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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 active 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); Roberts, Gary L. (West Richland, WA); Call, Charles J. (Pasco, WA); Wegeng, Robert S. (Richland, WA); Wang, Yong (Richland, WA)

2001-01-01T23:59:59.000Z

2

Microchannel Heat Exchangers with Carbon Dioxide  

Science Conference Proceedings (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

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

E-Print Network (OSTI)

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

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

2012-01-01T23:59:59.000Z

4

The Geometric Characterization and Thermal Performance of a Microchannel Heat Exchanger  

E-Print Network (OSTI)

The Geometric Characterization and Thermal Performance of a Microchannel Heat Exchanger for Diesel exchanger that extracts the heat from the exhaust. In this study, a cross-flow microchannel heat exchanger was geometrically examined and thermally tested under laboratory conditions. The heat exchanger, referred

Tullos, Desiree

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

1985-01-01T23:59:59.000Z

6

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

7

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

8

Efficient, Low-cost Microchannel Heat Exchanger  

? Buildings (chillers, cooling towers, heat pump water heaters) ... ? Renewable energy (concentrated solar power, residential solar hot water,

9

NUMERICAL MODELING AND OPTIMIZATION OF SINGLE PHASE MANIFOLD-MICROCHANNEL PLATE HEAT EXCHANGER.  

E-Print Network (OSTI)

??In recent years manifold-microchannel technology has received considerable attention from the research community as it has demonstrated clear advantage over state of the art heat… (more)

Arie, Martinus Adrian

2012-01-01T23:59:59.000Z

10

Effective material usage in a compact heat exchanger with periodic micro-channels / Bertus George Kleynhans.  

E-Print Network (OSTI)

??All modern High Temperature Reactors (HTR) thermal cycles have one thing in common: the use of some form of heat exchanger. This heat exchanger is… (more)

Kleynhans, Bertus George

2012-01-01T23:59:59.000Z

11

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

12

Experimental study of xurographic microchannel single-pass single-phase counterflow heat exchanger.  

E-Print Network (OSTI)

??Xurography is a relatively inexpensive rapid prototyping microfabrication method used to manufacture microfluidic devices. An experimental study of water flow in rectangular xurographic microchannel counterflow… (more)

Alshareef, Sultan M.

2012-01-01T23:59:59.000Z

13

Thermal Performance of the Multilayered Honeycomb Microchannel Heat Sink  

Science Conference Proceedings (OSTI)

To develop a high effectiveness, reliable, cost-effective compact heat exchanger is one of the key issues for effective use of thermal energy. By stacking multilayered flat thin rectangular plates with a number of regular honeycomb cells etched inside, ... Keywords: multilayer, honeycomb, microchannel, heat sink

Yonglu Liu; Xiaobing Luo; Wei Liu; Zhifeng Huang

2009-10-01T23:59:59.000Z

14

Development and Evaluation of Brazed Joints for a Plate Microchnanel Heat Exchanger.  

E-Print Network (OSTI)

??A brazing method is developed for high efficiency microchannel heat plate heat exchangers for waste heat recovery. Prototype elements for these heat exchangers are fabricated… (more)

Craymer, Kenneth L.

2011-01-01T23:59:59.000Z

15

Carbon nanotube heat-exchange systems  

DOE Patents (OSTI)

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

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

2008-11-11T23:59:59.000Z

16

Microelectronic chip cooling: an experimental assessment of a liquid-passing heat sink, a microchannel heat rejection module, and a microchannel-based recirculating-liquid cooling system  

Science Conference Proceedings (OSTI)

Results of heat transfer testing of heat absorption modules (HAM), heat rejection modules (HRM), and a recirculating-liquid cooling system are reported. Low-profile, Cu-based, microchannel heat exchangers (MHEs) were fabricated and used as the HAM as ...

Bin Lu; W. J. Meng; Fanghua Mei

2012-03-01T23:59:59.000Z

17

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)

[No author

2010-01-01T23:59:59.000Z

18

Heat exchanger  

DOE Patents (OSTI)

A heat exchanger is provided having first and second fluid chambers for passing primary and secondary fluids. The chambers are spaced apart and have heat pipes extending from inside one chamber to inside the other chamber. A third chamber is provided for passing a purge fluid, and the heat pipe portion between the first and second chambers lies within the third chamber.

Daman, Ernest L. (Westfield, NJ); McCallister, Robert A. (Mountain Lakes, NJ)

1979-01-01T23:59:59.000Z

19

HEAT EXCHANGER  

DOE Patents (OSTI)

A heat exchanger is designed for use in the transfer of heat between a radioactive fiuid and a non-radioactive fiuid. The exchanger employs a removable section containing the non-hazardous fluid extending into the section designed to contain the radioactive fluid. The removable section is provided with a construction to cancel out thermal stresses. The stationary section is pressurized to prevent leakage of the radioactive fiuid and to maintain a safe, desirable level for this fiuid. (AEC)

Fox, T.H. III; Richey, T. Jr.; Winders, G.R.

1962-10-23T23:59:59.000Z

20

Heat exchanger  

DOE Patents (OSTI)

A heat exchanger of the straight tube type in which different rates of thermal expansion between the straight tubes and the supply pipes furnishing fluid to those tubes do not result in tube failures. The supply pipes each contain a section which is of helical configuration.

Wolowodiuk, Walter (New Providence, NJ)

1976-01-06T23:59:59.000Z

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

Heat Exchangers  

Science Conference Proceedings (OSTI)

Table 16   Ceramic heat exchanger systems...Soaking pit 870â??1230 1600â??2250 Fe, Si, alkalis Solar Turbines â?¦ 4â??8 OD Ă? 180 long (440 tubes) Aluminum melt furnaces 1010 1850 Alkali salts Plate fin GTE 0.6, 1.6 25â??46 Multiple 870â??1370 1600â??2250 Clean (good), alkalis (poor) Coors 0.25, 1.0 30 Ă? 30 Ă? 46 Multiple Clean (good), alkalis (poor) Radiant...

22

Corrosive resistant heat exchanger  

DOE Patents (OSTI)

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

Richlen, Scott L. (Annandale, VA)

1989-01-01T23:59:59.000Z

23

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

24

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

25

Heat pipe array heat exchanger  

DOE Patents (OSTI)

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

Reimann, Robert C. (Lafayette, NY)

1987-08-25T23:59:59.000Z

26

SMALL PARTICLE HEAT EXCHANGERS  

E-Print Network (OSTI)

ON ~m Small Particle Heat Exchangers Arion J. Hunt June 1978d. LBL 7841 Small Particle Heat Exchangers by Arlon J. Huntgenerally to non-solar heat exchangers. These may be of the

Hunt, A.J.

2011-01-01T23:59:59.000Z

27

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

28

Woven heat exchanger  

DOE Patents (OSTI)

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, Roger R. (Idaho Falls, ID)

1987-01-01T23:59:59.000Z

29

Development of a novel ceramic microchannel reactor for methane steam reforming.  

E-Print Network (OSTI)

??Microchannel heat exchanger and reactor technology has recently gained interest as an innovative way to improve heat-exchanger efficiency, reduce size and weight, and utilize thermal… (more)

Murphy, Danielle M.

2013-01-01T23:59:59.000Z

30

Direct fired heat exchanger  

DOE Patents (OSTI)

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

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

1986-01-01T23:59:59.000Z

31

Heat Transfer and Pressure Drop During Condensation of Refrigerants in Microchannels .  

E-Print Network (OSTI)

??Two-phase flow, boiling, and condensation in microchannels have received considerable attention in the recent past due to the growing interest in the high heat fluxes… (more)

Agarwal, Akhil

2006-01-01T23:59:59.000Z

32

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

33

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 for performing the experimental measurements. TFT arrays were designed (which included design of photomask layout), microfabricated, packaged and assembled for testing with the experimental apparatus. Heat removal rates from the heated surface to the different testing fluids were measured by varying the coolant flow rates, wall temperatures, nanoparticle material, nanoparticle morphology (shape and nanoparticle size) as well as mass concentrations of nanoparticles in the coolants. Anomalous thermal behavior was observed in the forced convective heat transfer experiments. Precipitation of the nanoparticles on the heat exchanging surface was monitored using Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray spectroscopy (EDX). Isolated precipitation of nanoparticles is expected to cause formation of “nanofins” leading to enhancement of surface area and thus resulting in enhanced convective heat transfer to the nanofluid coolants. However, excessive precipitation (caused due to the agglomeration of the nanoparticles in the nanofluid coolant) causes scaling (fouling) of the heat exchanging surfaces and thus results in degradation of convective heat transfer. This study shows that the surface morphology plays a crucial role in determining the efficacy of convective heat transfer involving suspensions of nanoparticles in coolants (or nanofluids). Flow visualization and quantitative estimation of near-wall temperature profiles were performed using quantum dots and fluorescent dyes. This non-contact measurement technique for temperature and flow profiles in microchannels using quantum dots is expected to make pioneering contribution to the field of experimental flow visualization and to the study of micro/nano-scale heat transfer phenomena, particularly for forced convective heat transfer of various coolants, including nanofluids. Logical extensions of this study were explored and future directions were proposed. Preliminary experiments to demonstrate feasibility showed significant enhancement in the flow boiling heat flux values for nanofluids compared to that of pure solvent (DIW). Based on the novel phenomena observed in this study several other topics for future research were suggested, such as, using Surface Plasmon Resonance (SPR) platforms to monitor precipitation of nanoparticles on microchannel surfaces in real time (e.g., for generating surface isotherms).

Yu, Jiwon 1982-

2012-12-01T23:59:59.000Z

34

Heat and mass exchanger  

Science Conference Proceedings (OSTI)

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

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

2011-06-28T23:59:59.000Z

35

A corrosive resistant heat exchanger  

DOE Patents (OSTI)

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

Richlen, S.L.

1987-08-10T23:59:59.000Z

36

Greywater heat exchanger  

SciTech Connect

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

Holmberg, D.

1983-11-21T23:59:59.000Z

37

Classical Heat Exchanger Analysis  

Science Conference Proceedings (OSTI)

The industry methodology for heat exchanger performance and uncertainty analysis has been successful in dealing with the requirements of the Nuclear Regulatory Commission (NRC) issued in 1989 for safety-related service water systems, but has been found to have several significant limitations. The general objective of this report is to improve the industry performance and uncertainty analysis methodology and guidelines for implementation and analysis of heat exchanger performance. ...

2013-05-31T23:59:59.000Z

38

Radial flow heat exchanger  

DOE Patents (OSTI)

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

Valenzuela, Javier (Hanover, NH)

2001-01-01T23:59:59.000Z

39

Modular heat exchanger  

DOE Patents (OSTI)

A heat exchanger for use in nuclear reactors includes a heat exchange tube bundle formed from similar modules each having a hexagonal shroud containing a large number of thermally conductive tubes which are connected with inlet and outlet headers at opposite ends of each module, the respective headers being adapted for interconnection with suitable inlet and outlet manifold means. In order to adapt the heat exchanger for operation in a high temperature and high pressure environment and to provide access to all tube ports at opposite ends of the tube bundle, a spherical tube sheet is arranged in sealed relation across the chamber with an elongated duct extending outwardly therefrom to provide manifold means for interconnection with the opposite end of the tube bundle.

Culver, Donald W. (Poway, CA)

1978-01-01T23:59:59.000Z

40

The Neural Heat Exchanger  

E-Print Network (OSTI)

The "Neural Heat Exchanger" is an alternative, supervised learning method for multi-layer neural nets. It is inspired by the physical heat exchanger. Unlike backprop, it is entirely local. This makes its parallel implementation trivial. It was first presented during occasional talks since 1990, and is closely related to Hinton et. al.'s recent Helmholtz Machine (1995). For the first time, this paper presents the basic ideas in written form. To fully understand the Neural Heat Exchanger's advantages and limitations, however, much theoretical and empirical work remains to be done. 1 Introduction Most conventional supervised algorithms for multi-layer neural nets are not local in space and time. Backprop, for instance, requires a global control mechanism that first propagates activation signals through all successive layers, then waits until the error signals come back, then changes the weights. Many suspect, however, that the brain does use an entirely local algorithm. One advantage of...

Jürgen Schmidhuber

1996-01-01T23:59:59.000Z

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.


41

Heat transfer and heat exchangers reference handbook  

Science Conference Proceedings (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

42

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

43

Predicting particle deposition on HVAC heat exchangers  

E-Print Network (OSTI)

gas-side of finned tube heat- exchangers. Journal of Heatsurface interactions in heat exchanger fouling. Journal ofParticle Deposition on Heat Exchangers Epstein, N. , 1988.

Siegel, J A; Nazaroff, William W

2003-01-01T23:59:59.000Z

44

THERMOSIPHON WATER HEATERS WITH HEAT EXCHANGERS  

E-Print Network (OSTI)

the collector and heat exchanger (Uc and Uhel · ~Constant tNational Standard, "Solar Heat Exchangers," ANSI/ASME SES 1,connecting pipes header heat exchanger insulation maximum

Mertol, Atila

2012-01-01T23:59:59.000Z

45

Heat exchanger tube mounts  

DOE Patents (OSTI)

A heat exchanger in which tubes are secured to a tube sheet by internal bore welding is described. The tubes may be moved into place in preparation for welding with comparatively little trouble. A number of segmented tube support plates are provided which allow a considerable portion of each of the tubes to be moved laterally after the end thereof has been positioned in preparation for internal bore welding to the tube sheet. (auth)

Wolowodiuk, W.; Anelli, J.; Dawson, B.E.

1974-01-01T23:59:59.000Z

46

Flat plate heat exchangers  

SciTech Connect

A lightweight flat plate heat exchanger comprised of two or more essentially parallel flat plates which are formed and arranged to provide fluid flow passages between the plates. New combinations of plastic plates include the usage of transparent plastic foam and honeycomb structures. Improved shapes of flow passages include the usage of flow nozzles, flow diffusers, and jet pumps to increase fluid flow and heat transfer. The invention includes the usage of transparent plastic foam plates which are shaped to concentrate solar energy onto plastic tubes. Clear plastic tubes containing black heat transfer fluid are included. The invention includes the usage of spiral flow channels within plastic foam plates. Six different embodiments of the invention are included. Five of the embodiments could be used as efficient lightweight solar collectors.

Berringer, R.T.

1981-09-29T23:59:59.000Z

47

Optimization of Heat Exchanger Cleaning  

E-Print Network (OSTI)

The performance of heat integration systems is quantified in terms of the amount of heat that is recovered. This decreases with time due to increased fouling of the heat exchange surface. Using the "Total Fouling Related Expenses (TFRE)" approach, economic incentives for heat exchanger cleaning are evaluated using linear, exponential, and exponential finite decrease models of the heat recovery decay. A mathematical comparison of mechanical and chemical cleaning of heat exchangers has identified the most significant parameters which affect the choice between the two methods.

Siegell, J. H.

1986-06-01T23:59:59.000Z

48

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

E-Print Network (OSTI)

Microchannels have been studied extensively for electronic cooling applications ever since they were found to be effective in removing high heat flux from small areas. The rate of heat removed using microchannels depends on many factors including the geometry shape, solid and fluid materials used, and surface roughness, among others. Many configurations of microchannels have been studied with various materials and compared for their effectiveness in heat removal. However, there is little research done so far in using Phase Change Material (PCM) fluids and pin fins in microchannels to enhance the heat transfer. PCM fluids exhibit greater heat transfer when the phase change material undergoes liquid-to-solid transformation. Staggered pins in microchannels have also shown higher heat removal characteristics because of the continuous breaking and formation of the thermal and hydrodynamic boundary layer; they also exhibit higher pressure drop because pins act as flow obstructers. This paper presents 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). The heat transfer performance of a single phase fluid and PCM fluid in all of these microchannels and the corresponding pressure drop characteristics are also presented. An effective specific heat capacity model was used to account for the phase change process of PCM fluid. Comparison of heat transfer characteristics of single phase fluid and PCM fluid are presented for all the geometries considered. Among the straight microchannels, 1:8 geometry was found to have the highest Nusselt number. The use of PCM fluid in straight microchannels increased the Nusselt number by 3-7 percent compared to the single phase fluids. Among the staggered pin microchannels, circular pins were found to be more effective in terms of heat transfer by exhibiting higher Nusselt number. Circular pin microchannels were also found to have lower pressure drop compared to the square pin microchannels. Overall, for all the geometries considered, it was found that the PCM fluid enhances the heat transfer compared to the SPF fluid.

Kondle, Satyanarayana

2010-08-01T23:59:59.000Z

49

High Temperature Heat Exchanger Project  

Science Conference Proceedings (OSTI)

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

Anthony E. Hechanova, Ph.D.

2008-09-30T23:59:59.000Z

50

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)

1981-01-01T23:59:59.000Z

51

Modular heat exchanger  

DOE Patents (OSTI)

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

Giardina, A.R.

1981-03-03T23:59:59.000Z

52

Heat Exchangers for Solar Water Heating Systems | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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

53

Modeling particle deposition on HVAC heat exchangers  

E-Print Network (OSTI)

DEPOSITION ON HVAC HEAT EXCHANGERS JA Siegel 1,3 * and WWof fin-and-tube heat exchangers by particle deposition leadsparticle deposition on heat exchanger surfaces. We present a

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

2002-01-01T23:59:59.000Z

54

Heat exchanger using graphite foam  

DOE Patents (OSTI)

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

Campagna, Michael Joseph; Callas, James John

2012-09-25T23:59:59.000Z

55

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

56

Dependency of Heat Transfer Rate on the Brinkman Number in Microchannels  

E-Print Network (OSTI)

Heat generation from electronics increases with the advent of high-density integrated circuit technology. To come up with the heat generation, microscale cooling has been thought as a promising technology. Prediction of heat transfer rate is crucial in design of microscale cooling device but is not clearly understood yet. This work proposes a new correlation between heat transfer rate and Brinkman number which is nondimensional number of viscosity, flow velocity and temperature. It is expected that the equation proposed by this work can be useful to design microchannel cooling device.

H. S. Park

2008-01-07T23:59:59.000Z

57

Fuel Reformation: Microchannel Reactor Design  

DOE Green Energy (OSTI)

Fuel processing is used to extract hydrogen from conventional vehicle fuel and allow fuel cell powered vehicles to use the existing petroleum fuel infrastructure. Kilowatt scale micro-channel steam reforming, water-gas shift and preferential oxida-tion reactors have been developed capable of achieving DOE required system performance metrics. Use of a microchannel design effectively supplies heat to the highly endothermic steam reforming reactor to maintain high conversions, controls the temperature profile for the exothermic water gas shift reactor, which optimizes the overall reaction conversion, and removes heat to prevent the unwanted hydrogen oxidation in the prefer-ential oxidation reactor. The reactors combined with micro-channel heat exchangers, when scaled to a full sized 50 kWe automotive system, will be less than 21 L in volume and 52 kg in weight.

Brooks, Kriston P.; Davis, James M.; Fischer, Christopher M.; King, David L.; Pederson, Larry R.; Rawlings, Gregg C.; Stenkamp, Victoria S.; TeGrotenhuis, Ward E.; Wegeng, Robert S.; Whyatt, Greg A.

2005-09-01T23:59:59.000Z

58

Determination of Optimal Process Flowrates and Reactor Design for Autothermal Hydrogen Production in a Heat-Integrated Ceramic Microchannel Network  

E-Print Network (OSTI)

The present work aimed at designing a thermally efficient microreactor system coupling methanol steam reforming with methanol combustion for autothermal hydrogen production. A preliminary study was performed by analyzing three prototype reactor configurations to identify the optimal radial distribution pattern upon enhancing the reactor self-insulation. The annular heat integration pattern of Architecture C showed superior performance in providing efficient heat retention to the system with a 50 - 150 degrees C decrease in maximum external-surface temperature. Detailed work was performed using Architecture C configuration to optimize the catalyst placement in the microreactor network, and optimize reforming and combustion flows, using no third coolant line. The optimized combustion and reforming catalyst configuration prevented the hot-spot migration from the reactor midpoint and enabled stable reactor operation at all process flowrates studied. Best results were obtained at high reforming flowrates (1800 sccm) with an increase in combustion flowrate (300 sccm) with the net H2 yield of 53% and thermal efficiency of >80% from methanol with minimal insulation to the heatintegrated microchannel network. The use of the third bank of channels for recuperative heat exchange by four different reactor configurations was explored to further enhance the reactor performance; the maximum overall hydrogen yield was increased to 58% by preheating the reforming stream in the outer 16 heat retention channels. An initial 3-D COMSOL model of the 25-channeled heat-exchanger microreactor was developed to predict the reactor hotspot shape, location, optimum process flowrates and substrate thermal conductivity. This study indicated that low thermal conductivity materials (e.g. ceramics, glass) provides enhanced efficiencies than high conductivity materials (e.g. silicon, stainless steel), by maintaining substantial thermal gradients in the system through minimization of axial heat conduction. Final summary of the study included the determination of system energy density; a gravimetric energy density of 169.34 Wh/kg and a volumetric energy density of 506.02 Wh/l were achieved from brass architectures for 10 hrs operation, which is higher than the energy density of Li-Ion batteries (120 Wh/kg and 350 Wh/l). Overall, this research successfully established the optimal process flowrates and reactor design to enhance the potential of a thermally-efficient heat-exchanger microchannel network for autothermal hydrogen production in portable applications.

Damodharan, Shalini

2012-05-01T23:59:59.000Z

59

Thermal Response Testing for Geothermal Heat Exchangers ...  

Science Conference Proceedings (OSTI)

Thermal Response Testing for Geothermal Heat Exchangers Begins. The Net-Zero house features a geothermal heat pump ...

2013-03-12T23:59:59.000Z

60

THERMOSIPHON WATER HEATERS WITH HEAT EXCHANGERS  

E-Print Network (OSTI)

11 ector connecting pipes header heat exchanger insulationLt total connecting pipe length, m (ft) total number of heat

Mertol, Atila

2012-01-01T23:59:59.000Z

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 Exchangers - Chapter 11  

NLE Websites -- All DOE Office Websites (Extended Search)

P.E. Gene Culver Geo-Heat Center Klamath Falls, Oregon 97601 11.1 INTRODUCTION Most geothermal fluids, because of their elevated temperature, contain a variety of dissolved...

62

Carbon Material Based Heat Exchanger for Waste Heat Recovery ...  

Industrial processing plants Nuclear power Solar power ... Carbon Material Based Heat Exchanger for Waste Heat Recovery from Engine Exhaust Contact:

63

Efficient, Low-cost Microchannel Heat Exchanger - Energy ...  

Hydrogen and Fuel Cell; Hydropower, Wave and Tidal; Industrial Technologies; Solar ... Renewable energy (concentrated solar power, residential solar h ...

64

Intelligent predictive control of micro heat exchanger  

Science Conference Proceedings (OSTI)

An intelligent predictive control to temperature control of a micro heat exchanger is addressed. First, the dynamics of the micro heat exchanger is identified using a locally linear model. Then, the predictive control strategy based on this model of ...

Mehdi Galily; Farzad Habibipour Roudsari; Masoum Fardis; Ali Yazdian

2005-06-01T23:59:59.000Z

65

Synergistic diffuser/heat-exchanger design  

E-Print Network (OSTI)

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

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

2004-01-01T23:59:59.000Z

66

Industrial Plate Exchangers Heat Recovery and Fouling  

E-Print Network (OSTI)

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

Cross, P. H.

1981-01-01T23:59:59.000Z

67

Deposition of biological aerosols on HVAC heat exchangers  

E-Print Network (OSTI)

Methods to Maintain Heat Exchanger Coil Cleanliness. ASHRAEEngineering Foundation on Heat Exchanger Fouling, UnitedAerosols on HVAC Heat Exchangers Jeffrey Siegel and Iain

Siegel, Jeffrey; Walker, Iain

2001-01-01T23:59:59.000Z

68

Deposition of biological aerosols on HVAC heat exchangers  

E-Print Network (OSTI)

Methods to Maintain Heat Exchanger Coil Cleanliness. ASHRAEEngineering Foundation on Heat Exchanger Fouling, Unitedof HVAC Fin and Tube Heat Exchangers, To be published in the

Siegel, Jeffrey; Walker, Iain

2001-01-01T23:59:59.000Z

69

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

DOE Green Energy (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

70

Integrated Approach to Revamping Heat Exchangers Networks  

E-Print Network (OSTI)

A heat exchanger network constitutes the core of the plant energy systems interlinking the core process operation and the utility systems. This paper will illustrate an integrated approach for the revamp of a heat exchanger network by bringing together process simulation, pinch analysis and detailed heat exchanger design tools. The paper will illustrate the methodology using a refinery example.

