes of the downhole heat exchanger were sized based on the optimum geothermal mass flow rate and steady-state operation. Transient effect or time-dependent cooling of the Earth underground, and the optimum amount and size of perforations at the inner pipe entrance region to regulate the flow of the geothermal fluid were disregarded to simplify the analysis. The paper consists of an analytical and numerical thermodynamic optimization of a downhole coaxial heat exchanger used to extract the maximum possible energy from the Earth's deep underground (2km and deeper below the surface) for direct usage, and subject to a nearly linear increase in geothermal gradient with depth. The thermodynamic optimization process and entropy generation minimization (EGM) analysis were performed to minimize heat transfer and fluid friction irreversibilities. An optimum diameter ratio of the coaxial pipes for minimum pressure drop in both limits of the fully turbulent and laminar fully-developed flow regime was determined and observed to be nearly the same irrespective of the flow regime. Furthermore, an optimum geothermal mass flow rate and an optimum geometry of the downhole coaxial heat exchanger were determined for maximum net power output. Conducting an energetic and exergetic analysis to evaluate the performance of binary power cycle, higher Earth's temperature gradient and lower geofluid rejection temperatures were observed to yield maximum first- and second-law efficiencies.

P.J. Yekoladio; T. Bello-Ochende; J.P. Meyer

2013-01-01T23:59:59.000Z

259

Characteristics of a semicircular heat exchanger used in a water heated condenser pump .  

E-Print Network [OSTI]

??According to literature 6% of South Africas primary energy consumption could be saved if heat pumps were used to their full technical potential. Although there (more)

Da Veiga, Willem Richter

2009-01-01T23:59:59.000Z

260

Investigation of new heat exchanger design performance for solar thermal chemical heat pump.  

E-Print Network [OSTI]

?? The emergence of Thermally Driven Cooling system has received more attention recently due to its ability to utilize low grade heat from engine, incinerator (more)

Cordova, Cordova

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Experimental investigation of highly effective plate-fin heat exchanger surfaces  

Science Journals Connector (OSTI)

Results are presented of an experimental investigation of a new convective rational heat transfer augmentation law in plate-fin heat exchanger surfaces. This law is characterized by Nu/Nusm ? ?/?sm by comparing channels (heat transfer surfaces) with vortex promoters with similar smooth channels at equal Reynolds numbers. For experimental confirmation and investigation of this law, heat exchanger cores having three different plate-fin surfaces were developed and manufactured. Two surfaces are formed by short offset channels (interrupted surfaces) of equilateral triangular and rectangular cross sections. The third surface has channels of isosceles triangular cross sections, with transverse projections and grooves along the channel length direction. The experimental results and correlations are reported for the three surfaces. The experiments were conducted in a wind tunnel with specially developed precise instrumentation that ensured experimental uncertainties of ?? = 2.3% and ?Re = 1.7% at a 0.997 confidence level. Analysis of the results indicated that the fundamental character and causes limiting rational heat transfer augmentation to Nu/Nusm ? ?/?sm depend upon the heat transfer surface configuration. This paper consolidates the author's research on the subject reported in the Russian language over the last 25 years.

E.V. Dubrovsky

1995-01-01T23:59:59.000Z

262

Directly connected heat exchanger tube section and coolant-cooled structure  

DOE Patents [OSTI]

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.

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

2014-04-01T23:59:59.000Z

263

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

DOE Patents [OSTI]

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.

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

1988-01-01T23:59:59.000Z

264

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

E-Print Network [OSTI]

attention and maintenance and the installation of an adequate control system. A general FBWHB design methodology is presented along with a preliminary engineering design for a space heating application. A flowsheet, mass balance, and equipment sizes...

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

1980-01-01T23:59:59.000Z

265

Discussion of the internal heat exchanger's effect on the Organic Rankine Cycle  

Science Journals Connector (OSTI)

Abstract This paper explores the performances of IHE (Internal Heat Exchanger) in ORC (Organic Rankine Cycle) systems. Although previous studies hold multitudinous opinions, this study gives clear statements of IHE in both subcritical and supercritical ORC systems by setting a new model taking pressure drop in loops and acid dew point into consideration. Commonly used working fluids R123 and R600 are chosen for subcritical and supercritical cases separately. The temperature of the heat source applied is 200C and the mass flow rate of it is 1kg/s. The analysis is accomplished by program Engineering Equation Solver. A modified method of calculating maximum heat exchange in IHE is given when modeling a supercritical cycle, because of the momentously changing specific heat near the critical point. Besides, a new approach is put forward to calculate the outlet temperature of the heat source and find the location of pinch point in supercritical cases. The results provide that IHE is beneficial to a subcritical case, but it improves system performance only in part of the low pressure stage in a supercritical case. Moreover, after the acid dew point Tad is taken into account, it is found that IHE is able to enlarge euphemistically the maximum system net output in a subcritical case. And in a supercritical case, the original evaporation pressure which does not conform to the rule Th,out>Tad is available now. It is revealed that the utilization of IHE will strengthen the applicability of the system.

Yadong Zhu; Zhe Hu; Yaodong Zhou; Liang Jiang; Lijun Yu

2014-01-01T23:59:59.000Z

266

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

DOE Patents [OSTI]

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.

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

1997-04-22T23:59:59.000Z

267

Oscillating flow loss test results in Stirling engine heat exchangers. Final Report  

SciTech Connect (OSTI)

The results are presented for a test program designed to generate a database of oscillating flow loss information that is applicable to Stirling engine heat exchangers. The tests were performed on heater/cooler tubes of various lengths and entrance/exit configurations, on stacked and sintered screen regenerators of various wire diameters and on Brunswick and Metex random fiber regenerators. The test results were performed over a range of oscillating flow parameters consistent with Stirling engine heat exchanger experience. The tests were performed on the Sunpower oscillating flow loss rig which is based on a variable stroke and variable frequency linear drive motor. In general, the results are presented by comparing the measured oscillating flow losses to the calculated flow losses. The calculated losses are based on the cycle integration of steady flow friction factors and entrance/exit loss coefficients.

Koester, G.; Howell, S.; Wood, G.; Miller, E.; Gedeon, D.

1990-05-01T23:59:59.000Z

268

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

DOE Patents [OSTI]

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.

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

1997-01-01T23:59:59.000Z

269

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

E-Print Network [OSTI]

emphasis has been placed on the research of basic technologies. As a result, a better understanding of ceramic materials performance under corrosive, high temperature conditions has been obtained. Various types of high temperature seals have been.... The Babcock & Wilcox lITBDR is a heat exchanger containing fifty sets of silicon carbide ceramic bayonet tubes of 3.5 in outer diameter set into an air cooled metallic tubesheet (see Figure 4). The outer tubes are siliconized silicon carbide while...

Richlen, S. L.

270

The sacrificial cathodic protection of UNS C71500 heat exchanger tubes in Arabian Gulf sea water  

SciTech Connect (OSTI)

A laboratory investigation using a specially designed circulating test rig was carried out to study the effectiveness of achieving complete cathodic protection of UNS C71500 heat exchanger tubes in seawater applications. Results indicated that the galvanic current distribution covered the entire 6m length of the tube. The presence of sulfide ions as pollutants in seawater shifted the galvanic potentials of the tubes to more active potentials and prevented the formation of protective films that normally form.

Al-Hashem, A.; Carew, J.A.; Al-Sayegh, A. [Kuwait Inst. for Scientific Research, Safat (Kuwait). Materials Application Dept.

1997-12-01T23:59:59.000Z

271

Study of junction flows in louvered fin round tube heat exchangers using the dye injection technique  

SciTech Connect (OSTI)

Detailed studies of junction flows in heat exchangers with an interrupted fin design are rare. However, understanding these flow structures is important for design and optimization purposes, because the thermal hydraulic performance of heat exchangers is strongly related to the flow behaviour. In this study flow visualization experiments were performed in six scaled-up models of a louvered fin round tube heat exchanger. The models have three tube rows in a staggered layout and differ only in their fin spacing and louver angle. A water tunnel was designed and built and the flow visualizations were carried out using dye injection. At low Reynolds numbers the streakline follows the tube contours, while at higher Reynolds numbers a horseshoe vortex is developed ahead of the tubes. The two resulting streamwise vortex legs are destroyed by the downstream louvers (i.e. downstream the turnaround louver), especially at higher Reynolds numbers, smaller fin pitches and larger louver angles. Increasing the fin spacing results in a larger and stronger horseshoe vortex. This illustrates that a reduction of the fin spacing results in a dissipation of vortical motion by mechanical blockage and skin friction. Furthermore it was observed that the vortex strength and number of vortices in the second tube row is larger than in the first tube row. This is due to the thicker boundary layer in the second tube row, and the flow deflection, which is typical for louvered fin heat exchangers. Visualizations at the tube-louver junction showed that in the transition part between the angled louver and the flat landing a vortex is present underneath the louver surface which propagates towards the angled louver. (author)

Huisseune, H.; Willockx, A.; De Paepe, M. [Department of Flow, Heat and Combustion Mechanics, Ghent University, Sint-Pietersnieuwstraat 41, 9000 Gent (Belgium); T'Joen, C. [Department of Flow, Heat and Combustion Mechanics, Ghent University, Sint-Pietersnieuwstraat 41, 9000 Gent (Belgium); Department Radiation, Radionuclides and Reactors, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands); De Jaeger, P. [Department of Flow, Heat and Combustion Mechanics, Ghent University, Sint-Pietersnieuwstraat 41, 9000 Gent (Belgium); NV Bekaert SA, Bekaertstraat 2, 8550 Zwevegem (Belgium)

2010-11-15T23:59:59.000Z

272

Advanced Alloys for Compact, High-Efficiency, High-Temperature Heat-Exchangers  

SciTech Connect (OSTI)

Oak Ridge National Laboratory (ORNL) has conducted research and development for several years which has been focused on the behavior and performance improvements of sheets and foils of various alloys for compact heat-exchangers (recuperators) for advanced microturbines. The performance and reliability of such thin sections are challenged at 650-750 C by fine grain size causing excessive creep, and by moisture effects greatly enhancing oxidation attack in exhaust gas environments. Standard 347 stainless steel has been used successfully at or below 600 C, but has suffered from both of these kinds of degradation at 650 C and above. Alloys have been identified which can have very good properties for such heat-exchangers, especially with careful control of microstructure during processing, including alloy 625, HR120 and the new AL20-25+Nb. These alloys, and the mechanistic understanding behind their behavior, are also applicable to achieving the better heat-exchanger technology needed for fuel cells or other high-temperature, clean-energy applications.

Maziasz, Philip J [ORNL; Pint, Bruce A [ORNL; Shingledecker, John P [ORNL; Evans, Neal D [ORNL; Yamamoto, Yukinori [ORNL; More, Karren Leslie [ORNL; Lara-Curzio, Edgar [ORNL

2006-01-01T23:59:59.000Z

273

Characteristics of Fluid flow and heat transfer in Shellside of Heat Exchangers with Longitudinal Flow of Shellside Fluid with Different Supporting structures  

Science Journals Connector (OSTI)

In the paper, a simplified numerical model-the periodic unit duct model was presented for the numerical simulation of shellside characteristics in heat exchanger with longitudinal flow of shellside fluid, and its...

Yongqing Wang; Qiwu Dong; Minshan Liu

2007-01-01T23:59:59.000Z

274

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

E-Print Network [OSTI]

Over the last three years ESDU have been working with engineers from oil companies and the companies that serve them in order to produce a guide describing the current state of knowledge on fouling in pre-heat trains and ways in which it can...

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

275

Combustion air preheating for refinery heaters using plate-type heat exchangers  

SciTech Connect (OSTI)

Combustion air preheating by recovering heat from combustion gases is a cost effective method of increasing the overall thermal efficiency of the refining and petrochemical processes. This paper presents the advantages of the plate-type air preheaters made of smooth plates without extended surfaces. These exchangers provide a relatively high heat transfer coefficient at a relatively low pressure drop, resulting in a flexible and compact design. The air preheater design can easily be integrated into the heater design. Top mounting with natural draft becomes possible for many applications, eliminating the need for I.D. fan and expensive ductwork. The economical extent of heat recovery function of the fuel fired is presented based on practical experience. The use of porcelain enameled (glass coated) plates and of stainless steel materials allows the operation of the air preheater below the acidic and water dew point. Finally the paper presents the experience of the Canadian refineries and petrochemical plants with plate-type heat exchangers used for combustion air preheating.

Dinulescu, M.

1987-01-01T23:59:59.000Z

276

A study of PV/T collector with honeycomb heat exchanger  

Science Journals Connector (OSTI)

This paper present a study of a single pass photovoltaic/thermal (PV/T) solar collector combined with honeycomb heat exchanger. A PV/T system is a combination of photovoltaic panel and solar thermal components in one integrated system. In order to enhance the performance of the system a honeycomb heat exchanger is installed horizontally into the channel located under the PV module. Air is used as the heat remover medium. The system is tested with and without the honeycomb at irradiance of 828 W/m2 and mass flow rate spanning from 0.02 kg/s to 0.13 kg/s. It is observed that the aluminum honeycomb is capable of enhancing the thermal efficiency of the system efficiently. At mass flow rate of 0.11 kg/s the thermal efficiency of the system without honeycomb is 27% and with honeycomb is 87 %. Throughout the range of the mass flow rate the electrical efficiency of the PV module improved by 0.1 %. The improved design is suitable to be further investigated as solar drying system and space heating.

F. Hussain; M. Y. H. Othman; B. Yatim; H. Ruslan; K. Sopian; Z. Ibarahim

2013-01-01T23:59:59.000Z

277

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

SciTech Connect (OSTI)

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.

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

2014-07-01T23:59:59.000Z

278

Compact design improves efficiency and CAPEX -- combining plate heat exchangers and gas-liquid separators for gas processing savings  

SciTech Connect (OSTI)

This paper presents the unique combination of two well proven technologies: a compact large scale welded plate heat exchanger with a gas-liquid separator within the same pressure vessel. Explained are the benefits for raw gas processing on production sites where cost, weight and efficiency are of particular importance. Application of this Combined Heat Exchanger-Separator is presented for various gas processing schemes: Turbo Expander, Mechanical Refrigeration and Joule-Thompson.

Waintraub, L.; Sourp, T. [Proser (France)

1998-12-31T23:59:59.000Z

279

Pool boiling heat transfer enhancement over cylindrical tubes with water at atmospheric pressure, Part I: Experimental results  

E-Print Network [OSTI]

Pool boiling heat transfer enhancement over cylindrical tubes with water at atmospheric pressure online 4 May 2013 Keywords: Pool boiling Heat transfer enhancement Open microchannels Cylindrical tube boiling heat transfer over enhanced cylindrical microchannel test surfaces with water at atmospheric

Kandlikar, Satish

280

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

SciTech Connect (OSTI)

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)

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

2012-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

High Performance Trays and Heat Exchangers in Heat Pumped Distillation Columns  

E-Print Network [OSTI]

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

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

1981-01-01T23:59:59.000Z

282

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

DOE Patents [OSTI]

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.

Garrison, M.E.

1982-09-03T23:59:59.000Z

283

Numerical and experimental investigation of buoyancy effects in a plate heat exchanger  

Science Journals Connector (OSTI)

This paper presents an experimental and numerical investigation of the hydrodynamic and thermal fields in a two-channel chevron-type plate heat exchanger (PHE) under mixed convection conditions. Eight pairs of experiments were performed, with water on both sides, with Reynolds number varying between approximately 100 and 400. Each pair consisted of two experiments: one with aiding mixed convection and the other with opposing mixed convection conditions. The temperature distributions on the end-plates, the outlet temperatures, the heat flux and the Nusselt number obtained in the two positions of the PHE were compared. A validation of the numerical model in this flow regime has been made in order to analyze numerically the pressure losses and the flow structure. Comparisons of the experimental data obtained for the fluid outlet temperatures, heat transfer rate and Nusselt number showed that the heat transfer is improved under aiding mixed convection conditions. The numerical data analysis shows that opposing mixed convection deteriorates the symmetry of the flow distribution inside the PHE's channels and that aiding buoyancy forces cause higher pressure losses.

Iulian Gherasim; Matthew Taws; Nicolas Galanis; Cong Tam Nguyen

2013-01-01T23:59:59.000Z

284

Parametric sensitivity study of operating and design variables in wellbore heat exchangers  

Science Journals Connector (OSTI)

A numerical study was conducted to evaluate the potential for using Wellbore Heat Exchangers (WBHX) to extract heat for use in electricity generation. Variables studied included operational parameters such as wellbore geometries, working fluid properties, circulation rates, and regional properties including basal heat flux and formation rock type. Energy extraction is strongly affected by fluid residence time, heat transfer contact area, and formation thermal properties. Water appears to be the most appropriate working fluid. The effects of tubing properties and casing lengths are of second-order. On the basis of a sensitivity study, a Best Case model was simulated, and results compared against the geothermal fluid requirements of existing power generation plants that use low-temperature geothermal fluids. Even assuming ideal work conversion to electricity, a WBHX cannot supply sufficient energy to generate 200kWe at the onset of pseudo-steady-state (PSS) conditions. Using realistic conversion efficiencies it is unlikely that the system would be able to generate 50kWe at the onset of PSS.

