Sample records for scraped heat exchanger

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

    E-print Network

    Boyer, Edmond

    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

  2. Tempering of Chocolate in a Scraped Surface Heat Exchanger

    Microsoft Academic Search

    C. LOISEL; G. KELLER; G. LECQ; B. LAUNAY; M. OLLIVON

    1997-01-01

    Crystallization of dark chocolate during different tempering processes has been studied in-situ in a lab-scale Scraped Surface Heat Exchanger. The linear relationship between torque and viscosity made possible the control of chocolate crystallization during tempering by following torque variations vs. time and converting them to equivalent viscosity values. These variations of equivalent viscosity of chocolate observed during tempering were correlated

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

    E-print Network

    Paris-Sud XI, Université de

    *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

  4. Heat exchanger

    SciTech Connect

    Drury, C.R.

    1988-02-02

    A heat exchanger having primary and secondary conduits in heat-exchanging relationship is described comprising: at least one serpentine tube having parallel sections connected by reverse bends, the serpentine tube constituting one of the conduits; a group of open-ended tubes disposed adjacent to the parallel sections, the open-ended tubes constituting the other of the conduits, and forming a continuous mass of contacting tubes extending between and surrounding the serpentine tube sections; and means securing the mass of tubes together to form a predetermined cross-section of the entirety of the mass of open-ended tubes and tube sections.

  5. Corrosive resistant heat exchanger

    DOEpatents

    Richlen, Scott L. (Annandale, VA)

    1989-01-01

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

  6. Heat exchanger

    NASA Astrophysics Data System (ADS)

    Brackenbury, P. J.

    1983-12-01

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

  7. Heat exchanger

    DOEpatents

    Brackenbury, Phillip J. (Richland, WA)

    1986-01-01

    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.

  8. Heat exchanger

    DOEpatents

    Brackenbury, P.J.

    1983-12-08

    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.

  9. Segmented heat exchanger

    SciTech Connect

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

    2010-12-14

    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.

  10. Corrosive resistant heat exchanger

    Microsoft Academic Search

    Richlen; Scott L

    1989-01-01

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

  11. High temperature heat exchangers

    Microsoft Academic Search

    Y. Mori; A. E. Sheindlin; N. Afgan

    1986-01-01

    This book contains the proceedings from the XVII Symposium of the International Center for Heat and Mass Transfer on High Temperature Heat Exchangers, held August 1985 in Yugoslavia. Papers were presented under the following topics: High Temperature Heat Exchangers Development; Basic Problem in High Temperature Heat Exchangers; Heat Exchangers for High Temperature Recovery; and High Temperature Heat Exchangers for Future

  12. Heat pipe array heat exchanger

    DOEpatents

    Reimann, Robert C. (Lafayette, NY)

    1987-08-25

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

  13. Industrial heat exchangers

    Microsoft Academic Search

    A. J. Hayes; W. W. Liang; S. L. Richlen; E. S. Tabb

    1985-01-01

    This book presents the papers given at a symposium on the use of heat exchangers in the industrial plants. Topics considered include the US DOE and GRI research programs, advanced fixed boundary heat exchanger technology, commercial heat exchanger applications, thermo-hydraulic performance of heat-transfer equipment, field tests, the corrosion of heat exchanger materials, economics, cost benefit analysis, payback, and advanced assembly

  14. Woven heat exchanger

    DOEpatents

    Piscitella, R.R.

    1984-07-16

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

  15. Woven heat exchanger

    DOEpatents

    Piscitella, Roger R. (Idaho Falls, ID)

    1987-01-01

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

  16. Direct fired heat exchanger

    DOEpatents

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

    1986-01-01

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

  17. Wound tube heat exchanger

    DOEpatents

    Ecker, Amir L. (Duncanville, TX)

    1983-01-01

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

  18. Conquer heat exchanger fouling

    Microsoft Academic Search

    1996-01-01

    Fouling plays a dominant role in heat exchanger performance. It is extremely important to choose the most appropriate type of heat exchanger for a particular application and adopt proper values for fouling resistance. A design practice for shell-and-tube heat exchangers that will limit fouling to a minimum and thus ensure trouble-free operation is essential. Due to the availability of specialized

  19. Microtube strip heat exchanger

    SciTech Connect

    Doty, F.D.

    1991-07-08

    During the last quarter, Doty Scientific, Inc. (DSI) continued to make progress on the microtube strip (MTS) heat exchanger. DSI completed a heat exchanger stress analysis of the ten-module heat exchanger bank; and, performed a shell-side flow inhomogeneity analysis of the three-module heat exchanger bank. The company produced 50 tubestrips using an in-house CNC milling machine and began pressing them onto tube arrays. DSI revised some of the tooling required to encapsulate a tube array and press tubestrips into the array to improve some of the prototype tooling. 2 refs., 4 figs.

  20. Nature's Heat Exchangers.

    ERIC Educational Resources Information Center

    Barnes, George

    1991-01-01

    Discusses the heat-transfer systems of different animals. Systems include heat conduction into the ground, heat transferred by convection, heat exchange in lizards, fish and polar animals, the carotid rete system, electromagnetic radiation from animals and people, and plant and animal fiber optics. (MDH)

  1. Active microchannel heat exchanger

    DOEpatents

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

    2001-01-01

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

  2. Microscale Regenerative Heat Exchanger

    NASA Technical Reports Server (NTRS)

    Moran, Matthew E.; Stelter, Stephan; Stelter, Manfred

    2006-01-01

    The device described herein is designed primarily for use as a regenerative heat exchanger in a miniature Stirling engine or Stirling-cycle heat pump. A regenerative heat exchanger (sometimes called, simply, a "regenerator" in the Stirling-engine art) is basically a thermal capacitor: Its role in the Stirling cycle is to alternately accept heat from, then deliver heat to, an oscillating flow of a working fluid between compression and expansion volumes, without introducing an excessive pressure drop. These volumes are at different temperatures, and conduction of heat between these volumes is undesirable because it reduces the energy-conversion efficiency of the Stirling cycle.

  3. Heat and mass exchanger

    DOEpatents

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

    2011-06-28

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

  4. Heat and mass exchanger

    DOEpatents

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

    2007-09-18

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

  5. Thermoelectric heat exchange element

    DOEpatents

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

    2007-08-14

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

  6. Modular Heat Exchanger With Integral Heat Pipe

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey G.

    1992-01-01

    Modular heat exchanger with integral heat pipe transports heat from source to Stirling engine. Alternative to heat exchangers depending on integrities of thousands of brazed joints, contains only 40 brazed tubes.

  7. A corrosive resistant heat exchanger

    DOEpatents

    Richlen, S.L.

    1987-08-10

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

  8. Microtube strip heat exchanger

    NASA Astrophysics Data System (ADS)

    Doty, F. D.

    1990-12-01

    Doty Scientific (DSI) believes their microtube-strip heat exchanger will contribute significantly to the following: (1) the closed Brayton cycles being pursued at MIT, NASA, and elsewhere; (2) reverse Brayton cycle cryocoolers, currently being investigated by NASA for space missions, being applied to MRI superconducting magnets; and (3) high-efficiency cryogenic gas separation schemes for CO2 removal from exhaust stacks. The goal of this current study is to show the potential for substantial progress in high-effectiveness, low-cost, gas-to-gas heat exchangers for diverse applications at temperatures from below 100 K to above 1000 K. To date, the highest effectiveness measured is about 98 percent and relative pressure drops below 0.1 percent with a specific conductance of about 45 W/kgK are reported. During the pre-award period DSI built and tested a 3-module heat exchanger bank using 103-tube microtube strip (MTS) modules. To add to their analytical capabilities, DSI has acquired computational fluid dynamics (CFD) software. This report describes the pre-award work and the status of the ten tasks of the current project, which are: analyze flow distribution and thermal stresses within individual modules; design a heat exchanger bank of ten modules with 400 microtube per module; obtain production quality tubestrip die and AISI 304 tubestrips; obtain production quality microtubing; construct revised MTS heat exchanger; construct dies and fixtures for prototype heat exchanger; construct 100 MTS modules; assemble 8 to 10 prototype MTS heat exchangers; test prototype MTS heat exchanger; and verify test through independent means.

  9. Radial flow heat exchanger

    DOEpatents

    Valenzuela, Javier (Hanover, NH)

    2001-01-01

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

  10. Counterflow Regolith Heat Exchanger

    NASA Technical Reports Server (NTRS)

    Zubrin, Robert; Jonscher, Peter

    2013-01-01

    A problem exists in reducing the total heating power required to extract oxygen from lunar regolith. All such processes require heating a great deal of soil, and the heat energy is wasted if it cannot be recycled from processed material back into new material. The counterflow regolith heat exchanger (CoRHE) is a device that transfers heat from hot regolith to cold regolith. The CoRHE is essentially a tube-in-tube heat exchanger with internal and external augers attached to the inner rotating tube to move the regolith. Hot regolith in the outer tube is moved in one direction by a right-hand - ed auger, and the cool regolith in the inner tube is moved in the opposite direction by a left-handed auger attached to the inside of the rotating tube. In this counterflow arrangement, a large fraction of the heat from the expended regolith is transferred to the new regolith. The spent regolith leaves the heat exchanger close to the temperature of the cold new regolith, and the new regolith is pre-heated close to the initial temperature of the spent regolith. Using the CoRHE can reduce the heating requirement of a lunar ISRU system by 80%, reducing the total power consumption by a factor of two. The unique feature of this system is that it allows for counterflow heat exchange to occur between solids, instead of liquids or gases, as is commonly done. In addition, in variants of this concept, the hydrogen reduction can be made to occur within the counterflow heat exchanger itself, enabling a simplified lunar ISRU (in situ resource utilization) system with excellent energy economy and continuous nonbatch mode operation.

  11. The heat pipe exchanger with controllable heat exchanging area

    Microsoft Academic Search

    M. Oshiro; S. Takasu; M. Kurihara; K. Taneda; T. Nakamoto; H. Nakayama

    1984-01-01

    The heat transfer rate through the heat exchanger in an industrial boiler that burns heavy oils must be controlled so as not to decrease the exhaust gas temperature below the dew point of sulfuric acid. Two systems of heat pipe exchangers are examined: one controls the heat exchange area of the condenser section of the heat pipes and the other

  12. Downhole heat exchangers

    SciTech Connect

    Culver, G.; Lund, J.W. [Oregon Inst. of Tech., Klamath Falls, OR (United States). Geo-Heat Center

    1999-09-01

    The downhole heat exchanger (DHE) eliminates the problem of disposal of geothermal fluid, since only heat is taken from the well. The exchanger consists of a system of pipes or tubes suspended in the well through which clean secondary water is pumped or allowed to circulate by natural convection. These systems offer substantial economic savings over surface heat exchangers where a single-well system is adequate (typically less than 0.8 MWt, with well depths up to about 500 ft) and may be economical under certain conditions at well depths to 1500 ft. Several designs have proven successful; but, the most popular are a simple hairpin loop or multiple loops of iron pipe (similar to the tubes in a U-tube and shell exchanger) extending to near the well bottom. An experimental design consisting of multiple small tubes with headers at each end suspended just below the water surface appears to offer economic and heating capacity advantages. The paper describes design and construction details and New Zealand`s experience with downhole heat exchangers.

  13. Monogroove liquid heat exchanger

    NASA Technical Reports Server (NTRS)

    Brown, Richard F. (Inventor); Edelstein, Fred (Inventor)

    1990-01-01

    A liquid supply control is disclosed for a heat transfer system which transports heat by liquid-vapor phase change of a working fluid. An assembly (10) of monogroove heat pipe legs (15) can be operated automatically as either heat acquisition devices or heat discharge sources. The liquid channels (27) of the heat pipe legs (15) are connected to a reservoir (35) which is filled and drained by respective filling and draining valves (30, 32). Information from liquid level sensors (50, 51) on the reservoir (35) is combined (60) with temperature information (55) from the liquid heat exchanger (12) and temperature information (56) from the assembly vapor conduit (42) to regulate filling and draining of the reservoir (35), so that the reservoir (35) in turn serves the liquid supply/drain needs of the heat pipe legs (15), on demand, by passive capillary action (20, 28).

  14. Chimney heat exchanger

    SciTech Connect

    Whiteley, I.C.