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

2002-04-01T23:59:59.000Z

71

Geothermal shell and tube heat exchanger augmentation  

DOE Green Energy (OSTI)

The heat exchangers for a moderate temperature geothermal plant represent a major portion of the plant capital cost. Therefore, reduction in heat exchanger size will significantly improve the electrical power economics. The potential heat exchanger size reduction that could be achieved by reducing any combination heat transfer resistance terms is evaluated. A literature survey of heat transfer augmentation schemes is summarized and equations for evaluating the impact of cleaning frequency on heat exchanger size are presented. Recommendations are made specifically for the Raft River Thermal Loop, however, the techniques are applicable to any other geothermal plant or heat transfer system.

Neill, D.T.

1976-11-01T23:59:59.000Z

72

Fluidized bed heat exchanger utilizing angularly extending heat exchange tubes  

DOE Patents (OSTI)

A fluidized bed heat exchanger in which air is passed through a bed of particulate material containing fuel disposed in a housing. A steam/water natural circulation system is provided and includes a steam drum disposed adjacent the fluidized bed and a series of tubes connected at one end to the steam drum. A portion of the tubes are connected to a water drum and in the path of the air and the gaseous products of combustion exiting from the bed. Another portion of the tubes pass through the bed and extend at an angle to the upper surface of the bed.

Talmud, Fred M. (Berkeley Heights, NJ); Garcia-Mallol, Juan-Antonio (Morristown, NJ)

1980-01-01T23:59:59.000Z

73

NGNP Process Heat Utilization: Liquid Metal Phase Change Heat Exchanger  

DOE Green Energy (OSTI)

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

Piyush Sabharwall; Mike Patterson; Vivek Utgikar; Fred Gunnerson

2008-09-01T23:59:59.000Z

74

Testing and analysis of immersed heat exchangers  

DOE Green Energy (OSTI)

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

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

1986-08-01T23:59:59.000Z

75

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

NLE Websites -- All DOE Office Websites (Extended Search)

heat to water in a storage tank. Heat-transfer fluids, such as antifreeze, protect the solar collector from freezing in cold weather. Liquid-to-liquid heat exchangers have...

76

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

E-Print Network (OSTI)

Presenting Test Results Heat Exchanger Descriptions and Testof Residential Heat Exchangers Conclusions . . . . . . . .ventilation testing heat exchangers. system, a heat

Fisk, William J.

2013-01-01T23:59:59.000Z

77

Innovative heat exchangers for solar water heaters.  

E-Print Network (OSTI)

??The performance of two innovative collector-loop heat exchangers used in pumped circulation solar water heaters was investigated experimentally and numerically, and TRNSYS simulation models were… (more)

Soo Too, Yen Chean

2007-01-01T23:59:59.000Z

78

Modelling of Multistream LNG Heat Exchangers.  

E-Print Network (OSTI)

?? The main goal of this thesis is to find out if a liquefied natural gas multistream heat exchanger numerical model is achievable. This should… (more)

Soler Fossas, Joan

2011-01-01T23:59:59.000Z

79

Thermodynamic Efficiency of Heat Exchange Devices  

E-Print Network (OSTI)

The continued rise in the cost of energy 'has it imperative to augment the usual heat flow analyses for power plants, refineries, chemical plants and other energy intensive industries by adding analyses of available energy flow and device irreversibilities. The reclamation of what was formerly 'waste heat' by using additional, or more efficient, equipment has become not only economically feasible, but sometimes essential. A thermodynamic efficiency based on the second law of thermodynamics is defined for heat exchange devices. The efficiency can be simply written in terms of the mean absolute temperature levels of the two fluids exchanging heat, and an appropriate environment temperature. It is also shown that for a given ratio of hot to cold inlet temperatures, the efficiency and effectiveness for particular heat exchange configurations are related. Conclusions regarding the effect of stream temperatures on the efficiency of various types of exchangers are made. The concept is applied to typical heat exchange cases to demonstrate its applicability and sensitivity.

Witte, L. C.; Shamsundar, N.

1982-01-01T23:59:59.000Z

80

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

SciTech Connect

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

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

Efficient numerical modeling of borehole heat exchangers  

Science Conference Proceedings (OSTI)

This paper presents a finite element modeling technique for double U-tube borehole heat exchangers (BHE) and the surrounding soil mass. Focus is placed on presenting numerical analyses describing the capability of a BHE model, previously reported, to ... Keywords: BHE, Geothermal heat pumps, Geothermic, Heat transfer, Space heating

R. Al-Khoury; T. Kölbel; R. Schramedei

2010-10-01T23:59:59.000Z

82

Heat exchanger with a removable tube section  

DOE Patents (OSTI)

A heat exchanger is described in which the tube sheet is secured against primary liquid pressure, but which allows for easy removal of the tube section. The tube section is supported by a flange which is secured by a number of shear blocks, each of which extends into a slot which is immovable with respect to the outer shell of the heat exchanger. (auth)

Wolowodiuk, W.; Anelli, J.

1975-07-29T23:59:59.000Z

83

Stability analysis of heat exchanger dynamics  

Science Conference Proceedings (OSTI)

In the study of vapor compression cycle, momentum balance equation is often ignored in the heat exchanger model. In this paper, we investigate the effect of the momentum balance through a systematic study of the open loop stability of a heat exchanger. ...

Tiejun Zhang; John T. Wen; Juan Catano; Rongliang Zhou

2009-06-01T23:59:59.000Z

84

Guidance for an Effective Heat Exchanger Program  

Science Conference Proceedings (OSTI)

Heat exchangers are used extensively in the nuclear power generation industry. Their proper operation is essential for reliable and safe nuclear plant operation. Increased emphasis on heat exchanger reliability at nuclear power plants has resulted in the development of engineering programs or equivalent actions to maintain the required thermal performance and structural integrity.

2011-10-04T23:59:59.000Z

85

Heat Exchanger Thermal Performance Margin Guidelines  

Science Conference Proceedings (OSTI)

This report provides utility engineers with guidance on how to identify the thermal performance margin that is available in a given heat exchanger by comparing the thermal performance requirement at design limiting conditions to the thermal performance capability of the heat exchanger under those same conditions.

2005-11-30T23:59:59.000Z

86

HEAT EXCHANGER DEVICE AND METHOD FOR HEAT REMOVAL OR TRANSFER ...  

Systems and methods for a forced-convection heat exchanger are provided. In one embodiment, heat is transferred to or from a thermal load in thermal contact with a ...

87

Effects of particle concentration and surfactant use in convective heat transfer of CuO nanofluids in microchannel flow.  

E-Print Network (OSTI)

??Heat exchange systems used in everything from cars to microelectronics have rapidly advanced in recent years to offer high heat transfer rates in increasingly smaller… (more)

Byrne, Matthew Davidson

2011-01-01T23:59:59.000Z

88

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

89

Heat exchanger device and method for heat removal or transfer  

Science Conference Proceedings (OSTI)

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

Koplow, Jeffrey P. (San Ramon, CA)

2012-07-24T23:59:59.000Z

90

Particulate Fouling of HVAC Heat Exchangers Jeffrey Alexander Siegel  

E-Print Network (OSTI)

Particulate Fouling of HVAC Heat Exchangers by Jeffrey Alexander Siegel B.S. (Swarthmore College.......................................................................................xv CHAPTER 1: PARTICULATE FOULING OF HVAC HEAT EXCHANGERS ....1 1.1 Introduction.......................................................................11 CHAPTER 2: MODELING PARTICLE DEPOSITION ON HVAC HEAT EXCHANGERS

Siegel, Jeffrey

91

Fouling of HVAC fin and tube heat exchangers  

E-Print Network (OSTI)

Methods to Maintain Heat Exchanger Coil Cleanliness, ASHRAEof HVAC Fin and Tube Heat Exchangers Jeffrey Siegel and VanOF HVAC FIN AND TUBE HEAT EXCHANGERS Jeffrey Siegel 1,2 and

Siegel, Jeffrey; Carey, Van P.

2001-01-01T23:59:59.000Z

92

Second Law Optimization of Heat Exchangers  

E-Print Network (OSTI)

A new method for optimizing heat exchangers is developed in this paper. It is based on second law efficiency relationships rather than on the traditional heat exchanger effectiveness concept. The cost of energy is based on its availability level rather than on the simple cost of fuel required to meet the exchanger heat duty. Application of the method to a condensing heater shows that the optimum area based on second law efficiency can be quite different from the optimum area computed by the effectiveness method.

Witte, L. C.

1985-05-01T23:59:59.000Z

93

Heat exchanger with transpired, highly porous fins  

DOE Patents (OSTI)

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

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

2002-01-01T23:59:59.000Z

94

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

95

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

96

On Modeling Of Heat Exchangers In Modelica  

E-Print Network (OSTI)

It is demonstrated how Modelica TM is used in an application to develop models that are useful when solving real problems. Modelica is a new unified modeling language being developed in an international effort to promote object-oriented and non-causal modeling, and exchange of model libraries. The application is a heat exchanger where the media are liquids, typically water. This type of heat exchangers can be used for district heating of houses and for production of hot tap water. The model developed illustrates very nicely the power of Modelica. The modularization concepts support flexible model components which are easy to use and to adapt when making a model of a real system with heat exchangers. The concept of class parameters support medium parameterization and arrays of model components support discretization. The expressive power of Modelica allows complete listings of the developed model components to be given. The model produces simulation results that agree very well with measured data.

Sven Erik Mattsson

1997-01-01T23:59:59.000Z

97

Experimental Study of Hybrid Cooled Heat Exchanger.  

E-Print Network (OSTI)

??A test system for a hybrid cooled heat exchanger was designed, and the test facility was constructed based on ASHRAE Standard 41.2-1987. A conventional air-cooled… (more)

Tsao, Han-Chuan

2011-01-01T23:59:59.000Z

98

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 an estimated 2.9 Quads per year. To predict and control fouling, three OIP projects are currently exploring heat exchanger fouling in specific industrial applications. A fouling probe has been developed to determine empirically the fouling potential of an industrial gas stream and to derive the fouling thermal resistance. The probe is a hollow metal cylinder capable of measuring the average heat flux along the length of the tube. The local heat flux is also measured by a heat flux meter embedded in the probe wall. The fouling probe has been successfully tested in the laboratory at flue gas temperatures up to 2200°F and a local heat flux up to 41,000 BTU/hr-ft2. The probe has been field tested at a coal-fired boiler plant. Future tests at a municipal waste incinerator are planned. Two other projects study enhanced heat exchanger tubes, specifically the effect of enhanced surface geometries on tube bundle performance. Both projects include fouling in a liquid heat transfer fluid. Identifying and quantifying the factors affecting fouling in these enhanced heat transfer tubes will lead to techniques to mitigate fouling.

Peterson, G. R.

1989-09-01T23:59:59.000Z

99

Geothermal field tests: heat exchanger evaluation  

DOE Green Energy (OSTI)

Results of the heat exchanger tests conducted on a scale model of a heat exchanger that has been designed and fabricated for the Geothermal Test Facility show that this exchanger will lose 60% of its heat transfer capability and fall below design requirements after 92 hours of operation. When the test exchanger was clean and operating as close as possible to design conditions, its overall heat transfer coefficient was 426 BTU/hr-ft/sup 2/ - /sup 0/f. when calculating in the fouling factor of .0035 this gave a design coefficient of 171 BTU/hr-ft/sup 2/ - /sup 0/f which was reached after less than four days of steady state operation. Thermal shocking of the test heat exchanger once each hour while the exchanger was operating at design conditions had no effect on scale removal or heat transfer. Results of tube cleaning showed that chemical treatment with 30% hydrochloric acid followed by a high pressure water jet (6000 psig), was effective in removing scale from tubes contacted with geothermal brine. After cleaning, the tubes were examined and some pitting was observed throughout the length of one tube.

Felsinger, D.E.

1973-07-06T23:59:59.000Z

100

Ceramic heat exchangers: manufacturing techniques and performance  

SciTech Connect

The objective of the ceramic heat pipe program being conducted at Los Alamos is demonstration of the practical feasibility of this technology for the solution of severe high temperature recuperation functions. Ceramic heat pipe recuperators have been theoretically shown to offer distinct advantages over conventional ceramic heat exchangers from the standpoint of efficiency of heat recuperation and economics. The main stumbling block to their widespread utilization is related to the problems of materials for construction and the details of fabrication and assembly. The performance objectives of ceramic heat pipes and some aspects of the materials technology program aimed at solving the problem of economic ceramic heat pipe fabrication are described.

Merrigan, M.A.; Sandstrom, D.J.

1981-01-01T23:59:59.000Z

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.


101

Heat Exchanger Technologies for Distillation Columns  

E-Print Network (OSTI)

In this paper we look at the challenges that improvements in energy efficiency of distillation systems presents the heat exchanger designer. We examine each type of exchanger in turn. Heat exchanger size is minimized if the temperature driving force is maximized. The design should therefore seek to minimize the temperature changes during phase change. So, streams that are being condensed are kept as hot as possible. Streams that are being vaporized are kept as cool as possible. With one noted exception, this also leads to maximization of the thermodynamic efficiency and maximizes the scope for use of these streams in integrated systems.

Polley, G. T.

2002-04-01T23:59:59.000Z

102

Building Technologies Office: HVAC Optimized Heat Exchangers Research  

NLE Websites -- All DOE Office Websites (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

103

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

104

Heat transfer and fluid dynamics of air-water two-phase flow in micro-channels  

SciTech Connect

Heat transfer, pressure drop, and void fraction were simultaneously measured for upward heated air-water non-boiling two-phase flow in 0.51 mm ID tube to investigate thermo-hydro dynamic characteristics of two-phase flow in micro-channels. At low liquid superficial velocity j{sub l} frictional pressure drop agreed with Mishima-Hibiki's correlation, whereas agreed with Chisholm-Laird's correlation at relatively high j{sub l}. Void fraction was lower than the homogeneous model and conventional empirical correlations. To interpret the decrease of void fraction with decrease of tube diameter, a relation among the void fraction, pressure gradient and tube diameter was derived. Heat transfer coefficient fairly agreed with the data for 1.03 and 2.01 mm ID tubes when j{sub l} was relatively high. But it became lower than that for larger diameter tubes when j{sub l} was low. Analogy between heat transfer and frictional pressure drop was proved to hold roughly for the two-phase flow in micro-channel. But satisfactory relation was not obtained under the condition of low liquid superficial velocity. (author)

Kaji, Masuo; Sawai, Toru; Kagi, Yosuke [Department of Mechanical Engineering, School of Biology-Oriented Science and Technology, Kinki University, 930 Nishi-mitani, Kinokawa, Wakayama 649-6493 (Japan); Ueda, Tadanobu [Toyota Central R and D Laboratory, Incorporated, 41-1 Yokomichi, Nagakute, Aichi 480-1192 (Japan)

2010-05-15T23:59:59.000Z

105

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

106

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/into the ground. This paper summarizes the authors' studies on heat transfer in ground-coupled heat pump systems. Taking the fluid axial convective heat transfer and thermal “short-circuiting” among U-tube legs into account, a quasi-3-D model has been solved for heat transfer inside boreholes. The transient 2-D temperature response in a semi-infinite medium with a line-source of finite length has also been derived for heat conduction outside boreholes. In order to investigate the impact of groundwater advection on the performance of ground heat exchangers, an analytical solution is obtained for a line heat source in an infinite porous medium with groundwater advection. These explicit expressions have more solid theoretical basis, and can be easily incorporated into computer programs for thermal analysis and engineering design of ground heat exchangers.

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

2006-01-01T23:59:59.000Z

107

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

108

Energy absorber for sodium-heated heat exchanger  

DOE Patents (OSTI)

A heat exchanger is described in which water-carrying tubes are heated by liquid sodium and in which the results of accidental contact between the water and the sodium caused by failure of one or more of the water tubes is minimized. An energy absorbing chamber contains a compressible gas and is connected to the body of flowing sodium by a channel so that, in the event of a sodium-water reaction, products of the reaction will partially fill the energy absorbing chamber to attenuate the rise in pressure within the heat exchanger.

Essebaggers, J.

1975-12-01T23:59:59.000Z

109

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 in such an exchanger are derived and solved leading to an optimization problem. In this problem, the optimal subdivision of heat transfer surface to minimize required overall heat transfer surface, under certain restricted conditions, is sought. It is shown that the off-center nozzle location can be selected judiciously so as to maintain (or even improve heat transfer) while reducing the gross shellside pressure loss. Thus, the pumping costs are minimized without sacrificing heat transfer.

Singh, K. P.

1979-01-01T23:59:59.000Z

110

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

111

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 G. (Winchester, MA)

1993-01-01T23:59:59.000Z

112

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

113

Multidimensional numerical modeling of heat exchangers. [LMFBR  

SciTech Connect

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

114

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

115

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 Abstract The louvered fin heat exchanger, a type of compact heat exchanger, has been used heavily transfer along the tube wall of the compact heat exchanger through the use of winglets placed

Thole, Karen A.

116

Qualification of aluminum for OTEC heat exchangers  

DOE Green Energy (OSTI)

The basis for qualification of aluminum as a material for use as tubing in Ocean Thermal Energy Conversion heat exchangers is reviewed. Reference is made to compendia of data from tests of aluminum alloys in natural sea water and to applicable service records. Data from these sources were found to be inadequate to either qualify or disqualify aluminum. They serve only to identify the 5052 alloy and Alclad 3003 or 3004 as being worthy of additional testing under conditions more directly related to what will be encountered in OTEC heat exchangers. The principal deficiency of data from long-time tests in natural sea water is that in almost all of these tests the specimens were exposed under static conditions that caused the surfaces to be covered by marine fouling organisms that would not be present in heat exchanger tubes. The tests did not take into account possible effects of periodic mechanical or chemical treatments to remove fouling or chemical treatments (chlorination) to prevent fouling. A current testing program sponsored by the Department of Energy through Argonne National Laboratory is designed to provide the needed data. Limited tests in high velocity sea water have indicated that aluminum tubes would tolerate the velocities under 10 ft (3 m) per second likely to be used in OTEC heat exchangers.

LaQue, F.L.

1979-05-01T23:59:59.000Z

117

Heat exchanger Exergoeconomic lifecycle cost optimization  

Science Conference Proceedings (OSTI)

Considering lifecycle cost analysis during the design phase of thermal systems gives the design effort more worth. Furthermore thermodynamic exergetic optimization is proven to be useful method for determining the most lifecycle cost optimal design of ... Keywords: entropy generation, exergy destruction, heat exchanger, operating cost, optimization, thermodynamics

Liaquat Ali Khan; Ali El-Ghalban

2008-02-01T23:59:59.000Z

118

Service Water Heat Exchanger Testing Guidelines  

Science Conference Proceedings (OSTI)

This report will assist the Service Water Heat Exchanger (SWHX) test engineer in designing specific test methods which define and constrain the analysis, operational and measurement strategies for each specific SWHX application. The resulting test methods will provide the necessary assurance that the results of tests are sufficiently representative of the true capability of the SWHX.

1998-04-01T23:59:59.000Z

119

MGCR HEAT EXCHANGER TEST PROGRAM. Final Report  

SciTech Connect

The Maritime Gas-cooled Reactor (MGCR) project has conipleted the study and design of a closed-cycle gasturbine propulsion plant utilizing a helium- cooled nuclear reactor as the heat source. The cycle employs a counterflow shell- and-tube regenerator to attain a high thermodynamic cycle efficiency. A heat exchanger test program was conducted to compile and correlate sufficient experimental data for the aerodynamic and thermal design of the prototype regenerator. The model heat exchanger was similar in configaration to the prototype unit. The pressure-drop and heat-transfer performance of a compact parallel-flow tube bundle is given hoth in the unsupported configuration and with airfoil-shaped tube supports distributed along the bundle. The Fanning friction factor with the airfoil-shaped supports is approximately 70% greater than for the unsupported tube configuration. The airfoil supports effect a 40% increase in Colburn's heat transfer factor, j, over the unsupported configuration. Determinations of the unsupported-tube values of friction factor and Colburn-j agreed well with the literature. A section is devoted to the application of these data to the design of exchangers. The correlated data, representing some 1200 individual runs, cover a range of Reynolds number from 10,000 to 500,000. The moderate pressure-drop increment due to the airfoil-shaped supports, in conjunction with the favorable increase in heat-transfer rate, becomes especially important in the design of compact gas-to-gas heat exchangers with very low friction pressure losses. The concluding section of the report compares the size, weight, and cost of conventional baffled-shell units and the MGCR design for the requirements of the MGCR cycle. The MGCR design was one-fifth the volume, one-fourth the weight, and one-third the cost of comparable baffled-shell units. (auth)

Paulson, H.C. II

1961-04-01T23:59:59.000Z

120

Comparative Studies on Micro Heat Exchanger Optimisation Tatsuya Okabe  

E-Print Network (OSTI)

Comparative Studies on Micro Heat Exchanger Optimisation Tatsuya Okabe , Kwasi Foli ¡ , Markus- timisation of a micro heat exchanger (¤ HEX). The trend to- wards miniaturisation has led to the use of micro devices in industry and technology. Micro heat exchangers have very high heat transfer surface area

Coello, Carlos A. Coello

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

Plate heat exchanger system largest in United States  

SciTech Connect

This article focuses on the largest plate heat exchanger system in the USA having 70,000 sq. ft. of surface area. It is used as a sodium carbonate brine heat exchanger at the Kerr-McGee Chemical Corporation's Argus facility at Searles Valley in California's Mojave Desert. The heat interchange process and operation are discussed. Plate heat exchangers were found to be more cost effective than conventional heat exchangers in the process.

Canning, T. (Kerr-McGee Chemical Corp., Trona, CA); Regan, J.T.

1982-08-01T23:59:59.000Z

122

Dealing with Uncertainties During Heat Exchanger Design  

E-Print Network (OSTI)

Over the last thirty years much progress has been made in heat exchanger design methodology. Even so, the design engineer still has to deal with a great deal of uncertainty. Whilst the methods used to predict heat transfer coefficients are now quite sophisticated and take account of many physical factors, the results they yield are still inaccurate. Physical property information is required for the estimation of heat transfer coefficients. Available information is often of dubious accuracy. Even given accurate properties modern methods for the predictions of tube-side heat transfer coefficient can be expected to have an accuracy of only ± 10%. For the shell-side, higher errors (say, around ±15%) can be expected. Perhaps worst of all, comes the specification of fouling resistance (the allowance made for the thermal resistance presented by dirt layers deposited on the heat exchanger tubes). In most instances there is little science or understanding behind the specification of these resistances. Traditionally there have been two approaches to dealing with these uncertainties: over-specification of fouling resistance; and, addition of 'design margin' (i.e. addition of extra surface area). There are cases in which both approaches are adopted. The engineer specifying the required duty provides a higher than necessary fouling resistance whilst the exchanger designer adds design margin! Both approaches result in 'over-design'.

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

2001-05-01T23:59:59.000Z

123

Plant Support Engineering: Guidance for Replacing Heat Exchangers at Nuclear Power Plants with Plate Heat Exchangers  

Science Conference Proceedings (OSTI)

This report is the first of a "suite" of guidelines that will enable licensees to be "intelligent customers" when faced with replacing major plant components like heat exchangers to support license renewal and plant life extension.

2006-07-31T23:59:59.000Z

124

Triple loop heat exchanger for an absorption refrigeration system  

DOE Patents (OSTI)

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

Reimann, Robert C. (Lafayette, NY)

1984-01-01T23:59:59.000Z

125

HVAC Radial Air Bearing Heat Exchangers Research Project | Department of  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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

126

Preliminary SP-100/Stirling heat exchanger designs  

DOE Green Energy (OSTI)

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

Schmitz, P.; Tower, L. [Sverdrup Technology, Inc., Brook Park, OH (United States). Lewis Research Center Group; Dawson, R. [Aerospace Design and Fabrication Inc., Brook Park, OH (United States); Blue, B.; Dunn, P. [National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center

1994-09-01T23:59:59.000Z

127

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

DOE Green Energy (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

128

Fouling of HVAC fin and tube heat exchangers  

E-Print Network (OSTI)

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

Siegel, Jeffrey; Carey, Van P.