Gopi Nalla; G. Michael Shook; Gregory L. Mines; K. Kit Bloomfield

2005-01-01T23:59:59.000Z

285

EHD-based load controllers for \\{R134a\\} convective boiling heat exchangers  

Science Journals Connector (OSTI)

Abstract The objective of this study is to investigate the application of high voltage DC waveforms as a mechanism of load control for convective boiling systems. Electrohydrodynamics (EHD) induces flow pattern redistribution, which directly influences the system performance. EHD can provide a low power (<1W), fast responding method of enhancing two phase flow systems such as heat exchangers. This study compares the use of EHD for load control with control via changing the refrigerant side flow rate in terms of required power, response time and effect on flow parameters. It was found that EHD responds faster and requires less power when a constant exit condition is required for the heat exchanger. Two EHD based controllers; PI controller and a Smith predictor were established using LabVIEW and compared in terms of their response time and regulation behaviour subject to dynamic loading. The Smith predictor resulted in less overshoot and approximately a 50% reduction in settling time in response to dynamic loading. It has been shown that this EHD based controller can regulate subject to 25% deviation in load from the designed steady state load condition.

S. Nangle-Smith; J.S. Cotton

2014-01-01T23:59:59.000Z

286

Pilot scale ultrasound enabled plate heat exchanger its design and potential to prevent biofouling  

Science Journals Connector (OSTI)

Abstract A pilot scale 100-150 L/h plate heat exchanger (PHE) was retrofitted with ultrasound transducers without changing the main PHE design. The ultrasound enabled PHE (UPHE) and parallel split stream reference PHE (RPHE) were used to investigate the potential of ultrasound to prevent biofouling during processing of cheese milk inoculated with 103 CFU/mL Streptococcus thermophilus (TRS). Scanning laser vibrometry measurements showed that, for a 15-plate package, ultrasound conditions of 20 kHz and 70 W produced vibration magnitudes in the range of 500 1200 nm, corresponding to the size of the TRS. In one experiment, application of these ultrasound conditions was found to delay the onset of increase in product outlet TRS concentration by 3 h compared to the RPHE. Application of conditions where only micro-streaming occurred showed no effect on biofouling. The experimental result is a first indication that surface vibrations of the same order magnitude as the adhering microorganism may be a mechanism by which ultrasound can prevent biofouling in plate heat exchangers.

Natalie E. Hotrum; Peter de Jong; J. Coen Akkerman; Martijn B. Fox

2014-01-01T23:59:59.000Z

287

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

SciTech Connect (OSTI)

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.

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

2012-10-01T23:59:59.000Z

288

Laser heating of aqueous samples on a micro-optical-electro-mechanical system  

DOE Patents [OSTI]

A system of heating a sample on a microchip includes the steps of providing a microchannel flow channel in the microchip; positioning the sample within the microchannel flow channel, providing a laser that directs a laser beam onto the sample for heating the sample; providing the microchannel flow channel with a wall section that receives the laser beam and enables the laser beam to pass through wall section of the microchannel flow channel without being appreciably heated by the laser beam; and providing a carrier fluid in the microchannel flow channel that moves the sample in the microchannel flow channel wherein the carrier fluid is not appreciably heated by the laser beam.

Beer, Neil Reginald; Kennedy, Ian

2013-02-05T23:59:59.000Z

289

Separation process using microchannel technology  

DOE Patents [OSTI]

The disclosed invention relates to a process and apparatus for separating a first fluid from a fluid mixture comprising the first fluid. The process comprises: (A) flowing the fluid mixture into a microchannel separator in contact with a sorption medium, the fluid mixture being maintained in the microchannel separator until at least part of the first fluid is sorbed by the sorption medium, removing non-sorbed parts of the fluid mixture from the microchannel separator; and (B) desorbing first fluid from the sorption medium and removing desorbed first fluid from the microchannel separator. The process and apparatus are suitable for separating nitrogen or methane from a fluid mixture comprising nitrogen and methane. The process and apparatus may be used for rejecting nitrogen in the upgrading of sub-quality methane.

Tonkovich, Anna Lee (Dublin, OH); Perry, Steven T. (Galloway, OH); Arora, Ravi (Dublin, OH); Qiu, Dongming (Bothell, WA); Lamont, Michael Jay (Hilliard, OH); Burwell, Deanna (Cleveland Heights, OH); Dritz, Terence Andrew (Worthington, OH); McDaniel, Jeffrey S. (Columbus, OH); Rogers, Jr.; William A. (Marysville, OH); Silva, Laura J. (Dublin, OH); Weidert, Daniel J. (Lewis Center, OH); Simmons, Wayne W. (Dublin, OH); Chadwell, G. Bradley (Reynoldsburg, OH)

2009-03-24T23:59:59.000Z

290

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

SciTech Connect (OSTI)

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.

Im, Piljae [ORNL] [ORNL; Hughes, Patrick [ORNL] [ORNL; Liu, Xiaobing [ORNL] [ORNL

2012-01-01T23:59:59.000Z

291

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

SciTech Connect (OSTI)

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

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

1991-01-01T23:59:59.000Z

292

Direct contact liquid-liquid heat exchanger for solar heated and cooled buildings. Final report, January 1, 1979-May 30, 1980  

SciTech Connect (OSTI)

The technical and economic feasibility of using a direct contact liquid-liquid heat exchanger (DCLLHE) storage unit in a solar heating and cooling system is established. Experimental performance data were obtained from the CSU Solar House I using a DCLLHE for both heating and cooling functions. A simulation model for the system was developed. The model was validated using the experimental data and applied in five different climatic regions of the country for a complete year. The life-cycle cost of the system was estimated for each application. The results are compared to a conventional solar system, using a standard shell-and-tube heat exchanger. It is concluded that while thare is a performance advantage with a DCLLHE system over a conventional solar system, the advantage is not sufficiently large to overcome slightly higher capital and operating costs for the DCLLHE system.

Karaki, S.; Brothers, P.

1980-06-01T23:59:59.000Z

293

Direct contact liquid-liquid heat exchanger for solar-heated and -cooled buildings. Final report, January 1, 1979-May 30, 1980  

SciTech Connect (OSTI)

The procedure used was to obtain experimental performance data from a solar system using a DCLLHE for both heating and cooling functions, develop a simulation model for the system, validate the model using the data, apply the model in five different climatic regions of the country for a complete year, and estimate the life-cycle cost of the system for each application. The results are compared to a conventional solar system, using a standard shell-and-tube heat exchanger.

Karaki, S.; Brothers, P.

1980-06-01T23:59:59.000Z

294

Reply to Comment on Heat transfer and fluid flow in microchannels and nanochannels at high Knudsen number using thermal lattice-Boltzmann method  

Science Journals Connector (OSTI)

In this reply to the Comment by Li-Shi Luo, we discuss the results of the lattice Bhatnagar-Gross-Krook (LBGK) model for high-Knudsen-number (Kn) flow and heat transfer, in the range of Kn?1. We present various studies employing the LBGK model for high-Kn flow and heat transfer simulations. It is concluded that, with the use of the LBGK model in the thermal lattice Boltzmann method for Kn?0.8, some approximations appear in the negative pressure deviation from the linear distribution along the channel. But for Kn<0.8, the velocity and temperature profiles, compressibility effects, Knudsen layer capturing, and Knudsen paradox phenomenon can be predicted by the LBGK model. We also reject Li-Shi Luos claim about the nonconvergence of our numerical scheme by presenting a velocity profile across the channel corresponding to three different high-resolution meshes.

J. Ghazanfarian and A. Abbassi

2011-10-25T23:59:59.000Z

295

Experimental and numerical investigation on air-side performance of fin-and-tube heat exchangers with various fin patterns  

SciTech Connect (OSTI)

Air-side heat transfer and friction characteristics of five kinds of fin-and-tube heat exchangers, with the number of tube rows (N = 12) and the diameter of tubes (D{sub o} = 18 mm), have been experimentally investigated. The test samples consist of five types of fin configurations: crimped spiral fin, plain fin, slit fin, fin with delta-wing longitudinal vortex generators (VGs) and mixed fin with front 6-row vortex-generator fin and rear 6-row slit fin. The heat transfer and friction factor correlations for different types of heat exchangers were obtained with the Reynolds numbers ranging from 4000 to 10000. It was found that crimped spiral fin provides higher heat transfer and pressure drop than the other four fins. The air-side performance of heat exchangers with the above five fins has been evaluated under three sets of criteria and it was shown that the heat exchanger with mixed fin (front vortex-generator fin and rear slit fin) has better performance than that with fin with delta-wing vortex generators, and the slit fin offers best heat transfer performance at high Reynolds numbers. Based on the correlations of numerical data, Genetic Algorithm optimization was carried out, and the optimization results indicated that the increase of VG attack angle or length, or decrease of VG height may enhance the performance of vortex-generator fin. The heat transfer performances for optimized vortex-generator fin and slit fin at hand have been compared with numerical method. (author)

Tang, L.H.; Zeng, M.; Wang, Q.W. [State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049 (China)

2009-07-15T23:59:59.000Z

296

Multiple pollutant removal using the condensing heat exchanger. Task 2, Pilot scale IFGT testing  

SciTech Connect (OSTI)

The purpose of Task 2 (IFGT Pilot-Scale Tests at the B&W Alliance Research Center) is to evaluate the emission reduction performance of the Integrated flue Gas Treatment (IFGT) process for coal-fired applications. The IFGT system is a two-stage condensing heat exchanger that captures multiple pollutants - while recovering waste heat. The IFGT technology offers the potential of a addressing the emission of SO{sub 2} and particulate from electric utilities currently regulated under the Phase I and Phase II requirements defined in Title IV, and many of the air pollutants that will soon be regulated under Title III of the Clean Air Act. The performance data will be obtained at pilot-scale conditions similar to full-scale operating systems. The task 2 IFGT tests have been designed to investigate several aspects of IFGT process conditions at a broader range of variable than would be feasible at a larger scale facility. The performance parameters that will be investigated are as follows: SO{sub 2} removal; particulate removal; removal of mercury and other heavy metals; NO{sub x} removal; HF and HCl removal; NH{sub 3} removal; ammonia-sulfur compounds generation; and steam injection for particle removal. For all of the pollutant removal tests, removal efficiency will be based on measurements at the inlet and outlet of the IFGT facility. Heat recovery measurements will also be made during these tests to demonstrate the heat recovery provided by the IFGT technology. This report provides the Final Test Plan for the first coal tested in the Task 2 pilot-scale IFGT tests.

Jankura, B.J.

1996-01-01T23:59:59.000Z

297

Cooling power of the dilution refrigerator with a perfect continuous counterflow heat exchanger  

Science Journals Connector (OSTI)

The model of the perfect continuous counterflow heat exchanger introduced by Frossati et al. to describe the performance of dilution refrigerators is solved rigorously with the proper boundary condition. Unlike the original solution by Frossati et al. the present solution gives the refrigerator cooling power which is in good agreement with experimental data over the entire temperature range. The analysis of the cooling power using the present result allows more detailed evaluation of the refrigerator performance than has been possible with the analysis of the base temperature. An approximate expression for the cooling power is discussed which simplifies the prediction of the cooling rate of a large thermal load such as a copper nuclear?demagnetization stage.

Y. Takano

1994-01-01T23:59:59.000Z

298

Marine microfouling on aluminum and titanium heat exchanger surfaces at the CEER OTEC Puerto Rico facility  

SciTech Connect (OSTI)

Since 30 January, 1980, an OTEC biofouling experiment has been in progress off the southeast coast of Puerto Rico. The initiation and accumulation of microfouling on aluminum and titanium surfaces has been analyzed over a period of 143 days. Microfouling was assessed by determining the surface residue weight, organic carbon and nitrogen contents of this residue, the wet film thickness and the ATP content of this film. The development of biofouling on the aluminum and titanium surfaces appears to be different with respect to the relationship seen between biomass cycle and the bulk growth of the wet film on the respective surfaces. The increase in thermal resistance (R /SUB f/ ) of the aluminum and titanium heat exchanger tubes during the period of this experiment is correlated with the increase in the wet film volume associated with these test surfaces.

Tosteson, T.R.; Axtmayer, R.W.; Ballantine, D.L.; Imam, S.; Morgon, T.; Revuelta, R.; Sasscer, D.S.; Zaidi, B.R.

1980-12-01T23:59:59.000Z

299

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

SciTech Connect (OSTI)

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 700C. 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 850C 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.

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

2014-10-01T23:59:59.000Z

300

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

E-Print Network [OSTI]

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 ...

McCarthy, Matthew

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

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

E-Print Network [OSTI]

of the air. Ground water is a better heat source/sink for heat pump application (due to its superior thermal to extract heat from or reject heat to the environment. The majority of heat pumps use ambient air as the heat source and sink for a heat pump. Extensive research on horizontal ground coupled heat pump systems

Oak Ridge National Laboratory

302

Reformate Cleanup: The Case for Microchannel Architecture  

E-Print Network [OSTI]

Reformate Cleanup: The Case for Microchannel Architecture DOE Hydrogen and Fuel Cells 2003 Annual for MicrochannelMicrochannel ArchitectureArchitecture DOE Hydrogen and Fuel CellsDOE Hydrogen and Fuel Cells 2003, controls Integrated reformer/fuel cell demonstration at ~2 kWeFY 2002 WGS/PROX catalyst studies

303

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

SciTech Connect (OSTI)

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.

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

2011-07-14T23:59:59.000Z

304

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

SciTech Connect (OSTI)

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

Bimal Kad

2011-12-31T23:59:59.000Z

305

Technical Information Exchange on Pyrolysis Oil: Potential for a Renewab;e Heating Oil Substation Fuel in New England  

Broader source: Energy.gov [DOE]

This report summarizes the results of an information exchange sponsored by the DOE/EERE Bioenergy Technologies Office in Manchester, New Hampshire, on May 9-10, 2012. The participand identifies top challenges regarding feedstocks and production, logistics and compatibility, and operational issues, then prioritized next steps for expanding use of pyrolysis oil as a replacement for home heating oil in the Northeast

306

Comparison between a spray column and a sieve tray column operating as liquid-liquid heat exchangers  

SciTech Connect (OSTI)

The performance of a spray column and a sieve tray column was compared as a liquid-liquid heat exchanger. In carrying out these studies a 15.2 cm (6.0 in.) diameter column, 183 cm (6.0 ft) tall was utilized. The performance of the spray column as a heat exchanger was shown to correlate with the model of Letan-Kehat which has as a basis that the heat transfer is dominated by the wakeshedding characteristics of the drops over much of the column length. This model defines several hydrodynamic zones along the column of which the wake formation zone at the bottom appears to have the most efficient heat transfer. The column was also operated with four perforated plates spaced two column diameters apart in order to take advantage of the wake formation zone heat transfer. The plates induce coalescence of the dispersed phase and reformation of the drops, and thus cause a repetition of the wake formation zone. It is shown that the overall volumetric heat transfer coefficient in a perforated plate column is increased by a minimum of eleven percent over that in a spray column. A hydrodynamic model that predicts the performance of a perforated plate column is suggested.

Keller, A.; Jacobs, H.R.; Boehm, R.F.

1980-12-01T23:59:59.000Z

307

Prediction and measurement of pitting damage functions for condensing heat exchangers  

SciTech Connect (OSTI)

Pitting corrosion is a form of localized attack resulting in rapid penetration into a metal substrate. It is one of the most destructive and insidious forms of corrosion that occurs in industrial systems. Traditionally, the damage function (i.e., the number of pits vs the pit depth) is measured experimentally, and the development of damage has been described using empirical models. In general, the empirical models are successful because the distribution functions employed display great mathematical flexibility, but they require a significant database to achieve reliability. In fact, they really are successful only when the answer is known in advance. In this study, a deterministic method was developed to predict localized corrosion damage functions for condensing heat exchangers. The method incorporated calculations for the composition of the condensed environment and the electrochemical corrosion potential (E[sub corr]) of the alloy and included mechanistic treatments of pit nucleation and growth. The roles of important environmental parameters such as chloride concentration ([Cl[sup [minus

Macdonald, D.D.; Liu, C.; Urquidi-Macdonald, M. (Pennsylvania State Univ., University Park, PA (United States). Center for Advanced Materials); Stickford, G.H.; Hindin, B.; Agrawal, A.K. (Battelle Columbus Labs., Columbus, OH (United States)); Krist, K. (Gas Research Inst., Chicago, IL (United States))

1994-10-01T23:59:59.000Z

308

Standard practice for in situ examination of ferromagnetic Heat-Exchanger tubes using remote field testing  

E-Print Network [OSTI]

1.1 This practice describes procedures to be followed during remote field examination of installed ferromagnetic heat-exchanger tubing for baseline and service-induced discontinuities. 1.2 This practice is intended for use on ferromagnetic tubes with outside diameters from 0.500 to 2.000 in. [12.70 to 50.80 mm], with wall thicknesses in the range from 0.028 to 0.134 in. [0.71 to 3.40 mm]. 1.3 This practice does not establish tube acceptance criteria; the tube acceptance criteria must be specified by the using parties. 1.4 UnitsThe values stated in either inch-pound units or SI units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this practice to establ...