    1981-09-01

    A heat exchanger for installation on the top of a chimney of a building includes a housing having a lower end receiving the top of the chimney and an upper end with openings permitting the escape of effluent from the chimney and a heat exchanger assembly disposed in the housing including a central chamber and a spirally arranged duct network defining an effluent spiral path between the top of the chimney and the central chamber and a fresh air spiral path between an inlet disposed at the lower end of the housing and the central chamber, the effluent and fresh air spiral paths being in heat exchange relationship such that air passing through the fresh air spiral path is heated by hot effluent gases passing upward through the chimney and the effluent spiral path for use in heating the building. A pollution trap can be disposed in the central chamber of the heat exchanger assembly for removing pollutants from the effluent, the pollution trap including a rotating cage carrying pumice stones for absorbing pollutants from the effluent with the surface of the pumice gradually ground off to reveal fresh stone as the cage rotates.

  15. Microtube strip heat exchanger

    SciTech Connect

    Doty, F.D.

    1991-10-16

    This progress report is for the September--October 1991 quarter. We have demonstrated feasibility of higher specific conductance by a factor of five than any other work in high-temperature gas-to-gas exchangers. These laminar-flow, microtube exchangers exhibit extremely low pressure drop compared to alternative compact designs under similar conditions because of their much shorter flow length and larger total flow area for lower flow velocities. The design appears to be amenable to mass production techniques, but considerable process development remains. The reduction in materials usage and the improved heat exchanger performance promise to be of enormous significance in advanced engine designs and in cryogenics.

  16. Heat exchanger panel

    NASA Technical Reports Server (NTRS)

    Warburton, Robert E. (Inventor); Cuva, William J. (Inventor)

    2005-01-01

    The present invention relates to a heat exchanger panel which has broad utility in high temperature environments. The heat exchanger panel has a first panel, a second panel, and at least one fluid containment device positioned intermediate the first and second panels. At least one of the first panel and the second panel have at least one feature on an interior surface to accommodate the at least one fluid containment device. In a preferred embodiment, each of the first and second panels is formed from a high conductivity, high temperature composite material. Also, in a preferred embodiment, the first and second panels are joined together by one or more composite fasteners.

  17. Serpentine heat exchanger

    SciTech Connect

    Tomlinson, R.S.

    1991-01-08

    This patent describes a furnace having a burner means for providing hot products of combustion, and an air flow means for circulating conditioned air, a heat exchanger for transferring heat from products of combustion to conditioned air. The heat exchanger comprises first and second matched clamshell plates assembled together. The plates connected at their respective edges by a sealing means for providing a seal thereat, each the plate having an internal surface defining a depression. The depressions together defining a serpentine passageway, an entrance and exhaust ported formed in the passageway. The surfaces including elongated ribs for obstructing fluid flow adjacent the exhaust portal and for directing fluid flow to under-utilized portions in the passageway.

  18. Biomass heat exchanger furnace

    SciTech Connect

    Sukup, E.G.

    1984-05-22

    A hot air heat exchanger furnace that uses crop residue as a fuel source is provided for producing the heat required for various purposes, such as the drying of grains, peanuts, soybeans and other materials and for the heating of buildings. The furnace includes a combustion chamber, an upper manifold, a lower manifold, a plenum and a number of exhaust tubes. The exhaust tubes direct the flow of combustion gases from the combustion chamber in a serpentine path in the plenum between the upper and lower manifolds and into a stack. Meanwhile, ambient air passes into the plenum, past the heat transfer surfaces of the combustion chamber and the exhaust tubes as heat transfers to it. Then it passes out of the furnace.

  19. Microtube strip heat exchanger

    Microsoft Academic Search

    F. D. Doty

    1990-01-01

    Doty Scientific (DSI) believes their microtube-strip heat exchanger will contribute significantly to the following: (1) the closed Brayton cycles being pursued at MIT, NASA, and elsewhere; (2) reverse Brayton cycle cryocoolers, currently being investigated by NASA for space missions, being applied to MRI superconducting magnets; and (3) high-efficiency cryogenic gas separation schemes for CO2 removal from exhaust stacks. The goal

  20. Heat pipe heat exchanger design considerations

    Microsoft Academic Search

    K. T. Feldman; D. C. Lu

    1976-01-01

    Typical heat pipe heat exchangers (HPHX) are described, along with their advantages, uses, and some problems in HPHX design, and a computer HPHX analysis program is discussed with required input data. The computer program is being developed for analysis of heat exchange performance by finned-tube HPHX and thread-puddle-artery heat pipes. Copper-water heat pipes and carbon steel-Dowtherm A heat pipes are

  1. Preliminary analysis of heat pipe heat exchangers for heat recovery

    Microsoft Academic Search

    J. O. Amode; K. T. Feldman

    1975-01-01

    A preliminary analysis of fin tube heat pipe heat exchangers for air-to-air heat recovery was conducted. The analysis uses conventional heat exchanger design techniques and a new heat pipe design technique which includes probabilistic design of artery wick heat pipes. The heat transfer capability of the heat pipes may be matched with that of the finned tubes in order to

  2. Lightweight Long Life Heat Exchanger

    NASA Technical Reports Server (NTRS)

    Moore, E. K.

    1976-01-01

    A shuttle orbiter flight configuration aluminum heat exchanger was designed, fabricated, and tested. The heat exchanger utilized aluminum clad titanium composite parting sheets for protection against parting sheet pin hole corrosion. The heat exchanger, which is fully interchangeable with the shuttle condensing heat exchanger, includes slurpers (a means for removing condensed water from the downstream face of the heat exchanger), and both the core air passes and slurpers were hydrophilic coated to enhance wettability. The test program included performance tests which demonstrated the adequacy of the design and confirmed the predicted weight savings.

  3. Heat exchanger wrap-up

    Microsoft Academic Search

    Lunde

    1983-01-01

    Heat exchangers are used between the collector fluid and the storage tank in active solar energy systems. The thermal performance of heat exchangers can be predicted if the two parameters are known: the number of transfer units, which is the ratio of characteristic size for heat transfer to the smaller of the heat capacity flow rates, and the ratio of

  4. Fault-Tolerant Heat Exchanger

    NASA Technical Reports Server (NTRS)

    Izenson, Michael G.; Crowley, Christopher J.

    2005-01-01

    A compact, lightweight heat exchanger has been designed to be fault-tolerant in the sense that a single-point leak would not cause mixing of heat-transfer fluids. This particular heat exchanger is intended to be part of the temperature-regulation system for habitable modules of the International Space Station and to function with water and ammonia as the heat-transfer fluids. The basic fault-tolerant design is adaptable to other heat-transfer fluids and heat exchangers for applications in which mixing of heat-transfer fluids would pose toxic, explosive, or other hazards: Examples could include fuel/air heat exchangers for thermal management on aircraft, process heat exchangers in the cryogenic industry, and heat exchangers used in chemical processing. The reason this heat exchanger can tolerate a single-point leak is that the heat-transfer fluids are everywhere separated by a vented volume and at least two seals. The combination of fault tolerance, compactness, and light weight is implemented in a unique heat-exchanger core configuration: Each fluid passage is entirely surrounded by a vented region bridged by solid structures through which heat is conducted between the fluids. Precise, proprietary fabrication techniques make it possible to manufacture the vented regions and heat-conducting structures with very small dimensions to obtain a very large coefficient of heat transfer between the two fluids. A large heat-transfer coefficient favors compact design by making it possible to use a relatively small core for a given heat-transfer rate. Calculations and experiments have shown that in most respects, the fault-tolerant heat exchanger can be expected to equal or exceed the performance of the non-fault-tolerant heat exchanger that it is intended to supplant (see table). The only significant disadvantages are a slight weight penalty and a small decrease in the mass-specific heat transfer.

  5. "Bottle-Brush" Heat Exchanger

    NASA Technical Reports Server (NTRS)

    Tward, E.; Gatewood, J. R.

    1982-01-01

    Heat exchanger consists of a metal tube with wires extending inward from wall. Conduction of heat along wires improves heat transfer to gas or other filling. Fluid is heated throughout the cross section of tube. Suggested applications are refrigerators, heat engines, thermal instrumentation, and heat switches.

  6. Optimization of Heat Exchanger Cleaning

    E-print Network

    Siegell, J. H.

    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. INTRODUCTION In most... can be somewhat mitigated by periodic chemical or mechanical cleaning of the exchanger surface, and by the addition of antifoul ants. The typical decay in heat recovery capabil ity due to fou 1i ng and restoration afte r heat exchanger cleaning...

  7. Design of heat exchange element for plastic film heat exchanger

    Microsoft Academic Search

    E. C. Guyer; D. L. Brownell

    1984-01-01

    This report presents the results of an effort to design a plastic film heat exchanger element (PFHX) suitable for use in an industrial heat pump evaporator. This report addresses the selection of materials, the expected flow and heat transfer behavior, and the mechanical design features of a parallel plate type exchanger that uses thin plastic films as the boundary between

  8. Heat exchanger for electrothermal devices

    NASA Technical Reports Server (NTRS)

    Zavesky, Ralph J. (inventor); Sovey, James S. (inventor); Mirtich, Michael J. (inventor); Marinos, Charalampus (inventor); Penko, Paul F. (inventor)

    1986-01-01

    An improved electrothermal device is disclosed. An electrothermal thruster utilizes a generally cylindrical heat exchanger chamber to convert electricity to heat which raises the propellant temperature. A textured, high emissivity heat element radiatively transfers heat to the inner wall of this chamber that is ion beam morphologically controlled for high absorptivity. This, in turn, raises the temperature of a porous heat exchanger material in an annular chamber surrounding the cylindrical chamber. Propellant gas flows through the annular chamber and is heated by the heat exchanger material.

  9. Hybrid Heat Exchangers

    NASA Technical Reports Server (NTRS)

    Tu, Jianping Gene; Shih, Wei

    2010-01-01

    A hybrid light-weight heat exchanger concept has been developed that uses high-conductivity carbon-carbon (C-C) composites as the heat-transfer fins and uses conventional high-temperature metals, such as Inconel, nickel, and titanium as the parting sheets to meet leakage and structural requirements. In order to maximize thermal conductivity, the majority of carbon fiber is aligned in the fin direction resulting in 300 W/m.K or higher conductivity in the fin directions. As a result of this fiber orientation, the coefficient of thermal expansion (CTE) of the C-C composite in both non-fiber directions matches well with the CTE of various high-temperature metal alloys. This allows the joining of fins and parting sheets by using high-temperature braze alloys.

  10. Heat exchanger mat

    SciTech Connect

    Walmet, G. E.

    1985-04-16

    An improved heat exchanger mat and a method of dislodging and retrieving the mat from the bottom of a solar pond without disturbing an established thermal gradient. The mat is separated from the pond bottom by the injection of a dislodging medium between the mat and the bottom of the pond. When the pond contains a liner, the dislodging medium is injected between the mat and the pond liner. The mat utilizes a dual conduit network of one integral conduit for the flow of heat exchanger fluid and a second integral conduit for the flow of dislodging medium. The dislodging medium enters the dislodging conduit via an inlet and exits through a plurality of outlets located on the underside of the mat. The medium, as it exits, forces the mat upward and frees it from the bottom of the pond. Once the dislodging medium has separated the mat from the pond bottom, attached retrieval cords are used to remove the mat by drawing it up the side of the pond.

  11. Understanding ion cyclotron harmonic fast wave heating losses in the scrape off layer of tokamak plasmas

    SciTech Connect

    Bertelli, N [PPPL; Jaeger, E F; Hosea, J C; Phillips, C K; Berry, L; Bonoli, P T; Gerhardt, S P [PPPL; Green, D; LeBlanc, B [PPPL; Perkins, R J; Ryan, P M; Taylor, G; Valeo, E J; Wilso, J R; Wright, J C

    2014-07-01

    Fast waves at harmonics of the ion cyclotron frequency, which have been used successfully on National Spherical Torus Experiment (NSTX), will also play an important role in ITER and are a promising candidate for the Fusion Nuclear Science Facility (FNSF) designs based on spherical torus (ST). Experimental studies of high harmonic fast waves (HHFW) heating on the NSTX have demonstrated that substantial HHFW power loss occurs along the open field lines in the scrape-off layer (SOL), but the mechanism behind the loss is not yet understood. The full wave RF code AORSA, in which the edge plasma beyond the last closed flux surface (LCFS) is included in the solution domain, is applied to specific NSTX discharges in order to predict the effects and possible causes of this power loss. In the studies discussed here, a collisional damping parameter has been implemented in AORSA as a proxy to represent the real, and most likely nonlinear, damping processes. A prediction for the NSTX Upgrade (NSTX-U) experiment, that will begin operation next year, is also presented, indicating a favorable condition for the experiment due to a wider evanescent region in edge density.*Research supported by the U.S. DOE under Contract No. DE-AC02-09CH11466 with Princeton University.