2001-01-01T23:59:59.000Z

129

Plant Support Engineering: Heat Exchanger Tube Plugging Calculator  

Science Conference Proceedings (OSTI)

Many heat exchangers of various designs and construction are used in any power generating facility. The effect of inefficient heat exchangers can range from being a slow economic drain on the generation facility to completely shutting it down.

2009-06-29T23:59:59.000Z

130

Nuclear Maintenance Applications Center: Heat Exchanger Maintenance Guide  

Science Conference Proceedings (OSTI)

This guide provides plant personnel with information on the operation, maintenance, and performance of heat exchangers. The contents of this guide will assist plant personnel in improving heat exchanger reliability, performance, and maintenance practices.

2009-06-14T23:59:59.000Z

131

Foundation Heat Exchanger Model and Design Tool Development and Validation  

E-Print Network (OSTI)

. Feasibility of foundation heat exchangers in ground source heat pump systems in the United States. ASHRAE systems, with an estimated 1.7 million installed units with total installed heating capacity on the order Heat Exchangers for Residential Ground Source Heat Pump Systems - Numerical Modeling and Experimental

132

Heat Exchangers Fouling and Corrosion-A Detailed Investigation  

Science Conference Proceedings (OSTI)

Presentation Title, Aluminum Smelter Waste Heat Recovery Plant (Heat Exchangers Fouling and Corrosion-A Detailed Investigation). Author(s), Hadi Fanisalek, ...

133

An Innovative Compact Heat Exchanger Solution for Aluminium Off ...  

Science Conference Proceedings (OSTI)

Presentation Title, An Innovative Compact Heat Exchanger Solution for Aluminium Off-Gas Cooling and Heat Recovery. Author(s), El Hani Bouhabila, Erling ...

134

Investigation on a Microwave High-Temperature Air Heat Exchanger  

Science Conference Proceedings (OSTI)

In present paper, an energy efficient air heat exchanger, based on accumulation of the heat generated by microwave absorbing materials is presented according  ...

135

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.ravelet@laposte.net Geert-Jan Witkamp G.J.Witkamp@xs4all.nl Abstract In a cylindrical scraped heat exchanger crystallizer exchanger surface has been studied by direct measurements of the heat exchanger surface temperature

Paris-Sud XI, Université de

136

Modeling Direct and Inverse Problems in Ferritic Heat-Exchanger ...  

Science Conference Proceedings (OSTI)

Symposium, Data Analytics for Materials Science and Manufacturing. Presentation Title, Modeling Direct and Inverse Problems in Ferritic Heat- Exchanger Tubes.

137

Conceptualizations for cleaning OTEC heat exchangers  

DOE Green Energy (OSTI)

A critical operating aspect of Ocean Thermal Energy Conversion (OTEC) plants is the maintenance of clean surfaces on the seawater-side of the heat exchangers. The objective of this program was to assess the state of the art of biofouling control techniques and to evaluate the potential of these existing methods for solving the biofouling problems in the OTEC system. The first task of the program involved an in-depth review and discussion of various fouling control methods including water treatment, surface conditioning, and cleaning techniques. The methods considered applicable to OTEC were identified. This volume summarizes the second task of the program. The compatibility of the various cleaning and fouling control techniques with the different proposed heat exchanger designs and materials are discussed. Also provided are conceptual illustrations for adapting and incorporating the methods into an OTEC power plant. These conceptual designs suggest means for overcoming some of the shortcomings of the techniques which are considered suitable, however, detailed designs of the modified systems are beyond the scope of this report. Chlorination, chemical cleaning, Amertap recirculating sponge rubber balls, and MAN flow-driven brushes are the methods considered applicable for tubular heat exchangers with seawater inside the tubes. Water jets are suggested for the open-cycle and the ''trombone'' (Applied Physics Laboratory) heat exchanger designs. Although none of the methods are immediately applicable to OTEC in their present configuration, in several cases only minor developmental efforts should produce designs which can satisfy the stringent OTEC cleanliness requirements. Further research and development appear warranted for a number of other methods which indicate promise for long-range applicability. Specific recommendations are included.

Rice, M.S.; Hagel, D.; Conn, A.F.

1978-09-01T23:59:59.000Z

138

Boundary geometric control of a counter-current heat exchanger  

E-Print Network (OSTI)

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

139

ISHED1: Applying the LEM Methodology to Heat Exchanger Design  

E-Print Network (OSTI)

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

Michalski, Ryszard S.

140

INTEGRATED DESIGN AND CONTROL OF HEAT EXCHANGER NETWORKS  

E-Print Network (OSTI)

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

Skogestad, Sigurd

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

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

E-Print Network (OSTI)

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

Schmidhuber, Juergen

142

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

143

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 heat exchanger are found to result in large discrepancies with their own experimental data

Kandlikar, Satish

144

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. Before the design process can begin, product specifications, such as steam or water pressures and temperatures, and equipment, such as absorption chillers and heat exchangers, need to be identified and defined. The Energy Engineering Laboratory of the Mechanical Engineering Department of the University of Louisiana at Lafayette and the Louisiana Industrial Assessment Center has been donated an 800kW diesel turbine and a 100 ton absorption chiller from industries. This equipment needs to be integrated with a heat exchanger to work as a Combined Heat and Power system for the University which will supplement the chilled water supply and electricity. The design constraints of the heat recovery unit are the specifications of the turbine and the chiller which cannot be altered.

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

2009-05-01T23:59:59.000Z

145

Heat transfer and condensation of water vapour from humid air in compact heat exchangers.  

E-Print Network (OSTI)

??In this thesis, an experimental and simulation study of heat transfer in water-to-air compact-plate heat exchanger is presented. A compact-plate heat exchanger made of polypropylene,… (more)

Saraireh, Mohammad

2012-01-01T23:59:59.000Z

146

OXIDE DISPERSION-STRENGTHENED HEAT EXCHANGER TUBING  

Science Conference Proceedings (OSTI)

Oxide dispersion strengthened (ODS) alloys (e.g. the INCOLOY{reg_sign} MA956 alloy) are known for their excellent high temperature properties and are prime candidate materials for the construction of very high temperature heat exchangers that will be used in Vision 21 power plants. The main limitation of these materials is their poor weldability. Commercially available ODS tubing also tends to exhibit relatively poor circumferential creep strength due to current processing practices resulting in a fine grain size in the transverse direction. Thus far, these two characteristics of the ODS tubing have restricted its use to mostly non-pressure containing applications. The objectives of this program are to develop: (a) an MA956 tube with sufficient circumferential creep strength for long term use as heat exchanger tubing for very high temperatures; (b) a welding technique(s) for producing adequate joints between an MA956 tube and an MA956 tube, and an MA956 tube and an INCONEL 601 tube; (c) the bending strain limits, below which recrystallization will not occur in a MA956 tube during normal operation; and (d) the high temperature corrosion limits for the MA956 alloy with respect to working-fluid side and fireside environments. Also, this program seeks to generate data for use by heat exchanger designers and the ASME Boiler and Pressure Vessel Code, and perform an analysis of the mechanical property, tube bending, and corrosion data in order to determine the implications on the design of a very high temperature heat exchanger (T>1093 C/2000 F). After one year, work is currently being conducted on increasing the circumferential strength of a MA956 tube, developing joining techniques for this material, determining the tube bending strain limits, and establishing the high temperature corrosion parameters for the MA956 alloy in environments expected to be present in Vision 21 power plants. Work in these areas will is continuing into the next fiscal year, with success anticipated to produce innovative developments that will allow the reliable use of ODS alloys for heat exchanger tubing, as well as a variety of applications previously not possible with metallic materials.

Harper, Mark A.

2001-11-06T23:59:59.000Z

147

Graphite Foam Heat Exchangers for Thermal Management  

Science Conference Proceedings (OSTI)

Improved thermal management is needed to increase the power density of electronic and more effectively cool electronic enclosures that are envisioned in future aircraft, spacecraft and surface ships. Typically, heat exchanger cores must increase in size to more effectively dissipate increased heat loads, this would be impossible in many cases, thus improved heat exchanger cores will be required. In this Phase I investigation, MRi aimed to demonstrate improved thermal management using graphite foam (Gr-foam) core heat exchangers. The proposed design was to combine Gr-foams from POCO with MRi's innovative low temperature, active metal joining process (S-Bond{trademark}) to bond Gr-foam to aluminum, copper and aluminum/SiC composite faceplates. The results were very favorable, so a Phase II SBIR with the MDA was initiated. This had primarily 5 tasks: (1) bonding, (2) thermal modeling, (3) cooling chip scale packages, (4) evaporative cooling techniques and (5) IGBT cold plate development. The bonding tests showed that the ''reflow'' technique with S-Bond{reg_sign}-220 resulted in the best and most consistent bond. Then, thermal modeling was used to design different chip scale packages and IGBT cold plates. These designs were used to fabricate many finned graphite foam heat sinks specifically for two standard type IC packages, the 423 and 478 pin chips. These results demonstrated several advantages with the foam. First, the heat sinks with the foam were lighter than the copper/aluminum sinks used as standards. The sinks for the 423 design made from foam were not as good as the standard sinks. However, the sinks made from foam for the 478 pin chips were better than the standard heat sinks used today. However, this improvement was marginal (in the 10-20% better regime). However, another important note was that the epoxy bonding technique resulted in heat sinks with similar results as that with the S-bond{reg_sign}, slightly worse than the S-bond{reg_sign}, but still better than the standard heat sinks. Next, work with evaporative cooling techniques, such as heat pipes, demonstrated some unique behavior with the foam that is not seen with standard wick materials. This was that as the thickness of the foam increased, the performance got better, where with standard wick materials, as the thickness increases, the performance decreases. This is yet to be completely explained. Last, the designs from the thermal model were used to fabricate a series of cold plates with the graphite foam and compare them to similar designs using high performance folded fin aluminum sinks (considered standard in the industry). It was shown that by corrugating the foam parallel to fluid flow, the pressure drop can be reduced significantly while maintaining the same heat transfer as that in the folded fin heat sink. In fact, the results show that the graphite foam heat sink can utilized 5% the pumping power as that required with the folded fin aluminum heat sink, yet remove the same amount of heat.

Klett, J.W.

2004-06-07T23:59:59.000Z

148

Building Technologies Office: HVAC Radial Air Bearing Heat Exchanger  

NLE Websites -- All DOE Office Websites (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

149

HVAC Optimized Heat Exchangers Research Project | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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

150

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

Science Conference Proceedings (OSTI)

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

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

2008-11-01T23:59:59.000Z

151

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

152

Heat Transfer and Energy Diffusion Analysis of Cannula Ground Heat Exchanger  

Science Conference Proceedings (OSTI)

A heat transfer model about fluid flow and heat conduct in cannula ground heat exchanger were given in this article. The heat transfer characteristics were analyzed by means of numerical method of finite element. Affect of difference size of buried tubes ... Keywords: heat transfer, energy diffusion, ground heat exchanger, numerical method, couple mode

Jiang Yan; Gao Qing; Li Ming

2010-10-01T23:59:59.000Z

153

Heat exchanger for a Stirling engine  

SciTech Connect

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

154

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 steam boiler fuel to steam efficiencies in excess of 90%. The studies and evaluations done to date indicate that units of this type will be cost effective in sizes ranging from 10,000 to 300,0000 steam per hour as long as cold makeup water is available for preheating with the waste flue gases.

Sullivan, B.; Sullivan, P. A.

1983-01-01T23:59:59.000Z

155

Numerical study of 2D heat transfer in a scraped surface heat exchanger  

E-Print Network (OSTI)

Numerical study of 2D heat transfer in a scraped surface heat exchanger K.-H. Sun a,*, D.L. Pyle heat exchanger with non- Newtonian power law fluids is undertaken. Numerical results are generated of scraped surface heat exchanger design are assessed in the light of the results. Ă? 2003 Elsevier Ltd. All

156

Temperature profile of the infrared image Heat exchange between  

E-Print Network (OSTI)

T Temperature profile of the infrared image Heat exchange between atmosphere and ocean References part at high frequencies delivers the exchange time. Cool skin of the ocean the net heat flux between gas exchange and wind speed over the ocean, J. Geophys. Res. 97, 7373-7381, 1992, Nightingale, P

Jaehne, Bernd

157

Modelling and computation for designs of multistage heat exchanger systems  

Science Conference Proceedings (OSTI)

A multistage heat exchanger system is formed when it is desired to heat a single cold fluid stream with the help of several available hot streams. Usually only one specific size combination will lead to total minimum cost. The determination of these ... Keywords: Heat Exchangers, multistage, optimisation

A. Malhotra; S. B. Muhaddin

1990-12-01T23:59:59.000Z

158

Geothermal direct contact heat exchange. Final report  

DOE Green Energy (OSTI)

A glass direct contact heat exchange column was operated in the laboratory. The column was operated at atmospheric pressure using hot water and normal hexane. Column internals testing included an empty column, sieve trays, disk-and-doughnut trays, and two types of packing. Operation was very smooth in all cases and the minimum temperature approaches varied from less than 1/sup 0/C for packing to 13/sup 0/C for the empty column. High heat transfer rates were obtained in all cases, however, columns should be sized on the basis of liquid and vapor traffic. The solubilities of hydrocarbons were determined for normal hexane, pentane and butane in water and sodium chloride and calcium chloride brines at various temperatures. The values seem to be internally consistent and salt content was found to depress hydrocarbon solubility. Laboratory stripping tests showed that gas stripping can be used to remove hydrocarbon from reject hot water from the direct contact heat exchange column. Although the gas volumes required are small, stripping gas requirements cannot be accurately predicted without testing. A computer program was used to study the effect of operating variables on the thermodynamic cycle efficiencies. Optimum efficiencies for the moderate brine conditions studied were obtained with isopentane as working fluid and relatively low operating pressure. A preliminary design for a 50 MWe plant was prepared and plant capital cost and operating cost were estimated. These costs were combined with previously developed brine production and power transmission costs to provide an estimate of the cost of delivered power for a geothermal field at Heber, California. A pilot plant program is described that would be suitable for continuing the investigation of the direct contact process in the field. The program includes a suggested schedule and the estimated cost.

Sims, A.V.

1977-06-10T23:59:59.000Z

159

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

160

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

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

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

Science Conference Proceedings (OSTI)

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

Tundee, Sura; Terdtoon, Pradit; Sakulchangsatjatai, Phrut [Department of Mechanical Engineering, Faculty of Engineering, Chiang Mai University, Chiang Mai 50200 (Thailand); Singh, Randeep; Akbarzadeh, Aliakbar [Energy Conservation and Renewable Energy Group, School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, Bundoora East Campus, Bundoora, Victoria 3083 (Australia)

2010-09-15T23:59:59.000Z

162

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

Office of Scientific and Technical Information (OSTI)

GEOTHERMAL TECHNOLOGIES LEGACY COLLECTION - Sponsored by OSTI -- Chapter 11. Heat Exchangers Geothermal Technologies Legacy Collection HelpFAQ | Site Map | Contact Us | Admin Log...

163

Analysis of a heat exchanger-thermoelectric generator system  

DOE Green Energy (OSTI)

Analysis of a thermoelectric generator (TEG) in an ocean thermal energy conversion (OTEC) application is presented. An analytic model is developed for describing the heat exchanger-TEG interactions. This model is used to illustrate limitations of applying conventional fixed junction temperature assumptions to systems experiencing significant temperature drops across the heat exchanger surfaces. Design methods are developed for determining the thermoelectric element geometry that produces maximum output power. Results show that a heat exchanger-TEG system may deliver about 100 W/m/sup 2/ of heat exchanger surface. This compares favorably with conventional OTEC schemes.

Henderson, J.

1979-01-01T23:59:59.000Z

164

Design with Constructal Theory: Steam Generators, Turbines and Heat Exchangers.  

E-Print Network (OSTI)

?? This dissertation shows that the architecture of steam generators, steam turbines and heat exchangers for power plants can be predicted on the basis of… (more)

Kim, Yong Sung

2010-01-01T23:59:59.000Z

165

Thermal design of heat exchanger for a swimming pool.  

E-Print Network (OSTI)

??This paper tells about what is a heat exchanger made of in terms of thermal analysis and the important tools and factors which play vital… (more)

Teka, Addisu

2012-01-01T23:59:59.000Z

166

Designing and troubleshooting plate heat exchangers  

Science Conference Proceedings (OSTI)

Since they were introduced in the 1930s, plate heat exchangers (PHE) have improved considerably, becoming both cost-effective and versatile. PHE models offer an economical alternative to the more-traditional shell-and-tube models, in a more compact size. However, to allow PHEs to achieve top efficiency and to minimize maintenance costs and downtime, design engineers must carefully consider operating conditions and potential maintenance requirements. Process engineers, in turn, must be aware of simple, but critical, troubleshooting techniques. This article will outline both specification and operating tips. The paper discusses plate depth and patterns, materials selection, gasket material, temperature and gasket life, glued or gluefree gaskets, opening the PHE, replacing the gaskets, plate inspection, closing the PHE, corrosion and erosion.

Sloan, M.D. [Alfa Laval Thermal, Inc., Richmond, VA (United States). Service Div.

1998-05-01T23:59:59.000Z

167

Matrix heat exchanger including a liquid, thermal couplant  

DOE Patents (OSTI)

A tube-to-tube heat exchanger is disclosed with a thermally conductive matrix between and around the tubes to define annuli between the tubes and matrix. The annuli are filled to a level with a molten metal or alloy to provide a conductive heat transfer path from one tube through the matrix to the second tube. A matrix heat exchanger of this type is particularly useful for heat transfer between fluids which would react should one leak into the second.

Fewell, Thomas E. (Chattanooga, TN); Ward, Charles T. (Chattanooga, TN)

1976-01-01T23:59:59.000Z

168

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

E-Print Network (OSTI)

Eq. (18b) Dhe heat exchanger heat transfer parameter, Eq. (t1 Loop Thermosiphon Heat Exchanger,n ASHRAE Transactions,s . • Thermosiphon Heat Exchanger,n Part 2, 1980, No. 2588,

Mertol, A.

2013-01-01T23:59:59.000Z

169

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

E-Print Network (OSTI)

THERMOSIPHONS WITH HEAT EXCHANGERS A. Mertol, W. Place, T.Eq. (18b) Dhe heat exchanger heat transfer parameter, Eq. (t1 Loop Thermosiphon Heat Exchanger,n ASHRAE Transactions,

Mertol, A.

2013-01-01T23:59:59.000Z

170

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

171

Simulation of the heat exchangers dynamics in MATLAB&simulink  

Science Conference Proceedings (OSTI)

Heat exchangers that transfer energy from flue gas to steam are important units of thermal power stations. Their inertias are often decisive for the design of the steam temperature control system. In this paper, the analysis and the simulation of the ... Keywords: MATLAB&simulink, S-functions, finite difference method, heat exchangers, partial differential equations, real-time, simulation, superheaters

Pavel Nevriva; Stepan Ozana; Ladislav Vilimec

2009-10-01T23:59:59.000Z

172

Finite element modeling of borehole heat exchanger systems  

Science Conference Proceedings (OSTI)

Single borehole heat exchanger (BHE) and arrays of BHE are modeled by using the finite element method. Applying BHE in regional discretizations optimal conditions of mesh spacing around singular BHE nodes are derived. Optimal meshes have shown superior ... Keywords: Borehole heat exchanger, Borehole thermal energy store, FEFLOW, TRNSYS

H. -J. G. Diersch; D. Bauer; W. Heidemann; W. Rühaak; P. Schätzl

2011-08-01T23:59:59.000Z

173

An application of DCS device to a heat exchange process  

Science Conference Proceedings (OSTI)

In this paper, an application of distributed control system (DCS) device to a heat exchange process is shown. In details, first, nonlinear model and feedback tracking control scheme of a spiral heat exchange process are obtained. Second, the designed ... Keywords: DCS, nonlinear control, nonlinear model, right coprime factorization, robust stability

Junya Okazaki; Shengjun Wen; Mingcong Deng; Dongyun Wang

2012-10-01T23:59:59.000Z

174

Condensing Heat Exchanger for Optimization of Energy Efficiency  

E-Print Network (OSTI)

Historically, boiler efficiency has been limited due to the minimum temperature allowed at the stack. Heat lost up the stack was in exchange for keeping the flue gas temperature above the water vapor dew point. If water vapor was allowed to condense 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 for every 40F (4.5C) reduction in flue gas stack temperature. In the CHX® condensing heat exchanger, all gas wetted surfaces are covered with DuPont Teflon®. The Teflon covered heat exchanger surfaces are impervious to all acids normally resulting from the combustion of fossil fuels. This allows the flue gas to be cooled to below the water vapor dew point with no subsequent corrosion of the heat exchanger surfaces.

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

1995-04-01T23:59:59.000Z

175

Self-defrosting recuperative air-to-air heat exchanger  

DOE Patents (OSTI)

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

Drake, Richard L. (Delmar, NY)

1993-01-01T23:59:59.000Z

176

Liquid-fluidized-bed heat exchanger design parameters  

SciTech Connect

Liquid-fluidized-bed heat exchangers prevent scale accumulation on heat transfer surfaces and reduce the required heat transfer surface when scaling fluids, such as geothermal water, are used as the primary or working fluid. Liquid-fluidized-bed heat exchangers, principles of operation, and design parameters are described. Horizontal and vertical assemblies are discussed, including problems encountered with both designs. Bed-side heat transfer coefficients are given for limited cases, and a correlation is provided for calculating heat transfer coefficients for horizontal assemblies. A design example for a 60 kW/sub (e)/ (60 kW/sub (electric)/ preheater is included.

Allen, C.A.; Grimmett, E.S.

1978-04-01T23:59:59.000Z

177

Liquid-fluidized-bed heat exchanger flow distribution models  

DOE Green Energy (OSTI)

Allied Chemical Corporation at the Idaho National Engineering Laboratory is developing liquid-fluidized-bed shell-and-tube heat exchangers for geothermal applications. Sand fluidized by geothermal water on the shell side prevents scaling and increases heat transfer coefficients over conventional heat exchangers. Tests were conducted on two instrumented fluidized-bed heat exchanger models, constructed primarily of plexiglass, which differ in tube bundle orientation. One contains a horizontal bundle and the other a vertical tube bundle. Plexiglass construction allowed visual observation of flow patterns. The vertical model proved to have more uniform flow distribution and higher heat transfer coefficients than the horizontal model. The horizontal heat exchanger experienced piling on top of the tubes and areas of poor fluidization existed in the bed. Geometric considerations show that a horizontal design is more conducive to large flow rates than a vertical design. New design concepts for both vertical and horizontal assemblies and recommendations for further developmental work are presented.

Cole, L.T.; Allen, C.A.

1979-01-01T23:59:59.000Z

178

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

SciTech Connect

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

179

Heat Exchanger Visual Inspection - Partial Tube Blockage Considerations  

Science Conference Proceedings (OSTI)

 Challenges to the thermal performance capability of safety-related open cooling water system heat exchangers were a major reason the Nuclear Regulatory Commission (NRC) issued Generic Letter 89-13, “Service Water System Problems Affecting Safety Related Equipment.” GL 89-13 required licensees to commit to various actions to ensure that thermal performance requirements were met for heat exchangers supporting the ultimate heat sink (UHS) function. These actions may include periodic ...

2012-09-05T23:59:59.000Z

180

Direct-contact closed-loop heat exchanger  

DOE Patents (OSTI)

A high temperature heat exchanger with 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, Gregory F. (Naperville, IL); Minkov, Vladimir (Skokie, IL); Petrick, Michael (Joliet, IL)

1984-01-01T23:59:59.000Z

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.