American Society for Testing and Materials. Philadelphia

2010-01-01T23:59:59.000Z

309

Corrosion resistant coatings for silicon carbide heat exchanger tubes -- Volume 3. Final report  

SciTech Connect (OSTI)

The development of a silicon carbide (SiC) heat exchanger is a critical step in the development of the Externally-Fired Combined Cycle (EFCC) power system. SiC is the only material that provides the necessary combination of resistance to creep, thermal shock, and oxidation. While the SiC structure materials provide the thermomechanical and thermophysical properties needed for an efficient system, the mechanical properties of the SiC tubes are severely degraded through corrosion by the coal combustion products. To obtain the necessary service life of thousands of hours at temperature, a protective coating is needed that is stable with both the SiC tube and the coal combustion products, resists erosion from the particle laden gas stream, is thermal shock resistant, adheres to SiC during repeated thermal shocks (start-up, process upsets, shut-down), and allows the EFCC system to be cost competitive. This demanding set of technical performance and cost drivers was used in reviewing and selecting candidate protective materials. After a review of open literature, discussion with leading researchers in materials for coal combustion environments, and preliminary thermodynamic studies, a total of ten materials were identified for future study that were grouped into three categories: alumina-based materials, materials stable with SiO{sub 2}, and low expansion materials.

Boss, D.E.

1996-06-07T23:59:59.000Z

310

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

E-Print Network [OSTI]

was wrapped in insulation (a soft closed cell foam such asfoam before the entire exchanger was wrapped in insulation.

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

2012-01-01T23:59:59.000Z

311

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

SciTech Connect (OSTI)

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.

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

2007-01-01T23:59:59.000Z

312

Numerical Investigation on the Heat Transfer Enhancement Using Micro/Nano Phase-Change Particulate Flow.  

E-Print Network [OSTI]

??The introduction of phase change material fluid and nanofluid in micro-channel heat sink design can significantly increase the cooling capacity of the heat sink because (more)

Xing, Keqiang

2007-01-01T23:59:59.000Z

313

Volume Averaging Theory (VAT) based modeling and closure evaluation for fin-and-tube heat exchangers  

E-Print Network [OSTI]

made to simulate the heat transfer and fluid flow across theanalysis of heat transfer and fluid flow in a three-lent flow and heat transfer in a porous layer. J Fluids Eng

Zhou, Feng; Catton, Ivan

2012-01-01T23:59:59.000Z

314

Development of Closure for Heat Exchangers Based on Volume Averaging Theory  

E-Print Network [OSTI]

Analysis of Fluid Flow and Heat Transfer Characteristics inFigure 4.16: Fluid flow and heat transfer over a backwardof modeling the fluid flow and heat transfer within such

Zhou, Feng

2014-01-01T23:59:59.000Z

315

Development of Closure for Heat Exchangers Based on Volume Averaging Theory  

E-Print Network [OSTI]

Optimization for Pin-Fin Heat Sinks," Journal of ElectronicConvection," Journal of Heat Transfer, 115(1), pp. 75-81. [of spheres," Proc. 28th National Heat Transfer Conference,

Zhou, Feng

2014-01-01T23:59:59.000Z

316

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

E-Print Network [OSTI]

) Included in this reaction is the decomposition of methanol, which produces CO: CH3OH CO + 2H2 (90.5 kJ mol a picture of the methanol reformer which has been designed to produce hydrogen for a 1 kWe HTPEM fuel cellExperimental Evaluation of a Pt-based Heat Exchanger Methanol Reformer for a HTPEM Fuel Cell Stack

Berning, Torsten

317

NUMERICAL SIMULATION OF HEAT TRANSFER AND PRESSURE DROP IN PLATE HEAT EXCHANGERS USING FLUENT AS CFD TOOL.  

E-Print Network [OSTI]

??Corrugated walls are commonly used as passive devices for heat and mass transfer enhancement, being most effective in applications operated at transitional and turbulent Reynolds (more)

EGEREGOR, DAFE

2008-01-01T23:59:59.000Z

318

Lab-scale Experimentation and CFD Modeling of a Small Particle Heat Exchange Receiver  

Science Journals Connector (OSTI)

Abstract Concentrating solar power currently relies on high temperature central receivers that utilize liquid cooling and operate in power steam cycles. However, highly efficient central receivers are being designed to operate at higher temperatures in a gas turbine power cycle. To address this, San Diego State University's (SDSU) Combustion and Solar Energy Laboratory is experimenting with a lab-scale Small Particle Heat Exchange Receiver (SPHER) in order to understand performance and develop experience for designing and operating a full-scale 5 MW design. The full-scale design will be tested at the National Solar Thermal Test Facility at Sandia National Laboratories as part of the Department of Energy SunShot Initiative grant. The SPHER relies on carbon nanoparticles as an absorption medium and air as a working fluid. The carbon particles are generated onsite by the Carbon Particle Generator (CPG) and are mixed with dilution air prior to entering the SPHER. Lab scale on-sun testing is carried out with a 15kWe solar simulator. The lab scale experimental goal is to achieve an outlet flow of 650C at 5bar absolute operating pressure. To model the performance of the SPHER, CFD analysis is being used for comparison to lab scale testing. The lab scale SPHER is being modeled in ANSYS Fluent with coupled codes for oxidation and radiation input. In this paper, we present results of testing the lab-scale receiver and compare the measured outlet temperatures to predictions from the computer model. Finally, correlations are drawn for future experimenation and feasibility.

L. Frederickson; M. Dordevich; F. Miller

2014-01-01T23:59:59.000Z

319

In situ heat exchanger tube fouling thickness measurements using ultrasonics. Final report on a laboratory feasibility study  

SciTech Connect (OSTI)

The growth of fouling layers on heat exchanger surfaces and the corrosion of heat exchanger materials exposed to seawater have been recognized since the beginning of OTEC research as basic problems which could render the concept uneconomical. Consequently, a significant effort has been directed toward predicting, measuring, identifying, explaining and solving potential biofouling and corrosion phenomena. To address this problem, the feasibility of establishing a practical microacoustic technique to measure fouling film thickness in situ on typical OTEC heat exchanger tasks was studied. Seven techniques were studied for this application, including velocity measurements, acoustic diffraction, acoustic interferometer, Doppler flow velocity, pulse echo, critical angle, and surface (shear) wave effects. Of these, the latter five were laboratory tested using conventional microacoustic system components in various configuratons. Only the pulse echo technique yielded promising results. On fouled aluminum plates, thin film layers of 40 ..mu..m and greater were measured using a focused 30 MHz ceramic transducer operated at 25 MHz; this represents a resolution of about 2/3 wavelength. Measurements made on the inside of fouled 1'' aluminum pipes yielded film thicknesses of 75 to 125 ..mu..m. The thinnest layer resolved was approximately 1-1/4 wavelength. The resolution of slime layer thicknesses in the magnitudes of OTEC interest (5 to 30 ..mu..m) using pulse echo microacoustics will require transducer development. In particular, a higher operating frequency (150 to 200 MHz) and advanced material construction is recommended for further research.

Hirshman, J; Munier, R S.C.

1980-09-01T23:59:59.000Z

320

Microchannel High-Temperature Recuperator for Fuel Cell Systems...  

Office of Environmental Management (EM)

Microchannel High-Temperature Recuperator for Fuel Cell Systems - Fact Sheet, 2014 Microchannel High-Temperature Recuperator for Fuel Cell Systems - Fact Sheet, 2014 FuelCell...

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Hybrid slab-microchannel gel electrophoresis system  

DOE Patents [OSTI]

A hybrid slab-microchannel gel electrophoresis system. The hybrid system permits the fabrication of isolated microchannels for biomolecule separations without imposing the constraint of a totally sealed system. The hybrid system is reusable and ultimately much simpler and less costly to manufacture than a closed channel plate system. The hybrid system incorporates a microslab portion of the separation medium above the microchannels, thus at least substantially reducing the possibility of non-uniform field distribution and breakdown due to uncontrollable leakage. A microslab of the sieving matrix is built into the system by using plastic spacer materials and is used to uniformly couple the top plate with the bottom microchannel plate.

Balch, Joseph W. (Livermore, CA); Carrano, Anthony V. (Livermore, CA); Davidson, James C. (Livermore, CA); Koo, Jackson C. (San Ramon, CA)

1998-01-01T23:59:59.000Z

322

Distillation process using microchannel technology  

DOE Patents [OSTI]

The disclosed invention relates to a distillation process for separating two or more components having different volatilities from a liquid mixture containing the components. The process employs microchannel technology for effecting the distillation and is particularly suitable for conducting difficult separations, such as the separation of ethane from ethylene, wherein the individual components are characterized by having volatilities that are very close to one another.

Tonkovich, Anna Lee (Dublin, OH); Simmons, Wayne W. (Dublin, OH); Silva, Laura J. (Dublin, OH); Qiu, Dongming (Carbondale, IL); Perry, Steven T. (Galloway, OH); Yuschak, Thomas (Dublin, OH); Hickey, Thomas P. (Dublin, OH); Arora, Ravi (Dublin, OH); Smith, Amanda (Galloway, OH); Litt, Robert Dwayne (Westerville, OH); Neagle, Paul (Westerville, OH)

2009-11-03T23:59:59.000Z

323

Multiple pollutant removal using the condensing heat exchanger: Phase 1 final report, November 1995--June 1997. Addendum 2: Task 3 topical report -- Long term wear test  

SciTech Connect (OSTI)

Long-term operation of a condensing heat exchanger under typical coal-fired flue gas conditions was investigated in Phase 1, Task 3 of the Multiple Pollutant Removal Using the Condensing Heat Exchanger test program. The specific goal of this task was to determine the amount of wear, if any, on the Teflon{reg_sign}-covered heat transfer tubes in a condensing heat exchanger. A pilot-scale single-stage condensing heat exchanger (CHX{reg_sign}) was operated under typical coal-fired flue gas conditions on a continuous basis for a period of approximately 10 months. Operating conditions and particulate loadings for the test unit were monitored, Teflon{reg_sign} film thickness measurements were conducted, and surface replications (which duplicate the surface finish at the microscopic level) were taken at various times during the test. 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 (400 mg/dscm [0.35 lb/10{sup 6} Btu]). Evidence of wear was present only at the microscopic level, and even then was very minor in severity. Operation at high inlet particulate loadings resulted in accumulated ash deposits within the heat exchanger. Installation of a modified (higher flow rate) wash nozzle manifold substantially reduced subsequent deposit formation.

Kudlac, G.A.

1998-06-01T23:59:59.000Z

324

Design study of a coal-fired thermionic (THX) topped power plant. Volume IV. Thermionic heat exchanger design and costing  

SciTech Connect (OSTI)

This volume deals with the details of how thermionic conversion works, and how it is used in a coal-fired furnace to achieve power plant efficiencies of 45%, and overall costs of 36.3 mills/kWh. A review of the fundamental technical aspects of thermionic conversion is given. The overall Thermionic Heat Exchanger (THX) design, the heat pipe design, and the interaction of the heat pipes with the furnace are presented. Also, the operational characteristics of thermionic converters are described. Details on the computer program used to perform the parametric study are given. The overall program flow is reviewed along with the specifics of how the THX subroutine designed the converter to match the conditions imposed. Also, input costs and variables effecting the THX's performance are detailed. The efficiencies of the various power plants studied are given as a function of the air preheat temperature, size of the power plant, and thermionic level of performance.

Dick, R.S.; Britt, E.J.

1980-10-15T23:59:59.000Z

325

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

SciTech Connect (OSTI)

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 (750800 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/1.02.7 MPa for the cold side and 208790 C/1.02.7 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.

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

2014-04-01T23:59:59.000Z

326

Fluidized bed steam reactor including two horizontal cyclone separators and an integral recycle heat exchanger  

SciTech Connect (OSTI)

A reactor is described comprising: a vessel; a first furnace section disposed in said vessel; a second furnace section disposed in said vessel; means in each of said furnace sections for receiving a combustible fuel for generating heat and combustion gases; a first heat recovery area located adjacent said furnace sections; a second heat recovery area located adjacent said furnace sections; means for passing said combustion gases from said first furnace section to said first heat recovery area; and means for passing said combustion gases from said second furnace section to said second heat recovery area.

Gorzegno, W.P.

1993-06-15T23:59:59.000Z

327

Energy savings and cost-effectiveness of heat exchanger use as an indoor air quality mitigation measure in the BPA weatherization program  

Science Journals Connector (OSTI)

The Bonneville Power Administration (BPA) has proposed a ten year program to encourage the weatherization of electrically heated homes in the Pacific Northwest. The purpose of this program is to reduce residential electrical energy demand for space heating. If air infiltration rates are reduced by employing house tightening measures, indoor air quality mitigation measures may be required in residences with significant sources of indoor air contaminants. The use of residential air-to-air heat exchangers has been proposed as a possible strategy to assure that indoor air quality is not substantially degraded by house tightening. We examine the energy impact and cost effectiveness of heat exchanger utilization in tightened homes in the BPA region. Significant energy savings are predicted if homes are tightened and heat exchangers are utilized. From the homeowner's perspective, the results of our economic analysis indicate that, at the relatively low residential electric rates in the BPA region, the use of heat exchangers in existing homes that are tightened is not economically viable. On the other hand, from the utility perspective, it may be cost effective to use heat exchangers in the weatherization program if the marginal cost to the utility is compared with the cost of conserved energy.

Isaac Turiel; William J. Fisk; Mark Seedall

1983-01-01T23:59:59.000Z

328

Determination of fouling factors for shell-and-tube type heat exchangers exposed to Los Azufres geothermal fluids  

SciTech Connect (OSTI)

According to the latest estimates, there are about 1500 geothermal sites in Mexico, ninety percent of which can probably produce low enthalpy fluids only. Hot water discarded from geothermal flash plants adds to this stock which represents a considerable source of thermal energy. Its utilization for direct industrial applications or electricity generation through binary cycles requries heat exchangers. The IIE, with the financial support and technical cooperation of CFE, has for some time been experimenting with heaters of different types subject to geothermal brines. This paper describes the work done to date and the preliminary results obtained.

Hernandez-Galan, J.L. (Instituto de Investigaciones Electricas, Dante 36-6, 11590 Mexico City (MX)); Plauchu, A.L. (Geothermal Plants Design and Construction Mgr., CFE, AV. Camelinas 3527, Morelia, Mich., 58270 (MX))

1989-01-01T23:59:59.000Z

329

Cross-Roll Flow Forming of ODS Alloy Heat Exchanger Tubes for Hoop Creep Enhancement  

SciTech Connect (OSTI)

Mechanically alloyed oxide dispersion strengthened (ODS) Fe-Cr-Al alloy thin walled tubes and sheets, produced via powder processing and consolidation methodologies, are promising materials for eventual use at temperatures up to 1200 C in the power generation industry, far above the temperature capabilities of conventional alloys. Target end-uses range from gas turbine combustor liners to high aspect ratio (L/D) heat exchanger tubes. Grain boundary creep processes at service temperatures, particularly those acting in the hoop direction, are the dominant failure mechanisms for such components. The processed microstructure of ODS alloys consists of high aspect ratio grains aligned parallel to the tube axis, a result of dominant axial metal flow which aligns the dispersoid particles and other impurities in the longitudinal direction. The dispersion distribution is unaltered on a micro scale by recrystallization thermal treatments, but the high aspect ratio grain shape typically obtained limits transverse grain spacing and consequently the hoop creep response. Improving hoop creep in ODS-alloy components will require understanding and manipulating the factors that control the recrystallization behavior, and represents a critical materials design and development challenge that must be overcome in order to fully exploit the potential of ODS alloys. The objectives of this program are to (1) increase creep-strength at temperature in ODS-alloy tube and liner components by 100% via, (2) preferential cross-roll flow forming and grain/particle fibering in the critical hoop direction. The research program outlined here is iterative in nature and is intended to systematically (1) examine and identify post-extrusion forming methodologies to create hoop strengthened tubes, which will be (2) evaluated at ''in-service'' loads at service temperatures and environments. This research program is being conducted in collaboration with the DOE's Oak Ridge National Laboratory and the vested industrial partner Special Metals Corporation. In this ninth quarter of performance, program activities are continued for Tasks 2, 3 and 4 and are reported herein. Two sets of MA956 tube material samples rotary crossrolled at rolling angles of {beta} = 2{sup o} and 8{sup o} are processed in Task 3 and available for mechanical property testing in the remainder of this project. These samples are at various stages of creep testing and evaluation in Task 4. The creep rigs are being upgraded to handle long term testing at 1000 C and above. Reduced test times at accelerated temperatures will allow for additional testes to be conducted resulting in overall robust creep data statistics. The creep performance enhancement in cross-rolled MA956 material samples versus the base creep property is elucidated. Additional creep enhancements are derived when flow formed tubes are flattened at 900 C and recrystallized. The Larsen-Miller parameter for the improvised thermo-mechanical processing now approaches 52. At least 2-3 orders of magnitude of improvement in creep rates/day are demonstrated for the cross-rolled samples versus the base reference tests.

Bimal K. Kad

2006-04-10T23:59:59.000Z

330

Micro and nanostructured surfaces for enhanced phase change heat transfer  

E-Print Network [OSTI]

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, ...

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

2013-01-01T23:59:59.000Z

331

EulerianEulerian two-phase numerical simulation of nanofluid laminar forced convection in a microchannel  

E-Print Network [OSTI]

by a cooling system to guarantee their appropriate performance. One possible way to cool these devises canEulerian­Eulerian two-phase numerical simulation of nanofluid laminar forced convection August 2010 Accepted 5 August 2010 Keywords: Nanofluid Microchannel Two-phase Laminar Heat transfer a b

Harting, Jens

332

Experimental and thermodynamical analyses of the diesel exhaust vortex generator heat exchanger for optimizing its operating condition  

Science Journals Connector (OSTI)

Abstract In this research, a vortex generator heat exchanger is used to recover exergy from the exhaust of an OM314 diesel engine. Twenty vortex generators with 30 angle of attack are used to increase the heat recovery as well as the low back pressure in the exhaust. The experiments are prepared for five engine loads (0, 20, 40, 60 and 80% of full load), two exhaust gases amount (50and 100%) and four water mass flow rates (50, 40, 30 and 20g/s). After a thermodynamical analysis on the obtained data, an optimization study based on Central Composite Design (CCD) is performed due to complex effect of engine loads and water mass flow rates on exergy recovery and irreversibility to reach the best operating condition.