  12. Heat exchange assembly

    DOEpatents

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

    2004-06-08

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

  13. The Microtube Strip Heat Exchanger

    Microsoft Academic Search

    F. DAVID DOTY; GREG HOSFORD; J. B. SPITZMESSER; I JOHN DEWEY JONES

    1991-01-01

    The advantages of designing heat exchangers in the laminar-flow regime are discussed from a theoretical standpoint. It is argued that laminar-flow designs have the advantages of reducing thermodynamic and hydrodynamic irreversibilities, and hence increasing system efficiency. More concretely, laminar-flow heat exchangers are free from the turbulence-induced vibration common in conventional heat exchangers, and can thus offer longer life and greater

  14. Heat pipes in modern heat exchangers

    Microsoft Academic Search

    Leonard L. Vasiliev

    2005-01-01

    Heat pipes are very flexible systems with regard to effective thermal control. They can easily be implemented as heat exchangers inside sorption and vapour-compression heat pumps, refrigerators and other types of heat transfer devices. Their heat transfer coefficient in the evaporator and condenser zones is 103–105 W\\/m2K, heat pipe thermal resistance is 0.01–0.03 K\\/W, therefore leading to smaller area and

  15. Expert System For Heat Exchanger

    NASA Technical Reports Server (NTRS)

    Bagby, D. Gordon; Cormier, Reginald A.

    1991-01-01

    Diagnosis simplified for non-engineers. Developmental expert-system computer program assists operator in controlling, monitoring operation, diagnosing malfunctions, and ordering repairs of heat-exchanger system dissipating heat generated by 20-kW radio transmitter. System includes not only heat exchanger but also pumps, fans, sensors, valves, reservoir, and associated plumbing. Program conceived to assist operator while avoiding cost of keeping engineer in full-time attendance. Similar programs developed for heating, ventilating, and air-conditioning systems.

  16. Designing heat exchangers by computer

    Microsoft Academic Search

    Palen

    1986-01-01

    The design of heat exchangers by computer has come a long way in a short time due to the explosive development of computer hardware and the ingenuity of the software developers. It is already possible to design by computer a reasonably-sized heat exchanger for most services. However, the future potential is great for the computer to simulate performance for troubleshooting,

  17. Flow maldistribution in heat exchangers

    Microsoft Academic Search

    S. Lalot; P. Florent; S. K. Lang; A. E. Bergles

    1999-01-01

    Based on the study of gross flow maldistribution in an experimental electrical heater, this paper presents the effect of flow nonuniformity on the performance of heat exchangers. First, it is shown that it is much more important to understand maldistributions for electrical heaters than for two-fluid heat exchangers. The study of the flow distribution in a particular heater shows that

  18. High Temperature Heat Exchanger Project

    SciTech Connect

    Anthony E. Hechanova, Ph.D.

    2008-09-30

    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

  19. Reduced model simulations of the scrape-off-layer heat-flux width and comparison with experiment

    DOE PAGESBeta

    Myra, J. R. [Lodestar Research Corporation, Boulder, CO (United States); Russell, D. A. [Lodestar Research Corporation, Boulder, CO (United States); D'Ippolito, D. A. [Lodestar Research Corporation, Boulder, CO (United States); Ahn, J- W [Oak Ridge National Lab., TN (United States); Maingi, R. [Oak Ridge National Lab., TN (United States); Maqueda, R. J. [Princeton Plasma Physics Lab., NJ (United States); Lundberg, D. P. [Princeton Plasma Physics Lab., NJ (United States); Stotler, D. P. [Princeton Plasma Physics Lab., NJ (United States); Zweben, S. J. [Princeton Plasma Physics Lab., NJ (United States); Boedo, J. [Univ. of California at San Diego, CA (United States); Umansky, M. [Lawrence Livermore National Lab., Livermore, CA (United States)

    2011-01-10

    Reduced model simulations of turbulence in the edge and scrape-off-layer (SOL) region of a spherical torus or tokamak plasma are employed to address the physics of the scrape-off-layer heat flux width. The simulation model is an electrostatic two-dimensional fluid turbulence model, applied in the plane perpendicular to the magnetic field at the outboard midplane of the torus. The model contains curvature-driven-interchange modes, sheath losses, and both perpendicular turbulent diffusive and convective (blob) transport. These transport processes compete with classical parallel transport to set the SOL width. Midplane SOL profiles of density, temperature and parallel heat flux are obtained from the simulation and compared with experimental results from the National Spherical Torus Experiment (NSTX) [S. M. Kaye, et al., Phys. Plasmas 8, 1977 (2001)] to study the scaling of the heat flux width with power and plasma current. It is concluded that midplane turbulence is the main contributor to the SOL heat flux width for the low power H-mode discharges studied, while additional physics is required to explain the plasma current scaling of the SOL heat flux width observed experimentally in higher power discharges. Intermittent separatrix spanning convective cells are found to be the main mechanism that sets the near-SOL width in the simulations. The roles of sheared flows and blob trapping vs. emission are discussed.

  20. Modular heat exchanger

    DOEpatents

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

    1981-03-03

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

  1. Modular heat exchanger

    DOEpatents

    Giardina, A.R.

    1981-03-03

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

  2. 40 CFR 63.654 - Heat exchange systems.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...c) through (g) of this section if all heat exchangers within the heat exchange system either...heat exchange system. (ii) Selected heat exchanger exit line(s) so that each heat exchanger or group of heat exchangers within a...

  3. 40 CFR 63.654 - Heat exchange systems.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...c) through (g) of this section if all heat exchangers within the heat exchange system either...heat exchange system. (ii) Selected heat exchanger exit line(s) so that each heat exchanger or group of heat exchangers within a...

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

    SciTech Connect

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

    1998-07-01

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

  5. Heat exchanger with ceramic elements

    DOEpatents

    Corey, John A. (North Troy, NY)

    1986-01-01

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

  6. Heat exchanger using graphite foam

    SciTech Connect

    Campagna, Michael Joseph; Callas, James John

    2012-09-25

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

  7. Heat exchangers for low grade waste heat

    SciTech Connect

    Hay, E. [Nisymco Inc., Montreal, Quebec (Canada); Al-Witry, A.; Aroussi, A.; Hay, N. [Univ. of Nottingham (United Kingdom)

    1996-12-31

    The paper describes a user friendly computer program written for the design and optimization of roll bond aluminum heat exchangers and its validation against experimental test data. Test results for two different designs of heat exchanger panel, one serpentine and one dimple, are also given. The dimple design is shown to be superior to the serpentine one giving a 75% increase in heat transfer for a modest increase in pressure drop. Finally, a comparison of the economics of equivalent aluminum, stainless steel and titanium units for sea-water applications is presented.

  8. Evaluation of Surface Coatings on Heat Exchangers

    Microsoft Academic Search

    David J. Kukulka; Paul Leising

    Compact heat exchangers are very popular due to their relatively low cost, effectiveness and compactness. In many industries plate heat exchangers are being used to replace shell and tube heat exchangers. In order to utilize heat exchangers in dirty applications, coatings can be applied to the heat transfer surfaces to enhance effectiveness and minimize fouling. Coating selection is extremely important

  9. 4. Heat exchangers; Steam, steam processes

    E-print Network

    Zevenhoven, Ron

    1/74 4. Heat exchangers; Steam, steam processes Ron Zevenhoven Ã?bo Akademi University Thermal Engineering | 20500 Turku | Finland 2/74 4.1 Heat exchangers Ã?bo Akademi University | Thermal and Flow Engineering | 20500 Turku | Finland #12;3/74 Heat exchangers: General /1 In a heat exchanger heat

  10. Internal cooling of heat exchanger tubes

    SciTech Connect

    Chojnacki, D.; Huebner, S.; Mayers, R.

    1980-07-08

    A description is given of a method of injection of cooling media into a heat exchanger tube which comprises: injecting a controlled flow rate of gas into the heat exchanger tube; spraying a controlled flow rate of a fluid mist into each heat exchanger tube while maintaining a controlled gas flow rate into the heat exchanger tube; injecting a controlled flow rate of liquid into each heat exchanger tube.

  11. Heat exchanger demonstration expert system

    NASA Technical Reports Server (NTRS)

    Bagby, D. G.; Cormier, R. A.

    1988-01-01

    A real-time expert system intended for detecting and diagnosing faults in a 20 kW microwave transmitter heat exchanger is described. The expert system was developed on a LISP machine, Incorporated (LMI), Lambda Plus computer using Process Intelligent Control (PICON) software. The Heat Exhanger Expert System was tested and debugged. Future applications and extensions of the expert system to transmitters, masers, and antenna subassemblies are discussed.

  12. A gyrokinetic one-dimensional scrape-off layer model of an edge-localized mode heat pulse

    NASA Astrophysics Data System (ADS)

    Shi, E. L.; Hakim, A. H.; Hammett, G. W.

    2015-02-01

    An electrostatic gyrokinetic-based model is applied to simulate parallel plasma transport in the scrape-off layer to a divertor plate. The authors focus on a test problem that has been studied previously, using parameters chosen to model a heat pulse driven by an edge-localized mode in JET. Previous work has used direct particle-in-cell equations with full dynamics, or Vlasov or fluid equations with only parallel dynamics. With the use of the gyrokinetic quasineutrality equation and logical sheath boundary conditions, spatial and temporal resolution requirements are no longer set by the electron Debye length and plasma frequency, respectively. This test problem also helps illustrate some of the physics contained in the Hamiltonian form of the gyrokinetic equations and some of the numerical challenges in developing an edge gyrokinetic code.

  13. Lightweight long life heat exchanger

    NASA Technical Reports Server (NTRS)

    Moore, E. K.

    1975-01-01

    The design, fabrication, and evaluation of a full scale shuttle-type condensing heat exchanger constructed of aluminum and utilizing aluminum clad titanium parting sheets is described. A long term salt spray test of candidate parting sheet specimens is described. The results of an investigation into an alternate method of making composite sheet material are discussed.

  14. Ceramic heat exchanger

    SciTech Connect

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

    1998-01-01

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

  15. Ceramic heat exchanger

    DOEpatents

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

    1998-06-16

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

  16. Heat Exchanger Network Design, Monitoring and Optimization

    Microsoft Academic Search

    Uma Maheshwar Kiran Ati

    2009-01-01

    In process industries, heat exchanger networks represent an important part of the plant structure. The purpose of the networks is to maximize heat recovery, thereby lowering the overall plant costs. Previously published research on heat exchanger networks deals with two categories:\\u000a• Synthesis of heat exchanger networks with the goal of designing a structure that provides the lowest total (capital

  17. Experimental methods to determine heat exchanger performances

    NASA Astrophysics Data System (ADS)

    Marvillet, C.; Vidil, R.

    A heat exchanger test platform and experiments carried out thereon are described. The following studies are summarized: determination of the performances of a welded plate evaporator for a refrigeration unit; determination of the performance of a compact heat exchanger for gas turbine heat recovery; and determination of the performance of a fin and tube heat exchanger on diesel engine exhaust gases.

  18. Heat exchanger with oscillating flow

    NASA Technical Reports Server (NTRS)

    Scotti, Stephen J. (inventor); Blosser, Max L. (inventor); Camarda, Charles J. (inventor)

    1992-01-01

    Various heat exchange apparatuses are described in which an oscillating flow of primary coolant is used to dissipate an incident heat flux. The oscillating flow may be imparted by a reciprocating piston, a double action twin reciprocating piston, fluidic oscillators, or electromagnetic pumps. The oscillating fluid flows through at least one conduit in either an open loop or a closed loop. A secondary flow of coolant may be used to flow over the outer walls of at least one conduit to remove heat transferred from the primary coolant to the walls of the conduit.