181

Comparison of natural convection heat exchangers for solar water heating systems  

DOE Green Energy (OSTI)

Thermosyphon heat exchangers are used in indirect solar water heating systems to avoid using a pump to circulate water from the storage tank to the heat exchanger. In this study, the authors consider the effect of heat exchanger design on system performance. They also compare performance of a system with thermosyphon flow to the same system with a 40W pump in the water loop. In the first part of the study, the authors consider the impact of heat exchanger design on the thermal performance of both one- and two-collector solar water heaters. The comparison is based on Solar Rating and Certification Corporation (SRCC) OG300 simulations. The thermosyphon heat exchangers considered are (1) a one-pass, double wall, 0.22 m{sup 2}, four tube-in-shell heat exchanger manufactured by AAA Service and Supply, Inc., (the Quad-Rod); (2) a two-pass, double wall, 0.2 m{sup 2}, tube-in-shell made by Heliodyne, Inc., but not intended for commercial development; (3) a one-pass, single wall, 0.28 m{sup 2}, 31 tube-in-shell heat exchanger from Young Radiator Company, and (4) a one-pass single-wall, 0.61 m{sup 2}, four coil-in-shell heat exchanger made by ThermoDynamics Ltd. The authors compare performance of the systems with thermosyphon heat exchangers to a system with a 40 W pump used with the Quad-Rod heat exchanger. In the second part of the study, the effects of reducing frictional losses through the heat exchanger and/or the pipes connecting the heat exchanger to the storage tank, and increasing heat transfer area are evaluated in terms of OG300 ratings.

Davidson, J.; Liu, W.

1998-09-15T23:59:59.000Z

182

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

DOE Patents (OSTI)

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

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

1994-11-29T23:59:59.000Z

183

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)

Direct Contact Heat Exchanger . . . . . . . . . .DIRECT CONTACT HEAT EXCHANGER TEST LOOP . . . . . . . . TestCALIBRATION . CONVENTIONAL HEAT EXCHANGER . . . Subcritical

Engineering, Barber-Nicholas

2011-01-01T23:59:59.000Z

184

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

E-Print Network (OSTI)

Lau, W, and Yang, S. , “A Heat Exchanger between Forced FlowWITHIN A CYLINDRICAL HEAT EXCHANGER COOLED TO 14 K S. Qof the container is a heat exchanger between the hydrogen

Yang, S.W.; Oxford U.

2004-01-01T23:59:59.000Z

185

A NEW SOLAR THERMAL RECEIVER UTILIZING A SMALL PARTICLE HEAT EXCHANGER  

E-Print Network (OSTI)

A.J.Hunt, "Small Particle Heat Exchangers" Lawrence BerkeleyUtilizing A Small Particle Heat Exchanger ArIon]. Hunt AprilA SMALL PARTICLE HEAT EXCHANGER Arlon J. Hunt Lawrence

Hunt, Arlon J.

2011-01-01T23:59:59.000Z

186

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

187

SILICON CARBIDE CERAMICS FOR COMPACT HEAT EXCHANGERS  

Science Conference Proceedings (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

188

Acoustically enhanced heat exchange and drying apparatus  

DOE Patents (OSTI)

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

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

1987-07-10T23:59:59.000Z

189

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

190

Characterization of the Ground Thermal Response to Heating by a Deep Vertical Borehole Heat Exchanger.  

E-Print Network (OSTI)

??This thesis presents an experiment and an analysis that evaluates some of the long-standing assumptions in deep vertical borehole ground heat exchanger (GHX) theory. These… (more)

Olfman, Maeir Zalman

2012-01-01T23:59:59.000Z

191

Performance analysis of heat transfer processes from wet and dry surfaces : cooling towers and heat exchangers.  

E-Print Network (OSTI)

??The objective of this work is to study the thermal and hydraulic performance of evaporatively cooled heat exchangers, including closed wet cooling towers, and dry… (more)

Hasan, Ala Ali

2005-01-01T23:59:59.000Z

192

Performance Analysis of Heat Transfer Processes from Wet and Dry Surfaces: Cooling Towers and Heat Exchangers.  

E-Print Network (OSTI)

??The objective of this work is to study the thermal and hydraulic performance of evaporatively cooled heat exchangers, including closed wet cooling towers, and dry… (more)

Hasan, Ala Ali

2005-01-01T23:59:59.000Z

193

Evaluation of fluid bed heat exchanger optimization parameters. Final report  

SciTech Connect

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

194

1-MWE heat exchangers for OTEC. Final design report  

DOE Green Energy (OSTI)

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

Sprouse, A.M.

1980-06-19T23:59:59.000Z

195

Energy effectiveness of simultaneous heat and mass exchange devices  

E-Print Network (OSTI)

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

Narayan, G. Prakash

2010-01-01T23:59:59.000Z

196

The Influence of Availability Costs on Optimal Heat Exchanger Size  

E-Print Network (OSTI)

Optimizing heat exchangers based on second law rather than first law considerations ensures that the most efficient use of available energy is being made. Techniques for second-law optimizing heat exchangers have been developed recently that are straightforward and simple. The main difficulty lies in determining the proper cost of irrreversibility that is to be used in the optimization process. This paper demonstrates how this issue can be handled by including the irreversibility cost in a dimensionless parameter that represents the ratio of annual ownership costs to annual operating costs that include irreversibility costs. In this way, each heat exchanger designer can estimate the costs of irreversibilities for his particular system, and use the generalized method for determining the optimal heat exchanger size.

Witte, L. C.

1987-09-01T23:59:59.000Z

197

Failure Analysis of the Heat Exchanger Tubes Exposed to High ...  

Science Conference Proceedings (OSTI)

The bundle of the heat exchanger was removed from service after 8 years for metallurgical investigation. The tube side contains boiler feed water at 622oF and  ...

198

Data Center Rack Cooling with Rear-door Heat Exchanger  

NLE Websites -- All DOE Office Websites (Extended Search)

they can use treated water from a plate-and-frame heat exchanger connected to a cooling tower. These inherent features of a RDHx help reduce energy use while minimizing maintenance...

199

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

Office of Scientific and Technical Information (OSTI)

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

200

Process Heat Exchanger Options for the Advanced High Temperature Reactor  

Science Conference Proceedings (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

2011-06-01T23:59:59.000Z

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

Process Heat Exchanger Options for Fluoride Salt High Temperature Reactor  

Science Conference Proceedings (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

202

Experimental testing and analytical analysis of a plastic panel heat exchanger for greenhouse heating  

SciTech Connect

The performance of a plastic panel-type heat exchanger, suitable for greenhouse heating using low-grade (25 to 60/sup 0/C water) power plant reject heat, was investigated theoretically and experimentally. The theoretical analysis showed that a plastic panel heat exchanger would have an overall heat transfer coefficient, U/sub 0/, of about 18 w/m/sup 2/-/sup 0/C compared to about 12 w/m/sup 2/-/sup 0/C for a fin-tube heat exchanger, under typical greenhouse conditions. Furthermore the plastic heat exchanger would require less fan power due to reduced air pressure losses. The experimental data revealed a similar functional relationship for U/sub 0/ and air flow when compared with the theoretical calculations, however the experimental values of U/sub 0/ were consistently larger by 20 to 30%. It was concluded that a properly designed plastic heat exchanger can compete with metal fin tube type exchangers on a performance basis, but the plastic heat exchangers are 3 to 4 times larger by volume. However, because of the lower cost of plastic, a substantial cost reduction is expected. It appears that further study, examining heat exchanger lifetime, performance and costs, is warranted.

Olszewski, M.; Thomas, J.F.

1980-02-01T23:59:59.000Z

203

BOP Heat Exchanger NDE Application: Automated Analysis Software Evaluation  

Science Conference Proceedings (OSTI)

Aging power plant components, especially balance-of-plant (BOP) heat exchanger tubing, experience failures as a result of a variety of flaw damage mechanisms. Accurately sizing these flaws has always been delegated to the experience and knowledge of qualified eddy current data analysts. Manually reporting all BOP heat exchanger tubing flaws is not practical because of time constraints and because the number of tubing flaws can vary from tube to tube. Typically, only the worst flaw condition is reported, ...

2003-05-30T23:59:59.000Z

204

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 error analyses and design, the equation of measurement error of heat transfer in air side and water side about orifice meter for the finned-tube heat-exchanger was obtained. This paper studies the major factors that may influence the largest admitted measurement error of measurement instruments for heat transfer in water and air side, and analyzes the degree that water temperature and pressure measurement influence heat transfer in water side, and the degree that wet bulb temperature difference measurement influences heat transfer in air side. Finally, this paper indicates that the key problem of reducing heat transfer in water side is water temperature measurement of the in-out pipe of heat-exchanger, and wet bulb temperature difference is a key to decrease the heat transfer in air side for finned-tube heat-exchanger. This paper gives a theoretical instruction for designing the measurement system of a finned-tube heat-exchanger test-board

Chen, Y.; Zhang, J.

2006-01-01T23:59:59.000Z

205

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

E-Print Network (OSTI)

This article deals with the heat exchange coefficient varied with pulse frequency in the pulsation tube with different flow forms. The findings show that heat can be exchanged coefficient with the pulse frequency, and it has an optimal frequency. The laminar flow and turbulent flow have approximately the same optimal frequency, i.e., about 8 Hz. When the pulsation source was placed in the upstream and downstream position, the heat transformation was completed dissimilarly. These results are coincident with previous experiments. The article also gives some information on the applications of the heat transformation by pulse flow in the shell and tube heat exchanger.

Chen, Y.; Zhao, J.

2006-01-01T23:59:59.000Z

206

Acoustically enhanced heat exchange and drying apparatus  

DOE Patents (OSTI)

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

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

1989-01-01T23:59:59.000Z

207

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

E-Print Network (OSTI)

to the International Journal of Compact Heat Exchangers, May 2003 #12;2 Measurements and Predictions of the Heat Transfer at the Tube-Fin Junction for Louvered Fin Heat Exchangers Abstract The dominant thermal resistance for most compact heat exchangers occurs on the air side and thus a detailed understanding of air side heat

Thole, Karen A.

208

Design and technology of heat pipes for cooling and heat exchange  

SciTech Connect

This new book presents a comprehensive account of heat pipe design, technology, and operation. It is based on insights and techniques developed by the author during more than twenty years of investigating high-performance heat pipe systems. The book provides information on a unique device with the capability to transport heat isothermally at high rates with no external power input. Emphasis is on high-performance liquid metal heat pipes, although nonliquid metal heat pipes are treated, as well. The first three chapters deal with the nonmathematical background for understanding heat pipe operation and heat transport capability. Remaining chapters detail heat pipe characteristics and design methods. Of special interest are simplified equations for obtaining heat pipe heat transport limits, heat pipe heat exchangers, heat pipe transient behavior, and inverted (nonwetting) heat pipes. Operational boundaries on heat pipe temperature and heat transport rate are described, and step-by-step procedures are given for involved calculations.

Silverstein, C.C.

1992-01-01T23:59:59.000Z

209

Temperature control system for a J-module heat exchanger  

DOE Patents (OSTI)

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

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

1978-01-01T23:59:59.000Z

210

Performance monitoring and replacement of heat exchanger components and materials  

Science Conference Proceedings (OSTI)

This book contains papers presented at the 1990 International Joint Power Generation Conference. Included are the following articles: A comparison of heat transfer coefficients, Extend heat exchanger and condenser life with metal alloy inserts, Design, service conditions and deaerator cracking in Dutch utility boilers.

Maurer, J.R. (Allegheny Ludlum Steel (US))

1990-01-01T23:59:59.000Z

211

Direct use geothermal applications for brazed plate heat exchangers  

DOE Green Energy (OSTI)

Brazed plate heat exchanger were placed in three geothermal fluids (Klamath Falls, OR; Boise, ID; and Pagosa Springs, CO) to determine the effect of H{sub 2}S on braze material. Based on subsequent analysis, it appears that the rate of corrosion of the braze material is much slower than corrosion of copper tube materials in the same fluids. Minimum expected life of the heat exchangers based on these corrosion rates is reported to be 12 years in fluids of less than 1 ppm H{sub 2}S and 10 years in fluids of less than 5 ppm. Based on these expected lives, and using a 3% inflation rate and 8% discount rate, brazed plate heat exchangers are a clear economic choice in which the capital cost is 50% or less of the cost of a plate and frame heat exchanger for the same duty. Due to their single pass design, brazed plate heat exchangers are generally limited to approach temperatures of 10{degrees} or greater. Size limitations restrict applications to 100 gpm and/or 200 ft{sup 2} heat transfer surface area.

Rafferty, K.

1992-12-31T23:59:59.000Z

212

Direct use geothermal applications for brazed plate heat exchangers  

DOE Green Energy (OSTI)

Brazed plate heat exchanger were placed in three geothermal fluids (Klamath Falls, OR; Boise, ID; and Pagosa Springs, CO) in order to determine the effect of H[sub 2]S on braze material. Based on subsequent analysis, it appears that the rate of corrosion of the braze material is much slower than corrosion of copper tube materials in the same fluids. Minimum expected life of the heat exchangers based on these corrosion rates is reported to be 12 years in fluids of less than 1 ppm H[sub 2]S and 10 years in fluids of less than 5 ppm. Based on these expected lives, and using a 3% inflation rate and 8% discount rate, brazed plate heat exchangers are a clear economic choice in which the capital cost is 50% or less of the cost of a plate and frame heat exchanger for the same duty. Due to their single pass design, brazed plate heat exchangers are generally limited to approach temperatures of 10[degree] or greater. Size limitations restrict applications to 100 gpm and/or 200 ft[sup 2] heat transfer surface area.

Rafferty, K.

1993-02-01T23:59:59.000Z

213

Direct use geothermal applications for brazed plate heat exchangers  

DOE Green Energy (OSTI)

Brazed plate heat exchanger were placed in three geothermal fluids (Klamath Falls, OR; Boise, ID; and Pagosa Springs, CO) in order to determine the effect of H{sub 2}S on braze material. Based on subsequent analysis, it appears that the rate of corrosion of the braze material is much slower than corrosion of copper tube materials in the same fluids. Minimum expected life of the heat exchangers based on these corrosion rates is reported to be 12 years in fluids of less than 1 ppm H{sub 2}S and 10 years in fluids of less than 5 ppm. Based on these expected lives, and using a 3% inflation rate and 8% discount rate, brazed plate heat exchangers are a clear economic choice in which the capital cost is 50% or less of the cost of a plate and frame heat exchanger for the same duty. Due to their single pass design, brazed plate heat exchangers are generally limited to approach temperatures of 10{degree} or greater. Size limitations restrict applications to 100 gpm and/or 200 ft{sup 2} heat transfer surface area.

Rafferty, K.

1993-02-01T23:59:59.000Z

214

Direct use geothermal applications for brazed plate heat exchangers  

DOE Green Energy (OSTI)

Brazed plate heat exchanger were placed in three geothermal fluids (Klamath Falls, OR; Boise, ID; and Pagosa Springs, CO) to determine the effect of H[sub 2]S on braze material. Based on subsequent analysis, it appears that the rate of corrosion of the braze material is much slower than corrosion of copper tube materials in the same fluids. Minimum expected life of the heat exchangers based on these corrosion rates is reported to be 12 years in fluids of less than 1 ppm H[sub 2]S and 10 years in fluids of less than 5 ppm. Based on these expected lives, and using a 3% inflation rate and 8% discount rate, brazed plate heat exchangers are a clear economic choice in which the capital cost is 50% or less of the cost of a plate and frame heat exchanger for the same duty. Due to their single pass design, brazed plate heat exchangers are generally limited to approach temperatures of 10[degrees] or greater. Size limitations restrict applications to 100 gpm and/or 200 ft[sup 2] heat transfer surface area.

Rafferty, K.

1992-01-01T23:59:59.000Z

215

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

216

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

217

NEPS reactor and heat exchanger. Summary status (December 1978)  

SciTech Connect

The design of a 3 MW(+) heat-pipe cooled nuclear reactor for electric propulsion of spacecrafts has been evolving continually. Several modifications have been made to make the reactor design more tolerant of potential heat pipe failures. Design parameters and operating characteristics for the modified reactor are presented. The desirability of separating the reactor assembly from the thermionic converter assembly has been recognized, and an intermediate heat exchanger to couple the two subassemblies together has been conceptualized.

Koenig, D.R.

1979-06-01T23:59:59.000Z

218

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

219

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. The simulation model discretized the ground heat exchanger into elements and computed the temperature distribution surrounding the heat exchanger on a minute-by-minute basis. Hundreds of runs were made with the model for a wide range of ground temperatures, ground thermal properties (density, thermal conductivity, and specific heat), and outdoor weather. A set of sizing charts were developed from the model runs that could provide quick reference on the size of the ground heat exchanger. Corrections for ground temperature, ground density, ground thermal conductivity, and indoor air temperature were presented. Soil temperature and thermal conductivity were found to be the most important parameters for sizing GCHP heat exchangers. Results from the simplified method were compared to two available heat exchanger sizing methods: the National Water Well Association (NWWA) and the International Ground Source Heat Pump Association (IGSHPA). The simplified method predicted shorter lengths than those from either of these two methods.

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

1994-01-01T23:59:59.000Z

220

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 with a condensing heat exchanger can be used when heat exchange is required between two streams and where at leastH, consistency etc.). To increase the efficiency of heat exchange, a cascade of these units in series can be used

McCarthy, John E.

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

Research about correlation between the performance of plate heat exchanger and the number of plates  

Science Conference Proceedings (OSTI)

Plate heat exchangers are very important equipments used in industrial applications. The paper presents an analysis related to the influence of the number of plates on the performance of a heat exchanger. 3D models are made for eight cases and using ... Keywords: finite element method, fluid flow, heat exchanger effectiveness, log mean temperature difference, mesh, number of plates, plate heat exchanger

Roxana Grigore; Sorin Popa; Aneta Hazi; Gheorghe Hazi

2010-04-01T23:59:59.000Z

222

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

Science Conference Proceedings (OSTI)

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

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

2011-04-01T23:59:59.000Z

223

THERMOSIPHON WATER HEATERS WITH HEAT EXCHANGERS  

E-Print Network (OSTI)

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

Mertol, Atila

2012-01-01T23:59:59.000Z

224

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

NLE Websites -- All DOE Office Websites (Extended Search)

on the wall surface allowing heat transfer intensification. The shape of the device is created in a way that reduces overall hydraulic resistance to the insert. No.: M-856...

225

Assessment of next generation nuclear plant intermediate heat exchanger design.  

DOE Green Energy (OSTI)

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

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

2008-10-17T23:59:59.000Z

226

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 surface of louvered fin heat exchangers. It is shown that delta winglets placed on louvered fins produce Elsevier Ltd. All rights reserved. Keywords: Compact heat exchanger; Vortex generator; Louvered fins 1

Thole, Karen A.

227

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

DOE Patents (OSTI)

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

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

1996-12-03T23:59:59.000Z

228

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

Science Conference Proceedings (OSTI)

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

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

2011-01-01T23:59:59.000Z

229

Physica E 29 (2005) 390398 Quantum, cyclic, and particle-exchange heat engines  

E-Print Network (OSTI)

Physica E 29 (2005) 390­398 Quantum, cyclic, and particle-exchange heat engines T.E. Humphreya,�, H `particle-exchange' (PE) heat engines to achieve reversibility and finite power. In the next several in cyclic heat engines when the heat exchange between the working gas and the heat reservoir

Linke, Heiner

230

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

231

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

E-Print Network (OSTI)

DLM on the other hand con- pipes heat loss from ows. para 11~ headers~ connecting pipes~ and heat exchanger tubes) isconnecting pipes (riser and downcomer) and a heat exchanger

Mertol, A.

2013-01-01T23:59:59.000Z

232

Liquid Crystal Technique Application for Heat Transfer Investigation in a Fin-Tube Heat Exchanger Element  

Science Conference Proceedings (OSTI)

The use of thermochromic liquid crystal technique (LCT) and true-colour image processing system in heat transfer modelling is described. Experimental procedure, led on rig at Technical University of Gdansk, cover full-field flow patterns in heat exchanger ... Keywords: heat transfer, thermochromic liquid crystals, vortex generator, wind tunnel

M. Wierzbowski; J. Stasiek

2002-04-01T23:59:59.000Z

233

Diffusion Welding of Compact Heat Exchangers for Nuclear Applications  

Science Conference Proceedings (OSTI)

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

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

2012-06-01T23:59:59.000Z

234

A modular phase change heat exchanger for a solar oven  

Science Conference Proceedings (OSTI)

A modular energy storing heat exchanger designed to use pentaerythritol for thermal storage (solid-solid phase change at 182 C) is tested in an oven by circulating heat transfer oil which is electrically heated in a manner to simulate a concentrating solar collector. Three efficiencies for heating the system under controlled and measured power input are determined - the heat exchanger efficiency, the efficiency of the heater with distribution lines, and the total system efficiency. Thermal energy retention times and cooking extraction times are determined, and along with the efficiencies, are compared with the results previously reported for a nonmodular heat exchanger. The modular configuration provides a highly improved extraction rate for cooking due to its wrap-around character and its increased surface-to-volume ratio. A full scale glass model of the copper tubing of the system is described and flow observations reported demonstrating how uniformly the parallel pumping branches perform and how trapped air pockets affect pumping power. A technique for measuring pumping power is described and its application to the system is quantified to show that less than 1 watt is required to circulate the heat transfer oil even when the system includes the solar collector and its longer connecting tubes.

Bushnell, D.L.; Sohi, M. (Northern Illinois Univ., DeKalb (United States))

1992-10-01T23:59:59.000Z

235

Heat exchangers for high-temperature thermodynamic cycles  

SciTech Connect

The special requirements of heat exchangers for high temperature thermodynamic cycles are outlined and discussed with particular emphasis on cost and thermal stress problems. Typical approaches that have been taken to a comprehensive solution intended to meet all of the many boundary conditions are then considered by examining seven typical designs including liquid-to-liquid heat exchangers for nuclear plants, a heater for a closed cycle gas turbine coupled to a fluidized bed coal combustion chamber, steam generators for nuclear plants, a fossil fuel-fired potassium boiler, and a potassium condenser-steam generator. (auth)

Fraas, A.P.

1975-01-01T23:59:59.000Z

236

Internal dust recirculation system for a fluidized bed heat exchanger  

DOE Patents (OSTI)

A fluidized bed heat exchanger in which air is passed through a bed of particulate material containing fuel disposed in a housing. A steam/water natural circulation system is provided in a heat exchange relation to the bed and includes a steam drum disposed adjacent the bed and a tube bank extending between the steam drum and a water drum. The tube bank is located in the path of the effluent gases exiting from the bed and a baffle system is provided to separate the solid particulate matter from the effluent gases. The particulate matter is collected and injected back into the fluidized bed.

Gamble, Robert L. (Wayne, NJ); Garcia-Mallol, Juan A. (Morristown, NJ)

1981-01-01T23:59:59.000Z

237

Compact Ceramic Heat Exchangers for Corrosive Waste Gas Applications  

E-Print Network (OSTI)

The development of large ceramic heat exchangers is described and performance data given for units installed on steel industry soaking pits in the U.K. Operational experience since 1973 confirms that ceramic heat exchangers capable of operating with high airside pressures have long lives and low maintenance even when operating with dirty gases at 1350 deg. C and preheating combustion air to 800 deg. C. The design of compact units suitable for factory assembly is also described. Units have been developed for low temperature corrosive gas situations and have been applied to the pottery industry and are being developed for coal fired air heaters for the food industry.

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

1982-01-01T23:59:59.000Z

238

Applying Learnable Evolution Model to Heat Exchanger Design  

E-Print Network (OSTI)

A new approach to evolutionary computation, called Learnable Evolution Model (LEM), has been applied to the problem of optimizing tube structures of heat exchangers. In contrast to conventional Darwiniantype evolutionary computation algorithms that use various forms of mutation and/or recombination operators, LEM employs machine learning to guide the process of generating new individuals. A system, ISHED1, based on LEM, automatically searches for the highest capacity heat exchangers under given technical and environmental constraints. The results of experiments have been highly promising, often producing solutions exceeding the best human designs.

Kenneth A. Kaufman; Ryszard S. Michalski

2000-01-01T23:59:59.000Z

239

Using Plate Heat Exchangers to Increase Energy Efficiency  

E-Print Network (OSTI)

"In recent years, there has been an increasing awareness of Plate Heat Exchangers (PHE's) in industrial processes around the world. While PHE's have historically been classified as compact heat exchangers, compactness is often a secondary advantage that makes them well suited for retrofit applications in process plants that are often space limited. The primary advantage of PHE's are their high efficiency, flexibility, and reliability. Because of their efficiency, PHE's are being used in more applications where shell and tube heat exchangers were historically used. The high efficiency of the PHE offers the greatest benefits to the process industries. The countercurrent flow configuration, high heat transfer coefficients, and low fouling tendencies result in a heat exchanger that is extremely economical and efficient, especially in energy recovery applications where low LMTD's are common. This paper will review PHE design and construction and show how PHE's can be used to recover energy in many industrial processes. An economical analysis will be included to show the competitiveness of PHE's in energy recovery applications. The paper will review the advantages, benefits, and limitations of PHE's. Recent advances in PHE technology will also be discussed. "

Bailey, K.