M. Hatami; D.D. Ganji; M. Gorji-Bandpy

2015-01-01T23:59:59.000Z

333

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

E-Print Network [OSTI]

and the effectiveness of the porous wall are always maximum when it is operated with the number of transfer units of the porous matrix greater than two (ntu 2). Furthermore, if the porous matrix is composed of a packed bed matrix is minimum when ntu 2. This suggest that for many design requirements, the porous media exchanger

Wirtz, Richard A.

334

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

E-Print Network [OSTI]

from the hydraulic section #12;3 1. Introduction Geothermal energy (geo-exchange) systems have been engineering applications and is now recognized as a cost effective standard for energy conservation. In geo such systems in this environment. This is a starting point for a future development in the geothermal energy

Al-Shayea, Naser Abdul-Rahman

335

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

E-Print Network [OSTI]

creating unique visual and quantitative data. These data were then analyzed using a resistance type heat transfer model and five different zero gravity flow regime maps. Results from this analysis included: (i) presenting zero gravity data that correlated...

Westheimer, David Thomas

2012-06-07T23:59:59.000Z

336

Numerical Analysis of Fluid Flow and Heat Transfer within Grooved Flat Mini Heat Pipes  

Science Journals Connector (OSTI)

A Theoretical study is carried out in order to verify the Mini Heat Pipe (MHP) concept for cooling high ... as an integrated part of a Flat Mini Heat Pipe (FMHP). Hence, a detailed ... with axial microchannels is...

Jed Mansouri; Samah Maalej; Mohamed Sassi

2013-01-01T23:59:59.000Z

337

Hybrid slab-microchannel gel electrophoresis system  

DOE Patents [OSTI]

A hybrid slab-microchannel gel electrophoresis system is described. The hybrid system permits the fabrication of isolated microchannels for biomolecule separations without imposing the constraint of a totally sealed system. The hybrid system is reusable and ultimately much simpler and less costly to manufacture than a closed channel plate system. The hybrid system incorporates a microslab portion of the separation medium above the microchannels, thus at least substantially reducing the possibility of non-uniform field distribution and breakdown due to uncontrollable leakage. A microslab of the sieving matrix is built into the system by using plastic spacer materials and is used to uniformly couple the top plate with the bottom microchannel plate. 4 figs.

Balch, J.W.; Carrano, A.V.; Davidson, J.C.; Koo, J.C.

1998-05-05T23:59:59.000Z

338

Heat Exchanger Network Design and Economic Analysis for Coal-fired Power Plant retrofitted with CO2 Capture  

Science Journals Connector (OSTI)

Abstract Addition of CO2 capture unit to an existing power plant to satisfy environmental regulations has adverse effects on the energy efficiency of the power plant. Heat integration through proper design of heat exchanger network (HEN) remains the most effective way to reduce this energy penalty as well as reducing CO2 emission. Pinch technology remains the most widely used techniques due to its physical insight. This paper aims to present HEN design and economic analysis for power plant retrofitted with post-combustion CO2 capture. The benchmark presented is based on the recent work of Khalilpour and Abbas (2011) (i.e. Ref. [1]). Improvements to Khalilpour and Abbas (2011) include: (1) the use of cost and economic data to evaluate achievable trade-offs between energy, capital and utility cost. This is to determine the optimal minimum temperature difference; (2) redesigning of HEN with the newly determined minimum temperature difference and (3) its comparison with the HEN design presented in Ref. [1]. The results show that the energy penalty imposed on the power plant with CO2 capture plant can be reduced through heat integration of HEN, thus utility cost savings was maximized and the cost of addition of HEN was recovered within a short payback period of about 2.8 years.

Salihu Adamu Girei; Meihong Wang; Aminu Alhaji Hamisu

2013-01-01T23:59:59.000Z

339

Parametric performance studies on fluidized-bed heat exchangers. Task I. Fouling characteristics. Yearly technical progress report, 28 July 1981-31 July 1982  

SciTech Connect (OSTI)

Analyses and experiments are being performed in this program to investigate the heat transfer performance of single and multi-stage shallow fluidized beds for application to the recovery of heat from sources such as waste heat, and coal combustion or coal gasification. The work, which is an extension of that done previously under contracts EC-77-C-03-1433 and DE-AC03-79-ET11348, consists of three tasks. In Task 1, tests have been conducted to investigate the effects of liquid condensate fouling on fluidized bed heat exchanger performance. Liquid condensates used in these tests were water and glycerol (which is more viscous than water). The tests showed that fluidized bed heat exchanger performance is degraded by condensation within the bed and the degradation is caused by bed particles adhering to the heat exchanger surface, not by particle agglomeration. Liquid condensate did not continuously build up within the bed. After a period of dry-out, heat transfer equal to that obtained prior to condensation was again obtained. 8 figures, 1 table.

None

1982-09-01T23:59:59.000Z

340

Multiple pollutant removal using the condensing heat exchanger: Preliminary test plan for Task 2, Pilot scale IFGT testing  

SciTech Connect (OSTI)

The purpose of Task 2 (IFGT Pilot-Scale Tests at the B&W Alliance Research Center) is to evaluate the emission reduction performance of the Integrated Flue Gas Treatment (IFGT) process for coal-fired applications. The IFGT system is a two-stage condensing heat exchanger that captures multiple pollutants -- while recovering waste heat. The IFGT technology offers the potential of addressing the emission of S0{sub 2} and particulate from electric utilities currently regulated under the Phase 1 and Phase 2 requirements defined in Title IV, and many of the air pollutants that will soon be regulated under Title III of the Clean Air Act. The performance data will be obtained at pilot-scale conditions similar to full-scale operating systems. The Task 2 IFGT tests have been designed to investigate several aspects of IFGT process conditions at a broader range of variables than would be feasible at a larger scale facility. The data from these tests greatly expands the IFGT performance database for coals and is needed for the technology to progress from the component engineering phase to system integration and commercialization. The performance parameters that will be investigated are as follows: SO{sub 2} removal; particulate removal; removal of mercury and other heavy metals; NO{sub x} removal; HF and HCl removal; NH{sub 3} removal; ammonia-sulfur compounds generation; and steam injection for particle removal. For all of the pollutant removal tests, removal efficiency will be based on measurements at the inlet and outlet of the IFGT facility. Heat recovery measurements will also be made during these tests to demonstrate the heat recovery provided by the IFGT technology. This report provides a preliminary test plan for all of the Task 2 pilot-scale IFGT tests.

Jankura, B.J.

1995-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Recovery of Water from Boiler Flue Gas Using Condensing Heat Exchangers ProMIS/Project No.: DE-NT0005648  

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

Edward Levy Edward Levy Principal Investigator Director, Lehigh University Energy Research Center RecoveRy of WateR fRom BoileR flue Gas usinG condensinG Heat excHanGeRs PRomis/PRoject no.: de-nt0005648 Background As the United States' population grows and demand for electricity and water increases, power plants located in some parts of the country will find it increasingly difficult to obtain the large quantities of water needed to maintain operations. Most of the water used in a thermoelectric power plant is used for cooling, and the U.S. Department of Energy (DOE) has been focusing on possible techniques to reduce the amount of fresh water needed for cooling. Many coal-fired power plants operate with stack temperatures in the 300 °F range to minimize fouling and corrosion problems due to sulfuric acid condensation and to

342

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

DOE Patents [OSTI]

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.

Hall, Mark N. (Richland, WA)

1996-01-01T23:59:59.000Z

343

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

DOE Patents [OSTI]

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.

Hall, M.N.

1996-04-30T23:59:59.000Z

344

Technical assessment of the Office of Industrial Programs' Advanced Heat Exchanger Program  

SciTech Connect (OSTI)

The DOE's AHX Program is an integral part of the OIP's Waste Heat Recovery Program whose goals are to increase the end-use energy efficiency of industry and agricultural operations, and to expand the energy options for manufacturing processes by providing technologies which use various fuels including coal, renewables, oil, and natural gas. The OIP and PNL convened a panel of industry experts to conduct a technical assessment of OIP's AHX program. This report documents the results of the panel's assessment.

Rinker, F.G.; Bergles, A.E.; Marciniak, T.J.; Batman, J.

1987-02-01T23:59:59.000Z

345

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

E-Print Network [OSTI]

desirable. Henceforth, various turbulence models were used to study their impact on the heat transfer solution for these problems. The present numerical work focuses on improving the CFD model and methodologies in order to capture... NOMENCLATURE Sc Supercritical Tcr Critical temperature Vcr Critical volume Tpc Pseudo-critical temperature Ppc Pseudo-critical pressure Pcr Critical pressure Pop Operating pressure Tw Wall temperature Tb Bulk temperature Tin Inlet...

Fatima, Roma

2012-02-14T23:59:59.000Z

346

Evaluation Metrics for Intermediate Heat Exchangers for Next Generation Nuclear Reactors  

SciTech Connect (OSTI)

The Department of Energy (DOE) is working with industry to develop a next generation, high-temperature gas-cooled reactor (HTGR) as a part of the effort to supply the United States with abundant, clean, and secure energy as initiated by the Energy Policy Act of 2005 (EPAct; Public Law 109-58,2005). The NGNP Project, led by the Idaho National Laboratory (INL), will demonstrate the ability of the HTGR to generate hydrogen, electricity, and/or high-quality process heat for a wide range of industrial applications.

Piyush Sabharwall; Eung Soo Kim; Nolan Anderson

2011-06-01T23:59:59.000Z

347

Technology development for corrosion-resistant condensing heat exchangers. Final report, September 1984-October 1985  

SciTech Connect (OSTI)

The report presents the results of a study to develop technology to support gas-appliance manufacturers in the selection of corrosion-resistant materials for high-efficiency, gas-fired residential space-heating equipment. Condensate sampling during the 1984-85 heating season has indicated that condensate chloride levels from indoor-air combustion normally vary by 200 or 300% from week-to-week due to normal homeowner activities. Several homes, however, had chloride levels greater than the benchmark level (26 ppm) nearly every week. These results support the hypothesis that high indoor chloride levels are more likely caused by on-going homeowner activities than by a rare chloride-producing event. The mean chloride level found in outdoor-air condensate samples was five to eight times lower than the mean of the indoor data. The chloride level corresponding to the 99.5 percentile for the outdoor samples could not be estimated because of the limited amount of outdoor data.

Stickford, G.H.; Hindin, B.; Talbert, S.G.; Agrawal, A.K.; Murphy, M.J.

1985-10-01T23:59:59.000Z

348

On-Line Monitoring and Diagnostics of the Integrity of Nuclear Plant Steam Generators and Heat Exchangers, Volumes 1, 2.  

SciTech Connect (OSTI)

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. ???????????????????????????????· 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. ???????????????????????????????· 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. ???????????????????????????????· Development of a hybrid modeling technique for process diagnosis and its evaluation using laboratory heat exchanger test data. ???????????????????????????????· 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. ???????????????????????????????· Development of advanced signal processing methods using wavelet transforms and image processing techniques for isolating flaw types. ???????????????????????????????· 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

Upadhyaya, Belle R.; Hines, J. Wesley; Lu, Baofu; Huang, Xuedong; Penha, Rosani, L.; Perillo, Sergio, R.; Zhao, Ke

2005-06-03T23:59:59.000Z

349

On-Line Monitoring and Diagnostics of the Integrity of Nuclear Plant Steam Generators and Heat Exchangers.  

SciTech Connect (OSTI)

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.

Belle R. Upadhyaya; J. Wesley Hines

2004-09-27T23:59:59.000Z

350

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]

Fluid Mechanics - 1 An oil is used in a heat exchanger. The internal geometry consists of many small diameter tubes of fixed length (mounted in a bundle as indicated in the sketch). The oil is pumped). Assume the steady flow of the oil through each small tube is in the laminar regime. It is proposed

Virginia Tech

351

Rheology and Convective Heat Transfer of Colloidal Gas Aphrons in Horizontal Minichannels  

E-Print Network [OSTI]

Single-phase convective heat transfer in microchannels: aand Newell, M. E. , 1967. Heat transfer in fully developed3 /s at 130 W. Water CGA Heat Transfer Coefficient, h (W/m 2

Tseng, H.; Pilon, L.; Warrier, G.

2006-01-01T23:59:59.000Z

352

System and method for optically locating microchannel positions  

DOE Patents [OSTI]

A system and method is disclosed for optically locating a microchannel position. A laser source generates a primary laser beam which is directed at a microchannel plate. The microchannel plates include microchannels at various locations. A back-reflectance beam detector receives a back-reflected beam from the plate. The back-reflected beam is generated when the primary beam reflects off of the plate. A photodiode circuit generates a trigger signal when the back-reflected beam exceeds a predetermined threshold, indicating a presence of the microchannel. The method of the present invention includes the steps of generating a primary beam, directing the primary beam to a plate containing a microchannel, receiving from the plate a back-reflected beam generated in response to the primary beam, and generating a trigger signal when the back-reflected beam exceeds a predetermined threshold which corresponds to a presence of the microchannel.

Brewer, Laurence R. (Oakland, CA); Kimbrough, Joseph (Pleasanton, CA); Balch, Joseph (Livermore, CA); Davidson, J. Courtney (Livermore, CA)

2001-01-01T23:59:59.000Z

353

High power density fuel cell comprising an array of microchannels  

DOE Patents [OSTI]

A phosphoric acid fuel cell according to one embodiment includes an array of microchannels defined by a porous electrolyte support structure extending between bottom and upper support layers, the microchannels including fuel and oxidant microchannels; fuel electrodes formed along some of the microchannels; and air electrodes formed along other of the microchannels. A method of making a phosphoric acid fuel cell according to one embodiment includes etching an array of microchannels in a substrate, thereby forming walls between the microchannels; processing the walls to make the walls porous, thereby forming a porous electrolyte support structure; forming anode electrodes along some of the walls; forming cathode electrodes along other of the walls; and filling the porous electrolyte support structure with a phosphoric acid electrolyte. Additional embodiments are also disclosed.

Sopchak, David A; Morse, Jeffrey D; Upadhye, Ravindra S; Kotovsky, Jack; Graff, Robert T

2014-05-06T23:59:59.000Z

354

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

SciTech Connect (OSTI)

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

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

2012-07-01T23:59:59.000Z

355

Electrokinetic transport in microchannels with random roughness  

SciTech Connect (OSTI)

We present a numerical framework to model the electrokinetic transport in microchannels with random roughness. The three-dimensional microstructure of the rough channel is generated by a random generation-growth method with three statistical parameters to control the number density, the total volume fraction, and the anisotropy characteristics of roughness elements. The governing equations for the electrokinetic transport are solved by a high-efficiency lattice Poisson?Boltzmann method in complex geometries. The effects from the geometric characteristics of roughness on the electrokinetic transport in microchannels are therefore modeled and analyzed. For a given total roughness volume fraction, a higher number density leads to a lower fluctuation because of the random factors. The electroosmotic flow rate increases with the roughness number density nearly logarithmically for a given volume fraction of roughness but decreases with the volume fraction for a given roughness number density. When both the volume fraction and the number density of roughness are given, the electroosmotic flow rate is enhanced by the increase of the characteristic length along the external electric field direction but is reduced by that in the direction across the channel. For a given microstructure of the rough microchannel, the electroosmotic flow rate decreases with the Debye length. It is found that the shape resistance of roughness is responsible for the flow rate reduction in the rough channel compared to the smooth channel even for very thin double layers, and hence plays an important role in microchannel electroosmotic flows.

Wang, Moran [Los Alamos National Laboratory; Kang, Qinjun [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

356

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]

with application to air-cooled stacks for combined heat and power by Thomas Schmeister B.Sc., University to air-cooled stacks for combined heat and power by Thomas Schmeister B.Sc., University of Colorado, 1991 cells as a heat and electrical power source for residential combined heat and power (CHP

Victoria, University of

357

Numerical modeling of the aerodynamics, heat exchange, and combustion of a polydisperse ensemble of coke-ash particles in ascending axisymmetric two-phase flow  

SciTech Connect (OSTI)

A two-dimensional stationary model of motion, heat and mass exchange, and chemical reaction of polydisperse coke and ash particles in ascending gas-suspension flow has been constructed with allowance for the turbulent and pseudo turbulent mechanisms of transfer in the dispersed phase. The system of equations that describes motion and heat transfer in the solid phase has been closed at the level of the equations for the second moments of velocity and temperature pulsations, whereas the momentum equations of the carrying medium have been closed using the equation for turbulent gas energy, which allows for the influence of the particles and heterogeneous reactions.

B.B. Rokhman [National Academy of Sciences of Ukraine, Kiev (Ukraine). Institute of Coal Power Technologies

2009-07-15T23:59:59.000Z

358

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

SciTech Connect (OSTI)

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.