  19. Heat exchanger with oscillating flow

    NASA Technical Reports Server (NTRS)

    Scotti, Stephen J. (inventor); Blosser, Max L. (inventor); Camarda, Charles J. (inventor)

    1993-01-01

    Various heat exchange apparatuses are described in which an oscillating flow of primary coolant is used to dissipate an incident heat flux. The oscillating flow may be imparted by a reciprocating piston, a double action twin reciprocating piston, fluidic oscillators or electromagnetic pumps. The oscillating fluid flows through at least one conduit in either an open loop or a closed loop. A secondary flow of coolant may be used to flow over the outer walls of at least one conduit to remove heat transferred from the primary coolant to the walls of the conduit.

  20. Air-Side Heat Transfer in Finned Tube Heat Exchangers

    Microsoft Academic Search

    R. L. WEBB

    1980-01-01

    Because of the low heat transfer coefficient of gases, it is necessary to use extended surfaces on the gas side when exchanging heat with liquids or two-phase fluids. Such finned tube exchangers are a very important basic class of heat exchangers. Although finned tube exchangers have been in existence for 50 yr, there have been numerous developments in the technology.

  1. Oxidizer heat exchanger component test

    NASA Technical Reports Server (NTRS)

    Kanic, P. G.

    1988-01-01

    The RL10-IIB engine, is capable of multimode thrust operation. The engine operates at two low-thrust levels: tank head idle (THI), approximately 1 to 2 percent of full thrust; and pumped idle, 10 percent of full thrust. Operation at THI provides vehicle propellant settling thrust and efficient thermal conditioning; PI operation provides vehicle tank prepressurization and maneuver thrust for low-g deployment. Stable combustion of the RL10-IIB engine during the low-thrust operating modes can be accomplished by using a heat exchanger to supply gaseous oxygen to the propellant injector. The oxidized heat exchanger (OHE) vaporizes the liquid oxygen using hydrogen as the energy source. This report summarizes the test activity and post-test data analysis for two possible heat exchangers, each of which employs a completely different design philosophy. One design makes use of a low-heat transfer (PHT) approach in combination with a volume to attenuate pressure and flow oscillations. The test data showed that the LHT unit satisfied the oxygen exit quality of 0.95 or greater in both the THI and PI modes while maintaining stability. The HHT unit fulfilled all PI requirements; data for THI satisfactory operation is implied from experimental data that straddle the exact THI operating point.

  2. Synergistic diffuser/heat-exchanger design

    E-print Network

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

    2004-01-01

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

  3. Heat Exchanger Fouling- Prediction, Measurement and Mitigation

    E-print Network

    Peterson, G. R.

    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...

  4. Second Law Optimization of Heat Exchangers

    E-print Network

    Witte, L. C.

    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...

  5. Integrated Approach to Revamping Heat Exchangers Networks

    E-print Network

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

    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...

  6. Pressurized bellows flat contact heat exchanger interface

    NASA Technical Reports Server (NTRS)

    Voss, Fred E. (inventor); Howell, Harold R. (inventor); Winkler, Roger V. (inventor)

    1990-01-01

    Disclosed is an interdigitated plate-type heat exchanger interface. The interface includes a modular interconnect to thermally connect a pair or pairs of plate-type heat exchangers to a second single or multiple plate-type heat exchanger. The modular interconnect comprises a series of parallel, plate-type heat exchangers arranged in pairs to form a slot therebetween. The plate-type heat exchangers of the second heat exchanger insert into the slots of the modular interconnect. Bellows are provided between the pairs of fins of the modular interconnect so that when the bellows are pressurized, they drive the plate-type heat exchangers of the modular interconnect toward one another, thus closing upon the second heat exchanger plates. Each end of the bellows has a part thereof a thin, membrane diaphragm which readily conforms to the contours of the heat exchanger plates of the modular interconnect when the bellows is pressurized. This ensures an even distribution of pressure on the heat exchangers of the modular interconnect thus creating substantially planar contact between the two heat exchangers. The effect of the interface of the present invention is to provide a dry connection between two heat exchangers whereby the rate of heat transfer can be varied by varying the pressure within the bellows.

  7. A New Design of Heat Exchanger

    Microsoft Academic Search

    D. L. Astanovskii; L. Z. Astanovskii

    2003-01-01

    Broad use of heat exchangers in various branches of industry, in transportation, and in everyday living predetermines continued improvement of these designs to intensify the heat-exchange process and lower costs. Moreover, it is necessary to ensure: • the possibility of conducting the heat-exchange process with large pressure and temperature gradients in the heat-exchange medium, and over a broad range of

  8. Empirical scalings of cross-field heat diffusivities in the scrape-off layer of Alcator C-Mod from a 2-D interpretive model

    Microsoft Academic Search

    M. V. Umansky; B LaBombard

    1999-01-01

    A new 2-D interpretive code for the tokamak edge plasma, EDGEFIT, has been developed. It infers the anomalous cross-field heat diffusivity, ?, in the scrape-off layer (SOL) of Alcator C-Mod from the experimental data solving the heat conduction equation in the real magnetic geometry. Measurements of temperature from the Langmuir probes on the divertor target plates are used for setting

  9. 21 CFR 870.4240 - Cardiopulmonary bypass heat exchanger.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...false Cardiopulmonary bypass heat exchanger. 870.4240 Section 870...4240 Cardiopulmonary bypass heat exchanger. (a) Identification. A cardiopulmonary bypass heat exchanger is a device, consisting...

  10. 21 CFR 870.4240 - Cardiopulmonary bypass heat exchanger.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...false Cardiopulmonary bypass heat exchanger. 870.4240 Section 870...4240 Cardiopulmonary bypass heat exchanger. (a) Identification. A cardiopulmonary bypass heat exchanger is a device, consisting...

  11. 21 CFR 870.4240 - Cardiopulmonary bypass heat exchanger.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...false Cardiopulmonary bypass heat exchanger. 870.4240 Section 870...4240 Cardiopulmonary bypass heat exchanger. (a) Identification. A cardiopulmonary bypass heat exchanger is a device, consisting...

  12. 21 CFR 870.4240 - Cardiopulmonary bypass heat exchanger.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...false Cardiopulmonary bypass heat exchanger. 870.4240 Section 870...4240 Cardiopulmonary bypass heat exchanger. (a) Identification. A cardiopulmonary bypass heat exchanger is a device, consisting...

  13. 21 CFR 870.4240 - Cardiopulmonary bypass heat exchanger.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...false Cardiopulmonary bypass heat exchanger. 870.4240 Section 870...4240 Cardiopulmonary bypass heat exchanger. (a) Identification. A cardiopulmonary bypass heat exchanger is a device, consisting...

  14. Heat exchanger expert system logic

    NASA Technical Reports Server (NTRS)

    Cormier, R.

    1988-01-01

    The reduction is described of the operation and fault diagnostics of a Deep Space Network heat exchanger to a rule base by the application of propositional calculus to a set of logic statements. The value of this approach lies in the ease of converting the logic and subsequently implementing it on a computer as an expert system. The rule base was written in Process Intelligent Control software.

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

    SciTech Connect

    Culver, G.

    1990-11-01

    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.

  16. Ceramic heat exchanger design methodology. Final report

    Microsoft Academic Search

    1984-01-01

    This document describes the methodology employed by Solar Turbines Incorporated in designing a high pressure, ceramic heat exchanger test module. The unit was designed and fabricated to demonstrate and advance the use of structural ceramics in a typical industrial heat exchanger configuration. The specific configuration adopted is an axial-counterflow unit with ceramic tube heat exchanger elements and a ceramic exhaust

  17. Cryogenic Heat Exchanger with Turbulent Flows

    ERIC Educational Resources Information Center

    Amrit, Jay; Douay, Christelle; Dubois, Francis; Defresne, Gerard

    2012-01-01

    An evaporator-type cryogenic heat exchanger is designed and built for introducing fluid-solid heat exchange phenomena to undergraduates in a practical and efficient way. The heat exchanger functions at liquid nitrogen temperature and enables cooling of N[subscript 2] and He gases from room temperatures. We present first the experimental results of…

  18. Towards a new generation heat exchanger models

    Microsoft Academic Search

    Geert W. Haarlemmer; Jérôme Pigourier

    2008-01-01

    In the quest for more dependable process models, attending to small detail and integrating increasing their internal complexity will improve dynamic behavior and simulation accuracy. Although detailed heat exchanger models in dedicated steady state design programs are common, steady state process models and dynamic simulations have been based largely on shorteut heat exchanger calculations. However, detailed heat exchanger models can

  19. MODELING PARTICLE DEPOSITION ON HVAC HEAT EXCHANGERS

    E-print Network

    LBNL-49339 MODELING PARTICLE DEPOSITION ON HVAC HEAT EXCHANGERS J.A. Siegel1,3 * and W.W. Nazaroff2 Fouling of fin-and-tube heat exchangers by particle deposition leads to diminished effectiveness on heat exchanger surfaces. We present a model that accounts for impaction, diffusion, gravitational

  20. Performance of a variable conductance heat pipe heat exchanger

    Microsoft Academic Search

    P. D. Chancelor

    1983-01-01

    The performance of an air to air heat exchanger in which heat is transferred to a finned evaporator and from a finned condenser via a heat pipe was evaluated. The variable conductance heat pipe is to the condenser fins a heat source and to the evaporator fins a heat sink. The principal advantage of the variable conductance heat pipe heat

  1. Finned Small Diameter Tube Heat Exchanger

    NASA Astrophysics Data System (ADS)

    Dang, Chaobin; Daiguji, Hirofumi; Hihara, Eiji; Tokunaga, Masahide

    The performance of fined small tube heat exchangers was investigated both experimentally and theoretically. The Inner diameters of tubes were 1.0mm, 2.1mm and 4.0mm. Exchanged heat and pressure drop obtained from numerical simulation agreed well with the experimental ones. Calculation results show that the volume of a 2.0mm tube heat exchanger can be reduced to 33% of that of a 4mm tube heat exchanger with the same capacity. In addition the distribution of two-phase flow in a branching unit was investigated by measuring downstream temperature distribution. The flow distribution in a branching unit strongly affects the exchanged heat.

  2. Fluidized bed heat exchanger utilizing angularly extending heat exchange tubes

    DOEpatents

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

    1980-01-01

    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.

  3. Heat Exchanger Technologies for Distillation Columns

    E-print Network

    Polley, G. T.

    Heat Exchanger Technologies for Distillation Columns G.T.Polley Pinchtechnology.com In this paper we look at the challenges that improvements in energy efficiency of distillation systems presents the heat exchanger designer. We examine... each type of exchanger in turn. Heat exchanger size is minimised if the temperature driving force is maximised. The design should therefore seek to minimise the temperature changes during phase change. So, streams that are being condensed are kept...

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

    SciTech Connect

    Piyush Sabharwall; Mike Patterson; Vivek Utgikar; Fred Gunnerson

    2008-09-01

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

  5. Determining the best type of heat exchangers for heat recovery

    Microsoft Academic Search

    ?smail Teke; Özden A?ra; ?. Özgür Atay?lmaz; Hakan Demir

    2010-01-01

    It is a common problem to choose the most appropriate heat exchanger configuration for heat recovery. In this study, a new model has been developed for determining the area and type of the most appropriate waste heat recovery heat exchanger for maximum net gain. A non-dimensional E number has been defined based on known technical and economic parameters such as

  6. FEM analysis of multifluid heat exchangers

    Microsoft Academic Search

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

    2004-01-01

    Heat exchangers are devices for exchanging energy between two or more fluids. They find applications in various industries like power, process, electronics, refining, cryogenics, chemicals, metals and manufacturing sector. Even though heat exchanger designs have been reported quite extensively, they are generally limited to steady-state performance, single phase fluids, a few of the many possible flow arrangements and only two

  7. Testing and analysis of immersed heat exchangers

    SciTech Connect

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

    1986-08-01

    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.

  8. Improved ceramic heat exchange material

    NASA Technical Reports Server (NTRS)

    Mccollister, H. L.