1999-05-01T23:59:59.000Z

240

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

SciTech Connect

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

Mittereder, N.; Poerschke, A.

2013-11-01T23:59:59.000Z

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.


241

Distributive Distillation Enabled by Microchannel Process Technology  

SciTech Connect

The application of microchannel technology for distributive distillation was studied to achieve the Grand Challenge goals of 25% energy savings and 10% return on investment. In Task 1, a detailed study was conducted and two distillation systems were identified that would meet the Grand Challenge goals if the microchannel distillation technology was used. Material and heat balance calculations were performed to develop process flow sheet designs for the two distillation systems in Task 2. The process designs were focused on two methods of integrating the microchannel technology â?? 1) Integrating microchannel distillation to an existing conventional column, 2) Microchannel distillation for new plants. A design concept for a modular microchannel distillation unit was developed in Task 3. In Task 4, Ultrasonic Additive Machining (UAM) was evaluated as a manufacturing method for microchannel distillation units. However, it was found that a significant development work would be required to develop process parameters to use UAM for commercial distillation manufacturing. Two alternate manufacturing methods were explored. Both manufacturing approaches were experimentally tested to confirm their validity. The conceptual design of the microchannel distillation unit (Task 3) was combined with the manufacturing methods developed in Task 4 and flowsheet designs in Task 2 to estimate the cost of the microchannel distillation unit and this was compared to a conventional distillation column. The best results were for a methanol-water separation unit for the use in a biodiesel facility. For this application microchannel distillation was found to be more cost effective than conventional system and capable of meeting the DOE Grand Challenge performance requirements.

Arora, Ravi

2013-01-22T23:59:59.000Z

242

Measurement of the thermal performance of a Borehole Heat Exchanger while injecting air bubbles in the groundwater.  

E-Print Network (OSTI)

?? The most common way to exchange heat with the ground in Ground Source Heat Pump (GSHP) applications is with borehole heat exchangers (energy col-lectors… (more)

Calzada, Eduard

2012-01-01T23:59:59.000Z

243

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

244

Xenon Recirculation-Purification with a Heat Exchanger  

E-Print Network (OSTI)

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

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

2011-03-04T23:59:59.000Z

245

Heat transfer characteristics of a three-phase volume boiling direct contact heat exchanger  

DOE Green Energy (OSTI)

The advantages of direct contact heat transfer over heat transfer utilizing conventional metallic heat exchangers are listed. The performance characteristics of a three-phase direct contact heat exchanger in near counterflow operation were evaluated using water as the continuous phase fluid and refrigerant 113 as the dispersed phase fluid. Conclusions are drawn from the results having to do with refrigerant injection technique, vessel operating height, mass flow rate of refrigerant, water inlet temperature, operation at pinch point temperature differences below 13 to 20/sup 0/C, and operation with a dispersed phase fluid less dense than water. (MHR)

Blair, C.K.; Boehm, R.F.; Jacobs, H.R.

1976-03-01T23:59:59.000Z

246

Fouling characteristics of compact heat exchangers and enhanced tubes.  

Science Conference Proceedings (OSTI)

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

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

1999-07-15T23:59:59.000Z

247

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

248

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

2005-12-20T23:59:59.000Z

249

Heat exchanger with intermediate evaporating and condensing fluid  

DOE Patents (OSTI)

A shell and tube-type heat exchanger, such as a liquid sodium-operated steam generator for use in nuclear reactors, comprises a shell containing a primary fluid tube bundle, a secondary fluid tube bundle at higher elevation, and an intermediate fluid vaporizing at the surface of the primary fluid tubes and condensing at the surface of the secondary fluid tubes.

Fraas, Arthur P. (Knoxville, TN)

1978-01-01T23:59:59.000Z

250

Heat exchanger with leak detecting double wall tubes  

DOE Patents (OSTI)

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

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

1981-01-01T23:59:59.000Z

251

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

E-Print Network (OSTI)

exchanger, comfort. #12;AN OPTIMIZED TWO-CAPACITY ADVANCED ELECTRIC HEAT PUMP S. E. Veyo* ABSTRACT A two constrained optimization procedure was used to select heat exchanger proportions, air flow rates National Laboratory. * S. E. Veyo, Mgr., Heat Exchange Systems, Westinghouse R&D Center, Pittsburgh, PA

Oak Ridge National Laboratory

252

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

E-Print Network (OSTI)

F244 45 (2008-5) - 623 - Adjoint-Based Shape Optimization of a Heat-Exchanger Passage with Heat Institute, Sinkawa, Mitaka-shi, Tokyo 181-0004 Optimal shape design for heat exchangers including conjugate, Wavy Wall, Heat Exchanger 1. Pironneau(1) (2) (2) 2. 2 (m ) (M ) : Pr = 0.71 Ub Re 100 3. 1 1

Kasagi, Nobuhide

253

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

E-Print Network (OSTI)

Optimal Allocation of Heat Exchanger Inventory in a Serial Type Diabatic Distillation Column Edward the column . We have previously shown (Jimenez et al. 2003) that optimaloperation of serial heat exchangers total heat exchanger area in different trays and calculate the optimal allocation of a given heat

Salamon, Peter

254

Heat Exchange Between Ocean and Atmosphere in the Eastern North Pacific for 1961-71  

E-Print Network (OSTI)

Heat Exchange Between Ocean and Atmosphere in the Eastern North Pacific for 1961-71 N. E. CLARK, L of total heat exchange and departuresfroma long-term mean; 2)long-term monthly mean valuesof the total heat exchange, incom- ing solar radiation, effectiveback radiation, and evaporative and sensible heat transfer

255

Interbasin Heat Exchange; a Study of the Response to Changes in Wind Patterns  

E-Print Network (OSTI)

Interbasin Heat Exchange; a Study of the Response to Changes in Wind Patterns Hanna E. N. Kling of the vertical air-sea heat exchange through the "heat potential". An analogy is electrical potential Fo = "#$ Q = SST - relaxation temperature; the air-sea heat exchange Fo = divergence of Q

Corell, Hanna

256

Mechanisms of heat exchange between water and rock in karst conduits  

E-Print Network (OSTI)

Mechanisms of heat exchange between water and rock in karst conduits M. D. Covington,1 A. J water quality, have explored the mechanisms for heat transport and heat exchange in surface streams flux can be significant. In contrast, convective heat exchange through the conduit air is often

Saar, Martin O.

257

HEAT EXCHANGE IN THE YELLOWFIN TUNA, THUNNUS ALBACARES, AND SKIPJACK TUNA, KATSUWONUS PELAMIS, AND THE  

E-Print Network (OSTI)

HEAT EXCHANGE IN THE YELLOWFIN TUNA, THUNNUS ALBACARES, AND SKIPJACK TUNA, KATSUWONUS PELAMIS. The central heat exchanger in T. albacares, while also in the haemal arch, is simpler, consisting of two small not conserve heat. The skipjack tunas, Euthynnu~ and Kat~u'Wonus, have well-developed central heat exchangers

258

Brain emotional learning based intelligent controller applied to neurofuzzy model of micro-heat exchanger  

Science Conference Proceedings (OSTI)

In this paper, an intelligent controller is applied to govern the dynamics of electrically heated micro-heat exchanger plant. First, the dynamics of the micro-heat exchanger, which acts as a nonlinear plant, is identified using a neurofuzzy network. ... Keywords: Emotion based learning, Heat exchanger, Intelligent control, Locally linear models, Neurofuzzy models, Nonlinear system identification

Hossein Rouhani; Mahdi Jalili; Babak N. Araabi; Wolfgang Eppler; Caro Lucas

2007-04-01T23:59:59.000Z

259

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

DOE Patents (OSTI)

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

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

1998-07-21T23:59:59.000Z

260

Thermal performance of a geofluid direct-contact heat exchanger  

DOE Green Energy (OSTI)

A sieve-tray direct-contact heat exchanger was used to transfer heat from a 280/sup 0/F geothermal fluid to the working fluid, isobutane, in the Raft River 60kW prototype plant. A series of experiments were run at different working fluid-to-geofluid flow ratios which produced different boiling conditions. In this paper, the results of these experiments are analyzed on the basis of thermal performance. The flow ratio, the geofluid outlet temperature, the working fluid inlet temperature, the amount of working fluid dissolved or entrained in geofluid, and tray efficiency are varied and preheating temperature profiles are calculated. These are compared with the experimentally obtained temperature profiles and the relative effects of the variables are evaluated. From this, it was determined that the approach temperature difference was on the order of .1/sup 0/ after 17 preheating trays, and the tray efficiencies, which appear to be about the same for all trays, reached approx. 70%. It was also determined that entrainment has a negligible effect on column thermal performance. The thermal performance of this column compares favorably with a spray-tower direct-contact heat exchanger and a shell-and-tube heat exchanger in terms of overall heat-transfer coefficient. Distributor tray and boiling tray behavior are discussed. These is some discussion of operations and thermal hydraulics as well.

Wiggins, D.J.; Mines, G.L.; Wahl, E.

1983-01-01T23:59:59.000Z

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

Heat exchanger efficiently operable alternatively as evaporator or condenser  

DOE Patents (OSTI)

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

Ecker, Amir L. (Dallas, TX)

1981-01-01T23:59:59.000Z

262

Secondary Heat Exchanger Design and Comparison for Advanced High Temperature Reactor  

Science Conference Proceedings (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 exchangers—helical coiled heat exchanger and printed circuit heat exchanger—as possible options for the AHTR secondary heat exchangers with the following three different options: (1) A single heat exchanger transfers all the heat (3,400 MW(t)) from the intermediate heat transfer loop to the power conversion system or process plants; (2) Two heat exchangers share heat to transfer total heat of 3,400 MW(t) from the intermediate heat transfer loop to the power conversion system or process plants, each exchanger transfers 1,700 MW(t) with a parallel configuration; and (3) Three heat exchangers share heat to transfer total heat of 3,400 MW(t) from the intermediate heat transfer loop to the power conversion system or process plants. Each heat exchanger transfers 1,130 MW(t) with a parallel configuration. A preliminary cost comparison will be provided for all different cases along with challenges and recommendations.

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

2012-06-01T23:59:59.000Z

263

Heat Pump Cycle with Solution Circuit and Internal Heat Exchange  

E-Print Network (OSTI)

Vapor compression heat pumps which employ working fluid mixtures rather than pure substances offer significant advantages leading to larger temperature lifts at low pressure ratios or to completely new applications. The main feature of such cycles is the fact that the working fluid mixture does not evaporate completely in the evaporator. The remaining liquid phase is then recirculated by means of a liquid pump into the condenser. This yields significant improvements compared to conventional systems: -Adjustable gliding temperature intervals in desorber and absorber by merely adjusting the flow rate through the liquid pump and/or –Dramatically reducing pressure ratios (to typically 45% of the one for a single working fluid heat pump) for a given temperature lift due to staging of the solution circuit. The latter is accomplished when a two-stage version of this cycle is used. In this paper, another version of such cycles will be discussed which offers the same low pressure ratio as a previously discussed two-stage cycle, but requires only one liquid pump. The performance of this cycle has been calculated and the results are presented.

Radermacher, R.

1986-06-01T23:59:59.000Z

264

GLEF direct-contact heat-exchanger program. Final report  

DOE Green Energy (OSTI)

A number of flash-binary cycles for the Salton Sea Known Geothermal Area have been evaluated leading to the identification of the optimum one. The brine coming from the well is separated in a flash tank producing a liquid and a vapor stream. The liquid is used in a direct contact preheater to bring the working fluid (isopentane) to the saturation point. The isopentane is then vaporized in a shell and tube heat exchanger by use of the flashed steam. The isopentane vapor is expanded in a turbine driving the generator, condensed in a surface condenser and finally returned to the preheater by the main feed pump. A review of the theoretical correlations available for the design of direct contact heat exchangers has been carried out as well as the design and fabrication of a test facility to evaluate the performance of direct contact heat exchangers under various conditions and to verify the cycle analysis. The results of the test data support the assumptions made in the system analysis and in particular, the terminal temperature differences established in the heat balance have been achieved. The column length calculation procedure has been tested and found satisfactory under the test conditions.

Della Vida, P.L.; Franz, F.J.; Weinreich, R.S.

1980-03-01T23:59:59.000Z

265

GLEF direct-contact heat-exchanger program  

DOE Green Energy (OSTI)

A number of flash-binary cycles for the Salton Sea Known Geothermal Area have been evaluated leading to the identification of the optimum one. The brine coming from the well is separated in a flash tank producing a liquid and a vapor stream. The liquid is used in a direct contact preheater to bring the working fluid (isopentane) to the saturation point. The isopentane is then vaporized in a shell and tube heat exchangers by use of the flashed steam. The isopentane vapor is expanded in a turbine driving the generator, condensed in a surface condenser and finally returned to the preheater by the main feed pump. A review of the theoretical correlations available for the design of direct contact heat exchangers has been carried out as well as the design and fabrication of a test facility to evaluate the performance of direct contact heat exchangers under various conditions and to verify the cycle analysis. The results of the test data support the assumptions made in the system analysis and in particular, the terminal temperature differences established in the heat balance have been achieved. The column length calculation procedure has been tested and found satisfactory under the test conditions.

Della Vida, P.L.; Franz, F.J.; Weinreich, R.S.

1980-03-01T23:59:59.000Z

266

The Influence of Different Inflow Water Rate and Temperature on Heat Exchange Performance of Underground Heat Pump  

Science Conference Proceedings (OSTI)

in the paper, the influence of different inflow water rate and temperature on heat exchange performance of underground heat pump were discussed by experiment, two vital parameters was defined to measure the properties of ground heat exchanger: Energy ... Keywords: heat pump, underground tube, influential factors, parameters

Zheng Min; Li Bai-yi

2011-11-01T23:59:59.000Z

267

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

Science Conference Proceedings (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

268

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

E-Print Network (OSTI)

Water Solar Tank Warm Water Hot Water Heater Water Tank Heatsolar thermosiphon water heaters with heat exchangers in storage tanks.solar water heater with a heat exchanger in the storage tank.

Mertol, A.

2013-01-01T23:59:59.000Z

269

Design of compact intermediate heat exchangers for gas cooled fast reactors  

E-Print Network (OSTI)

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

Gezelius, Knut, 1978-

2004-01-01T23:59:59.000Z

270

Boiler Room Coal Drying Heat Exchanger Numerical Computational Simulation and Analysis  

Science Conference Proceedings (OSTI)

Northeast area city district heating boiler room of coal with high moisture content, have caused a large number of waste of coal resources. Boiler coal drying heat exchanger is a long design cycle, testing workload and investment is more equipment. In ... Keywords: District heating boiler room, Dry heat exchanger, Numerical simulation, Heat transfer calculation

Zhao Xuefeng, Xiong Wen-zhuo

2012-07-01T23:59:59.000Z

271

ETTM-HE (Heat Exchanger)CBT Module, Version 1.0  

Science Conference Proceedings (OSTI)

The Heat Exchangers Computer-Based Training/Engineering Technical Training Modules Course (HE CBT/ETTM) version 1.0 is a web-based training module that provides graphics and interactive features to enhance learning and theory of operation for a variety of heat exchangers. This application introduces the basic heat transfer principles of heat exchangers and how these principles apply to typical nuclear plant exchanger applications. This computer-based training (CBT) module is intended for use by new engi...

2006-10-31T23:59:59.000Z

272

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

DOE Patents (OSTI)

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

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

1981-11-24T23:59:59.000Z

273

Energy Recovery By Direct Contact Gas-Liquid Heat Exchange  

E-Print Network (OSTI)

Energy from hot gas discharge streams can be recovered by transfer directly to a coolant liquid in one of several available gas-liquid contacting devices. The design of the device is central to the theme of this paper, and experimental work has verified that the analogy between heat transfer and mass transfer can be used for design purposes. This enables the large amount of available mass transfer data for spray, packed and tray columns to be used for heat transfer calculations. Additional information is provided on flow arrangements for integrating direct contact exchangers into systems for recovering the energy transferred to the liquid.

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

1988-09-01T23:59:59.000Z

274

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 counterflow CHE consisting of 3 helical coils. Two separate tests were conducted, one where water was used as heat transfer fluid (HTF) on the coil and shell sides, respectively; while the second one made use of MPCM slurry and water on the coil and shell sides, respectively. The NTU-effectiveness relationship of the CHE when MPCM fluid is used approaches that of a heat exchanger with a heat capacity ratio of zero. The heat transfer results have shown that when using a MPCM slurry, an increase in heat transfer rate can be obtained when compared to heat transfer results obtained using straight heat transfer sections. It has been concluded that the increased specific heat of the slurry as well as the fluid dynamics in helical coil pipes are the main contributors to the increased heat transfer.

Gaskill, Travis

2011-12-01T23:59:59.000Z

275

A heat exchanger between forced flow helium gas at 14 to 18 K and liquid hydrogen at 20 K circulated by natural convection  

E-Print Network (OSTI)

LBNL-53719 A HEAT EXCHANGER BETWEEN FORCED FLOW HELIUM GAShydrogen absorber and the heat exchanger between the liquidpasses through the heat exchanger in the absorber shell. The

Green, M.A.; Ishimoto, S.; Lau, W.; Yang, S.

2003-01-01T23:59:59.000Z

276

Heat Exchanger Workstation Condenser Application (HEWCA), Version 2.0  

Science Conference Proceedings (OSTI)

Heat Exchanger Workstation—Condenser Application (HEWCA) Version 2.0 is software used for performance analysis for steam surface condensers. Description HEWCA Version 2.0 is used to configure steam surface condensers, to run performance analyst calculations with different algorithms and to view results. The Performance Advisor Module can help the user diagnose probable causes of condenser performance deficiency. Platform Requirements Windows™ 2000 / XP / Vista

2008-11-20T23:59:59.000Z

277

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

E-Print Network (OSTI)

Bond Graph Model of a Vertical U-Tube Steam Condenser Coupled with a Heat Exchanger K. Medjaher1+ A and thus the bottom well acts as a heat exchanger. The storage of hydraulic and thermal energies steam condenser; Heat exchanger; Bond graph 1. Introduction Modern process engineering plants

Paris-Sud XI, Université de

278

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

E-Print Network (OSTI)

#12;Vertical Concentric Tube Ground Couoled Heat Exchangers V. C. Mei and S. K. Fischer* Abstract exchangers for use in heat-pump applications is described. The experimental apparatus consists. This heat exchanger was placed in a 0.20-m (8-in.) inside-diameter well and backfilled with sand

Oak Ridge National Laboratory

279

Numerical Analysis of a Multi-Row Multi-Column Compact Heat Exchanger  

E-Print Network (OSTI)

Numerical Analysis of a Multi-Row Multi-Column Compact Heat Exchanger Ashkan Motamedi1, Arturo of a compact heat exchanger to analyze the interaction between the fluid and its geometry. The overall as the inner-tube fluid. Two heat exchanger configurations, in which the tube arrangement is either in

Pacheco, Jose Rafael

280

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

E-Print Network (OSTI)

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

Sen, Mihir

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

A simple model of impact dynamics in many dimensional systems, with applications to heat exchangers  

E-Print Network (OSTI)

A simple model of impact dynamics in many dimensional systems, with applications to heat exchangers present a simple hybrid model of impact dynamics in heat exchangers. The method, based on graph theory and experimental evidence. 1 Introduction A heat exchanger typically consists of a large number of thin pipes

Bristol, University of

282

Control Structure Selection for Optimal Operation of a Heat Exchanger Network  

E-Print Network (OSTI)

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

Skogestad, Sigurd

283

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

E-Print Network (OSTI)

Written date: January 19, 2012 Preliminary study on the mechanical behaviour of heat exchanger pile of Figures: 6 Abstract: The effects of temperature changes on the mechanical behaviour of heat exchanger cycles. 2 Key words: Model tests, heat exchanger pile, settlement, soil/structure interaction

284

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

E-Print Network (OSTI)

Applying Learnable Evolution Model to Heat Exchanger Design Kenneth A. Kaufman and Ryszard S), has been applied to the problem of optimizing tube structures of heat exchangers. In contrast. A system, ISHED1, based on LEM, automatically searches for the highest capacity heat exchangers under given

Michalski, Ryszard S.

285

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

E-Print Network (OSTI)

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

Skogestad, Sigurd

286

THERMAL PERFORMANCE OF A DUAL-CHANNEL, HELIUM-COOLED, TUNGSTEN HEAT EXCHANGER  

E-Print Network (OSTI)

THERMAL PERFORMANCE OF A DUAL-CHANNEL, HELIUM-COOLED, TUNGSTEN HEAT EXCHANGER Dennis L. Youchison-cooled, refractory heat exchangers are now under consideration for first wall and divertor applications-channel, helium-cooled heat exchanger made almost entirely of tungsten was designed and fabricated by Thermacore

California at Los Angeles, University of

287

Large Eddy Simulations and stereoscopic particle image velocimetry measurements in a scraped heat exchanger crystallizer  

E-Print Network (OSTI)

*Corresponding author: M.Rodriguez@tudelft.nl Abstract The transport phenomena in scraped heat exchanger crystallizers are critical for the process performance. Fluid flow and turbulence close to the heat exchanger with a focus on the bottom region where the heat exchanging surface was located. The simulations were validated

Paris-Sud XI, Université de

288

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

E-Print Network (OSTI)

OPTIMALDESIGN OF MICRO BARE-TUBE HEAT EXCHANGER Sawat Paitoonsurikarn, Nobuhide Kasagi, and Yuji-8656, Japan Email: sawat@thtlab.t.u-tokyo.ac.jp; Fax: +81-(3)-5800-6999 Keywords: Compact Heat Exchanger, Tube on the simulated annealing technique has been developed for a compact heat exchanger that employs only small

Kasagi, Nobuhide

289

Problems with specifying Tmin in design of processes with heat exchangers  

E-Print Network (OSTI)

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

Skogestad, Sigurd

290

Artificial neural network control of a heat exchanger in a closed flow air circuit  

Science Conference Proceedings (OSTI)

This paper experimentally investigates the control of a heat exchanger in a closed flow air circuit. The temperature inside the test section of the test facility has been maintained at a set value by variation of air flow rate over the heat exchanger ... Keywords: Air circuit, Heat exchanger, Multi-layer perceptron, Neural network control, PID control

Kapil Varshney; P. K. Panigrahi

2005-07-01T23:59:59.000Z

291

Nondestructive Evaluation: 10th EPRI Balance-of-Plant Heat Exchanger NDE Symposium Proceedings  

Science Conference Proceedings (OSTI)

EPRI's 10th Balance-of-Plant Heat Exchanger NDE Symposiumheld in San Antonio, Texas, June 1618, 2008focused on lessons learned and experiences related to inspection, repair, and condition assessment of balance-of-plant (BOP) heat exchangers. This year's symposium scope has extended to non-heat exchanger BOP components, such as buried piping and storage tanks.