Dumidu Wijayasekara; Milos Manic; Piyush Sabharwall; Vivek Utgikar

2011-07-01T23:59:59.000Z

359

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 Yongpan Chen Zhen Liang Ph.D. Professor Doctoral Candidate Instructor School of Municipal & Environmental Eng, Harbin Institute of Technology Harbin P. R. China, 150090 zhangjili@hit.edu.cn Abstract: Considering a heating/cooling coil... heat indoor, as is given by Equation (5) (noted in difference scheme), where Qr denotes sensible heat amount indoor (KW); ? denotes time variable (s); ? r denotes air density indoor (Kg/m3); CP denotes air specific heat at constant pressure (KJ...

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

2006-01-01T23:59:59.000Z

360

Process for separating nitrogen from methane using microchannel process technology  

DOE Patents [OSTI]

The disclosed invention relates to a process for separating methane or nitrogen from a fluid mixture comprising methane and nitrogen, the process comprising: (A) flowing the fluid mixture into a microchannel separator, the microchannel separator comprising a plurality of process microchannels containing a sorption medium, the fluid mixture being maintained in the microchannel separator until at least part of the methane or nitrogen is sorbed by the sorption medium, and removing non-sorbed parts of the fluid mixture from the microchannel separator; and (B) desorbing the methane or nitrogen from the sorption medium and removing the desorbed methane or nitrogen from the microchannel separator. The process is suitable for upgrading methane from coal mines, landfills, and other sub-quality sources.

Tonkovich, Anna Lee (Marysville, OH); Qiu, Dongming (Dublin, OH); Dritz, Terence Andrew (Worthington, OH); Neagle, Paul (Westerville, OH); Litt, Robert Dwayne (Westerville, OH); Arora, Ravi (Dublin, OH); Lamont, Michael Jay (Hilliard, OH); Pagnotto, Kristina M. (Cincinnati, OH)

2007-07-31T23:59:59.000Z

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

A change in the temperature or a transformation of the phase of a material requires an exchange of heat with the surroundings. This exchange of heat can be used to store thermal  

E-Print Network [OSTI]

. Transformations of singlecomponent material typically occur at constant temperature. For example, ice transforms to water at a constant temperature of 0 °C. The heat required to produce the transformation is called are heated separately; the heating power applied to the sample and the reference is controlled to produce

Braun, Paul

362

Convective exergy losses of developing slip flow in microchannels  

Science Journals Connector (OSTI)

A numerical formulation of convective exergy losses in microchannels is developed. Using a new convection model (called Non-Inverted Skew Upwind Scheme (NISUS)), the predicted velocity field is post-processed to determine frictional irreversibilities within the microchannel. Boundary conditions are established from a first-order slip velocity, based on streamwise temperature gradients and transverse velocity gradients at the wall. Parametric studies are conducted for varying flow rates, channel aspect ratios, slip coefficients and pressure ratios across the microchannel. The predicted exergy destruction results provide useful new data, from which design modifications can be made to reduce power input when transporting fluid through a microchannel.

E.O.B. Ogedengbe; G.F. Naterer; M.A. Rosen

2007-01-01T23:59:59.000Z

363

Dissociation of carbon dioxide in atmospheric pressure microchannel plasma devices.  

E-Print Network [OSTI]

??Plasma discharge of carbon dioxide at atmospheric pressure was successfully demonstrated in microchannel plasma devices at breakdown voltages lower than 1 kVRMS. Optical emissions of (more)

Oh, Taegon

2013-01-01T23:59:59.000Z

364

The Economic and Environmental Aspects of Heat Exchanger Cleaning -- How FP&L Has Used the Newly Patented MCC Process to Clean Turbine Lube Oil Coolers to Maximize Efficiency and Minimize Waste  

E-Print Network [OSTI]

of efficient and timely cleaning of heat exchangers. There are great differences in the cleaning processes that are used to clean exchanger bundles in industry today. The cleaning of turbine lube oil coolers is a specialized case in point. A newly patented...

Wood, H. A. T.

365

Research on Convective Heat Transfer and Mass Transfer of the Evaporator in Micro/Mini-Channel  

E-Print Network [OSTI]

With the development of science and technology, various heating and cooling equipment have a development trend of micromation. Micro-fabrication processes make it possible to conduct research on condensation heat transfer in micro-channels. Based...

Su, J.; Li, J.

2006-01-01T23:59:59.000Z

366

Guide to Geothermal Heat Pumps  

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

Geothermal Heat Pumps Work Using a heat exchanger, a geothermal heat pump can move heat from one space to another. In summer, the geothermal heat pump extracts heat from a building...

367

MAGNITUDE AND VARIANCE OF ACOUSTIC ENERGY DENSITY IN MICROCHANNEL ACOUSTOPHORESIS  

E-Print Network [OSTI]

and Martin Wiklund1 1 Dept. of Applied Physics, Royal Institute of Technology (KTH), Stockholm, SWEDEN 2 Dept modulation, Acoustic energy density, Microchannel INTRODUCTION Microchannel acoustophoresis is a powerful) causing a half-wave resonance across the channel width or height. However, a generic problem with SF

368

A mathematical model for the simulation of closed-loop earth-coupled heat exchangers for a water source heat pump  

E-Print Network [OSTI]

and Braud, 1986). Conditions in Texas are well suited for earth-coupled heat pumps. Groundwater temperatures across Texas range from 17 to 22 'C (Kemler, 1947). Hildenbrandt and Elite t (1979) found that this temperature range gives a high coefficient... the element is (Dusinberre, 1961): (TF. + TF. where: Qout the rate at which heat leaves the element, W; h = a surface heat transfer coefficient, W/m2 'C; As = the pipe surface area in contact with the fluid, m2; TPS = the temperature of the pipe surface...

De Lange, Kevin Jon

1988-01-01T23:59:59.000Z

369

Countermeasures to Microbiofouling in Simulated Ocean Thermal Energy Conversion Heat Exchangers with Surface and Deep Ocean Waters in Hawaii  

Science Journals Connector (OSTI)

...thermal energy from warm ocean waters. A small fraction...converted to electrical power and waste heat is rejected...water pumped from the ocean depth. Solar energy absorbed by the ocean surface provides the heat...Thermal losses, the power requirements to pump large...

Leslie Ralph Berger; Joyce A. Berger

1986-06-01T23:59:59.000Z

370

Methods for applying microchannels to separate methane using liquid absorbents, especially ionic liquid absorbents from a mixture comprising methane and nitrogen  

DOE Patents [OSTI]

Methods of using microchannel separation systems including absorbents to improve thermal efficiency and reduce parasitic power loss. Energy is typically added to desorb methane and then energy or heat is removed to absorb methane using a working solution. The working solution or absorbent may comprise an ionic liquid, or other fluids that demonstrate a difference in affinity between methane and nitrogen in a solution.

Tonkovich, Anna Lee Y. (Dublin, OH); Litt, Robert D. (Westerville, OH); Dongming, Qiu (Dublin, OH); Silva, Laura J. (Plain City, OH); Lamont, Micheal Jay (Plain City, OH); Fanelli, Maddalena (Plain City, OH); Simmons, Wayne W. (Plain city, OH); Perry, Steven (Galloway, OH)

2011-10-04T23:59:59.000Z

371

Process for oil shale retorting using gravity-driven solids flow and solid-solid heat exchange  

DOE Patents [OSTI]

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.

Lewis, Arthur E. (Los Altos, CA); Braun, Robert L. (Livermore, CA); Mallon, Richard G. (Livermore, CA); Walton, Otis R. (Livermore, CA)

1986-01-01T23:59:59.000Z

372

Process for oil shale retorting using gravity-driven solids flow and solid-solid heat exchange  

DOE Patents [OSTI]

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.

Lewis, A.E.; Braun, R.L.; Mallon, R.G.; Walton, O.R.

1983-09-21T23:59:59.000Z

373

Application of RCC-MR for the structural design of tube sheet of intermediate heat exchanger for a sodium cooled fast reactor  

Science Journals Connector (OSTI)

Abstract The structural mechanics behavior of tube sheets of a sodium to sodium heat exchanger for a fast reactor, with circular tube holes pattern, less addressed subject in the literature, is investigated in detail. The tube sheet design rules recommended in the French design code RCC-MR-2007 and the associated solid mechanics basis are explained. A finite element analysis of tube sheets of intermediate heat exchanger of a typical 500MWe pool type fast reactor is presented to study the effects of some specific parameters viz., (i) small solid rim portion with connecting shell and (ii) grooves on rim area. For the analysis, the distribution of holes on the last row is assumed to be symmetric and axial stiffening of tubes on tube sheet is included toward realistic estimation of stresses in the tube sheets. The effects are studied on the primary and secondary stresses induced along the interface between solid to perforated region. The aspects covered include linearization of radial and circumferential stress components, thereby deriving primary membrane and bending stress intensities along the radial directions with particular focus at the interfaces between solid portions and perforated portions including the effect of filet radius at the junction of tube sheet and shell. These investigations thus help to optimize the design of IHX tube sheets with high confidence. The analysis has been carried out by CAST3M, a structure analysis software granted by CEA, France.

Suman Gupta; P. Chellapandi

2014-01-01T23:59:59.000Z

374

Evaluation of stack criteria pollutant gas absorption in the new generation thermoelectric water condenser fitted with laminar impinger type heat exchangers  

SciTech Connect (OSTI)

Title IV of the Clean Air Act Amendments of 1990 authorized the Environmental Protection Agency to establish an Acid Rain Program to reduce the adverse effects of acidic deposition. The Act specifically stipulated that CEMS (continuous emissions monitoring systems) be used to measure the stack emissions under this program. Along with these rules, comes the task of the Stack Tester (Reference Method) to routinely perform RATA (Relative Accuracy Test Audit) tests on the installed CEMS. This paper presents a laboratory and field test sequence to evaluate the signal attenuation through the gas sample conditioning, water condensation removal process, using laminar flow impinger heat exchangers. This method is compared to the EPA CFR 40, Part 60, Appendix A, Method 6, glass impinger train, commonly used by RATA stack testers. CFR 40, Part 75 revisions as of the CAAA 1990, requires more stringent certification and CEMS performance standards. These standards are summarized and related to gas absorption in both the thermoelectric cooler heat exchanger and the Method 6 glass impinger train system. As an incentive to reduce the frequency of RATA tests required per year, emitters are encouraged to achieve relative accuracies of 7.5% or less compared to the reference method. This incentive requires better reference method test apparatus definition. This paper will explore these alternatives and provide test data for comparison to the currently available apparatus. Also discussed is the theory of Electronic Gas Sample Coolers and their practical application to the removal of water from stack gas.

Baldwin, T. [Baldwin Environmental, Inc., Reno, NV (United States)

1995-12-31T23:59:59.000Z

375

Covered Product Category: Residential Geothermal Heat Pumps ...  

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

heat exchangers. Most large systems use vertical heat exchangers, which consist of polyethylene u-tube pipes in deep (typically 150-250 feet) boreholes. Horizontal loops require...

376

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]

Heat transfer results for a given slot shaped channel with a 3:1 aspect ratio are presented using various configurations of a trapezoid shaped spiral wound strips to enhance swirl and tumble motion in the channel. The Reynolds numbers investigated...

Segura, D.; Acharya, S.

2012-01-01T23:59:59.000Z

377

Microchannel Reactor System for Catalytic Hydrogenation  

SciTech Connect (OSTI)

We successfully demonstrated a novel process intensification concept enabled by the development of microchannel reactors, for energy efficient catalytic hydrogenation reactions at moderate temperature, and pressure, and low solvent levels. We designed, fabricated, evaluated, and optimized a laboratory-scale microchannel reactor system for hydrogenation of onitroanisole and a proprietary BMS molecule. In the second phase of the program, as a prelude to full-scale commercialization, we designed and developed a fully-automated skid-mounted multichannel microreactor pilot plant system for multiphase reactions. The system is capable of processing 1 10 kg/h of liquid substrate, and an industrially relevant immiscible liquid-liquid was successfully demonstrated on the system. Our microreactor-based pilot plant is one-of-akind. We anticipate that this process intensification concept, if successfully demonstrated, will provide a paradigm-changing basis for replacing existing energy inefficient, cost ineffective, environmentally detrimental slurry semi-batch reactor-based manufacturing practiced in the pharmaceutical and fine chemicals industries.

Adeniyi Lawal; Woo Lee; Ron Besser; Donald Kientzler; Luke Achenie

2010-12-22T23:59:59.000Z

378

Contraction/expansion flow of dilute elastic solutions in microchannels  

E-Print Network [OSTI]

An experimental study is conducted on the nature of extensional flows of mobile dilute polymer solutions in microchannel. By observing such fluids on the microscale it is possible to generate large strain rates ([approximately] ...

Scott, Timothy Peter, 1980-

2004-01-01T23:59:59.000Z

379

Rotary magnetic heat pump  

DOE Patents [OSTI]

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.

Kirol, L.D.

1987-02-11T23:59:59.000Z

380

Proceedings of NHTC'00: 34 th National Heat Transfer Conference  

E-Print Network [OSTI]

Proceedings of NHTC'00: 34 th National Heat Transfer Conference Pittsburgh, Pennsylvania, August 20 ON SINGLE- AND TWO-PHASE HEAT TRANSFER CHARACTERISTICS IN A MICROCHANNEL Michael S June Graduate Student study investigates the heat transfer characteristics of single and two-phase flows in a 200 m wide

Kandlikar, Satish

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Heat pump having improved defrost system  

DOE Patents [OSTI]

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.

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

1998-12-08T23:59:59.000Z

382

Experimental development of the predictive relations for the eddy exchange coefficients for momentum and heat in the atmospheric boundary layer  

E-Print Network [OSTI]

, increase in w by removing the dummy -1 bases was 4. 2 cm/sec , and u for these runs was 330 cm/sec -I ?? Using sin [w/u] as a measure of the tilt of the wind field gave an inclination of . 72', in fair agreement with KAIMAL's relation. Therefore.... '?'illlam H. Clayton Direct measurements of the eddy fluxes of mo. . . entum and heat were. made in the atmospheric boundary layer simultaneously with measurements of the profiles of average wind velocity and tempera- ture to evaluate the capability...

Jensen, Paul Alfred

2012-06-07T23:59:59.000Z

383

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]

Computational Fluid Mechanics and Heat Transfer. New York,the two fluids and enhance heat transfer between them. Most1]. This EPM fluid dynamics and heat transfer computational

Urquiza, Eugenio

2009-01-01T23:59:59.000Z

384

1 6/11/2003 Progress in Microchannel SteamProgress in  

E-Print Network [OSTI]

1 6/11/2003 Progress in Microchannel SteamProgress in Reformation of Hydrocarbon Fuels Progress in MicrochannelMicrochannel SteamSteam Reformation of HydrocarbonReformation of Hydrocarbon FuelsFuels 2003 steam reformer at higher temperature. Productivity for benchmark fuel increased 3X between 650°C and 850

385

Antiproton, positron, and electron imaging with a microchannel plate/phosphor detector  

E-Print Network [OSTI]

Antiproton, positron, and electron imaging with a microchannel plate/phosphor detector ALPHA; accepted 2 November 2009; published online 1 December 2009 A microchannel plate MCP /phosphor screen Microchannel plate MCP /phosphor screen based diag- nostics have proved invaluable in studying the evolution

Fajans, Joel

386

Heat pump system  

DOE Patents [OSTI]

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.

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

1983-01-01T23:59:59.000Z

387

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]

out f Fig. 4 Fluid flow and heat transfer over a backwardtaking the fluid flow and heat transfer over a backward1980, Numerical Heat Transfer and Fluid Flow, Hemisphere

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

2011-01-01T23:59:59.000Z

388

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]

Fig. 3 Journal of Heat Transfer Grid system for 2-row caseDomain and Grid System. Since the fin-and- tube heat

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

2011-01-01T23:59:59.000Z

389

RESEARCH PAPER Fouling and its mitigation in silicon microchannels used  

E-Print Network [OSTI]

RESEARCH PAPER Fouling and its mitigation in silicon microchannels used for IC chip cooling Jeffrey@rit.edu 123 Microfluid Nanofluid (2008) 5:357­371 DOI 10.1007/s10404-007-0254-4 #12;lE electrophoretic and micro- electronics. In recent years, the proliferation of Micro Electro Mechanical Systems (MEMS) has

Kandlikar, Satish

390

Low-Cost Manufacturable Microchannel Systems for Passive  

E-Print Network [OSTI]

for use in fuel cell systems need development in order to achieve cost targets. Low-cost, highLow-Cost Manufacturable Microchannel Systems for Passive PEM Water Management IIPS Number 16910 LowLow--CostCost;2 Project objective: Create a low cost and passive PEM water management system Project objective

391

Nucleation characteristics and stability considerations during flow boiling in microchannels  

E-Print Network [OSTI]

[4,5]. The major concerns relate to (i) increased effects of surface tension forces, (ii) reverse of Hsu [6]. Bubbles are formed over the cavities that are present on a heater surface. As a bubble coversNucleation characteristics and stability considerations during flow boiling in microchannels Satish

Kandlikar, Satish

392

Modeling gas flow through microchannels and nanopores Subrata Roya)  

E-Print Network [OSTI]

Modeling gas flow through microchannels and nanopores Subrata Roya) and Reni Raju Computational. A two-dimensional finite-element based microscale flow model is developed to efficiently predict is modeled using either the continuum or the molecular approach.1­4 The con- tinuum approach solves

Roy, Subrata

393

Shell and Tube Heat Exchangers  

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

Ultra-Deepwater Advisory Committee Ultra-Deepwater Advisory Committee 2011 Annual Plan Comments, Findings and Recommendations April 2011 An Advisory Committee to the Secretary of Energy Ultra-Deepwater Advisory Committee Report Page 2 of 14 TABLE OF CONTENTS 1.0 INTRODUCTION ............................................................................................................ 3 2.0 EXECUTIVE SUMMARY ................................................................................................ 5 3.0 SUBCOMMITTEE REPORTS ........................................................................................ 5 3.1 R&D PORTFOLIO FINDINGS AND RECOMMENDATIONS ............................... 5 3.2 PROGRAM PROCESS FINDINGS AND RECOMMENDATIONS ..................... 11

394

Shell and Tube Heat Exchangers  

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

Comments and Recommendations 2007 Ultra-Deepwater Annual Plan July, 2007 Ultra-Deepwater Advisory Committee Report TABLE OF CONTENTS 1.0 INTRODUCTION............................................................................................................... 3 2.0 EXECUTIVE SUMMARY AND RECOMMENDATIONS ................................................... 4 3.0 SUB GROUP REPORTS .................................................................................................. 5 3.1 R&D THEME CONTENT ....................................................................................... 6 3.2 SOLICITATION PROCESS ................................................................................... 8 3.3 ENVIRONMENTAL ...............................................................................................