    1977-01-01

    Improved corrosion resistant ceramic materials that are suitable for use as regenerative heat exchangers for vehicular gas turbines is reported. Two glass-ceramic materials, C-144 and C-145, have superior durability towards sulfuric acid and sodium sulfate compared to lithium aluminosilicate (LAS) Corning heat exchange material 9455. Material C-144 is a leached LAS material whose major crystalline phase is silica keatite plus mullite, and C-145 is a LAS keatite solid solution (S.S.) material. In comparison to material 9455, material C-144 is two orders of magnitude better in dimensional stability to sulfuric acid at 300 C, and one order of magnitude better in stability to sodium sulfate at 1000 C. Material C-145 is initially two times better in stability to sulfuric acid, and about one order of magnitude better in stability to sodium sulfate. Both C-144 and C-145 have less than 300 ppm delta L/L thermal expansion from ambient to 1000 C, and good dimensional stability of less than approximately 100 ppm delta L/L after exposure to 1000 C for 100 hours. The glass-ceramic fabrication process produced a hexagonal honeycomb matrix having an 85% open frontal area, 50 micrometer wall thickness, and less than 5% porosity.

  9. Application of heat flux transducers to determine perioperative heat exchange

    Microsoft Academic Search

    T. Perl; A. Bräuer; W. Weyland; U. Braun

    2004-01-01

    Perioperative hypothermia is a common problem in anaesthesia. To maintain a constant body heat content it is necessary to achieve a steady state of metabolic heat production and external heat exchange. During anaesthesia and surgery this balance is disturbed. The heat production is decreased to a level below resting metabolic heat production while heat losses increase due to the surgical

  10. Graphite Foam Heat Exchangers for Thermal Management

    Microsoft Academic Search

    Klett

    2004-01-01

    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

  11. Waste heat exchanger increases efficiency, reduces cost

    Microsoft Academic Search

    J. D. Brady; J. S. Crews

    1985-01-01

    This article describes how after one year of continuous operation, a waste heat exchanger system has proven to be an effective means of reducing fuel consumption and operating costs for a steam generator. At maximum boiler firing conditions, the exchanger increases heat absorption by 8.9% on oil and by 8.0% on natural gas. To serve adequately for waste heat recovery

  12. Solar energy collector and heat exchanger

    Microsoft Academic Search

    Pyle

    1979-01-01

    A solar energy collector and heat exchanger for use in a solar energy system that provides space heating and preheating of water for a building or residence is disclosed. The solar collector and heat exchanger comprises a rectangularly shaped, box-like housing. A thermal pane glass panel covers the top of the housing and permits radiant energy to pass therethrough to

  13. Oxidizer heat exchanger component testing

    NASA Technical Reports Server (NTRS)

    Kmiec, T.; Kanic, P.

    1986-01-01

    As part of the RL10 Rocket Engine Product Improvement Program, Oxidizer Heat Exchanger (OHE) stages 1, 2, and 3 were designed and fabricated during late 1983 and early 1984. The purpose of the OHE is to provide gaseous oxygen to the propellant injector for stable engine operation at tank head idle and pumped idle operating modes. This report summarizes the OHE stages 1 and 3 rig testing, and includes the separation of the stage 1-and-2 assembly and the remanifolding of stage 1. The OHE performance analysis and analytical model modifications for both stages are also presented. The flow tests were accomplished during the time period from 9 October 1984 to 12 November 1984.

  14. Advanced Micro-Heat Exchangers for High Heat Flux

    Microsoft Academic Search

    Chien-Yuh Yang; Chun-Ta Yeh; Wei-Chi Liu; Bing-Chwen Yang

    2007-01-01

    Three micro-heat exchangers for use in a liquid cooling system with a long offset strip, short offset strip, and chevron flow path based on the traditional heat transfer enhancement concepts were designed and tested. A straight channel heat exchanger was also made for comparison. The liquid crystal thermography method described by Lin and Yang (2005) was used to observe the

  15. High temperature heat exchange: nuclear process heat applications

    SciTech Connect

    Vrable, D.L.

    1980-09-01

    The unique element of the HTGR system is the high-temperature operation and the need for heat exchanger equipment to transfer nuclear heat from the reactor to the process application. This paper discusses the potential applications of the HTGR in both synthetic fuel production and nuclear steel making and presents the design considerations for the high-temperature heat exchanger equipment.

  16. Probe Measures Fouling As In Heat Exchangers

    NASA Technical Reports Server (NTRS)

    Marner, Wilbur J.; Macdavid, Kenton S.

    1990-01-01

    Combustion deposits reduce transfer of heat. Instrument measures fouling like that on gas side of heat exchanger in direct-fired boiler or heat-recovery system. Heat-flux probe includes tube with embedded meter in outer shell. Combustion gases flow over probe, and fouling accumulates on it, just as fouling would on heat exchanger. Embedded heat-flow meter is sandwich structure in which thin Chromel layers and middle alloy form thermopile. Users determine when fouling approaches unacceptable levels so they schedule cleaning and avoid decreased transfer of heat and increased drop in pressure fouling causes. Avoids cost of premature, unnecessary maintenance.

  17. Heat exchanger for power generation equipment

    DOEpatents

    Nirmalan, Nirm Velumylm; Bowman, Michael John

    2005-06-14

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

  18. A hybrid methodology for detailed heat exchanger design in the optimal synthesis of heat exchanger networks

    Microsoft Academic Search

    J. M. García; J. M. Ponce; M. Serna

    2006-01-01

    This paper presents a hybrid method for the synthesis and optimization of heat exchanger networks, which includes detailed design of heat exchangers. This task is achieved by combining the pinch design method with mathematical programming techniques, together with an optimal design algorithm of shell and tube heat exchangers based on the rigorous Bell-Delaware method. As result, the stream pressure drops

  19. Experience with borehole heat exchangers in Switzerland

    Microsoft Academic Search

    L. Rybach; R. J. Hopkirk

    1994-01-01

    Switzerland undertakes, like many other countries, great efforts to reduce its dependence from foreign fossil fuels. Indigenous sources of energy like the heat content of the subsurface are especially in focus, also due to environmental concern (greenhouse effect due to COâ emissions). The most popular and technically advanced space heating system to use ground heat is the borehole heat exchanger

  20. Industrial heat exchangers: Types and functions

    Microsoft Academic Search

    R. K. Shah

    1991-01-01

    Types and functions of industrial heat exchangers are detailed with classifications according to the transfer processes, number of fluids, degree of surface compactness, construction features, flow arrangements, and heat transfer mechanisms. The terminology associated with a variety of these exchangers is introduced and practical applications are outlined.

  1. Evolution of Heat Exchanger Design Techniques

    Microsoft Academic Search

    Jerry Taborek

    1979-01-01

    The principles of ‘ rating’ and ‘ design ’ of shell-and-tube heat exchangers are described as they developed from manual type methods to computerized applications. Criteria for initial design considerations, identification of limiting cases, and analysis of intermediate and final designs are described in sufficient detail to serve as a guide for heat exchanger designers. Future developments in the art

  2. Thermodynamic Efficiency of Heat Exchange Devices

    E-print Network

    Witte, L. C.; Shamsundar, N.

    1982-01-01

    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...

  3. Modeling of Heat Transfer in Geothermal Heat Exchangers

    E-print Network

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

    2006-01-01

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

  4. Brazed plate heat exchangers for geothermal applications

    SciTech Connect

    Rafferty, K. (Geo-Heat Center, Klamath Falls, OR (United States))

    1993-08-01

    Most geothermal fluids used for direct use purposes contain various chemical species which can be detrimental to conventional materials of construction. For this reason, the standard design practice is to isolate the geothermal fluid from the balance of the system through the use of a heat exchanger. In the majority of applications, the plate and frame heat exchanger has been the design of choice for this duty. Recently, a low-cost version of the plate heat exchanger, the brazed plate heat exchanger has become available. Due to their simpler construction these units can be economically produced in very small sizes. Considering the reduced cost these exchangers could greatly enhance the economics of small direct use geothermal systems. Brazed plate heat exchangers 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[degrees]F or greater. Size limitations restrict applications to 100 gpm and/or 200 ft[sup 2] heat transfer surface area. 7 refs., 7 figs., 2 tabs.

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

    E-print Network

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

  6. Solar greenhouse heating using an underground heat exchange system

    Microsoft Academic Search

    T. Masao; D. Kiyoshi; O. Toshiaki; O. Yoshihiro

    1982-01-01

    The air temperature in a greenhouse on a sunny day often exceeds the optimum temperature level for the growth of crops. Therefore, there are frequent occasions when it becomes necessary to discharge the excess heat. This has given rise to the development by some investigators of an underground heat exchange system for heating greenhouses which utilizes this excess heat. The

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

    DOEpatents

    Koplow, Jeffrey P

    2013-12-10

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

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

    SciTech Connect

    Koplow, Jeffrey P. (San Ramon, CA)

    2012-07-24

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

  9. Phase Change Material Heat Exchanger Life Test

    NASA Technical Reports Server (NTRS)

    Lillibridge, Sean; Stephan, Ryan; Lee, Steve; He, Hung

    2008-01-01

    Low Lunar Orbit (LLO) poses unique thermal challenges for the orbiting space craft, particularly regarding the performance of the radiators. The emitted infrared (IR) heat flux from the lunar surface varies drastically from the light side to the dark side of the moon. Due to the extremely high incident IR flux, especially at low beta angles, a radiator is oftentimes unable to reject the vehicle heat load throughout the entire lunar orbit. One solution to this problem is to implement Phase Change Material (PCM) Heat Exchangers. PCM Heat Exchangers act as a "thermal capacitor," storing thermal energy when the radiator is unable to reject the required heat load. The stored energy is then removed from the PCM heat exchanger when the environment is more benign. Because they do not use an expendable resource, such as the feed water used by sublimators and evaporators, PCM Heat Exchangers are ideal for long duration Low Lunar Orbit missions. The Advanced Thermal Control project at JSC is completing a PCM heat exchanger life test to determine whether further technology development is warranted. The life test is being conducted on four nPentadecane, carbon filament heat exchangers. Fluid loop performance, repeatability, and measurement of performance degradation over 2500 melt-freeze cycles will be performed and reported in the current document.

  10. Heat exchanger saves $400,000 in waste heat recovery

    Microsoft Academic Search

    L. Confer; K. L. Kramer

    1987-01-01

    A condensing type heat exchanger operating at Henkel Corporation's plant in Kankakee, IL, has enabled the plant to save $400,000 in energy costs within the first 22 months of operation, recouping the initial capital investment for the unit within that time frame. The heat exchanger enables the plant to accomplish what historically was considered taboo - to cool boiler stack

  11. Heat exchanger, head and shell acceptance criteria

    SciTech Connect

    Lam, P.S.; Sindelar, R.L.

    1992-09-01

    Instability of postulated flaws in the head component of the heat exchanger could not produce a large break, equivalent to a DEGB in the PWS piping, due to the configuration of the head and restraint provided by the staybolts. Rather, leakage from throughwall flaws in the head would increase with flaw length with finite leakage areas that are bounded by a post-instability flaw configuration. Postulated flaws at instability in the shell of the heat exchanger or in the cooling water nozzles could produce a large break in the Cooling Water System (CWS) pressure boundary. An initial analysis of flaw stability for postulated flaws in the heat exchanger head was performed in January 1992. This present report updates that analysis and, additionally, provides acceptable flaw configurations to maintain defined structural or safety margins against flaw instability of the external pressure boundary components of the heat exchanger, namely the head, shell, and cooling water nozzles. Structural and flaw stability analyses of the heat exchanger tubes, the internal pressure boundary of the heat exchangers or interface boundary between the PWS and CWS, were previously completed in February 1992 as part of the heat exchanger restart evaluation and are not covered in this report.

  12. Controlling Heat-Exchanger Outlet Temperature

    NASA Technical Reports Server (NTRS)

    Daniels, C. M.

    1983-01-01

    Nearly constant temperature maintained regardless of fluid flow. Mixing heated and unheated fluids ensures constant temperature at outlet of heat exchanger. Main stream fluid heated, and bypass fluid unheated. Devised to maintain constant-temperature output under varying flow rates. Used with fluids other than liquid oxygen - water for example.

  13. 40 CFR 63.1328 - Heat exchange systems provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 true Heat exchange systems provisions. 63.1328...IV Polymers and Resins § 63.1328 Heat exchange systems provisions. ...subpart. (h) The compliance date for heat exchange systems subject to the...