2008-08-27T23:59:59.000Z

292

Heat exchanger bypass system for an absorption refrigeration system  

DOE Patents (OSTI)

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

Reimann, Robert C. (Lafayette, NY)

1984-01-01T23:59:59.000Z

293

Horizontal Heat Exchanger Design and Analysis for Passive Heat Removal Systems  

Science Conference Proceedings (OSTI)

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

Vierow, Karen

2005-08-29T23:59:59.000Z

294

THERMAL DESIGN METHODOLOGY FOR LOW FLOW RATE SINGLE-PHASE AND TWO-PHASE MICRO-CHANNEL HEAT SINKS  

E-Print Network (OSTI)

in Engine Cooling Systems,'' Experimental Heat Transfer, Fluid Mechanics, and Thermodynamics 1997, June 1997, ``A Correlation for Boiling Heat Transfer to Saturated Fluids in Convective Flow,'' Ind. Eng. Chem the engines in automotive applications. Heat is transferred essentially under subcooled flow boiling

Qu, Weilin

295

Deaerator heat exchanger for combined cycle power plant  

SciTech Connect

This patent describes a combined cycle power plant. It comprises a steam turbine including an inlet portion for receiving motive steam and an exhaust portion for exhausting the motive steam that is spent by the steam turbine; a condenser connected to the exhaust portion of the steam turbine for receiving the spent motive steam and for condensing the spent motive steam to a supply of condensate; a gas turbine including an exhaust portion for exhausting waste heat that is produced by the gas turbine in the form of exhaust gases; a heat recovery steam generator connected between the exhaust portion of the gas turbine and the steam turbine, for receiving the waste heat exhausted by the gas turbine, for generating the motive steam from a supply of feedwater heated by the waste heat, and for supplying the motive steam to the steam turbine; a deaerator connected to the condenser for receiving the supply of condensate and for deaerating the condensate to provide the supply of feedwater to the heat recovery steam generator; and a heat exchanger.

Pavel, J.; Richardson, B.L.

1990-10-09T23:59:59.000Z

296

High Performance Catalytic Heat Exchanger for SOFC Systems - FuelCell Energy  

NLE Websites -- All DOE Office Websites (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

297

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

SciTech Connect

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

298

The feasibility of the manufacturing of a printed circuit type heat exchanger produced from graphite / Izak Jacobus Venter de Kock.  

E-Print Network (OSTI)

??The development of high temperature heat exchangers will play a vital part in the success of High Temperature Nuclear Reactors (HTRs). Manufacturing such heat exchangers… (more)

De Kock, Izak Jacobus Venter

2009-01-01T23:59:59.000Z

299

Countercurrent direct contact heat exchange process and system  

DOE Patents (OSTI)

Recovery of energy from geothermal brines and other hot water sources by direct contact heat exchange with a working fluid, such as a hydrocarbon working fluid, e.g. isobutane. The process and system consists of a plurality of stages, each stage including mixing and settling units. In the first stage, hot brine and arm working fluid are intimately mixed and passed into a settler wherein the brine settles to the bottom of the settler and the hot working fluid rises to the top. The hot working fluid is passed to a heat engine or turbine to produce work and the working fluid is then recycled back into the system. The system is comprised of a series of stages each containing a settler and mixer, and wherein the working fluid and the brine flow in a countercurrent manner through the stages to recover the heat from the brine in increments and raise the temperature of the working fluid in increments.

Wahl, III, Edward F. (Claremont, CA); Boucher, Frederic B. (San Juan Capistrano, CA)

1979-01-01T23:59:59.000Z

300

Condensation analysis for plate-frame heat exchangers  

SciTech Connect

A theoretical analysis is presented to predict single component and binary-mixture condensation in plate-frame heat exchangers. A thermodynamic property model based on the Peng-Robinson equation of state was developed for the binary-mixture equilibrium and formulated into a performance prediction program. A set of equations was formulated and a calculation algorithm was developed to predict the local rate of heat and mass transfer for binary mixtures. Friction-factor and heat-transfer-coefficient correlations were developed using experimental data obtained with ammonia condensation. The role of the mass-transfer resistance associated with the condensation process were analyzed for a propane/butane mixture using two limiting cases: (1) no liquid-phase mass-transfer resistance, and (2) infinite liquid-phase mass-transfer resistance. The results show that the vapor-phase mass-transfer resistance is the controlling mechanism for binary-mixture condensation.

Arman, B.; Rabas, T.J.

1995-07-01T23:59:59.000Z

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.


301

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 be mitigated. One result has been the identification and description of heat exchanger technologies that experience has shown to have a role to play in reducing fouling. This paper describes these developments. As shown elsewhere, the rate at which pre-heat train exchangers foul is controlled by fluid velocity and by wall temperature. Technologies which promote the heat transfer on the crude oil side of an exchanger are therefore favoured. (Note: promotion of the heat transfer on the hot side of the unit is not generally favoured, for this is likely to raise the wall temperature on the crude side). The working party identified three exchanger technologies that made use of this principle: • helical baffles • twisted tubes • tube inserts. These technologies will be discussed in turn.

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

2002-04-01T23:59:59.000Z

302

Natural convection heat exchangers for solar water heating systems. Technical progress report, October 1, 1995--November 30, 1995  

DOE Green Energy (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

303

Natural convection heat exchangers for solar water heating systems. Technical progress report, April 1, 1995--May 31, 1995  

DOE Green Energy (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

304

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

DOE Green Energy (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

305

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

Science Conference Proceedings (OSTI)

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

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

2010-10-15T23:59:59.000Z

306

A continuous heat regenerative adsorption refrigerator using spiral plate heat exchanger as adsorbers: improvements  

SciTech Connect

Spiral plate heat exchangers as adsorbers have been proposed, and a prototype heat regenerative adsorption refrigerator using activated carbon-methanol pair has been developed and tested. Various improvements have been made, the authors get a specific cooling power for 2.6 kg-ice/day-kg adsorbent at the condition of generation temperature lower than 100 C. Discussions on the arrangements of thermal cycles and influences of design are shown.

Wang, R.Z.; Wu, J.Y.; Xu, Y.X. [Shanghai Jiao Tong Univ. (China). Inst. of Refrigeration and Cryogenics

1999-02-01T23:59:59.000Z

307

Simulation model air-to-air plate heat exchanger  

Science Conference Proceedings (OSTI)

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

Wetter, Michael

1999-01-01T23:59:59.000Z

308

POSTING: Technician 5 Heat and Greenhouse gas Exchange The Centre for Earth Observation Science (CEOS) within the Faculty of Environment,  

E-Print Network (OSTI)

POSTING: Technician 5 ­ Heat and Greenhouse gas Exchange technician in support of multidisciplinary research on heat and greenhouse gas

309

Natural convection heat exchangers for solar water heating systems. Technical progress report, July 15, 1996--September 14, 1996  

DOE Green Energy (OSTI)

This report very briefly summarizes project objectives, results, and current activities. The goals of the 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. Results include the experimental study of thermosyphon heat exchangers, which led to modeling equations that correlate the overall heat transfer coefficient-area product (UA) to mixed convection regime parameters. Current activities include the development and evaluation of a side-arm heat exchanger computer model and modification of the experimental facility for fundamental heat exchanger studies.

Davidson, J.H.

1998-06-01T23:59:59.000Z

310

Natural convection heat exchangers for solar water heating systems. Technical progress report, May 15, 1996--July 14, 1996  

DOE Green Energy (OSTI)

This progress report very briefly summarizes study results and includes an experimental plan developed for the fundamental study of heat transfer in thermosyphon side-arm heat exchangers. The study will investigate the influence of the Reynolds and Grashof numbers on the thermosyphon flow side of the heat exchanger, and the influence of the flow rate on the forced flow side of the heat exchanger. Detailed temperature, flow rate, and pressure data will be obtained for four, seven, and nine tube-in-shell heat exchanger designs. Correlations will be developed for the heat transfer and friction coefficients, and a semi-empirical model will be developed to predict the performance of thermosyphon heat exchangers in solar water heaters.

Davidson, J.H.

1998-06-01T23:59:59.000Z

311

Localized corrosion of aluminum alloys for OTEC heat exchangers  

DOE Green Energy (OSTI)

The effects of dissolved oxygen, pH and temperature on the rate of initiation and growth of pitting and crevice corrosion of aluminum alloy 5052 and pure aluminum have been determined. Variations in pH and temperature rather than dissolved oxygen are shown to account for increased corrosion rates of 5000 series aluminum alloys that have been reported for deep ocean exposures. The impact of these results on the use of aluminum for OTEC heat exchanger tubing and on possible approaches to corrosion control are discussed.

Dexter, S C

1979-01-01T23:59:59.000Z

312

HECDOR: a heat exchanger cost and design optimization routine  

DOE Green Energy (OSTI)

An update is presented on a series of four computer codes developed by the Bureau of Mines. The programs were developed to evaluate design parameters and cost of heat exchangers. The major differences in three of the programs were concerned with pumping costs; the first (N = 1) used both fluids, the second (N = 2) used tube side fluid, and the third (N = 3) used shell side fluid as a base for prime parameters. All three assumed no change in phase. The fourth program (N = 4) assumed a change of phase on the shell side.

Turner, S.E.; Madsen, W.W.

1977-04-01T23:59:59.000Z

313

Nondestructive Evaluation: Structural Health Monitoring for Heat Exchanger Shells  

Science Conference Proceedings (OSTI)

The heat exchanger shell is a pressure vessel that surrounds and encloses a tube bundle. The shell is susceptible to corrosion and wear, which originates from the inside of the vessel and is caused by steam impingement and flow conditions. The shells are nominally 30 to 50 ft (9.1 to 15.2 m) in length and 30 to 60 in. (76.2 to 152.4 cm) in diameter; the wall thickness is approximately 0.75 in. (1.91 cm). Ultrasonic thickness readings are currently performed on distinct regions on the shell wall to suppor...

2008-03-14T23:59:59.000Z

314

Experimental evaluation of a simulation model for wrap-around heat exchanger, solar storage tanks  

DOE Green Energy (OSTI)

The thermal performance of a commercially available 80 gallon, solar storage tank with an integral wrap-around heat exchanger is characterized experimentally an indoor test stand. The experimental results are used to evaluated the accuracy of a previously developed simulation model. Heat input on the collector side of the heat exchanger is held constant causing the heat transfer to reach a quasi-steady state. Temperatures in the heat exchanger and tank increase with time, however, the temperature differences across the heat exchanger remain nearly constant. Several combinations of heat input and collector loop flow are investigated. The development of the tank temperature profiles over time and the overall heat transfer performance predicted by the model are compared with experimental results. The influence of an electric auxiliary heater located in the top of the solar storage tank on the heat exchanger performance is investigated. Experimental normalization of the model is considered and modifications to the model and experiments are recommended.

Miller, J.A.; Hittle, D.C.

1995-05-01T23:59:59.000Z

315

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

Science Conference Proceedings (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

316

Plate Fin Heat Exchanger Model with Axial Conduction and Variable Properties  

E-Print Network (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 ...

Hansen, B J; Klebaner, A; 10.1063/1.4706971

2012-01-01T23:59:59.000Z

317

A Plastic-Core Compact Heat Exchanger for Energy Conservation  

E-Print Network (OSTI)

This paper describes a compact, single-pass, cross-flow type, gas-to-gas heat exchanger with a polyolefin (polyethylene or polypropylene) core whose seams are welded through a proprietary process. It is constructed of several extruded polyolefin sheets with passageway cross-section of 4 mm (0.159 inch) by 4.4 mm (0.173 inch) which are separated by ribs of the same material that form the cross-flow passages of 137 mm (5.4 inches) by 3.8 mm (0.15 inch). The overall dimensions of a typical single-core unit are 1676 mm (5.5 ft) x 1219 mm (4 ft) x 3048 mm (10 ft) high including the core, the supply, and exhaust gas assemblies. The efficiency of this heat exchanger is on the order of 60-80% and it does not deteriorate with time because the exposed surfaces tend to resist fouling. Pressure drop was in the range of 0.2 -0.6 inches of water column. Applications include efficiency improvements in boiler and HVAC operations, drying, food processing, and the paper, chemical, and agricultural industries.

Lazaridis, A.; Rafailidis, E.

1995-04-01T23:59:59.000Z

318

Performance studies of a solar energy storing heat exchanger  

Science Conference Proceedings (OSTI)

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

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

1988-01-01T23:59:59.000Z

319

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)

Determining the quality and quantity of heat produced by proton exchange membrane fuel cells Determining the quality and quantity of heat produced by proton exchange membrane fuel cells with application, the coolant is pumped to a heat recovery system. A water-to-air heat exchange system or water-to-water heat

Victoria, University of

320

Continuation of Studies on Development of ODS Heat Exchanger Tubing  

SciTech Connect

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

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

Analysis of Heat Exchanger Network in Atmosphere-Vacuum Distillation of Crude Oil  

Science Conference Proceedings (OSTI)

Heat exchanger network (HEN) is constructed by hot streams which need cooling and some cold streams which need heating in the atmosphere-vacuum distillation process of crude oil. HEN synthesis technology of atmosphere-vacuum distillation of crude oil ... Keywords: energy saving, heat exchanger network, synthesis

Ge Yu-lin; Wang Ping; Shen Sheng-qiang

2011-02-01T23:59:59.000Z

322

Natural convection heat exchangers for solar water heating systems. Technical progress report, February 1, 1996--March 31, 1996  

DOE Green Energy (OSTI)

This progress report describes the thermodynamic testing and modeling of a thermosyphon heat exchanger used in solar water heating systems. Testing of a four tube-in-shell thermosyphon heat exchanger was performed in two parts. The first portion of the test increased the collector fluid while the storage tank remained isothermal. After the collector fluid temperature was raised to 95 C, the second part of the test allowed the storage tank to gain heat. The test was performed for two collector flow rates. Measured values included collector side forced flow rate, temperature differences across the heat exchanger, vertical temperature distribution in the storage tank, vertical water temperature profile in the heat exchanger, and pressure drop on the thermosyphon side of the heat exchanger. The overall heat transfer coefficient-area product (UA) values obtained confirmed that models which assume UA depends solely on thermosyphon flow rate do not adequately characterize thermosyphon heat exchangers. This is because heat transfer in thermosyphon exchangers occurs in the mixed convection, rather than forced flow, regime. A linear regression equation was developed to better predict UA using the Prandtl, Reynolds, and Grashof numbers and dimensionless parameters based on fluid properties calculated for the average hot and cold leg temperatures. 9 figs.

Davidson, J.H.

1998-06-01T23:59:59.000Z

323

forth through the heat exchangers, thereby phasing the rates at which heat is absorbed and rejected from  

E-Print Network (OSTI)

#12;forth through the heat exchangers, thereby phasing the rates at which heat is absorbed balance as shown in Fig. 3 still indi- cated a greater heat loss to the engine coolant than predicted. This was caused by excessive heat leak- age from the hot to the cold working spaces, primarily by the flow leakage

Oak Ridge National Laboratory

324

Geothermal direct-contact heat exchange. Final report  

DOE Green Energy (OSTI)

A glass direct contact heat exchange column was operated in the laboratory at atmospheric pressure using hot water and normal hexane. Column internals tested included an empty column, sieve trays, disk-and-doughnut trays, and two types of packing. Operation was very smooth in all cases and the minimum temperature approaches varied from less than 1{sup 0}C for packing to 13{sup 0}C for the empty column. High heat transfer rates were obtained in all cases, however, columns should be sized on the basis of liquid and vapor traffic. The solubilities of hydrocarbons were determined for normal hexane, pentane and butane in water and sodium chloride and calcium chloride brines at various temperatures. The values seem to be internally consistent and salt content was found to depress hydrocabon solubility. Laboratory stripping tests showed that gas stripping can be used to remove hydrocarbon from reject hot water from the direct contact heat exchange column. Although the gas volumes required are small, stripping gas requirements cannot be accurately predicted without testing. A computer program was used to study the effect of operating variables on thermodynamic cycle efficiencies. Optimum efficiencies for the moderate brine conditions studied were obtained with isopentane as working fluid and relatively low operating pressure. A preliminary design for a 50 MWe plant was prepared and plant capital cost and operating cost were estimated. These costs were combined with previously developed brine production and power transmission costs to provide an estimate of the cost of delivered power for a geothermal field at Heber, California. A pilot plant program is described that would be suitable for continuing the investigation of the direct contact process in the field. The program includes a suggested schedule and the estimated cost.

Sims, A.V.

1976-06-10T23:59:59.000Z

325

Investigation of heat exchanger flow arrangement on performance and cost in a geothermal binary cycle  

DOE Green Energy (OSTI)

The performance of an idealized geothermal binary-fluid-cycle energy conversion system is shown to be a function of the temperatures of brine and working fluid leaving the heat exchanger. System power output, heat exchanger area required and initial well and heat exchanger costs are determined for counterflow, single and multi-pass parallel-counterflow exchangers. Results are presented graphically as functions of the brine and working fluid exit temperatures from the exchanger. Use of the system analysis developed is illustrated by showing quantitatively the advantage of the counterflow over the other flow arrangements considered.

Giedt, W.H.

1976-06-15T23:59:59.000Z

326

Reducing exergy losses of liquid fluid using embedded open parallel microchannels within the surface  

Science Conference Proceedings (OSTI)

This paper presents an analysis of entropy generation of forced convection heat transfer of liquid fluid over the horizontal surface with embedded open parallel microchannels at constant heat flux boundary conditions. The governing partial differential ... Keywords: constant heat flux, embedded open parallel microchannels, entropy generation, exergy losses, liquid fluid

M. H. Yazdi; S. Abdullah; I. Hashim; K. Sopian

2008-12-01T23:59:59.000Z

327

Direct-contact air/molten salt heat exchange for solar-thermal systems  

DOE Green Energy (OSTI)

Heat exchangers employing direct contact between molten draw salt and air were studied for use in solar industrial process heat (IPH) systems. Direct-contact systems consisting of a fin-tube preheater and a spray or packed column were compared to conventional heat exchangers. Direct contact reduced the IPH system cost by 5% to 10%. The direct-contact heat exchangers cost only 15% to 30% as much as comparable conventional exchangers. However, the rate of salt degradation by CO/sup 2/ and H/sub 2/O must be determined to see if it is acceptable.

Wright, J.D.; d'Agincourt, C.

1982-05-01T23:59:59.000Z

328

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

SciTech Connect

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

329

DESIGN AND CONSTRUCTION OF HEAT EXCHANGER TEST STAND WITH INITIAL TEST RESULTS.  

E-Print Network (OSTI)

??Continual development of internal combustion engines requires greater performance from liquid coolants and heat exchangers to maintain optimal temperature. For the purpose of experimental testing… (more)

Albrecht, Daniel David

2009-01-01T23:59:59.000Z

330

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

E-Print Network (OSTI)

??This work examines the effects of gravitational acceleration on the flow boiling process. A test facility focusing on an annular heat exchanger was designed, built… (more)

Westheimer, David Thomas

2012-01-01T23:59:59.000Z

331

Design of shell and tube heat exchanger using specified pressure drop.  

E-Print Network (OSTI)

??The pressure drops used in heat exchange of shell and tube type, the situations are particular and put ahead of the design exercise. In such… (more)

Bilimoria, Vimalkumar B.

2010-01-01T23:59:59.000Z

332

Modeling And Fouling Detection Of The Aircraft Environmental Control System Heat Exchanger.  

E-Print Network (OSTI)

??A Diagnostics, Prognostics and Health Management (DPHM) solution is proposed for the operation of the aircraft environmental control system (ECS) cross flow heat exchanger. In… (more)

Shah, Shoaib A.

2009-01-01T23:59:59.000Z

333

Analysis and modelling of membrane heat exchanger in HVAC energy recovery systems.  

E-Print Network (OSTI)

??The performance of membrane heat exchangers for HVAC total energy recovery systems was evaluated through experimentation and detailed system modelling. The operating principle of the… (more)

Nasif, Mohammad Shakir

2008-01-01T23:59:59.000Z

334

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

E-Print Network (OSTI)

Recent work to consolidate pinch-based procedures for targeting, design and analysis of heat exchanger networks (HENs) has focused on the production of powerful, user-friendly software. Advanced optimization techniques, such as mixed integer non-linear programming, have been added to established pinch procedures to increase the power of these techniques, enabling users to generate optimized HENs in an interactive computational environment. Additional procedures for improved HEN area targeting and retrofit network modifications have also been developed. Within ICI these developments (along with several others) have been incorporated in the MIDAS software package. This paper outlines some of the technical developments that have taken place to make this possible and illustrates some of the capabilities of the new software.

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

1987-09-01T23:59:59.000Z

335

Testing and analysis of load-side immersed heat exchangers for solar domestic hot water systems  

DOE Green Energy (OSTI)

This report describes work to determine the performance of load-side heat exchangers for use in residential solar domestic hot water systems. We measured the performance of four heat exchangers: a smooth coil and a finned coil having heat transfer areas of 2.5 m/sup 2/ (26 ft/sup 2/) and those having areas of 1.7 m/sup 2/ (19 ft/sup 2/). A numerical model using the thermal network program MITAS was constructed, and results were compared to the experimental results. Research showed a smooth coil with only 70% of the surface area of a finned coil performed better than the finned coil. Also, load-side heat exchangers can maintain and enhance stratification in storage tanks, permitting the use of control strategies that take advantage of stratified storage tanks to increase system performance. The analytical model, which agreed reasonably well with the experimental results, was used to vary heat exchanger flow rate and area and initial tank temperature for both a smooth- and a finned-coil heat exchanger. Increasing the heat exchanger flow rate and area results in higher heat transfer rates but not necessarily optimal performance. Lower initial tank temperatures resulted in reduced tank stratification. The smooth heat exchanger outperformed the finned heat exchanger with the same outside surface area. 15 refs., 37 figs., 9 tabs.

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

1987-10-01T23:59:59.000Z

336

A trial to improve surface heat exchange simulation through sensitivity experiments over a desert steppe site  

Science Conference Proceedings (OSTI)

It is still a daunting challenge for land surface models (LSMs) to correctly represent surface heat exchange for water-limited desert steppe ecosystems. This study aims at improving the ability of the Noah LSM to simulate surface heat fluxes ...

Guo Zhang; Guangsheng Zhou; Fei Chen; Michael Barlage; Lulin Xue

337

Characterization of Turbulent Latent and Sensible Heat Flux Exchange between the Atmosphere and Ocean in MERRA  

Science Conference Proceedings (OSTI)

Turbulent fluxes of heat and moisture across the atmosphere–ocean interface are fundamental components of the earth’s energy and water balance. Characterizing both the spatiotemporal variability and the fidelity of these exchanges of heat and ...

J. Brent Roberts; Franklin R. Robertson; Carol A. Clayson; Michael G. Bosilovich

2012-02-01T23:59:59.000Z

338

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 gas streams to electricity. The NTU-effectiveness method, exergy, and ...

Latcham, Jacob G. (Jacob Greco)

2009-01-01T23:59:59.000Z

339

DEVELOPMENT OF AN ADVANCED HEAT EXCHANGER MODEL FOR STEADY STATE AND FROSTING CONDITIONS.  

E-Print Network (OSTI)

??Air-to-refrigerant fin-and-tube heat exchangers are a key component in the heating, air conditioning and refrigeration industry. Considering their dominance, the industry has focused immensely on… (more)

Singh, Varun

2009-01-01T23:59:59.000Z

340

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

Science Conference Proceedings (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

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

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

E-Print Network (OSTI)

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

Skogestad, Sigurd

342

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)

effect on offset fin heat exchanger performance: predictiveA. L. London. Compact Heat Exchangers. 3 rd ed. , New York,Model for Transient Heat Exchanger Response. ” Int. J. Heat

Urquiza, Eugenio

2009-01-01T23:59:59.000Z

343

Long Term Geothermal Heat Pump System Ground Loop Heat Exchanger Performance: Field Data from a Quick Service Restaurant Application  

Science Conference Proceedings (OSTI)

This report summarizes measured long-term performance of the ground loop heat exchanger in a geothermal heat pump system in a McDonald's Quick Service Restaurant located in Westland near Detroit, Michigan. Heat build-up in the soil around the heat exchanger over a long period of time has always been a concern, but only limited data has been available in the past. The gradual increase in the return loop temperature over a period of five years is evidence of the heat built up in the ground loop field, whic...

2003-01-22T23:59:59.000Z

344

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

E-Print Network (OSTI)

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

Garbe, Christoph S.

345

Thermal Analysis and Stress Analysis of the Heat-Exchange Pipe Based on ANSYS  

Science Conference Proceedings (OSTI)

ANSYS to be as a finite element analysis software has powerful features in thermal analysis and structural analysis. Based on ANSYS thermal analysis function, this paper selects SOLID90 unit, for thermal analysis on the heat-exchange pipe of heat exchanger ... Keywords: ANSYS, temperature distribution, stress distribution

Fenhua Li; Jian Xing; Yuan Liu

2011-04-01T23:59:59.000Z

346

Modeling of wire-on-tube heat exchangers using finite element method  

Science Conference Proceedings (OSTI)

Wire-on-tube heat exchangers are analysed under normal operating conditions (free convection) using finite element method. Galerkin's weighted residual method is used to minimise the errors. The effects of ambient temperatures and mass flow rates of ... Keywords: finite element method, free convection, phase change, wire on-tube heat exchangers

G. A. Quadir; G. M. Krishnan; K. N. Seetharamu

2002-03-01T23:59:59.000Z

347

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

Science Conference Proceedings (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

348

Status report - advanced heat exchanger technology for a CCGT power generation system  

Science Conference Proceedings (OSTI)

This report gives laboratory and field test results of a specially designed heat exchanger for coal-fired power plants. The system incorporates an atmospheric fluidized bed and combustion system for pulverized coal. The heat exchanger was made from both metallic and ceramic materials.