395

Shell and Tube Heat Exchangers  

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

Advisory Committee Comments and Recommendations 2013 Annual Plan November 2012 2 TABLE OF CONTENTS 1.0 INTRODUCTION..............................................................................................................3 2.0 EXECUTIVE SUMMARY AND RECOMMENDATION HIGHLIGHTS .................5 3.0 TOPICAL REPORTS .......................................................................................................7 3.1 POLICY FINDINGS AND RECOMMENDATIONS ....................................................8 3.2 RESEARCH AND DEVELOPMENT FINDINGS AND RECOMMENDATIONS .10 3.3 TECHNOLOGY TRANSFER AND OUTREACH PROGRAM FINDINGS AND RECOMMENDATIONS .................................................................................................16

396

Shell and Tube Heat Exchangers  

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

Unconventional Resources Technology Unconventional Resources Technology Advisory Committee Comments and Recommendations 2007 Unconventional Gas Research and Development Annual Plan July, 2007 Unconventional Resources Technology Advisory Committee Report TABLE OF CONTENTS 1.0 INTRODUCTION............................................................................................................... 3 2.0 EXECUTIVE SUMMARY AND RECOMMENDATIONS ................................................... 4 3.0 SUB GROUP REPORTS .................................................................................................. 6 3.1 TECHNOLOGY TRANSFER ................................................................................. 7 3.2 REGULATION .......................................................................................................

397

High pressure ceramic heat exchanger  

DOE Patents [OSTI]

Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present header assembly when used with recuperators reduces the brittle effect of a portion of the ceramic components. Thus, the present header assembly used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present header assembly is comprised of a first ceramic member, a second ceramic member, a reinforcing member being in spaced relationship to the first ceramic member and the second ceramic member. The header assembly is further comprised of a refractory material disposed in contacting relationship with the first ceramic member, the second ceramic member and the reinforcing member and having a strengthening member wrapped around the refractory material. The present header assembly provides a high strength load bearing header assembly having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures.

Harkins, Bruce D. (San Diego, CA); Ward, Michael E. (Poway, CA)

1999-01-01T23:59:59.000Z

398

High pressure ceramic heat exchanger  

DOE Patents [OSTI]

Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present header assembly when used with recuperators reduces the brittle effect of a portion of the ceramic components. Thus, the present header assembly used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present header assembly is comprised of a first ceramic member, a second ceramic member, a strengthening reinforcing member being in spaced relationship to the first ceramic member and the second ceramic member. The header assembly is further comprised of a refractory material disposed in contacting relationship with the first ceramic member, the second ceramic member and the strengthening reinforcing member. The present header assembly provides a high strength load bearing header assembly having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures.

Harkins, Bruce D. (San Diego, CA); Ward, Michael E. (Poway, CA)

1998-01-01T23:59:59.000Z

399

Designing Flexible Heat Exchanger Networks  

E-Print Network [OSTI]

major drawback is that this approach is inadequate for multiperiod problems. It starts with a design for one period nd makes it flexible for other periods. Further, it guarantees flexibility at minimum capital cost without regard to the energy cost....06 0.0 0.0 26.30 1136.18 26.30 C2 9.68 288.8 0.0 0.0 19.211 646.96 19.11 TDTAL AREA 145.59 Total Annualized Capital Cost: $172,700/year Total Energy Cost: $147,178/year Total Annualized Cost: $319,878/year Table 5 OPTIMAL MULTI PERIOD...

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

400

High pressure ceramic heat exchanger  

DOE Patents [OSTI]

Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present header assembly when used with recuperators reduces the brittle effect of a portion of the ceramic components. Thus, the present header assembly used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present header assembly is comprised of a first ceramic member, a second ceramic member, a strengthening reinforcing member being in spaced relationship to the first ceramic member and the second ceramic member. The header assembly is further comprised of a refractory material disposed in contacting relationship with the first ceramic member, the second ceramic member and the strengthening reinforcing member. The present header assembly provides a high strength load bearing header assembly having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures. 5 figs.

Harkins, B.D.; Ward, M.E.

1998-09-22T23:59:59.000Z

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Radial Flow Bearing Heat Exchanger  

Broader source: Energy.gov [DOE]

Lead Performer: Sandia National Laboratories - Albuquerque, NM Partners: -- Tribologix - Golden, CO -- United Technologies Research Center - East Hartford, CT -- University of Maryland - College Park, MD -- Oak Ridge National Laboratory - Oak Ridge, TN -- Whirlpool - Benton Harbor, MI -- Optimized Thermal Systems - College Park, MD

402

HEAT EXCHANGE AND WEATHER FORECASTING  

Science Journals Connector (OSTI)

...energy into kinetic energy. In the scheme of...that the potential energy has to be re- stored...time, search for energy sources and sinks...earth's surfaces as a converter of radiation into...where K is the thermal diffusivity; in...the mobility of the ocean waters, we see that...

Sverre Petterssen

1959-01-01T23:59:59.000Z

403

Optimization of Heat Exchanger Cleaning  

E-Print Network [OSTI]

. An illustration of their effect on 1.6 the TFKE is shown in Figure 1U where the data 75% Restoration from Figure 6 is compared to curves with T = SUU days, annual anti foul ant costs of $IUU,OUU, and a constant Qf. For this example, the use of antifoulants.... An illustration of their effect on 1.6 the TFKE is shown in Figure 1U where the data 75% Restoration from Figure 6 is compared to curves with T = SUU days, annual anti foul ant costs of $IUU,OUU, and a constant Qf. For this example, the use of antifoulants...

Siegell, J. H.

404

Shell and Tube Heat Exchangers  

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

Ultra-Deepwater Advisory Committee Ultra-Deepwater Advisory Committee 2012 Annual Plan Comments, Findings and Recommendations March, 2012 An Advisory Committee to the Secretary of Energy Ultra-Deepwater Advisory Committee Report Page 2 of 12 TABLE OF CONTENTS 1.0 INTRODUCTION ............................................................................................................. 3 2.0 EXECUTIVE SUMMARY ................................................................................................. 5 3.0 SUBCOMMITTEE REPORT ............................................................................................ 5 3.1 R&D PROGRAM PORTFOLIO FINDINGS AND RECOMMENDATIONS ........................ 5 4.0 ULTRA-DEEPWATER ADVISORY COMMITTEE - 2011-2013 .................................... 11

405

Shell and Tube Heat Exchangers  

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

Advisory Committee Comments and Recommendations 2012 Annual Plan February 2012 2 TABLE OF CONTENTS 1.0 INTRODUCTION..............................................................................................................3 2.0 EXECUTIVE SUMMARY AND RECOMMENDATION HIGHLIGHTS .................5 3.0 TOPICAL REPORTS .......................................................................................................7 3.1 POLICY & REGULATION FINDINGS AND RECOMMENDATIONS .........................8 3.2 ENVIRONMENTAL FINDINGS AND RECOMMENDATIONS ..................................10 3.3 RESEARCH AND DEVELOPMENT PROGRAM FINDINGS AND RECOMMENDATIONS ...................................................................................................11

406

6th World Conference on Experimental Heat Transfer, Fluid Mechanics, and Thermodynamics  

E-Print Network [OSTI]

6th World Conference on Experimental Heat Transfer, Fluid Mechanics, and Thermodynamics April 17-21, 2005, Matsushima, Miyagi, Japan Modeling on convective boiling heat transfer in a microtube based visualization, Microchannel, Periodic flow pattern variation 1. INTRODUCTION Convective boiling heat transfer

Kasagi, Nobuhide

407

Heat transfer and friction characteristics of air flow in microtubes Chien-Yuh Yang a,  

E-Print Network [OSTI]

Heat transfer and friction characteristics of air flow in microtubes Chien-Yuh Yang a, , Chia September 2011 Keywords: Microtube Heat transfer Liquid Crystal Thermography a b s t r a c t Several researches dealing with the single-phase forced convection heat transfer inside microchannels have been

Kandlikar, Satish

408

Refrigerant charge management in a heat pump water heater  

DOE Patents [OSTI]

Heat pumps that heat or cool a space and that also heat water, refrigerant management systems for such heat pumps, methods of managing refrigerant charge, and methods for heating and cooling a space and heating water. Various embodiments deliver refrigerant gas to a heat exchanger that is not needed for transferring heat, drive liquid refrigerant out of that heat exchanger, isolate that heat exchanger against additional refrigerant flowing into it, and operate the heat pump while the heat exchanger is isolated. The heat exchanger can be isolated by closing an electronic expansion valve, actuating a refrigerant management valve, or both. Refrigerant charge can be controlled or adjusted by controlling how much liquid refrigerant is driven from the heat exchanger, by letting refrigerant back into the heat exchanger, or both. Heat pumps can be operated in different modes of operation, and segments of refrigerant conduit can be interconnected with various components.

Chen, Jie; Hampton, Justin W.

2014-06-24T23:59:59.000Z

409

Technical Information Exchange on Pyrolysis Oil: Potential for...  

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

renewable heating oil substitution Technical Information Exchange on Pyrolysis Oil: Potential for a renewable heating oil substitution Two-day agenda from the workshop: Technical...

410

A Reduced-Order Model of a Chevron Plate Heat Exchanger for Rapid Thermal Management by Using Thermo-Chemical Energy Storage  

E-Print Network [OSTI]

The heat flux demands for electronics cooling applications are quickly approaching the limits of conventional thermal management systems. To meet the demand of next generation electronics, a means for rejecting high heat fluxes at low temperatures...

Niedbalski, Nicholas

2012-10-19T23:59:59.000Z

411

Microchannel Distillation of JP-8 Jet Fuel for Sulfur Content Reduction  

SciTech Connect (OSTI)

In microchannel based distillation processes, thin vapor and liquid films are contacted in small channels where mass transfer is diffusion-limited. The microchannel architecture enables improvements in distillation processes. A shorter height equivalent of a theoretical plate (HETP) and therefore a more compact distillation unit can be achieved. A microchannel distillation unit was used to produce a light fraction of JP-8 fuel with reduced sulfur content for use as feed to produce fuel-cell grade hydrogen. The HETP of the microchannel unit is discussed, as well as the effects of process conditions such as feed temperature, flow rate, and reflux ratio.

Zheng, Feng; Stenkamp, Victoria S.; TeGrotenhuis, Ward E.; Huang, Xiwen; King, David L.

2006-09-16T23:59:59.000Z

412

Conversion of Biomass Syngas to DME Using a Microchannel Reactor  

Science Journals Connector (OSTI)

Conversion of Biomass Syngas to DME Using a Microchannel Reactor ... The purpose of the research discussed here is to develop such a process capable of converting syngas generated from gasification of dispersed biomass resources. ... MeOH was converted to water and hydrocarbons, with up to 70% selectivity to C2-4 olefins, at 100% conversion, over ZSM-5 class zeolite catalysts modified with P compds. ...

Jianli Hu; Yong Wang; Chunshe Cao; Douglas C. Elliott; Don J. Stevens; James F. White

2005-02-18T23:59:59.000Z

413

Heat rejection system  

DOE Patents [OSTI]

A cooling system for rejecting waste heat consists of a cooling tower incorporating a plurality of coolant tubes provided with cooling fins and each having a plurality of cooling channels therein, means for directing a heat exchange fluid from the power plant through less than the total number of cooling channels to cool the heat exchange fluid under normal ambient temperature conditions, means for directing water through the remaining cooling channels whenever the ambient temperature rises above the temperature at which dry cooling of the heat exchange fluid is sufficient and means for cooling the water.

Smith, Gregory C. (Richland, WA); Tokarz, Richard D. (Richland, WA); Parry, Jr., Harvey L. (Richland, WA); Braun, Daniel J. (Richland, WA)

1980-01-01T23:59:59.000Z

414

A numerical study on the effects of 2d structured sinusoidal elements on fluid flow and heat transfer at microscale  

E-Print Network [OSTI]

Computational fluid dynamics Microchannel Minichannel Surface roughness Roughness elements Heat transfer Fluid to achieve enhancement in heat transfer with relatively low cooling fluid flow rate [1]. In spite of havingA numerical study on the effects of 2d structured sinusoidal elements on fluid flow and heat

Kandlikar, Satish

415

Thulium-170 heat source  

SciTech Connect (OSTI)

An isotopic heat source is formed using stacks of thin individual layers of a refractory isotopic fuel, preferably thulium oxide, alternating with layers of a low atomic weight diluent, preferably graphite. The graphite serves several functions: to act as a moderator during neutron irradiation, to minimize bremsstrahlung radiation, and to facilitate heat transfer. The fuel stacks are inserted into a heat block, which is encased in a sealed, insulated and shielded structural container. Heat pipes are inserted in the heat block and contain a working fluid. The heat pipe working fluid transfers heat from the heat block to a heat exchanger for power conversion. Single phase gas pressure controls the flow of the working fluid for maximum heat exchange and to provide passive cooling.

Walter, C.E.; Van Konynenburg, R.; VanSant, J.H.

1990-09-06T23:59:59.000Z

416

Thulium-170 heat source  

DOE Patents [OSTI]

An isotopic heat source is formed using stacks of thin individual layers of a refractory isotopic fuel, preferably thulium oxide, alternating with layers of a low atomic weight diluent, preferably graphite. The graphite serves several functions: to act as a moderator during neutron irradiation, to minimize bremsstrahlung radiation, and to facilitate heat transfer. The fuel stacks are inserted into a heat block, which is encased in a sealed, insulated and shielded structural container. Heat pipes are inserted in the heat block and contain a working fluid. The heat pipe working fluid transfers heat from the heat block to a heat exchanger for power conversion. Single phase gas pressure controls the flow of the working fluid for maximum heat exchange and to provide passive cooling.

Walter, Carl E. (Pleasanton, CA); Van Konynenburg, Richard (Livermore, CA); VanSant, James H. (Tracy, CA)

1992-01-01T23:59:59.000Z

417

Microchannel Networks for Nanowire Patterning Benjamin Messer, Jae Hee Song, and Peidong Yang*  

E-Print Network [OSTI]

Microchannel Networks for Nanowire Patterning Benjamin Messer, Jae Hee Song, and Peidong Yang - ] nanowires on substrates using microchannel networks.5 This strategy relies on the solvent evaporation induced self-assembly of [Mo3Se3 -] infinite chains within the micro- channels. Aligned [Mo3Se3 - ] wires6

Yang, Peidong

418

Optimization of the Readout Electronics for Microchannel Plate Delay Line Anodes  

E-Print Network [OSTI]

Optimization of the Readout Electronics for Microchannel Plate Delay Line Anodes John Vallerga and future space missions use microchannel plate (MCP) detectors with delay line anode readouts (e.g. FUSE Telescope). Delay line anodes are used to measure the position of the centroid of the charge clouds

Colorado at Boulder, University of

419

Heat pump employing optimal refrigerant compressor for low pressure ratio applications  

DOE Patents [OSTI]

What is disclosed is a heat pump apparatus for conditioning a fluid characterized by a fluid handler for circulating the fluid in heat exchange relationship with a refrigerant fluid; two refrigerant heat exchangers; one for effecting the heat exchange with the fluid and a second refrigerant-heat exchange fluid heat exchanger for effecting a low pressure ratio of compression of the refrigerant; a rotary compressor for compressing the refrigerant with low power consumption at the low pressure ratio; at least one throttling valve connecting at the inlet side of heat exchanger in which liquid refrigerant is vaporized; a refrigerant circuit serially connecting the above elements; refrigerant in the circuit; 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.

Ecker, Amir L. (Dallas, TX)

1982-01-01T23:59:59.000Z

420

The Coupling Performance of a Solar-Air Heat Pump  

Science Journals Connector (OSTI)

Based on the advantages and disadvantages of single air source heat pump, single solar energy heat pump and switch solar-air dual heat source heat pumps, a new type of solar-air composite heat source heat pump system has been proposed to realize the utilization and complementary advantages of two renewable energy: air and solar. It also provided a feasible method to improve the city's ecological environment, and plays a leading role in the villages and small towns construction. Design the composite heat exchanger with double heat sources. The heat exchanger had dual function of tube-fin and tube heat exchangers, break through the traditional model that heat exchanger in working can realize heat exchange only between the same gases or liquid heat sources, and realized the heat exchange between two heat sources. It laid the technological and equips mental foundation for realizing the synchronization and composite using of solar energy and air.