  14. 14 CFR 23.1125 - Exhaust heat exchangers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 false Exhaust heat exchangers. 23.1125 Section 23...System § 23.1125 Exhaust heat exchangers. For reciprocating engine...apply: (a) Each exhaust heat exchanger must be constructed and...

  15. 14 CFR 23.1125 - Exhaust heat exchangers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 false Exhaust heat exchangers. 23.1125 Section 23...System § 23.1125 Exhaust heat exchangers. For reciprocating engine...apply: (a) Each exhaust heat exchanger must be constructed and...

  16. 40 CFR 63.1435 - Heat exchanger provisions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Heat exchanger provisions. 63.1435 Section...Polyols Production § 63.1435 Heat exchanger provisions. (a) The owner...requirements of § 63.104 for heat exchange systems, with the...

  17. 14 CFR 23.1125 - Exhaust heat exchangers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 false Exhaust heat exchangers. 23.1125 Section 23...System § 23.1125 Exhaust heat exchangers. For reciprocating engine...apply: (a) Each exhaust heat exchanger must be constructed and...

  18. 40 CFR 63.1435 - Heat exchanger provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 true Heat exchanger provisions. 63.1435 Section...Polyols Production § 63.1435 Heat exchanger provisions. (a) The owner...requirements of § 63.104 for heat exchange systems, with the...

  19. 14 CFR 29.1125 - Exhaust heat exchangers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 false Exhaust heat exchangers. 29.1125 Section 29...System § 29.1125 Exhaust heat exchangers. For reciprocating engine...apply: (a) Each exhaust heat exchanger must be constructed and...

  20. 40 CFR 63.1435 - Heat exchanger provisions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2011-07-01 true Heat exchanger provisions. 63.1435 Section...Polyols Production § 63.1435 Heat exchanger provisions. (a) The owner...requirements of § 63.104 for heat exchange systems, with the...

  1. 14 CFR 29.1125 - Exhaust heat exchangers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 false Exhaust heat exchangers. 29.1125 Section 29...System § 29.1125 Exhaust heat exchangers. For reciprocating engine...apply: (a) Each exhaust heat exchanger must be constructed and...

  2. 14 CFR 25.1125 - Exhaust heat exchangers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 false Exhaust heat exchangers. 25.1125 Section 25...System § 25.1125 Exhaust heat exchangers. For reciprocating engine...apply: (a) Each exhaust heat exchanger must be constructed and...

  3. 14 CFR 29.1125 - Exhaust heat exchangers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 false Exhaust heat exchangers. 29.1125 Section 29...System § 29.1125 Exhaust heat exchangers. For reciprocating engine...apply: (a) Each exhaust heat exchanger must be constructed and...

  4. 14 CFR 25.1125 - Exhaust heat exchangers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 false Exhaust heat exchangers. 25.1125 Section 25...System § 25.1125 Exhaust heat exchangers. For reciprocating engine...apply: (a) Each exhaust heat exchanger must be constructed and...

  5. 40 CFR 63.1435 - Heat exchanger provisions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Heat exchanger provisions. 63.1435 Section...Polyols Production § 63.1435 Heat exchanger provisions. (a) The owner...requirements of § 63.104 for heat exchange systems, with the...

  6. 14 CFR 25.1125 - Exhaust heat exchangers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 false Exhaust heat exchangers. 25.1125 Section 25...System § 25.1125 Exhaust heat exchangers. For reciprocating engine...apply: (a) Each exhaust heat exchanger must be constructed and...

  7. 14 CFR 29.1125 - Exhaust heat exchangers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 false Exhaust heat exchangers. 29.1125 Section 29...System § 29.1125 Exhaust heat exchangers. For reciprocating engine...apply: (a) Each exhaust heat exchanger must be constructed and...

  8. 14 CFR 23.1125 - Exhaust heat exchangers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 false Exhaust heat exchangers. 23.1125 Section 23...System § 23.1125 Exhaust heat exchangers. For reciprocating engine...apply: (a) Each exhaust heat exchanger must be constructed and...

  9. 14 CFR 25.1125 - Exhaust heat exchangers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 false Exhaust heat exchangers. 25.1125 Section 25...System § 25.1125 Exhaust heat exchangers. For reciprocating engine...apply: (a) Each exhaust heat exchanger must be constructed and...

  10. 14 CFR 23.1125 - Exhaust heat exchangers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 false Exhaust heat exchangers. 23.1125 Section 23...System § 23.1125 Exhaust heat exchangers. For reciprocating engine...apply: (a) Each exhaust heat exchanger must be constructed and...

  11. 14 CFR 29.1125 - Exhaust heat exchangers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 false Exhaust heat exchangers. 29.1125 Section 29...System § 29.1125 Exhaust heat exchangers. For reciprocating engine...apply: (a) Each exhaust heat exchanger must be constructed and...

  12. 14 CFR 25.1125 - Exhaust heat exchangers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 false Exhaust heat exchangers. 25.1125 Section 25...System § 25.1125 Exhaust heat exchangers. For reciprocating engine...apply: (a) Each exhaust heat exchanger must be constructed and...

  13. 40 CFR 63.1435 - Heat exchanger provisions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Heat exchanger provisions. 63.1435 Section...Polyols Production § 63.1435 Heat exchanger provisions. (a) The owner...requirements of § 63.104 for heat exchange systems, with the...

  14. Microchannel heat exchangers for advanced climate control

    NASA Astrophysics Data System (ADS)

    Martin, Peter M.; Bennett, Wendy D.; Johnston, John W.

    1995-09-01

    This paper presents details of fabrication and performance testing of prototype microchannel heat exchangers. The microchannel heat exchangers are being developed for advanced cooling and climate control applications, and are designed for heat loads of 100 W/cm2. Bulk and surface micromachining techniques are used to fabricate the test devices. Each heat exchanger section consists of over 150 microchannels etched in silicon substrates by either chemical etching or ion milling processes. The channels are 100-micrometers deep, 100-micrometers wide, and spaced 50- to 100-micrometers apart and connected with headers. Other heat exchangers have also been fabricated in copper and aluminum using machining and ion milling processes. Process steps involved photolithographic patterning, deposition of etch masks, ion or chemical etching, electrostatic bonding of the silicon to glass, insulator deposition, lamination of silicon to metals, application of thin heater coatings with busbars, and installation of the inlet/outlet hardware and valves. Recent hear exchangers have the silicon laminated to copper substrates. Performance testing focuses on determining the performance characteristics of the microchannel heat exchangers over a wide range of flow and heat transfer conditions. The working fluid for heat transfer is restricted to water or SUVA refrigerant HCFC-124 (R-124). Testing with water is run under single-phase conditions. The tests with R-124 are run under single-and two-phase flow conditions.

  15. Heat Exchanger Support Bracket Design Calculations

    SciTech Connect

    Rucinski, Russ; /Fermilab

    1995-01-12

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

  16. Heat exchanger with transpired, highly porous fins

    DOEpatents

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

    2002-01-01

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

  17. Heat transfer coefficients of shell and coiled tube heat exchangers

    Microsoft Academic Search

    M. R. Salimpour

    2009-01-01

    In the present study, the heat transfer coefficients of shell and helically coiled tube heat exchangers were investigated experimentally. Three heat exchangers with different coil pitches were selected as test section for both parallel-flow and counter-flow configurations. All the required parameters like inlet and outlet temperatures of tube-side and shell-side fluids, flow rate of fluids, etc. were measured using appropriate

  18. Fireplace heat exchanger apparatus and method

    SciTech Connect

    Faustini, C.

    1983-05-03

    A fireplace heat exchanger apparatus and method utilizes a tubular grate for holding fuel to be burned having a bottom portion for collecting a liquid such that the liquid will be vaporized by the heat from the fuel burned in the grate and carried into a space to be heated by air forced through the tubular grate to substantially increase the amount of heat obtained from burning of fuel.

  19. Condensing Heat Exchangers Optimize Steam Boilers

    E-print Network

    Sullivan, B.; Sullivan, P. A.

    1983-01-01

    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...

  20. Experimental comparison of heat transfer enhancement methods in heat exchangers

    Microsoft Academic Search

    Hosni I. Abu-Mulaweh

    This paper presents an experimental comparison of four different types of heat transfer enhancement techniques or methods in heat exchangers: two insert devices (a displacement device and a swirl flow device), extended surfaces, and obstruction devices. The objective of these experiments is to assist undergraduate mechanical engineering students in understanding the basic heat transfer processes and the methods and devices

  1. Degradation Monitoring of Industrial Heat Exchangers

    Microsoft Academic Search

    B R Upadhyayaa; E. Eryurekb

    This paper presents the results of monitoring device-level and system-level faults in industrial heat exchangers. The device-level\\u000a faults refer to degradation of sensors and control actuators. In the case of heat exchanger (HX) studies presented here, system-level\\u000a fault refers to fouling of HX tubing during plant operation. The objective of the research performed at The University of\\u000a Tennessee was to

  2. Joule-Thomson expander and heat exchanger

    NASA Technical Reports Server (NTRS)

    Norman, R. H.

    1976-01-01

    The Joule-Thomson Expander and Heat Exchanger Program was initiated to develop an assembly (JTX) which consists of an inlet filter, counterflow heat exchanger, Joule-Thomson expansion device, and a low pressure jacket. The program objective was to develop a JTX which, when coupled to an open cycle supercritical helium refrigerating system (storage vessel), would supply superfluid helium (He II) at 2 K or less for cooling infrared detectors.

  3. The role of parallel heat transport in the relation between upstream scrape-off layer widths and target heat flux width in H-mode plasmas of NSTX.

    SciTech Connect

    Ahn, J W; Boedo, J A; Maingi, R; Soukhanovskii, V A

    2009-01-05

    The physics of parallel heat transport was tested in the Scrape-off Layer (SOL) plasma of the National Spherical Torus Experiment (NSTX) [M. Ono, et al., Nucl. Fusion 40, 557 (2000) and S. M. Kaye, et al., Nucl. Fusion 45, S168 (2005)] tokamak by comparing the upstream electron temperature (T{sub e}) and density (n{sub e}) profiles measured by the mid-plane reciprocating probe to the heat flux (q{sub {perpendicular}}) profile at the divertor plate measured by an infrared (IR) camera. It is found that electron conduction explains the near SOL width data reasonably well while the far SOL, which is in the sheath limited regime, requires an ion heat flux profile broader than the electron one to be consistent with the experimental data. The measured plasma parameters indicate that the SOL energy transport should be in the conduction-limited regime for R-R{sub sep} (radial distance from the separatrix location) < 2-3 cm. The SOL energy transport should transition to the sheath-limited regime for R-R{sub sep} > 2-3cm. The T{sub e}, n{sub e}, and q{sub {perpendicular}} profiles are better described by an offset exponential function instead of a simple exponential. The conventional relation between mid plane electron temperature decay length ({lambda}{sub Te}) and target heat flux decay length ({lambda}{sub q}) is {lambda}{sub Te} = 7/2{lambda}{sub q}, whereas the newly-derived relation, assuming offset exponential functional forms, implies {lambda}{sub Te} = (2-2.5){lambda}{sub q}. The measured values of {lambda}{sub Te}/{lambda}{sub q} differ from the new prediction by 25-30%. The measured {lambda}{sub q} values in the far SOL (R-R{sub sep} > 2-3cm) are 9-10cm, while the expected values are 2.7 < {lambda}{sub q} < 4.9 cm (for sheath-limited regime). We propose that the ion heat flux profile is substantially broader than the electron heat flux profile as an explanation for this discrepancy in the far SOL.

  4. Brayton-cycle heat exchanger technology program

    NASA Technical Reports Server (NTRS)

    Killackey, J. J.; Coombs, M. G.; Graves, R. F.; Morse, C. J.

    1976-01-01

    The following five tasks designed to advance this development of heat exchanger systems for close loop Brayton cycle power systems are presented: (1) heat transfer and pressure drop data for a finned tubular heat transfer matrix. The tubes are arranged in a triangular array with copper stainless steel laminate strips helically wound on the tubes to form a disk fin geometry; (2) the development of a modularized waste heat exchanger. Means to provide verified double containment are described; (3) the design, fabrication, and test of compact plate fin heat exchangers representative of full scale Brayton cycle recuperators; (4) the analysis and design of bellows suitable for operation at 1600 F and 200 psia for 1,000 cycles and 50,000 hours creep life; and (5) screening tests used to select a low cost braze alloy with the desirable attributes of a gold base alloy. A total of 22 different alloys were investigated; the final selection was Nicrobraz 30.