Wright, D.E.; Tignac, L.L.

1982-01-01T23:59:59.000Z

349

Investigation of Interior Airflow Visualization of U-type Fin-and-Tube Heat Exchanger  

Science Conference Proceedings (OSTI)

The interior airflow visualization of a U-type fin-and-tube heat exchanger was investigated numerically and experimentally. Numerical results presented detail information of whole airflow field. Smoke test using dry ice showed visualization of airflow, ... Keywords: Fin-and-tube heat exchanger, interior airflow, CFD, visualization, smoke test

Shihua Lu; Weihua Liu; Hu Huang; Qihe Li

2010-06-01T23:59:59.000Z

350

Repair Technology for Degraded Pressure Vessel and Heat Exchanger Shells: RRAC Task 91  

Science Conference Proceedings (OSTI)

The ability to repair pressure vessels and heat exchangers offers utilities significant cost savings compared to replacing these components. This is especially the case if outage time and loss of production are factored into the cost of replacement. This guide provides a review of various current and proposed repair methods that can be used for pressure vessel and heat exchanger applications.

2002-12-02T23:59:59.000Z

351

Fouling reduction characteristics of a no-distributor-fluidized-bed heat exchanger for flue gas heat recovery  

Science Conference Proceedings (OSTI)

In conventional flue gas heat recovery systems, the fouling by fly ashes and the related problems such as corrosion and cleaning are known to be major drawbacks. To overcome these problems, a single-riser no-distributor-fluidized-bed heat exchanger is devised and studied. Fouling and cleaning tests are performed for a uniquely designed fluidized bed-type heat exchanger to demonstrate the effect of particles on the fouling reduction and heat transfer enhancement. The tested heat exchanger model (1 m high and 54 mm internal diameter) is a gas-to-water type and composed of a main vertical tube and four auxiliary tubes through which particles circulate and transfer heat. Through the present study, the fouling on the heat transfer surface could successfully be simulated by controlling air-to-fuel ratios rather than introducing particles through an external feeder, which produced soft deposit layers with 1 to 1.5 mm thickness on the inside pipe wall. Flue gas temperature at the inlet of heat exchanger was maintained at 450{sup o}C at the gas volume rate of 0.738 to 0.768 CMM (0.0123 to 0.0128 m{sup 3}/sec). From the analyses of the measured data, heat transfer performances of the heat exchanger before and after fouling and with and without particles were evaluated. Results showed that soft deposits were easily removed by introducing glass bead particles, and also heat transfer performance increased two times by the particle circulation. In addition, it was found that this type of heat exchanger had high potential to recover heat of waste gases from furnaces, boilers, and incinerators effectively and to reduce fouling related problems.

Jun, Y.D.; Lee, K.B.; Islam, S.Z.; Ko, S.B. [Kongju National University, Kong Ju (Republic of Korea). Dept. for Mechanical Engineering

2008-07-01T23:59:59.000Z

352

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

E-Print Network (OSTI)

Fouling of heat exchangers costs the U.S. industries hundreds of millions of dollars every year in increased equipment costs, maintenance costs, energy losses and losses in production. The designer of heat exchangers usually allows for fouling 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 is provided that gives the percent decrease in heat flux, for a constant driving temperature difference, as a function of the clean overall heat transfer coefficient and the fouling factor. Another plot gives the increase in surface area due to fouling for the same heat transfer rate and driving temperature difference, as a function of the clean overall heat transfer coefficient and the fouling factor. The overall heat transfer market was divided into four sectors: the chemical, petroleum, electric utility and other industries. The 1982 U.S. sales of all industrial heat exchangers, excepting boilers and automotive radiators, was about 285,000 units amounting to about $1.6 billion. The total heat duty of all the heat exchangers in industrial operation, including electric utilities, was estimated at 11.7 Quads. If this represented the amount of heat transferred through clean heat exchangers, the decrease in energy transferred due to fouling or the cost of fouling in terms of energy lost was estimated at 2.9 Quads annually. The cost of fouling, in providing for additional surface area to compensate for a decrease in heat transfer, was conservatively estimated at $180 million in 1982.

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

1988-09-01T23:59:59.000Z

353

State of technology of direct contact heat exchanging  

DOE Green Energy (OSTI)

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

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

1984-05-01T23:59:59.000Z

354

High Performance Trays and Heat Exchangers in Heat Pumped Distillation Columns  

E-Print Network (OSTI)

Vapor recompression of distillation columns overheads, followed by subsequent condensation in the reboiler results in substantial operating cost savings compared to conventional steam driven reboiler systems. The use of high performance heat exchangers and distillation trays permits additional energy savings by lower reboiler temperature differences, and reduced reflux requirements for a fixed column height, due to closer tray spacings. This paper surveys the heat pump systems currently in operation using high performance UCC MD trays and High Flux tubing. Design considerations for high or low pressure level towers, with single or dual stage compression equipment are discussed, along with the various control methods. Factors affecting startup, part load, and off design operation of the equipment are also reviewed.

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

1981-01-01T23:59:59.000Z

355

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

DOE Green Energy (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

356

The Role of Filtration in Maintaining Clean Heat Exchanger Coils  

SciTech Connect

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

357

MODELING OF VERTICAL GROUND LOOP HEAT EXCHANGERS FOR GROUND SOURCE  

E-Print Network (OSTI)

for cooling-dominated commercial buildings utilize supplemental heat rejecters such as cooling towers, fluid of supplemental heat rejecters for cooling dominated buildings allows the design of smaller borehole fields. Heat

358

Unique method for liquid nitrogen precooling of a plate fin heat exchanger in a helium refrigeration cycle  

E-Print Network (OSTI)

Unique method for liquid nitrogen precooling of a plate fin heat exchanger in a helium refrigeration cycle

Weber, T B; Howell, G; Racine, M; Weisend, J G

2004-01-01T23:59:59.000Z

359

The use of Hewlett Packard minicomputers for data acquisition and data analysis in heat exchanger research and development  

E-Print Network (OSTI)

The use of Hewlett Packard minicomputers for data acquisition and data analysis in heat exchanger research and development

Lepp, R M; Shaw, J D; Tromp, J H

1984-01-01T23:59:59.000Z

360

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

Researchers at ORNL developed a down-well heating apparatus that efficiently heats subterranean geological deposits, such as oil shale, to extract ...

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

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

DOE Patents (OSTI)

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

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

1996-11-05T23:59:59.000Z

362

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)

M. and A. L. London. Compact Heat Exchangers. 3 rd ed. , NewOffset Strip Fin Compact Heat Exchanger. ” ExperimentalKays, W. M. , “Compact Heat Exchangers,” AGARD Lecture Ser.

Urquiza, Eugenio

2009-01-01T23:59:59.000Z

363

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

E-Print Network (OSTI)

The Role of Interocean Exchanges on Decadal Variations of the Meridional Heat Transport explanation for the increase in the MHT across 348S is the heat con- vergence through interocean exchanges is released to the atmo- sphere through air­sea heat exchange. Although there is no question that the Agulhas

364

JOURNAL OF MICROELECTROMECHANICAL SYSTEMS, VOL. 10, NO. 1, MARCH 2001 107 Fabrication of Metallic Heat Exchangers Using  

E-Print Network (OSTI)

Heat Exchangers Using Sacrificial Polymer Mandrils Francisco Arias, Scott R. J. Oliver, Bing Xu, R metallic heat exchangers having 300­700 m internal channels. The mandrils were prepared using two soft lithographic techniques-replica molding, and microembossing. To fabricate the heat exchangers, the polymeric

Prentiss, Mara

365

Heat Exchanger Monitoring and Its Application to Cleaning and Antifoulant Use  

E-Print Network (OSTI)

Many refineries and chemical plants are presently experiencing considerable fuel savings and reduced maintenance costs as a result of their heat exchanger monitoring activities. Significant energy credits can be generated with proper applications 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 to measure base fouling, to determine optimum cleaning cycles, and to determine the effects of an antifoulant to control fouling.

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

1983-01-01T23:59:59.000Z

366

Natural convection heat exchangers for solar water heating systems. Technical progress report, August 1, 1995--September 30, 1995  

DOE Green Energy (OSTI)

The goals of this project are: (1) to develop guidelines for the design and use of thermosyphon 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. The tasks for the project are as follows: (1) Develop a model of the thermal performance of thermosyphon heat exchangers in solar water heating applications. A test protocol will be developed which minimizes the number of tests required to adequately account for mixed convection effects. The TRNSYS component model will be fully integrated in a system component model and will use data acquired with the specified test protocol. (2) Conduct a fundamental study to establish friction and heat transfer correlations for conditions and geometries typical of thermosyphon heat exchangers in solar systems. Data will be obtained as a function of a buoyancy parameter based on Grashof and Reynolds numbers. The experimental domain will encompass the ranges expected in solar water heating systems.

Davidson, J.H.

1998-06-01T23:59:59.000Z

367

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

DOE Green Energy (OSTI)

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

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

2011-12-01T23:59:59.000Z

368

Plate Fin Heat Exchanger Model with Axial Conduction and Variable Properties  

Science Conference Proceedings (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

369

Design Option of Heat Exchanger for the Next Generation Nuclear Plant  

DOE Green Energy (OSTI)

The Next Generation Nuclear Plant (NGNP), a very High temperature Gas-Cooled Reactor (VHTGRS) 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 VHTGRS 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. As part of the system integration of the VHTGRS and hydrogen production plant, the intermediate heat exchanger is used to transfer the process heat from VHTGRS to hydrogen plant. Therefore, the design and configuration of the intermediate heat exchanger are very important. This paper will include analysis of one stage versus two stage heat exchanger design configurations and thermal stress analyses of a printed circuit heat exchanger, helical coil heat exchanger, and shell/tube heat exchanger.

Eung Soo Kim; Chang Oh

2008-09-01T23:59:59.000Z

370

He II Heat Exchanger Test Unit for the LHC Inner Triplet  

E-Print Network (OSTI)

The Inner Triplet Heat Exchanger Test Unit (IT-HXTU) is a 30-m long thermal model designed at Fermilab, built in US industry, fully automated and tested at CERN as part of the US LHC program to develop the LHC Interaction Region quadrupole system. The cooling scheme of the IT-HXTU is based on heat exchange between stagnant pressurized He II in the magnet cold mass and saturated He II (two-phase) flowing in a heat exchanger located outside of and parallel to the cold mass. The purposes of this test are, among others, to validate the proposed cooling scheme and to define an optimal control strategy to be implemented in the future LHC accelerator. This paper discusses the results for the heat exchanger test runs and emphasizes the thermal and hydraulic behavior of He II for the inner triplet cooling scheme.

Blanco-Vińuela, E; Huang, Y; Nicol, T H; Peterson, T; Van Weelderen, R

2002-01-01T23:59:59.000Z

371

Analytical model of a microscale heat exchanger: ambient interaction and general end-wall boundary conditions.  

E-Print Network (OSTI)

??Developments in manufacturing have led to progressively smaller and more complex micro-electro-mechanical systems (MEMS), many of which employ heat exchangers to enhance performance. Due to… (more)

Spann, Bryan T

2010-01-01T23:59:59.000Z

372

9th EPRI Balance-of-Plant Heat Exchanger NDE Symposium Proceedings  

Science Conference Proceedings (OSTI)

The 9th EPRI Balance-of-Plant Heat Exchanger NDE Symposium was held in Big Sky, Montana on June 26 28, 2006. It consisted of four pre-symposium short courses and two and one-half days of combined paper presentations and vendors fair. Attendees included representatives from domestic and international utilities, research organizations, NDE service and equipment vendors, and heat exchanger component repair and replacement organizations. This biennial symposium serves as a forum for plant engineers, NDE spec...

2006-08-11T23:59:59.000Z

373

Guideline for Condition Assessment and Inspection of Fossil Plant Heat Exchangers  

Science Conference Proceedings (OSTI)

Heat exchangers experience tube failures due primarily to inside surface pitting and flow-induced fretting wear at tube-to-tube support plate intersections. A fast volumetric tube-wall examination technique by eddy current is used from inside the tubes to test and maintain the structural integrity of installed tubing. Because heat exchanger tubing examination is not mandated, the eddy current examination practices vary from one contracted vendor to another. This document attempts to bridge the gap by pro...

2001-11-29T23:59:59.000Z

374

Nondestructive Evaluation: 11th EPRI Balance-of-Plant Heat Exchanger NDE Symposium Proceedings  

Science Conference Proceedings (OSTI)

The Electric Power Research Institute's (EPRI's) 11th Balance-of-Plant Heat Exchanger Nondestructive Evaluation Symposiumheld in Stevenson, Washington, August 911, 2010 focused on nondestructive evaluation (NDE) technologies and lessons learned related to the inspection, condition assessment, and repair of balance-of-plant (BOP) heat exchanger components. As in the past, this year's symposium included pre-symposium tutorial courses followed by technology transfer through paper presentations and the vendo...

2010-09-30T23:59:59.000Z

375

Eddy Current Testing of Service Water Heat Exchangers for Engineers Guideline  

Science Conference Proceedings (OSTI)

Service water (SW) heat exchangers experience tube failures due primarily to Inside Diameter (ID) pitting and flow-induced fretting wear at tube-to-tube support plate intersections. Eddy current is a fast volumetric tube wall examination technique performed from inside a tube to test and maintain structural integrity of the installed tubing. Because the service water heat exchanger tubing examination is not mandated under the ASME Code or the Regulatory Guide requirements, eddy current examination practi...

1999-02-24T23:59:59.000Z

376

An experimental study on the thermal performance of ground heat exchanger  

Science Conference Proceedings (OSTI)

A knowledge of ground thermal properties is most important for the proper design of large GHE (ground heat exchanger) systems. Thermal response tests have so far been used primarily not only for in situ determination of design data for GHE systems, but also for the evaluation of grout material, heat exchanger types and groundwater effects. The main purpose has been to determine in situ values of effective ground thermal conductivity, including the effect of groundwater flow and natural convection in boreholes. (author)

Lim, Kyoungbin; Lee, Sanghoon [Department of Mechanical Engineering, Hanbat University, Daejon (Korea); Lee, Changhee [Department of Mechanical Engineering, Hanyang University, 1271 Sa1 Ansan, Kyungki-do 425791 (Korea)

2007-08-15T23:59:59.000Z

377

Review: Convective heat and mass exchange predictions at leaf surfaces: Applications, methods and perspectives  

Science Conference Proceedings (OSTI)

Convective heat and mass exchange of leaves with the environment is relevant for a better understanding of plant physiological processes in response to environmental factors for a wide range of applications. Methods for quantifying these exchanges have ... Keywords: Artificial leaf, Convective transfer coefficient, Plant, Review, Stomata, Transpiration

Thijs Defraeye, Pieter Verboven, Quang Tri Ho, Bart Nicolai

2013-08-01T23:59:59.000Z

378

NEI Corporation Technology Promotes Efficiency in Heat Exchangers...  

Office of Science (SC) Website

Top image: Filmwise condensation (FWC), Bottom image: Dropwise condensation (DWC) R&D Opportunity In electrical utilities and in many process industries, improved heat...

379

Incorporating Radiant Heat Exchange into Finite Element Models of ...  

Science Conference Proceedings (OSTI)

In order to simplify this non-linear mode of heat transfer, the effects of ... Technical Risk Mitigation Through Rheometallurgical Generation of Process and ...

380

Performance Analysis of Tube-Fin Heat Exchanger under Vibration.  

E-Print Network (OSTI)

??The effects of vibration on the airside heat transfer and pressure drop characteristics are experimented and analyzed. The experiment is conducted on a flat tube… (more)

Kannan, Jayaprakash

2012-01-01T23:59:59.000Z

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.


381

Heat exchanger design: why guess a design fouling factor when it can be optimized  

DOE Green Energy (OSTI)

A new general surface heat exchanger design relationship is derived that uniquely relates the optimum design fouling resistance and the optimum design heat transfer coefficient with the ratio of cleaning cost to capital plus operating costs, at the optimum design condition. Implementation of this simple result to practical problems in design, however, requires numerical techniques. A new shell and tube heat exchanger design program, SIZEHX, is applied to a problem of current interest to confirm the derivation. SIZEHX can cost effectively perform single-step, multiparameter cost optimizations on single phase or supercritical exchanger arrays with variable fluid properties and arbitrary linear fouling for single-pass, segmentally baffled shell-and-tube configurations for a variety of fluid pairs, including hydrocarbon mixtures. The economic influence of several general design parameters on a geothermal exchanger are presented in the form of 3-D computer generated plots.

Pope, W.L.; Pines, H.S.; Fulton, R.L.; Doyle, P.A.

1978-06-01T23:59:59.000Z

382

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

E-Print Network (OSTI)

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

Adames, Adrian A

2010-01-01T23:59:59.000Z

383

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

Science Conference Proceedings (OSTI)

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

VIlim, R.; Nuclear Engineering Division

2009-03-12T23:59:59.000Z

384

Development of direct heat exchangers for geothermal brines. Final report, October 4, 1977--June 30, 1978  

DOE Green Energy (OSTI)

A series of experiments during a period of eight months was conducted with the existing Direct Contact Heat Exchanger (DCHX) Loop in order to better understand the thermal and hydraulic characteristics of the equipment. Modifications were made to the equipment which were designed to improve heat transfer and reduce the cost of the heat exchangers. Additional changes were made to the equipment to conduct turbine experiments, condenser experiments, and carryover tests. Further studies of the amounts of dissolved isobutane in the geothermal brine and methods of recovering this dissolved isobutane were also made. The procedures used and the results of the tests performed are presented.

Urbanek, M.W.

1978-01-01T23:59:59.000Z

385

SunShot Initiative: High-Flux Microchannel Solar Receiver  

NLE Websites -- All DOE Office Websites (Extended Search)

(CSP) R&D funding opportunity announcement (FOA), are working to develop an advanced heat exchanger for use in CSP receivers. The heat exchanger has the potential to...

386

Recovery of Water from Boiler Flue Gas Using Condensing Heat Exchangers  

Science Conference Proceedings (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

387

Recovery of Water from Boiler Flue Gas Using Condensing Heat Exchangers  

Science Conference Proceedings (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

388

Performance Assessment of 239 Series Sub-cooling Heat Exchangers for the Large Hadron Collider  

E-Print Network (OSTI)

Helium sub-cooling heat exchangers of the counter-flow type are used to minimize the vapor fraction produced in the final expansion of the 1.9 K distributed cooling loops used for cooling the superconducting magnets of the Large Hadron Collider (LHC). These components are of compact design, featuring low-pressure drop and handling very low pressure vapor at low temperature. Following a qualification phase of prototypes, a contract has been placed in European industry for the supply of 239 heat exchanger units. Different levels of extracted heat load require three different variants of heat exchangers. This paper will describe the manufacturing phase with emphasis on the main difficulties encountered to keep the production quality after a brief recall of the prototype phase. Finally, the acceptance tests performed at room temperature and at the nominal cryogenic condition at the factory and at CEA-Grenoble will be presented.

Riddone, G; Roussel, P; Moracchioli, R; Tavian, L

2006-01-01T23:59:59.000Z

389

Evaluation Methodology for Advance Heat Exchanger Concepts Using Analytical Hierarchy Process  

Science Conference Proceedings (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

390

Welding of dissimilar alloys for high temperature heat exchangers for SOFC  

DOE Green Energy (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

391

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

Science Conference Proceedings (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 plant’s 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

392

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)

of heat with the surroundings. This exchange of heat can be used to store thermal energy. CurrentlyA change in the temperature or a transformation of the phase of a material requires an exchange, the storage of thermal energy is used to increase the efficiency of heating and cooling of buildings

Braun, Paul

393

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

E-Print Network (OSTI)

Since its beginning, the Advanced Heat Exchangers Program of the U.S. Department of Energy - Office of Industrial Programs has made significant contributions to the development of advanced heat exchanger technology to save energy for U.S. industry. Currently the Program is field testing two large ceramic tubular high temperature waste heat recuperators and one large fluidized bed waste heat boiler and another fluidized bed waste heat recuperator is being readied for field tests. As a result of technology "needs" areas being identified during the development phases of these large systems, a stronger 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 developed. Other areas of research include development of advanced NDE techniques for study of ceramic materials and development of new forming techniques. A new effort of great promise is the study of ceramic composites as a potential heat exchanger material. This paper will briefly discuss the program, and describe the projects and research efforts that comprise the Advanced Heat Exchangers Program.

Richlen, S. L.

1986-06-01T23:59:59.000Z

394

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

Science Conference Proceedings (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

395

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

Science Conference Proceedings (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

396

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

Science Conference Proceedings (OSTI)

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

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

2011-01-01T23:59:59.000Z

397

ADVANCED HEAT EXCHANGERS USING TUNABLE NANOSCALE-MOLECULAR ASSEMBLY  

Science Conference Proceedings (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

398

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

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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

399

HEAT TRANSFER ANALYSIS FOR ION-EXCHANGE COLUMN SYSTEM  

SciTech Connect

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

Lee, S.; King, W.

2011-05-23T23:59:59.000Z

400

Modelling the vertical heat exchanger in thermal basin  

Science Conference Proceedings (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

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

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

E-Print Network (OSTI)

In order to satisfy the testing requirement of finned-tube heat-exchanger test-board, this paper designs an exclusive auto-monitor and control subsystem, studies the fuzzy control means for the supply air temperature of the heat-exchanger, and accomplishes the fuzzy control performance test. According to the experimental results, this auto-monitor and control subsystem could not only reduce the testing time for thermodynamic performances of finned-tube heat-exchanger, but also actualize easily the stable control of the supply air temperature of the heat-exchanger.

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

2006-01-01T23:59:59.000Z

402

Bubble confinement in flow boiling of FC-72 in a ''rectangular'' microchannel of high aspect ratio  

SciTech Connect

Boiling in microchannels remains elusive due to the lack of full understanding of the mechanisms involved. A powerful tool in achieving better comprehension of the mechanisms is detailed imaging and analysis of the two-phase flow at a fundamental level. Boiling is induced in a single microchannel geometry (hydraulic diameter 727 {mu}m), using a refrigerant FC-72, to investigate the effect of channel confinement on bubble growth. A transparent, metallic, conductive deposit has been developed on the exterior of the rectangular microchannel, allowing simultaneous uniform heating and visualisation to be achieved. The data presented in this paper is for a particular case with a uniform heat flux applied to the microchannel and inlet liquid mass flowrate held constant. In conjunction with obtaining high-speed images and videos, sensitive pressure sensors are used to record the pressure drop across the microchannel over time. Bubble nucleation and growth, as well as periodic slug flow, are observed in the microchannel test section. The periodic pressure fluctuations evidenced across the microchannel are caused by the bubble dynamics and instances of vapour blockage during confined bubble growth in the channel. The variation of the aspect ratio and the interface velocities of the growing vapour slug over time, are all observed and analysed. We follow visually the nucleation and subsequent both 'free' and 'confined' growth of a vapour bubble during flow boiling of FC-72 in a microchannel, from analysis of our results, images and video sequences with the corresponding pressure data obtained. (author)

Barber, Jacqueline [School of Engineering, University of Edinburgh, The King's Buildings, Mayfield Road, Edinburgh, EH9 3JL (United Kingdom); Aix-Marseille Universite (UI, UII) - CNRS Laboratoire IUSTI, UMR 6595, 5 Rue Enrico Fermi, Marseille 13453 (France); Brutin, David; Tadrist, Lounes [Aix-Marseille Universite (UI, UII) - CNRS Laboratoire IUSTI, UMR 6595, 5 Rue Enrico Fermi, Marseille 13453 (France); Sefiane, Khellil [School of Engineering, University of Edinburgh, The King's Buildings, Mayfield Road, Edinburgh, EH9 3JL (United Kingdom)

2010-11-15T23:59:59.000Z

403

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)

Considering a heating/cooling coil with adjustable heat-exchange area, an unequal type is put forward in this paper. Aiming at the application of such heat exchanger in an air-handling unit, restriction conditions are given for the minimum heat-exchanging unit in accordance with the requirement of control precision of indoor temperature and humidity. The structure adjustable heat exchanger improved the hydraulic adjusting characteristics of existing air handling units in the respective structure, and overcame the problems of existing air-handling units such as a narrow hydraulic adjusting range due to the rapid-opening performance of the continuous motor-driven value. As a result, such kind of heat exchanger is extremely suitable to fuzzy control.