Yin Liu; Jing Ma; Guanghui Zhou

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Design of an annular microchannel reactor (AMR) for hydrogen and/or syngas production via methane steam reforming  

Science Journals Connector (OSTI)

Abstract A bench-scale annular microchannel reactor (AMR) prototype with microchannel width of 0.3mm and total catalyst length of 9.53נ10?2m active for the endothermic steam reforming of methane is presented. Experimental results at a steam to methane feed molar ratio of 3.3:1, reactor temperature of 1023K, and pressure of 11bar confirm catalyst power densities upwards of 1380W per cm3 of catalyst at hydrogen yields >98% of thermodynamic equilibrium. A two-dimensional steady-state computational fluid dynamic model of the AMR prototype was validated using experimental data and subsequently employed to identify suitable operating conditions for an envisioned mass-production AMR design with 0.3mm annular channel width and a single catalyst length of 254mm. Thermal efficiencies, defined based upon methane and product hydrogen higher heating values (HHVs), of 72.757.7% were obtained from simulations for methane capacities of 0.52SLPM (space velocities of 195,000782,000h?1) at hydrogen yields corresponding to 99%75% of equilibrium values. Under these conditions, analysis of local composition, temperature and pressure indicated that catalyst deactivation via coke formation or Nickel oxidation is not thermodynamically favorable. Lastly, initial analysis of an envisioned 10kW autothermal reformer combining 19 parallel \\{AMRs\\} within a single methane-air combustion chamber, based upon existing manufacturing capabilities within Power & Energy, Inc., is presented.

Holly Butcher; Casey J.E. Quenzel; Luis Breziner; Jacques Mettes; Benjamin A. Wilhite; Peter Bossard

2014-01-01T23:59:59.000Z

422

Parametric study of a silica gel-water adsorption refrigeration cycle -- The influence of thermal capacitance and heat exchanger UA-values on cooling capacity, power density, and COP  

SciTech Connect (OSTI)

The influence of heat exchanger UA-values (adsorber/desorber, evaporator, and condenser) is investigated for an adsorption chiller, with consideration given to the thermal capacitance of the adsorber/desorber by means of a lumped-parameter cycle simulation model developed by the authors and co-workers for the single-stage silica gel-water adsorption chiller. The closed-cycle-type chiller, for use in air conditioning, is driven by low-grade waste heat (85 C [185 F]) and cooled by water at 31 C (88 F) and operates on relatively short cycle times (420 seconds adsorption/desorption; 30 second adsorber/desorber sensible cooling and heating). The results showed cycle performance to be considerably affected by the thermal capacitance and UA-value of the adsorber/desorber, which is attributed to the severe sensible cooling/heating requirements resulting from batched cycle operation. The model is also sensitive to the evaporator UA-value--but to a lesser extent. The condenser UA-value is the least sensitive parameter due to the working pair adsorption behavior in the temperature range defined for desorption and condensation.

Boelman, E.C.; Saha, B.B.; Kashiwagi, Takao [Tokyo Univ. of Agriculture and Technology (Japan). Dept. of Mechanical Systems Engineering

1997-12-31T23:59:59.000Z

423

High-heat-load synchrotron tests of room-temperature, silicon crystal monochromators at the CHESS F-2 wiggler station  

SciTech Connect (OSTI)

This note summarizes the results of the single crystal monochromator high-heat-load tests performed at the CHESS F-2 wiggler station. The results from two different cooling geometries are presented: (1) the ``pin-post`` crystal and (2) the ``criss-cross`` crystal. The data presented were taken in August 1993 (water-cooled pin-post) and in April 1995 (water- and gallium-cooled pin-post crystal and gallium-cooled criss-cross crystal). The motivation for trying these cooling (or heat exchanger) geometries is to improve the heat transfer efficiency over that of the conventional slotted crystals. Calculations suggest that the pin-post or the microchannel design can significantly improve the thermal performance of the crystal. The pin-post crystal used here was fabricated by Rocketdyne Albuquerque Operations. From the performance of the conventional slotted crystals, it was thought that increased turbulence in the flow pattern may also enhance the heat transfer. The criss-cross crystal was a simple attempt to achieve the increased flow turbulence. The criss-cross crystal was partly fabricated in-house (cutting, etching and polishing) and bonded by RAO. Finally, a performance comparison among all the different room temperature silicon monochromators that have been tested by the APS is presented. The data includes measurements with the slotted crystal and the core-drilled crystals. Altogether, the data presented here were taken at the CHESS F-2 wiggler station between 1991 and 1995.

Lee, W.K.; Fernandez, P.B.; Graber, T.; Assoufid, L.

1995-09-08T23:59:59.000Z

424

Process for making unsaturated hydrocarbons using microchannel process technology  

DOE Patents [OSTI]

The disclosed invention relates to a process for converting a feed composition comprising one or more hydrocarbons to a product comprising one or more unsaturated hydrocarbons, the process comprising: flowing the feed composition and steam in contact with each other in a microchannel reactor at a temperature in the range from about 200.degree. C. to about 1200.degree. C. to convert the feed composition to the product, the process being characterized by the absence of catalyst for converting the one or more hydrocarbons to one or more unsaturated hydrocarbons. Hydrogen and/or oxygen may be combined with the feed composition and steam.

Tonkovich, Anna Lee (Dublin, OH); Yuschak, Thomas (Lewis Center, OH); LaPlante, Timothy J. (Columbus, OH); Rankin, Scott (Columbus, OH); Perry, Steven T. (Galloway, OH); Fitzgerald, Sean Patrick (Columbus, OH); Simmons, Wayne W. (Dublin, OH); Mazanec, Terry (Solon, OH) Daymo, Eric (Dublin, OH)

2011-04-12T23:59:59.000Z

425

Lattice Boltzmann simulation of rarefied gas flows in microchannels  

Science Journals Connector (OSTI)

For gas flows in microchannels, slip motion at the solid surface can occur even if the Mach number is negligibly small. Since the Knudsen number of the gas flow in a long microchannel can vary widely and the Navier-Stokes equations are not valid for Knudsen numbers beyond 0.1, an alternative method that can be applicable to continuum, slip and transition flow regimes is highly desirable. The lattice Boltzmann equation (LBE) approach has recently been expected to have such potential. However, some hurdles need to be overcome before it can be applied to simulate rarefied gas flows. The first major hurdle is to accurately model the gas molecule and wall surface interactions. In addition, the Knudsen number needs to be clearly defined in terms of LBE properties to ensure that the LBE simulation results can be checked against experimental measurements and other simulation results. In this paper, the Maxwellian scattering kernel is adopted to address the gas molecule and surface interactions with an accommodation coefficient (in addition to the Knudsen number) controlling the amount of slip motion. The Knudsen number is derived consistently with the macroscopic property based definition. The simulation results of the present LBE model are in quantitative agreement with the established theory in the slip flow regime. In the transition flow regime, the model captures the Knudsen minimum phenomenon qualitatively. Therefore, the LBE can be a competitive method for simulation of rarefied gas flows in microdevices.

Yonghao Zhang; Rongshan Qin; David R. Emerson

2005-04-05T23:59:59.000Z

426

Complex Compound Chemical Heat Pumps  

E-Print Network [OSTI]

industrial heat pumps. The main emphasis was directed towards a conceptual temperature amplifier bench scale prototype design, which allows for the conversion to heat amplifier operation by the mere exchange of adsorbent working fluid component without...

Rockenfeller, U.; Langeliers, J.; Horn, G.

427

Heat Pipes: An Industrial Application  

E-Print Network [OSTI]

This paper reviews the basics of heat pipe exchangers. Included are how they are constructed, how they operate, where they have application, and various aspects of evaluating a potential application. After discussing the technical aspects of heat...

Murray, F.

1984-01-01T23:59:59.000Z

428

NETL F 451.1/1-1, Categorical Exclusion Designation Form  

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

High Temp and Pressure Microchannel HX for SCO2 Power Cycles CMU will explore the manufacturing process for the additive manufactured heat exchanger designed by OSU. The...

429

Investigating the stability of viscoelastic stagnation flows in T-shaped microchannels  

E-Print Network [OSTI]

We investigate the stability of steady planar stagnation flows of a dilute polyethylene oxide (PEO) solution using T-shaped microchannels. The precise flow rate control and well-defined geometries achievable with microfluidic ...

Soulage, Johannes

430

Development of photo-patterned composite structures in microchannels for oil reservoir research  

E-Print Network [OSTI]

Starting from unstructured glass microchannels, we develop a new method of micromodel fabrication. We build composite structures in a bottom-up manner with ultraviolet projection lithography where the composite structures ...

Lee, Hyundo

2014-01-01T23:59:59.000Z

431

Dehydrogenation of liquid fuel in microchannel catalytic reactor  

DOE Patents [OSTI]

The present invention is an improved process for the storage and delivery of hydrogen by the reversible hydrogenation/dehydrogenation of an organic compound wherein the organic compound is initially in its hydrogenated state. The improvement in the route to generating hydrogen is in the dehydrogenation step and recovery of the dehydrogenated organic compound resides in the following steps: introducing a hydrogenated organic compound to a microchannel reactor incorporating a dehydrogenation catalyst; effecting dehydrogenation of said hydrogenated organic compound under conditions whereby said hydrogenated organic compound is present as a liquid phase; generating a reaction product comprised of a liquid phase dehydrogenated organic compound and gaseous hydrogen; separating the liquid phase dehydrogenated organic compound from gaseous hydrogen; and, recovering the hydrogen and liquid phase dehydrogenated organic compound.

Toseland, Bernard Allen (Coopersburg, PA); Pez, Guido Peter (Allentown, PA); Puri, Pushpinder Singh (Emmaus, PA)

2010-08-03T23:59:59.000Z

432

Axially Tapered And Bilayer Microchannels For Evaporative Cooling Devices  

DOE Patents [OSTI]

The invention consists of an evaporative cooling device comprising one or more microchannels whose cross section is axially reduced to control the maximum capillary pressure differential between liquid and vapor phases. In one embodiment, the evaporation channels have a rectangular cross section that is reduced in width along a flow path. In another embodiment, channels of fixed width are patterned with an array of microfabricated post-like features such that the feature size and spacing are gradually reduced along the flow path. Other embodiments incorporate bilayer channels consisting of an upper cover plate having a pattern of slots or holes of axially decreasing size and a lower fluid flow layer having channel widths substantially greater than the characteristic microscale dimensions of the patterned cover plate. The small dimensions of the cover plate holes afford large capillary pressure differentials while the larger dimensions of the lower region reduce viscous flow resistance.

Nilson, Robert (Cardiff, CA); Griffiths, Stewart (Livermore, CA)

2005-10-04T23:59:59.000Z

433

Collimator application for microchannel plate image intensifier resolution improvement  

DOE Patents [OSTI]

A collimator is included in a microchannel plate image intensifier (MCPI). Collimators can be useful in improving resolution of MCPIs by eliminating the scattered electron problem and by limiting the transverse energy of electrons reaching the screen. Due to its optical absorption, a collimator will also increase the extinction ratio of an intensifier by approximately an order of magnitude. Additionally, the smooth surface of the collimator will permit a higher focusing field to be employed in the MCP-to-collimator region than is currently permitted in the MCP-to-screen region by the relatively rough and fragile aluminum layer covering the screen. Coating the MCP and collimator surfaces with aluminum oxide appears to permit additional significant increases in the field strength, resulting in better resolution. 2 figs.

Thomas, S.W.

1996-02-27T23:59:59.000Z

434

High density, optically corrected, micro-channel cooled, v-groove monolithic laser diode array  

DOE Patents [OSTI]

An optically corrected, micro-channel cooled, high density laser diode array achieves stacking pitches to 33 bars/cm by mounting laser diodes into V-shaped grooves. This design will deliver > 4kW/cm{sup 2} of directional pulsed laser power. This optically corrected, micro-channel cooled, high density laser is usable in all solid state laser systems which require efficient, directional, narrow bandwidth, high optical power density pump sources. 13 figs.

Freitas, B.L.

1998-10-27T23:59:59.000Z

435

E-Print Network 3.0 - adiabatic compression heating Sample Search...  

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

Heating 12;Adiabatic Descending... and Diabatic Adiabatic means occurring without loss or gain of heat. Diabatic means occurring... with an exchange of heat. ... Source:...

436

Lightning Dock Geothermal Space Heating Project: Lightning Dock...  

Open Energy Info (EERE)

and home heating systems, which consisted of pumping geothermal water and steam through passive steam heaters, and convert the systems to one using modern heat exchange units. It...

437

Heat Integrate Heat Engines in Process Plants  

E-Print Network [OSTI]

and refrigeration systems. In many instances these real heat engines may appear as a complex process consisting of flash vessels, heat exchangers, compressors, furnaces, etc. See Figure 18a, which shows a simplified diagram of a "steam Rankine cycle." How... and rejection profiles of the real machine. For example, the heat acceptance and re jection profiles for the steam Rankine cycle shown in Figure 18a have been drawn on T,H coordinates in Figure 18b. Thus providing we know the heat acceptance and rejection...

Hindmarsh, E.; Boland, D.; Townsend, D. W.

438

Infrared Thermography applied to measurement of Heat transfer coefficient of water in a pipe heated by Joule effect  

E-Print Network [OSTI]

)" #12;1. Introduction Brazed aluminium heat exchangers are composed of flat tubes on the refrigerant exchangers with round tube, such as charge reduction and higher heat transfer coefficient. But, according are thus not suitable to small-channel heat exchangers. As a consequence, the refrigerant distribution

Boyer, Edmond

439

Waste Heat Recovery from Industrial Process Heating Equipment -  

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

Waste Heat Recovery from Industrial Process Heating Equipment - Waste Heat Recovery from Industrial Process Heating Equipment - Cross-cutting Research and Development Priorities Speaker(s): Sachin Nimbalkar Date: January 17, 2013 - 11:00am Location: 90-2063 Seminar Host/Point of Contact: Aimee McKane Waste heat is generated from several industrial systems used in manufacturing. The waste heat sources are distributed throughout a plant. The largest source for most industries is exhaust / flue gases or heated air from heating systems. This includes the high temperature gases from burners in process heating, lower temperature gases from heat treat, dryers, and heaters, heat from heat exchangers, cooling liquids and gases etc. The previous studies and direct contact with the industry as well as equipment suppliers have shown that a large amount of waste heat is not

440

Technical Information Exchange on Pyrolysis Oil: Potential for...  

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

Renewab;e Heating Oil Substation Fuel in New England Technical Information Exchange on Pyrolysis Oil: Potential for a Renewab;e Heating Oil Substation Fuel in New England This...

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Ultrafast gating of proximity-focused microchannel-plate intensifiers  

SciTech Connect (OSTI)

Proximity-focused, microchannel-plate (MCP) image intensifiers have been used at Los Alamos for many years to allow single frame film and video exposure times in the range of 2.5 to 10 ns. There is now a program to reduce gating times to < 1 ns. This paper reviews previous work and the problems in achieving good resolution with gating times of < 1 ns. The key problems involve applying fast electrical gating signals to the tube elements. We present computer modeling studies of the combined tube, tube connection, and pulser system and show that low photocathode surface resistivity must be obtained to permit fast gating between the photocathode and the MCP input. We discuss ways of making low-resistivity S20 photocathodes, using gallium arsenide photocathodes, and various means of gating the tubes. A variety of pulser designs are being experimentally evaluated including spark gaps, avalanche transistors, Krytron tubes with sharpening gaps, step recovery diodes, and photoconductive elements (PCEs). The results of these studies are presented. Because of the high capacitances involved in most gating schemes, the tube connection geometry must be of low-impedance design, and our solution is presented. Finally, ways of testing these high-speed camera systems are discussed.

Lundy, A.S.; Iverson, A.E.

1982-01-01T23:59:59.000Z

442

Note: Precision viscosity measurement using suspended microchannel resonators  

SciTech Connect (OSTI)

We report the characterization of a suspended microchannel resonator (SMR) for viscosity measurements in a low viscosity regime (<10 mPa s) using two measurement schemes. First, the quality factor (Q-factor) of the SMR was characterized with glycerol-water mixtures. The measured Q-factor at 20 Degree-Sign C exhibits a bilinear behavior with the sensitivity of 1281 (mPa s){sup -1} for a lower (1-4 mPa s) and 355 (mPa s){sup -1} for a higher viscosity range (4-8 mPa s), respectively. The second scheme is the vibration amplitude monitoring of the SMR running in a closed loop feedback. When compared in terms of the measurement time, the amplitude-based measurement takes only 0.1 {approx} 1 ms while the Q-factor-based measurement takes {approx}30 s. However, the viscosity resolution of the Q-factor-based measurement is at least three times better than the amplitude-based measurement. By comparing the Q-factors of heavy water and 9.65 wt.% glycerol-water mixture that have very similar viscosities but different densities, we confirmed that the SMR can measure the dynamic viscosity without the density correction. The obtained results demonstrate that the SMR can measure the fluid viscosity with high precision and even real-time monitoring of the viscosity change is possible with the amplitude-based measurement scheme.