  5. Comparison of heat transfer rates between a straight tube heat exchanger and a helically coiled heat exchanger

    Microsoft Academic Search

    D. G. Prabhanjan; G. S. V. Raghavan; T. J. Rennie

    2002-01-01

    The purpose of this study was to determine the relative advantage of using a helically coiled heat exchanger versus a straight tube heat exchanger for heating liquids. The particular difference in this study compared to other similar studies was the boundary conditions for the helical coil. Most studies focus on constant wall temperature or constant heat flux, whereas in this

  6. Heat transfer from oriented heat exchange areas

    NASA Astrophysics Data System (ADS)

    Vantuch, Martin; Huzvar, Jozef; Kapjor, Andrej

    2014-03-01

    This paper deals with the transfer of heat-driven heat transfer surface area in relation to the construction of the criterion equation for "n" horizontal pipe one about another. On the bases of theoretical models have been developed for calculating the thermal performance of natural convection by Churilla and Morgan, for various pipe diameters and temperatures. These models were compared with models created in CFD-Fluent Ansys the same boundary conditions. The aim of the analyse of heat and fluxional pipe fields "n" pipes one about another at natural convection is the creation of criterion equation on the basis of which the heat output of heat transfer from pipe oriented areas one above another with given spacing could be quantified. At presence a sum of criterion equations exists for simple geometrical shapes of individual oriented geometrical areas but the criterion equation which would consider interaction of fluxional field generated by free convection from multiple oriented areas is not mentioned in standardly accessible technical literature and other magazine publications.

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

    E-print Network

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

    . 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...

  8. Finned-Tube Heat Exchanger Optimization Methodology

    Microsoft Academic Search

    Susan W. Stewart; Sam V. Shelton; Kristinn A. Aspelund

    2005-01-01

    Heat exchangers play a dominant role in the performance of most energy systems; however, optimization of these components is a complex task due to the coupled nature of the design parameters involved. Anytime the heat transfer coefficient is increased in these components, there is a corresponding increase in frictional pressure drop; therefore, a delicate balance is required between these two

  9. Dealing with Uncertainties During Heat Exchanger Design

    E-print Network

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

    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...

  10. Inner heat source model with heat and moisture transfer in soil around the underground heat exchanger

    Microsoft Academic Search

    Xinguo Li; Jun Zhao; Qian Zhou

    2005-01-01

    This paper presents an inner heat source model of underground heat exchanger based on the heat and mass transfer theory in soil. A number of factors such as moisture movement in soil, soil type, and soil property were taken into account in the model. The underground heat exchanger was simplified as the equivalent inner heat source term in the model.

  11. Phase Change Material Heat Exchanger Life Test

    NASA Technical Reports Server (NTRS)

    Lillibridge, Sean; Stephan, Ryan

    2009-01-01

    Low Lunar Orbit (LLO) poses unique thermal challenges for the orbiting space craft, particularly regarding the performance of the radiators. The IR environment of the space craft varies drastically from the light side to the dark side of the moon. The result is a situation where a radiator sized for the maximal heat load in the most adverse situation is subject to freezing on the dark side of the orbit. One solution to this problem is to implement Phase Change Material (PCM) Heat Exchangers. PCM Heat Exchangers act as a "thermal capacitor," storing thermal energy when there is too much being produced by the space craft to reject to space, and then feeding that energy back into the thermal loop when conditions are more favorable. Because they do not use an expendable resource, such as the feed water used by sublimators and evaporators, PCM Heat Exchangers are ideal for long duration LLO missions. In order to validate the performance of PCM Heat Exchangers, a life test is being conducted on four n-Pentadecane, carbon filament heat exchangers. Fluid loop performance, repeatability, and measurement of performance degradation over 2500 melt-freeze cycles will be performed.

  12. Heat Exchanger With Internal Pin Elements

    DOEpatents

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

    2004-01-13

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

  13. High effectiveness contour matching contact heat exchanger

    NASA Technical Reports Server (NTRS)

    Blakely, Robert L. (inventor); Roebelen, George J., Jr. (inventor); Davenport, Arthur K. (inventor)

    1988-01-01

    There is a need in the art for a heat exchanger design having a flexible core providing contour matching capabilities, which compensates for manufacturing tolerance and distortion buildups, and which accordingly furnishes a relatively uniform thermal contact conductance between the core and external heat sources under essentially all operating conditions. The core of the heat exchanger comprises a top plate and a bottom plate, each having alternate rows of pins attached. Each of the pins fits into corresponding tight-fitting recesses in the opposite plate.

  14. Observer-based monitoring of heat exchangers.

    PubMed

    Astorga-Zaragoza, Carlos-Manuel; Alvarado-Martínez, Víctor-Manuel; Zavala-Río, Arturo; Méndez-Ocaña, Rafael-Maxim; Guerrero-Ramírez, Gerardo-Vicente

    2008-01-01

    The goal of this work is to provide a method for monitoring performance degradation in counter-flow double-pipe heat exchangers. The overall heat transfer coefficient is estimated by an adaptive observer and monitored in order to infer when the heat exchanger needs preventive or corrective maintenance. A simplified mathematical model is used to synthesize the adaptive observer and a more complex model is used for simulation. The reliability of the proposed method was demonstrated via numerical simulations and laboratory experiments with a bench-scale pilot plant. PMID:17706652

  15. An active heat and moisture exchanger.

    PubMed

    Kapadia, F; Shelly, M P; Anthony, J M; Park, G R

    1992-12-01

    We have carried out a laboratory evaluation of an active heat and moisture exchanging filter (aHMEF). The device consists of a conventional heat and moisture exchanging filter (HMEF) with an additional heating element and water supply. It was compared with a standard HMEF using a model lung. The aHMEF with the heating element alone, reduced 2-hourly water loss compared with the HMEF (P < 0.001); with both the heating element and additional water, this was reduced further (P < 0.001). The mean catheter mount temperature with the HMEF and heater was 32.7 (SD 1.8) degrees C and with the complete aHMEF was 34.6 (1.6) degrees C. The maximum temperature with the heating element in use was 37.7 degrees C. We conclude that the aHMEF provided effective, controllable and convenient humidification of inspired gases. PMID:1467111

  16. Thermal\\/mechanical heat exchange design: Karl Gardner Memorial Session

    Microsoft Academic Search

    K. P. Singh; S. M. Shenkman

    1986-01-01

    This book presents the papers given at a conference on heat exchangers. Topics considered at the conference included uncertainty analysis of heat exchanger thermal-hydraulic designs, stress analysis, the mechanical design and fabrication of shell and tube heat exchangers in the US, and expert systems for design integration using an application to the total design of shell and tube heat exchangers

  17. 40 CFR 63.654 - Heat exchange systems.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...of this section. (1) All heat exchangers that are in organic HAP service...exchange system does not contain any heat exchangers that are in organic HAP service...organic HAP service or from each heat exchanger exit line for each heat...

  18. 40 CFR 63.104 - Heat exchange system requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...where the cooling water enters and exits each heat exchanger or any combination of heat exchangers. (i) For samples taken at the entrance...samples taken at the entrance and exit of each heat exchanger or any combination of heat exchangers in...

  19. Multiple Sensor Fault Detection in Heat Exchanger Systems

    E-print Network

    Paris-Sud XI, Université de

    Multiple Sensor Fault Detection in Heat Exchanger Systems Abdelwahab Aïtouche* , Didier Maquin strategy is presented for a heat exchanger system for which the process model consists of a set of linear equations, and can be found in heat exchangers. The increasing importance of heat exchangers in the industry

  20. 40 CFR 63.654 - Heat exchange systems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...of this section. (1) All heat exchangers that are in organic HAP service...exchange system does not contain any heat exchangers that are in organic HAP service...organic HAP service or from each heat exchanger exit line for each heat...

  1. 40 CFR 63.654 - Heat exchange systems.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...of this section. (1) All heat exchangers that are in organic HAP service...exchange system does not contain any heat exchangers that are in organic HAP service...organic HAP service or from each heat exchanger exit line for each heat...

  2. Physical Aspects of Scraped Heat Exchanger Crystallizers: An Application in Eutectic Freeze Crystallization

    Microsoft Academic Search

    M. Rodriguez Pascual

    2009-01-01

    One of the most important natural resources is fresh water. An unfortunate issue is however, the low availability and high demand of fresh water world-wide. From the total resources industry consumes about 20 % (1200 km3 yearly) [UN, 2007]. Industrial aqueous waste streams are therefore widely occurring, and their reuse becomes obligatory. For the recovery of water from dilute solutions

  3. ETR HEAT EXCHANGER BUILDING, TRA644. WORKERS ARE INSTALLING HEAT EXCHANGER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    ETR HEAT EXCHANGER BUILDING, TRA-644. WORKERS ARE INSTALLING HEAT EXCHANGER PIPING. INL NEGATIVE NO. 56-3122. Jack L. Anderson, Photographer, 9/21/1956 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

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

    E-print Network

    Singh, K. P.

    1979-01-01

    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...

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

    E-print Network

    Radermacher, R.

    uated based on enthalpy and mass balances. First these values were calculated for each pair of heat exchangers (A,B and C,D) separately. Then the requirement was imposed that the heat released by B must be compl etely absorbed by C. This match... that the surface area of the 1 iquid/l iquid heat exchanger is infinitely large, and that the efficiency of the pump is 0.7. The compression is assumed to be isentropic and the compression efficiency is set equal to the "'01 umetric efficiency, '1'1, given...

  6. Modeling particle deposition on HVAC heat exchangers

    SciTech Connect

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

    2002-01-01

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

  7. Heat exchanger for coal gasification process

    DOEpatents

    Blasiole, George A. (Greensburg, PA)

    1984-06-19

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

  8. Heat exchanger containing a component capable of discontinuous movement

    DOEpatents

    Wilson, David Gordon (Winchester, MA)

    2002-01-01

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

  9. Heat exchanger containing a component capable of discontinuous movement

    DOEpatents

    Wilson, David Gordon

    2001-04-17

    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.

  10. Heat exchanger containing a component capable of discontinuous movement

    DOEpatents

    Wilson, David G. (Winchester, MA)

    1993-01-01

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

  11. Full wave simulations of fast wave heating losses in the scrape-off layer of NSTX and NSTX-U

    NASA Astrophysics Data System (ADS)

    Bertelli, N.; Jaeger, E. F.; Hosea, J. C.; Phillips, C. K.; Berry, L.; Gerhardt, S. P.; Green, D.; LeBlanc, B.; Perkins, R. J.; Ryan, P. M.; Taylor, G.; Valeo, E. J.; Wilson, J. R.

    2014-08-01

    Full wave simulations of fusion plasmas show a direct correlation between the location of the fast-wave cut-off, radiofrequency (RF) field amplitude in the scrape-off layer (SOL) and the RF power losses in the SOL observed in the National Spherical Torus eXperiment (NSTX). In particular, the RF power losses in the SOL increase significantly when the launched waves transition from evanescent to propagating in that region. Subsequently, a large amplitude electric field occurs in the SOL, driving RF power losses when a proxy collisional loss term is added. A 3D reconstruction of absorbed power in the SOL is presented showing agreement with the RF experiments in NSTX. Loss predictions for the future experiment NSTX-Upgrade (NSTX-U) are also obtained and discussed.