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

2006-01-01T23:59:59.000Z

404

A Cryogenic Test Station for Subcooling Helium Heat Exchangers for LHC  

E-Print Network (OSTI)

The superconducting magnets of the Large Hadron Collider (LHC) will be cooled at 1.9 K by distributed cooling loops where counter-flow heat exchangers will be integrated. To qualify potential suppliers for the 250-units series production, prototypes of various technologies have been selected by CERN and a test station was set up at CEA-Grenoble. This test station, is constituted of a cryostat allowing an easy access to the heat exchanger to be tested as well as very low pressure pumping facilities.

Roussel, P; Tavian, L

2000-01-01T23:59:59.000Z

405

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

SciTech Connect

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

406

Development of numerical models of vertical ground heat exchangers and experimental verification : domain decomposition and state model reduction approach.  

E-Print Network (OSTI)

??Ground-source heat pump systems with vertical ground heat exchangers (GHE) are gaining popularity worldwide for their higher coefficients of performance and lower CO2 emissions. However,… (more)

KIM, Eui-Jong

2011-01-01T23:59:59.000Z

407

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

2011-01-01T23:59:59.000Z

408

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

DOE Green Energy (OSTI)

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

Jacobs, H.R.

1985-01-01T23:59:59.000Z

409

Microchannel apparatus and methods of conducting catalyzed oxidative dehydrogenation  

DOE Patents (OSTI)

Methods of oxidative dehydrogenation are described. Surprisingly, Pd and Au alloys of Pt have been discovered to be superior for oxidative dehydrogenation in microchannels. Methods of forming these catalysts via an electroless plating methodology are also described. An apparatus design that minimizes heat transfer to the apparatus' exterior is also described.

Tonkovich, Anna Lee (Dublin, OH); Yang, Bin (Columbus, OH); Perry, Steven T. (Galloway, OH); Mazanec, Terry (Solon, OH); Arora, Ravi (New Albany, OH); Daly, Francis P. (Delaware, OH); Long, Richard (New Albany, OH); Yuschak, Thomas D. (Lewis Center, OH); Neagle, Paul W. (Westerville, OH); Glass, Amanda (Galloway, OH)

2011-08-16T23:59:59.000Z

410

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

DOE Green Energy (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

411

Optimal Design of Shell-and-Tube Heat Exchangers by Different Strategies of Differential Evolution  

E-Print Network (OSTI)

This paper presents the application of Differential Evolution (DE) for the optimal design of shell-and-tube heat exchangers. The main objective in any heat exchanger design is the estimation of the minimum heat transfer area required for a given heat duty, as it governs the overall cost of the heat exchanger. Lakhs of configurations are possible with various design variables such as outer diameter, pitch, and length of the tubes; tube passes; baffle spacing; baffle cut etc. Hence the design engineer needs an efficient strategy in searching for the global minimum. In the present study for the first time DE, an improved version of Genetic Algorithms (GAs), has been successfully applied with different strategies for 1,61,280 design configurations using Bells method to find the heat transfer area. In the application of DE 9680 combinations of the key parameters are considered. For comparison, GAs are also applied for the same case study with 1080 combinations of its parameters. For this optimal design problem, it is found that DE, an exceptionally simple evolution strategy, is significantly faster compared to GA and yields the global optimum for a wide range of the key parameters.

B. V. Babu; S. A. Munawar

2001-01-01T23:59:59.000Z

412

A Heat Exchanger Process for Removal of H{sub2}S Gas  

SciTech Connect

A heat exchanger process has been developed for the removal of H{sub 2}S and other noncondensable gases from geothermal steam. The process utilizes a heat exchanger to condense water from geothermal steam while allowing H{sub 2}S and other noncondensable gases to pass through in the vapor phase. The condensed water is evaporated to form a clean steam from which over 90 percent of the H{sub 2}S and other noncondensable gases have been removed. Some of the important advantages of the heat exchanger process are shown in Table 1. The system can be located upstream of a power plant turbine which eliminates much of the potential for corrosion, as well as the requirement for removing H{sub 2}S from water collected in the main condenser. Since almost all noncondensables are removed, much less steam is needed for air ejector operation. The heat exchanger process is simple: it has no chemical addition requirements or sludge by-products and utilizes standard equipment found in many power plant applications. The regular power plant operators and maintenance crews can easily understand and run the system with minimal attention. Capital and operating costs are competitive with those for currently available H{sub 2}S-abatement technology, although significant economic advantages over downstream abatement processes may result due to the use of clean steam in the turbines.

Coury, Glenn E.; Babione, Robert A.; Gosik, Robert J.

1980-12-01T23:59:59.000Z

413

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

E-Print Network (OSTI)

LBNL-47668 Fouling of HVAC Fin and Tube Heat Exchangers Jeffrey Siegel and Van P. Carey CIEE ENDORSEMENT OF OR AGREEMENT WITH THESE FINDINGS, NOR THAT OF ANY CIEE SPONSOR. #12;FOULING OF HVAC in residential, commercial and industrial HVAC applications. Invariably, indoor and outdoor air contaminants foul

414

Equatorial Waves in the Presence of Air-Sea Heat Exchange  

Science Conference Proceedings (OSTI)

Changes in propagation of free linear waves on the equatorial ?-plane associated with air-sea heat exchange are in investigated here. By using a mixed-layer model, with the waves considered as perturbations on a specified basic state, the usual ...

Howard P. Hanson

1983-07-01T23:59:59.000Z

415

Belgirate, Italy, 28-30 September 2005 MICROMACHINED HEAT EXCHANGER FOR A CRYOSURGICAL PROBE  

E-Print Network (OSTI)

with large refrigeration capacity [2-4] and techniques for real-time monitoring using ultrasound or magnetic that surrounds the cold end of the probe is controlled by the refrigeration power and surface temperature the design and fabrication of the micromachined recuperative heat exchanger for a Joule-Thomson cryosurgical

Paris-Sud XI, Université de

416

Machine tool for lamellar forming of sheet metal parts for heat exchangers - MFAH 260  

Science Conference Proceedings (OSTI)

The present paper was done for the design of a machine tool used in the manufacturing process of lamellar forming for heat exchangers made of stainless steel. It present the working cycle that the machine tool must execute in order to attains the needed ...

V. Ispas; A. Hordoan; M. Steopan

2008-05-01T23:59:59.000Z

417

Development, testing and certification of the sigma research, Maxi-Therm S-101 thermosyphon heat exchanger. Final report  

DOE Green Energy (OSTI)

The Maxi-Therm S-101 is a thermosyphon liquid-to-air heat exchanger for use in heating systems in residential single-family dwellings and small commercial applications. It is a pumpless heating module which, when attached to a water storage tank, comprises a self contained heating unit. Electric resistance heating elements can be installed in the storage tank to provide a backup or off-peak heating system. (MOW)

Hankins, J.D.

1979-10-01T23:59:59.000Z

418

Study on Micro-scale Ceramic Catalytic Combustor with Embedded Heat Exchange Channels Takashi OKAMASA, Gwang-Goo LEE, Yuji SUZUKI, and Nobuhide KASAGI  

E-Print Network (OSTI)

Study on Micro-scale Ceramic Catalytic Combustor with Embedded Heat Exchange Channels Takashi with embedded cross-flow heat exchange channels is desinged based on a series of CFD analysis. The relationship model. It is found that the efficiency of heat exchanger is deteriorated due to the heat condction

Kasagi, Nobuhide

419

Tellus 000, 000000 (0000) Printed 12 August 2009 (Tellus LATEX style file v2.2) Wind sensitivity of the inter-ocean heat exchange  

E-Print Network (OSTI)

of the inter-ocean heat exchange By HANNA CORELL1 , JOHAN NILSSON1 , KRISTOFER D¨O¨OS1 , and G¨ORAN BROSTR¨OM2 is used to investigate the impact of the wind field on the heat exchange between the ocean basins-OCEAN HEAT EXCHANGE 3 heat transport, and the meridional overturning by increasing the upwelling of deep

Nilsson, Johan

420

Theory and practice of near critical pressure direct contact heat exchange. Final report  

DOE Green Energy (OSTI)

The direct contact heat exchange (DCHE) system previously designed, developed, and tested, was operated successfully without scale deposition. Conceptual design, optimization, and cost analysis showed that an additional advantage is the reduction in cost due to the high capacity of the DCHE compared with conventional heat exchangers. The technical and economic feasibility of DCHE operated near or above the critical pressure of isobutane using isobutane in direct contact with geothermal brine was assessed. The program consisted of conceptual design with a preliminary process evaluation and feasibility analysis, design and construction of the experimental apparatus, experimental tests, a final revised process evaluation and feasibility analysis based on the experimental results, and preparation of a design procedure. No scaling problems were present in the direct contact heat exchanger or the test unit. Test runs show that no scale was deposited in either the packed column section or the sieve tray section for continuous runs of 76 and 160 hours using East Mesa well 6-2 brine. In fact, the sieve tray section after 160 hours operation was visibly cleaner after the run than before. Both the packed column section and the sieve tray section operated according to theoretical thermodynamic and hydraulic predictions. Operation of the supercritical isobutane direct contact heat exchange and associated test unit with geothermal brine was routine with automatic controls and without operator attention. A design procedure including the requisite equations for sieve tray direct contact heat exchange columns was developed. The procedure gives the optimum ratio of isobutane to brine, optimum number of trays and tray spacing, and the sieve tray layout variables, namely downcomer area, active hole area, bubbling area, and column cross sectional area.

Wahl, E.F.; Boucher, F.B.

1977-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
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421

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

SciTech Connect

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

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

2010-11-15T23:59:59.000Z

422

Interface Exchange as an Indicator for Eddy Heat Transport  

Science Conference Proceedings (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

423

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

Science Conference Proceedings (OSTI)

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

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

2012-09-01T23:59:59.000Z

424

Cooling Strings of Superconducting Devices below 2 K the Helium II Bayonet Heat Exchanger  

E-Print Network (OSTI)

High-energy particle accelerators and colliders contain long strings of superconducting devices - acceleration RF cavities and magnets - operating at high field, which may require cooling in helium II below 2 K. In order to maintain adequate operating conditions, the applied or generated heat loads must be extracted and transported with minimum temperature difference. Conventional cooling schemes based on conductive or convective heat transport in pressurized helium II very soon reach their intrinsic limits of thermal impedance over extended lengths. We present the concept of helium II bayonet heat exchanger, which has been developed at CERN for the magnet cooling scheme of the Large Hadron Collider (LHC), and describe its specific advantages as a slim, quasi-isothermal heat sink. Experimental results obtained on several test set-ups, and a prototype magnet string have permitted to validate its performance and sizing rules, for transporting linear heat loads in the W.m-1 range over distances of several tens o...

Lebrun, P; Tavian, L; Van Weelderen, R

1998-01-01T23:59:59.000Z

425

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

E-Print Network (OSTI)

Flue gases exiting the stack of a boiler create thermal losses normally amounting to 15 to 20 percent of the high heating value of the fuel fired. By capturing and using this lost energy using condensing heat recovery, the overall efficiency of the system can be raised to over 95 percent. This paper reviews the origins of stack heat losses, direct contact condensing heat recovery processes, the Rocket Research Company CON-X condensing recuperator equipment and systems, site specific case studies and fuels and condensate acidity. A detailed example of the determination of the magnitude of stack heat losses is presented along with a methodology for the reader to make a preliminary heat recovery evaluation.

Thorn, W. F.

1986-06-01T23:59:59.000Z

426

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

427

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

E-Print Network (OSTI)

, 1982). An analytical study of such heat exchangers, which uses a detailed mathematical model-tube heat exchangers. Six 6-in (152-mm) wells were drilled at depths of 53, 60, 70, 80, 90, and 100 ft (16 exchanger and circulation pump, both cooling and heating SPFs would have been higher had a water-to-air unit

Oak Ridge National Laboratory

428

Catalyst Screening and Kinetic Studies Using Microchannel Reactors  

SciTech Connect

A multi-parallel microchannel reactor system is described, as related to catalyst screening and discovery for heat-intensive heterogeneous catalytic reactions. Example systems are detailed, in which the rapid heat transfer of the screening device is utilized to maintain isothermal operation in multiple channels for catalyst screening as well as kinetic investigations. The advantages of the system and pertinent results are discussed, specifically for Fischer-Tropsch synthesis, methanol oxidation to formaldehyde, and methanol steam reforming.

Cao, Chunshe; Palo, Daniel R.; Tonkovich, Annalee Y.; Wang, Yong

2007-07-15T23:59:59.000Z

429

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

Science Conference Proceedings (OSTI)

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

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

2012-06-18T23:59:59.000Z

430

Wellsite verification testing of an advanced geothermal primary heat exchanger (APEX)  

DOE Green Energy (OSTI)

The well-site test phase is described of a research program conducted by Aerojet Liquid Rocket Company to establish the feasibility of using a recirculating solid bed material to eliminate heat exchanger fouling in geothermal service. The concept was directed towards application as the primary heat exchanger in a geothermal power plant which utilizes a binary cycle. The APEX approach was shown to be effective for condenser operation with fouling cooling water. Similarly, APEX could be applied for geothermal direct heat utilization, for example, the vapor generator in an absorption refrigeration system. Phase I of this program culminated in a laboratory demonstration of APEX concept feasibility with brine simulants. Testing under the current project phase of the research effort was conducted at the Geothermal Component Test Facility at East Mesa, California. Technical feasibility was established by testing the effectiveness of the bed material in preventing the fouling of a heat exchanger test section. The elimination of fouling was demonstrated using both geothermal well water and facility cooling water as the fouling fluids.

Addoms, J.F.; Gracey, C.M.

1977-01-01T23:59:59.000Z

431

Simultaneous synthesis of flexible heat exchanger network. Appl Thermal Eng 2002;22:907–18  

E-Print Network (OSTI)

BSTRACT In industry there is still lot of potential to make an energy system more efficient and thereby reduce the waste heat available. On the other hand there is an option to export the waste heat to another industry or to society. When the use of a heat exchanger network is considered for these tasks the optimization framework developed in this work can be implemented to calculate the cost of optimal investments. This thesis presents a framework for generating flexible heat exchanger networks (HEN) over a specified range of variations in the flow rates and temperatures of the streams, so that the total annual costs (TAC) as a result of utility charges, exchanger areas and selection of matches are minimized. The proposed framework includes (i) an initialization stage to reduce the problem size, (ii) a multiperiod simultaneous MINLP model to synthesize a flexible HEN configuration, (iii) a multiperiod LP feasibility test model to check the operability and identify critical conditions which are to be included in the possible resolve stage of the MINLP model, and (iv) an NLP improvement model for further optimization

Juha Aaltola; Juha Aaltola; Otamedia Oy

2003-01-01T23:59:59.000Z

432

Method for producing microchannels in drawn material  

DOE Patents (OSTI)

A microchannel glass article includes a glass body having a porous, spinodal nanostructure and defining at least one microchannel extending from a surface of the article substantially through the article.

D' urso, Brian R (Clinton, TN); Simpson, John T (Clinton, TN)

2009-12-29T23:59:59.000Z

433

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

SciTech Connect

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

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

1998-06-01T23:59:59.000Z

434

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

435

HRE-3 BLANKET HEAT EXCHANGER AS A FEEDWATER REACTOR RATHER THAN AS A STEAM GENERATOR  

SciTech Connect

There may be an advantage to designing the HRE-3 vertical shell and tube slurry heat exchanger as a feedwater heater rather than as a steam generator from the standpoint of space requirement and blowdown problems. This study of the effect of this arrangement on the thermal efficiency of the heat-power cycle indicates that the gross electrical generating capacity of HRE-3 would be reduced by about 500-kw, or about 3 to 4% of the output. It is concluded that, (a) there is sufficient merit in using the exchanger as a feedwater heater to warrant continued study of the concept, and (b) the effect on the thermal efficiency is so small as to not be a major deciding influence. (auth)

Robertson, R.C.

1958-04-14T23:59:59.000Z

436

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

SciTech Connect

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

437

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

438

Heat exchangers comprising at least one porous member positioned within a casing  

Science Conference Proceedings (OSTI)

A heat exchanger and associated methods for sublimating solid particles therein, for conveying fluids therethrough, or both. The heat exchanger includes a chamber, and a porous member having a porous wall having pores in communication with the chamber and an interior of the porous member. A first fluid is conveyed into the porous member while a second fluid is conveyed into the porous member through the porous wall. The second fluid may form a positive flow boundary layer along the porous wall to reduce or eliminate substantial contact between the first fluid and the interior of the porous wall. The combined first and second fluids are conveyed out of the porous member. Additionally, the first fluid and the second fluid may each be conveyed into the porous member at different temperatures and may exit the porous member at substantially the same temperature.

Turner, Terry D. (Idaho Falls, ID); Wilding, Bruce M (Idaho Falls, ID)

2011-11-22T23:59:59.000Z

439

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

440

State-of-the-art survey of joinability of materials for OTEC heat exchangers  

DOE Green Energy (OSTI)

Literature and industrial sources were surveyed to assess, on the basis of apparent economics and reliability, the joinability of both shell-and-tube and compact ocean thermal energy conversion (OTEC) heat exchangers. A no-leak requirement is mandatory to prevent mixing seawater and the ammonia working fluid. The operating temperature range considered is 7 to 28/sup 0/C (45 to 82/sup 0/F). Materials evaluated were aluminum, titanium, copper--nickel, AL-6X austenitic stainless steel, singly and in combination with steel and concrete. Many types of welding and brazing processes, roller expansion, magnaforming, O-ring sealing, and adhesive bonding were considered. The automatic gas tungsten-arc welding process and explosion welding processes are the only two joining processes that now appear to offer the high reliability required of no-leak shell-and-tube heat exchangers. Of these two processes, the gas tungsten-arc welding process appears to be the more economically attractive.

Beaver, R. J.

1978-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "microchannel heat exchanger" from the National Library of EnergyBeta (NLEBeta).
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We encourage you to perform a real-time search of NLEBeta
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441

Two-dimensional numerical simulation of a Stirling engine heat exchanger  

DOE Green Energy (OSTI)

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

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

1994-09-01T23:59:59.000Z

442

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

DOE Green Energy (OSTI)

A liquid hydrogen in a absorber for muon cooling requires that up to 300 W be removed from 20 liters of liquid hydrogen. The wall of the container is a heat exchanger between the hydrogen and 14 K helium gas in channels within the wall. The warm liquid hydrogen is circulated down the cylindrical walls of the absorber by free convection. The flow of the hydrogen is studied using FEA methods for two cases and the heat transfer coefficient to the wall is calculated. The first case is when the wall is bare. The second case is when there is a duct some distance inside the cooled wall.

Green, Michael A.; Oxford U.; Yang, S.W.; Green, M.A.; Lau, W.

2004-05-08T23:59:59.000Z

443

Welding and Repair Technology Center: Repair Technology for Degraded Pressure Vessel and Heat Exchanger Shells  

Science Conference Proceedings (OSTI)

BackgroundPressure vessels and heat exchangers are subject to a number of degradation mechanisms that can cause thinning of component walls and deterioration of internal components. With many repair options available, the Electric Power Research Institute (EPRI) Welding and Repair Technology Center (WRTC) has developed this report to assist operations and engineering personnel who are faced with defective or failed vessel components. Many available repair options allow ...

2013-10-30T23:59:59.000Z

444

8th EPRI Balance-of-Plant Heat Exchanger NDE Symposium  

Science Conference Proceedings (OSTI)

The Eighth EPRI Balance-of-Plant Heat Exchanger NDE Symposium was held in Key West, Florida on June 21-23, 2004. It consisted of three pre-symposium short courses and two and one-half days of combined paper presentations and vendor fair. Attendees included representatives from domestic and international utilities, research organizations NDE service and equipment vendors, and repair/replacement organizations. This biennial symposium serves as a forum for plant engineers and NDE specialists to meet, discus...

2004-08-25T23:59:59.000Z

445

Nondestructive Evaluation: Electromagnetic NDE Guide for Balance of Plant Heat Exchangers, Revision 3  

Science Conference Proceedings (OSTI)

This report is Revision 3 to the original report. It presents summaries of nondestructive evaluation (NDE) procedures used for assessing the integrity of BOP heat exchanger tubing. This report is a living document that will be modified and updated with new information as it becomes available. Care has been taken to reorganize the report in a user-friendly layout that can accommodate future growth. As new material, this report contains information about mockups and specific materials. User comments are en...

2009-12-22T23:59:59.000Z

446

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

E-Print Network (OSTI)

Cross flow heat exchange of textile cellular metal core sandwich panels J. Tian a , T.J. Lu b,*, H. Finally, the thermal performance of brazed woven tex- tiles is compared with other heat exchanger media be used as heat exchangers, node rotation precludes their use as structural members. In addition

Wadley, Haydn

447

Proceedings: Fifth EPRI Balance-of-Plant Heat Exchanger NDE Symposium  

Science Conference Proceedings (OSTI)

This publication is a compilation of the agenda and material presented at the Fifth EPRI Steam Balance-of-Plant Heat Exchanger NDE Symposium which was held on June 15-17, 1997 at Lake Tahoe, Nevada. Along with the proceedings of the symposium, an attendance list is included in this document. The topics that are presented in the symposium are included in this publication in a Plenary Session and Sessions 1, 2, 3 and 4. An overview of the American Society for Nondestructive Testing (ASNT) Central Certification Program is presented in the Plenary Session. The following is a sampling of titles presented in the other sessions: An Engineer's Guide to Eddy Current Testing; ID Pit Sizing in a Carbon Steel Tubed Fuel Oil Storage Transfer Heater; Pilgrim Feedwater Heater Tube Repair; Through the Tube Plugging Application for Once Through Heat Exchangers; PFEC Inspection Method for Detection and Sizing of Uniform Wall Thinning; Some Characteristics of Pulsed Eddy Current Technique in Ferromagnetic Heat Exchanger Tubing; Utility Perspective on PC Based Database Management and Analysis Software; and NDE Demonstration and Inspection of Ginna Power Plant Moisture Separator Finned Tubing.

None

1998-10-01T23:59:59.000Z

448

Two-phase gas-liquid flow characteristics inside a plate heat exchanger  

Science Conference Proceedings (OSTI)

In the present study, the air-water two-phase flow characteristics including flow pattern and pressure drop inside a plate heat exchanger are experimentally investigated. A plate heat exchanger with single pass under the condition of counter flow is operated for the experiment. Three stainless steel commercial plates with a corrugated sinusoidal shape of unsymmetrical chevron angles of 55 and 10 are utilized for the pressure drop measurement. A transparent plate having the same configuration as the stainless steel plates is cast and used as a cover plate in order to observe the flow pattern inside the plate heat exchanger. The air-water mixture flow which is used as a cold stream is tested in vertical downward and upward flow. The results from the present experiment show that the annular-liquid bridge flow pattern appeared in both upward and downward flows. However, the bubbly flow pattern and the slug flow pattern are only found in upward flow and downward flow, respectively. The variation of the water and air velocity has a significant effect on the two-phase pressure drop. Based on the present data, a two-phase multiplier correlation is proposed for practical application. (author)

Nilpueng, Kitti [Department of Mechanical Engineering, South East Asia University, Bangkok 10160 (Thailand); Wongwises, Somchai [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab (FUTURE), Department of Mechanical Engineering, King Mongkut's University of Technology Thonburi, Bangmod, Bangkok 10140 (Thailand)

2010-11-15T23:59:59.000Z

449

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

Science Conference Proceedings (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

450

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

DOE Patents (OSTI)

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

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

1994-01-01T23:59:59.000Z