Lee, I.; Lee, J. [Department of Mechanical Engineering, Sogang University, Seoul 121-742 (Korea, Republic of); Park, K. [Department of Mechanical, Industrial, and Systems Engineering, University of Rhode Island, Kingston, Rhode Island 02881 (United States)

2012-11-15T23:59:59.000Z

443

Geothermal Heat Pump Basics | Department of Energy  

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

Heat Pump Basics Heat Pump Basics Geothermal Heat Pump Basics August 19, 2013 - 11:12am Addthis Text Version 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. Depending on the latitude, ground temperatures range from 45°F (7°C) to 75°F (21°C). So, like a cave's, the ground's temperature is warmer than the air above it during winter and cooler than the air above it in summer. Geothermal heat pumps take advantage of this by exchanging heat with the earth through a ground heat exchanger. Geothermal heat pumps are able to heat, cool, and, if so equipped, supply

444

Method for controlling exhaust gas heat recovery systems in vehicles  

DOE Patents [OSTI]

A method of operating a vehicle including an engine, a transmission, an exhaust gas heat recovery (EGHR) heat exchanger, and an oil-to-water heat exchanger providing selective heat-exchange communication between the engine and transmission. The method includes controlling a two-way valve, which is configured to be set to one of an engine position and a transmission position. The engine position allows heat-exchange communication between the EGHR heat exchanger and the engine, but does not allow heat-exchange communication between the EGHR heat exchanger and the oil-to-water heat exchanger. The transmission position allows heat-exchange communication between the EGHR heat exchanger, the oil-to-water heat exchanger, and the engine. The method also includes monitoring an ambient air temperature and comparing the monitored ambient air temperature to a predetermined cold ambient temperature. If the monitored ambient air temperature is greater than the predetermined cold ambient temperature, the two-way valve is set to the transmission position.

Spohn, Brian L.; Claypole, George M.; Starr, Richard D

2013-06-11T23:59:59.000Z

445

Low-Cost Manufacturable Microchannel Systems for Passive PEM Water Management  

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

Manufacturable Manufacturable Microchannel Systems for Passive PEM Water Management IIPS Number 16910 Low Low - - Cost Cost Manufacturable Manufacturable Microchannel Systems for Passive Microchannel Systems for Passive PEM Water Management PEM Water Management IIPS Number 16910 IIPS Number 16910 Ward TeGrotenhuis, Susie Stenkamp, Curt Lavender Pacific Northwest National Laboratories Richland, WA HFCIT Kick Off Meeting February 2007 2 Project objective: Create a low cost and passive PEM water management system Project objective: Project objective: Create a low cost Create a low cost and passive PEM water management system and passive PEM water management system Specific Targets Addressed for 3.4.2 Automotive-Scale: 80 kWe Integrated Transportation Fuel Cell Power Systems Operating on Direct Hydrogen

446

Neuronal micro-culture engineering by microchannel devices of cellular scale dimensions  

E-Print Network [OSTI]

Purpose: The purpose of the current study was to investigate the effect of microchannel geometry on neuronal cultures and to maintain these cultures for long period of time (over several weeks) inside the closed microchannels of cellular scale dimensions. Methods: The primary hippocampal neurons from E-18 rat were cultured inside the closed polydimethylsiloxane (PDMS) microchannels of varying sizes. The effect of the channel geometry on the spatial and the temporal variations in the neural microenvironment was investigated by studying neural maturation and variation in the media osmolality respectively. The cultures were maintained for longer time spans by PDMS device pretreatment, control on media evaporation (by using hydrophobic ethylene propylene membrane) and an effective culture maintenance protocol. Further, the devices were integrated with the planar microelectrode arrays (MEA) to record spontaneous electrical activity. Results: A direct influence of channel geometry on neuron maturation was observed ...

Goyal, Gaurav

2015-01-01T23:59:59.000Z

447

Technical Note Solution of periodic heating problems by the  

E-Print Network [OSTI]

.R. Barber * Department of Mechanical Engineering, 2250 GG Brown Laboratory, University of Michigan, Ann in sliding solids [2], regenerative heat exchangers [3], solar heating systems [4] and heat con- duction

Barber, James R.

448

Vrmeverfring i bergvrmesystem; Heat transfer in ground source heat pump systems.  

E-Print Network [OSTI]

?? The borehole heat exchangers of today suffer from poor thermal and hydrodynamic performance. The purpose of this thesis is to improve the performance of (more)

Westin, Rasmus

2012-01-01T23:59:59.000Z

449

A Lightweight Material for Heat Exchange Applications  

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

(UHMW-PE) fiber and sheet production that will result in a thermally conductive plastic material. A number of lab-scale studies have shown that thermal conductivity is im-...

450

Sulfidation of coal gasifier heat exchanger alloys  

Science Journals Connector (OSTI)

Three steels, viz., INCOLOY* 800H, Fecralloy, and AlSI 310, were exposed to a simulated low Btu coal gasifier product gas at 450 C. Sulfidation...

S. R. J. Saunders; S. Schlierer

1986-03-01T23:59:59.000Z

451

Building-Integrated Heat & Moisture Exchange  

Energy Savers [EERE]

ventilation energy benefit as well as the insulation benefit of this hybrid envelopehvac technology. 2 Purpose and Objectives Problem Statement: State-of-the-industry energy...

452

Heat Exchanger Technologies for Distillation Columns  

E-Print Network [OSTI]

Conference, Houston, TX, April 16-19, 2002 Downcomer Ii IMass Transfer Ales I Hem Transrer Surf':lce I I I i i i i IDo-.>m" I Vapour Flow Figure 5. Alternative Inlegral Condenser Design Engineers unfamiliar with the thermodynamics of distillation...

Polley, G. T.

453

Heat Pump System Basics | Department of Energy  

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

Heat Pump System Basics Heat Pump System Basics Heat Pump System Basics August 19, 2013 - 11:02am Addthis Like a refrigerator, heat pumps use electricity to move heat from a cool space into a warm space, making the cool space cooler and the warm space warmer. Because they move heat rather than generate heat, heat pumps can provide up to four times the amount of energy they consume. Air-Source Heat Pump Transfers heat between the inside of a building and the outside air. Ductless Mini-Split Heat Pump Ductless versions of air-source heat pumps. Absorption Heat Pump Uses heat as its energy source. Geothermal Heat Pumps Use the constant temperature of the earth as the exchange medium instead of the outside air temperature. Addthis Related Articles A heat pump can provide an alternative to using your air conditioner. | Photo courtesy of iStockPhoto/LordRunar.

454

AN ARTIFICIAL NEURAL NETWORK FOR DIMENSIONS AND COST MODELLING OF INTERNAL MICRO-CHANNELS  

E-Print Network [OSTI]

AN ARTIFICIAL NEURAL NETWORK FOR DIMENSIONS AND COST MODELLING OF INTERNAL MICRO Engineering, Dublin City University, Dublin, Ireland ABSTRACT For micro-channel fabrication using laser micro evaluation. Artificial Neural Network (ANN) is one of the numerical methodologies that can be utilised

Lee, Hyowon

455

Numerical Simulation of Descending Curves Sinusoidal Microchannel for Cell Separation System  

Science Journals Connector (OSTI)

This paper deals with a new design of cell separation system. The presented system consists of focusing channel, cell separation device, micro pump, fluid flow sensor, sample storage unit, electronic circuit, central processing unit (CPU), micro controller, ... Keywords: Microfluidics, Microchannels, Cell separation system, Computational fluid dynamic (CFD)

Muhammad Waseem Ashraf; Shahzadi Tayyaba; Muhammad Ishaque; Nitin Afzulpurkar

2012-05-01T23:59:59.000Z

456

Lattice Boltzmann Simulations of Droplet Formation in a T-Shaped Microchannel  

Science Journals Connector (OSTI)

Lattice Boltzmann Simulations of Droplet Formation in a T-Shaped Microchannel ... Droplet formation was simulated with the lattice Boltzmann method, a method suitable for modeling on the mesoscale. ... We validated the lattice Boltzmann code with several benchmarks such as the flow profile in a rectangular channel, droplet deformation between two shearing plates, and a sessile drop on a plate with different wetting conditions. ...

S. van der Graaf; T. Nisisako; C. G. P. H. Schron; R. G. M. van der Sman; R. M. Boom

2006-03-25T23:59:59.000Z

457

Anisotropic particles align perpendicular to the flow direction in narrow microchannels  

Science Journals Connector (OSTI)

...microfluidic device is fabricated using optical lithography (27). The microchannel network is designed in AutoCAD 2011 (Autodesk) and printed on a mask foil with a UV-absorbent ink (Zitzmann GmbH). An inverse black and white image of the device design...

Martin Trebbin; Dagmar Steinhauser; Jan Perlich; Adeline Buffet; Stephan V. Roth; Walter Zimmermann; Julian Thiele; Stephan Frster

2013-01-01T23:59:59.000Z

458

Mixing in wicking structures and the use of enhanced mixing within wicks in microchannel devices  

DOE Patents [OSTI]

Advanced wicking structures and methods utilizing these structures are described. The use of advanced wicking structures can promote rapid mass transfer while maintaining high capillary pressure through the use of small pores. Particularly improved results in fluid contacting processes can be achieved by enhanced mixing within a wicking layer within a microchannel.

Stenkamp, Victoria S. (Richland, WA); TeGrotenhuis, Ward E. (Kennewick, WA); Wegeng, Robert S. (Alexandria, VA)

2009-06-02T23:59:59.000Z

459

Experimental investigations about using the earth as a heat storage medium and as a heat source for heat pumps. Final report  

SciTech Connect (OSTI)

The main purpose of the experimental investigation was to verify the computer program for calculating horizontal earth heat exchangers under practical conditions. The heat extraction from and the temperature distribution in the earth around the tubes of a horizontal earth heat exchanger were measured.

Nievergeld, P.; Koppenol, A.; van der Brugh, J.

1981-03-01T23:59:59.000Z

460

Geothermal Heat Pumps | Department of Energy  

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

Geothermal Heat Pumps Geothermal Heat Pumps Geothermal Heat Pumps June 24, 2012 - 5:08pm Addthis Watch how geothermal heat pumps heat and cool buildings by concentrating the naturally existing heat contained within the earth -- a clean, reliable, and renewable source of energy. How does it work? A geothermal heat pump uses the constant below ground temperature of soil or water to heat and cool your home. Geothermal heat pumps (GHPs), sometimes referred to as GeoExchange, earth-coupled, ground-source, or water-source heat pumps, have been in use since the late 1940s. They use the constant temperature of the earth as the exchange medium instead of the outside air temperature. This allows the system to reach fairly high efficiencies (300% to 600%) on the coldest winter nights, compared to 175% to 250% for air-source heat pumps on cool

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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461

The CO2 Reduction Potential of Combined Heat and Power in California's Commercial Buildings  

E-Print Network [OSTI]

P.C. (2001), Introduction to Advancd Batteries for EmergingPV) and solar thermal collectors; conventional batteries,flow batteries, and heat storage; heat exchangers for

Stadler, Michael

2010-01-01T23:59:59.000Z

462

Computational fluid dynamic modelling of enhanced heat transfer in tubes with inserts.  

E-Print Network [OSTI]

??Heat transfer is an important process in many different industrial processes including oil refming and energy generation. A shell and tube heat exchanger is one (more)

Osley, William Gruffydd

2014-01-01T23:59:59.000Z

463

E-Print Network 3.0 - additional direct heat Sample Search Results  

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

HEAT PUMP SYSTEM FIELD TESTS AT THE TECH COMPLEX Summary: .2, an additional 43% loss. Heat losses observed at the compressorheat exchangers, a necessary condition......

464

Proceedings of the Sixth International ASME Conference on Nanochannels, Microchannels and Minichannels June 23-25, 2008, Darmstadt, Germany  

E-Print Network [OSTI]

Proceedings of the Sixth International ASME Conference on Nanochannels, Microchannels TRANSFER IN MICROSCALE SINGLE PHASE FLOW: A CRITICAL REVIEW Perry L. Young Rochester Institute of Technology PerryLYoung@gmail.com Satish G. Kandlikar Rochester Institute of Technology sgkeme

Kandlikar, Satish

465

Fabrication of a Hybrid Microfluidic System Incorporating both Lithographically Patterned Microchannels and a 3D Fiber-Formed Microfluidic Network  

E-Print Network [OSTI]

A device containing a 3D microchannel network (fabricated using sacrificial melt-spun microfibers) sandwiched between lithographically patterned microfluidic channels offers improved delivery of soluble compounds to a large ...

Bellan, Leon M.

466

Task II: evaluation of heat-exchanger and turbine materials for use in a coal-fired fluidized-bed-combustion environment. Final report, July 1, 1976-July 31, 1980  

SciTech Connect (OSTI)

Specific alloys were tested as in-bed and above-bed heat exchanger materials in the fireside environment of a pressurized fluidized bed coal combustor (PFBCC). Corrosion conditions on the alloys exposed to normal and very low oxygen pressures in the presence of calcium sulfate deposits were simulated. Bayonet-type specimen probes of selected alloys were exposed in the Exxon Miniplant at probe control temperatures representative of conventional steam, advanced steam, helium and liquid metal energy conversion cycles. Corrosion/erosion testing of the air cooled, welded samples consisted of a 117-hour shakedown run followed by an incremental 1000-hour exposure. Metallurgical analyses were run on removed specimens. The test matrix for in-bed and above-bed exposure was: 1050/sup 0/F (566/sup 0/C): 2.25 Cr-1Mo and 9Cr-1Mo steels (in-bed only); 1200/sup 0/F (649/sup 0/C): 304 SS and Incoloy-800; 1400/sup 0/F (760/sup 0/C): Incoloy-800 and Hastelloy-X; and 1600/sup 0/F (871/sup 0/C); Hastelloy-X and Haynes-188. Subscale sulfides formed in most of the alloys. The most severe corrosion was noted in the ferritic 2.25Cr-1Mo and 9Cr-1Mo steels at a nominal control temperature of 1050/sup 0/F (566/sup 0/C) and in Hastelloy-X at 1400/sup 0/F (760/sup 0/C) exposed in-bed. The best overall behavior of in-bed alloys was observed for Incoloy-800, which had a maximum metal loss of about .007 in (.18 mm) in 1117 hours of exposure at both 1200/sup 0/F (649/sup 0/C) and 1400/sup 0/F (760/sup 0/C) but averaged more nearly .001 in (.025 mm) to .002 in (.051 mm) and in Haynes-188 which showed maximum wall thinning of less than .003 in (.076 mm) at 1600/sup 0/F (871/sup 0/C) in the longest time exposure.

Not Available

1981-09-30T23:59:59.000Z

467

Psychology on Exchange InternationalExchangeProgram  

E-Print Network [OSTI]

Psychology on Exchange InternationalExchangeProgram Psychology majors are welcome to apply Honours, you need to take into account the advice from the Department of Psychology (http://sydney.edu.au/ current_students/student_exchange/forms_downloads.shtml). Timing To meet Australian Psychology

Viglas, Anastasios

468

Heat pump system with selective space cooling  

DOE Patents [OSTI]

A reversible heat pump provides multiple heating and cooling modes and includes a compressor, an evaporator and heat exchanger all interconnected and charged with refrigerant fluid. The heat exchanger includes tanks connected in series to the water supply and a condenser feed line with heat transfer sections connected in counterflow relationship. The heat pump has an accumulator and suction line for the refrigerant fluid upstream of the compressor. Sub-cool transfer tubes associated with the accumulator/suction line reclaim a portion of the heat from the heat exchanger. A reversing valve switches between heating/cooling modes. A first bypass is operative to direct the refrigerant fluid around the sub-cool transfer tubes in the space cooling only mode and during which an expansion valve is utilized upstream of the evaporator/indoor coil. A second bypass is provided around the expansion valve. A programmable microprocessor activates the first bypass in the cooling only mode and deactivates the second bypass, and vice-versa in the multiple heating modes for said heat exchanger. In the heating modes, the evaporator may include an auxiliary outdoor coil for direct supplemental heat dissipation into ambient air. In the multiple heating modes, the condensed refrigerant fluid is regulated by a flow control valve. 4 figs.

Pendergrass, J.C.

1997-05-13T23:59:59.000Z

469

Heat pump system with selective space cooling  

DOE Patents [OSTI]

A reversible heat pump provides multiple heating and cooling modes and includes a compressor, an evaporator and heat exchanger all interconnected and charged with refrigerant fluid. The heat exchanger includes tanks connected in series to the water supply and a condenser feed line with heat transfer sections connected in counterflow relationship. The heat pump has an accumulator and suction line for the refrigerant fluid upstream of the compressor. Sub-cool transfer tubes associated with the accumulator/suction line reclaim a portion of the heat from the heat exchanger. A reversing valve switches between heating/cooling modes. A first bypass is operative to direct the refrigerant fluid around the sub-cool transfer tubes in the space cooling only mode and during which an expansion valve is utilized upstream of the evaporator/indoor coil. A second bypass is provided around the expansion valve. A programmable microprocessor activates the first bypass in the cooling only mode and deactivates the second bypass, and vice-versa in the multiple heating modes for said heat exchanger. In the heating modes, the evaporator may include an auxiliary outdoor coil for direct supplemental heat dissipation into ambient air. In the multiple heating modes, the condensed refrigerant fluid is regulated by a flow control valve.

Pendergrass, Joseph C. (Gainesville, GA)

1997-01-01T23:59:59.000Z

470

Hydroxide absorption heat pumps with spray absorber  

SciTech Connect (OSTI)

The absorber is one of the most expensive components of an absorption heat pump or chiller, respectively. In order to reduce the cost of a heat exchanger, much effort is invested into searching for additives for heat transfer enhancement. Another way to reduce heat exchange