  12. Full wave simulations of fast wave heating losses in the scrape-off layer of NSTX and NSTX-U

    SciTech Connect

    Bertelli, Nicola [Princeton Plasma Physics Laboratory (PPPL); Jaeger, E. F. [XCEL; Hosea, J. [Princeton Plasma Physics Laboratory (PPPL); Phillips, C. K. [Princeton Plasma Physics Laboratory (PPPL); Berry, Lee Alan [XCEL Engineering Inc., Oak Ridge; Gerhardt, S. [Princeton Plasma Physics Laboratory (PPPL); Green, David L [ORNL; LeBlanc, B [Princeton Plasma Physics Laboratory (PPPL); Perkins, R. J. [Princeton Plasma Physics Laboratory (PPPL); Ryan, Philip Michael [ORNL; Taylor, G. [Princeton Plasma Physics Laboratory (PPPL); Valeo, E. J. [Princeton Plasma Physics Laboratory (PPPL); Wilson, J. R. [Princeton Plasma Physics Laboratory (PPPL)

    2014-01-01

    Full wave simulations of fusion plasmas show a direct correlation between the location of the fast-wave cut-off, radiofrequency (RF) field amplitude in the scrape-off layer (SOL) and the RF power losses in the SOL observed in the National Spherical Torus eXperiment (NSTX). In particular, the RF power losses in the SOL increase significantly when the launched waves transition from evanescent to propagating in that region. Subsequently, a large amplitude electric field occurs in the SOL, driving RF power losses when a proxy collisional loss term is added. A 3D reconstruction of absorbed power in the SOL is presented showing agreement with the RF experiments in NSTX. Loss predictions for the future experiment NSTX-Upgrade (NSTX-U) are also obtained and discussed.

  13. Carbon nanotube heat-exchange systems

    DOEpatents

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

    2008-11-11

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

  14. Micro-Scale Regenerative Heat Exchanger

    NASA Technical Reports Server (NTRS)

    Moran, Matthew E.; Stelter, Stephan; Stelter, Manfred

    2004-01-01

    A micro-scale regenerative heat exchanger has been designed, optimized and fabricated for use in a micro-Stirling device. Novel design and fabrication techniques enabled the minimization of axial heat conduction losses and pressure drop, while maximizing thermal regenerative performance. The fabricated prototype is comprised of ten separate assembled layers of alternating metal-dielectric composite. Each layer is offset to minimize conduction losses and maximize heat transfer by boundary layer disruption. A grating pattern of 100 micron square non-contiguous flow passages were formed with a nominal 20 micron wall thickness, and an overall assembled ten-layer thickness of 900 microns. Application of the micro heat exchanger is envisioned in the areas of micro-refrigerators/coolers, micropower devices, and micro-fluidic devices.

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

    E-print Network

    Thole, Karen A.

    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

  16. Reset compensation applied on industrial heat exchangers

    Microsoft Academic Search

    Angel Vidal; A. Banos

    2009-01-01

    This work aims at improving the control of an industrial heat exchanger used in the thermal treatment in food industry. The goal is to investigate the potentials of a hybrid compensator previously developed by the authors, the PI+CI reset compensator, in the robust control when significant uncertainty is present. To this end, a PI+CI compensator has been designed by using

  17. Thermal performance testing of industrial heat exchangers

    Microsoft Academic Search

    Kenneth Bell

    2001-01-01

    Methods to perform thermal performance tests and analyze the results for heat exchangers in industrial process streams are discussed. Industrial test practices and operating conditions are compared with experimental methods. A thorough review of sources of error and their contribution to overall test uncertainty is described. The analysis includes methods to estimate the uncertainty of predicted performance based on test

  18. High performance finned tube heat exchanger design

    Microsoft Academic Search

    J. M. Mineur; G. F. Dunstan

    1979-01-01

    A rational approach to the design of gas-fired finned tube heat exchangers is presented. As a result of an extensive literature search and a study of flue gas properties, novel equations have been developed to facilitate design procedures. Comparisons are made between the theoretical performance of a finned tube boiler and those determined experimentally.

  19. A Ceramic Heat Exchanger for Solar Receivers

    NASA Technical Reports Server (NTRS)

    Robertson Jr., C.; Stacy, L.

    1985-01-01

    Design intended for high-temperature service. Proposed ceramic-tube and header heat exchangers used for solar-concentrating collector operating in 25- to 150-KW power range at temperatures between 2,000 degrees and 3,000 degrees F (1,095 degrees and 1,650 degrees C).

  20. Measurement of heat and moisture exchanger efficiency.

    PubMed

    Chandler, M

    2013-09-01

    Deciding between a passive heat and moisture exchanger or active humidification depends upon the level of humidification that either will deliver. Published international standards dictate that active humidifiers should deliver a minimum humidity of 33 mg.l(-1); however, no such requirement exists, for heat and moisture exchangers. Anaesthetists instead have to rely on information provided by manufacturers, which may not allow comparison of different devices and their clinical effectiveness. I suggest that measurement of humidification efficiency, being the percentage moisture returned and determined by measuring the temperature of the respired gases, should be mandated, and report a modification of the standard method that will allow this to be easily measured. In this study, different types of heat and moisture exchangers for adults, children and patients with a tracheostomy were tested. Adult and paediatric models lost between 6.5 mg.l(-1) and 8.5 mg.l(-1) moisture (corresponding to an efficiency of around 80%); however, the models designed for patients with a tracheostomy lost between 16 mg.l(-1) and 18 mg.l(-1) (60% efficiency). I propose that all heat and moisture exchangers should be tested in this manner and percentage efficiency reported to allow an informed choice between different types and models. PMID:24047355

  1. A conceptual description of heat exchanger for programming

    Microsoft Academic Search

    Yongsheng Tian

    2004-01-01

    This paper presents a conceptual description of heat exchangers based on modern software concepts. Relationships between software components associated with heat exchangers have been developed. The general requirements for each software component have been detailed. A heat transfer zone physical model is proposed for programming. The strategies to deal with different heat exchangers and different methodologies in calculations are proposed.

  2. Optimization in calculation of shell-tube heat exchanger

    Microsoft Academic Search

    Siying Sun; Yadong Lu; Caiqiu Yan

    2009-01-01

    Based on the energy conservation and the mass balance, a mathematical simulation for the transient heat exchange of a shell-tube heat exchanger is established, and a model for optimization of the heat exchanger design is proposed in which the objective function is the total entropy generation rate (TEGR), with consideration giving to both heat transfer and flow resistance. The results

  3. Comparative Studies on Micro Heat Exchanger Optimisation Tatsuya Okabe

    E-print Network

    Coello, Carlos A. Coello

    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

  4. IntroductiontoProcessEngineering(PTG) 4. Heat exchangers;

    E-print Network

    Zevenhoven, Ron

    #4/6 IntroductiontoProcessEngineering(PTG) VST rz13 1/72 4. Heat exchangers; Steam, steam processes.2013 #4/6 IntroductiontoProcessEngineering(PTG) VST rz13 2/72 4.1 Heat exchangers #12;#4/6 IntroductiontoProcessEngineering(PTG) VST rz13 3/72 Heat exchangers: General /1 · In a heat exchanger heat

  5. Low heat transfer oxidizer heat exchanger design and analysis

    NASA Technical Reports Server (NTRS)

    Kanic, P. G.; Kmiec, T. D.; Peckham, R. J.

    1987-01-01

    The RL10-IIB engine, a derivative of the RLIO, is capable of multi-mode thrust operation. This engine operates at two low thrust levels: tank head idle (THI), which is approximately 1 to 2 percent of full thrust, and pumped idle (PI), which is 10 percent of full thrust. Operation at THI provides vehicle propellant settling thrust and efficient engine thermal conditioning; PI operation provides vehicle tank pre-pressurization and maneuver thrust for log-g deployment. Stable combustion of the RL10-IIB engine at THI and PI thrust levels can be accomplished by providing gaseous oxygen at the propellant injector. Using gaseous hydrogen from the thrust chamber jacket as an energy source, a heat exchanger can be used to vaporize liquid oxygen without creating flow instability. This report summarizes the design and analysis of a United Aircraft Products (UAP) low-rate heat transfer heat exchanger concept for the RL10-IIB rocket engine. The design represents a second iteration of the RL10-IIB heat exchanger investigation program. The design and analysis of the first heat exchanger effort is presented in more detail in NASA CR-174857. Testing of the previous design is detailed in NASA CR-179487.

  6. Brayton heat exchange unit development program

    NASA Technical Reports Server (NTRS)

    Morse, C. J.; Richard, C. E.; Duncan, J. D.

    1971-01-01

    A Brayton Heat Exchanger Unit (BHXU), consisting of a recuperator, a heat sink heat exchanger and a gas ducting system, was designed, fabricated, and tested. The design was formulated to provide a high performance unit suitable for use in a long-life Brayton-cycle powerplant. A parametric analysis and design study was performed to establish the optimum component configurations to achieve low weight and size and high reliability, while meeting the requirements of high effectiveness and low pressure drop. Layout studies and detailed mechanical and structural design were performed to obtain a flight-type packaging arrangement. Evaluation testing was conducted from which it is estimated that near-design performance can be expected with the use of He-Xe as the working fluid.

  7. Efficient numerical modeling of borehole heat exchangers

    NASA Astrophysics Data System (ADS)

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

    2010-10-01

    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 simulate three-dimensional heat transfer processes in multiple borehole heat exchangers embedded in a multi-layer soil mass, in a computationally efficient manner. Geothermal problems which require very fine meshes, of the order of millions of finite elements, can be simulated using coarse meshes, of the order of a few hundred to a few thousand elements. Accordingly, significant reduction of CPU time is gained, rendering the model suitable for utilization in engineering practice. A validation example comparing computed results with measured results is presented. Parametric analyses are also presented describing the possible utilization of the model for research works and design optimization.

  8. Heat transfer analysis of boreholes in vertical ground heat exchangers

    Microsoft Academic Search

    Heyi Zeng; Nairen Diao; Zhaohong Fang

    2003-01-01

    A ground heat exchanger (GHE) is devised for extraction or injection of thermal energy from\\/into the ground. Bearing strong impact on GHE performance, the borehole thermal resistance is defined by the thermal properties of the construction materials and the arrangement of flow channels of the GHEs. Taking the fluid axial convective heat transfer and thermal “short-circuiting” among U-tube legs into

  9. Design, construction and testing of a thermosyphon heat exchanger for medium temperature heat recovery in bakeries

    Microsoft Academic Search

    A. R. Lukitobudi; A. Akbarzadeh; P. W. Johnson; P. Hendy

    1995-01-01

    Using water as the working fluid, air-to-air heat exchangers using thermosyphon heat pipes were designed, constructed and tested under medium temperature (below 300°C) operating conditions. A heat exchanger test rig has been constructed and developed wherein the heated air is recycled to the counterflow heat exchanger. The lengths of both the evaporator section and the condenser section of the heat

  10. Study on heat transfer of heat exchangers in the Stirling engine - Performance of heat exchangers in the test Stirling engine

    Microsoft Academic Search

    Mitsuo Kanzaka; Makio Iwabuchi

    1992-01-01

    The heat transfer performance of the actual heat exchangers obtained from the experimental results of the test Stirling engine is presented. The heater for the test engine has 120 heat transfer tubes that consist of a bare-tube part and a fin-tube part. These tubes are located around the combustion chamber and heated by the combustion gas. The cooler is the

  11. Study on heat transfer of heat exchangers in the Stirling engine - Performance of heat exchangers in the test Stirling engine

    NASA Astrophysics Data System (ADS)

    Kanzaka, Mitsuo; Iwabuchi, Makio

    1992-11-01

    The heat transfer performance of the actual heat exchangers obtained from the experimental results of the test Stirling engine is presented. The heater for the test engine has 120 heat transfer tubes that consist of a bare-tube part and a fin-tube part. These tubes are located around the combustion chamber and heated by the combustion gas. The cooler is the shell-and-tube-type heat exchanger and is chilled by water. It is shown that the experimental results of heat transfer performance of the heater and cooler of the test Stirling engine are in good agreement with the results calculated by the correlation proposed in our previous heat transfer study under the periodically reversing flow condition. Our correlation is thus confirmed to be applicable to the evaluation of the heat transfer coefficient and the thermal design of the heat exchangers in the Stirling engine.

  12. Triple loop heat exchanger for an absorption refrigeration system

    DOEpatents

    Reimann, Robert C. (Lafayette, NY)

    1984-01-01

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

  13. Preliminary SP-100/Stirling heat exchanger designs

    SciTech Connect

    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

    1994-09-01

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

  14. Preliminary SP-100/Stirling heat exchanger designs

    NASA Technical Reports Server (NTRS)

    Schmitz, Paul; Tower, Leonard; Dawson, Ronald; Blue, Brian; Dunn, Pat

    1993-01-01

    Analytic modeling of several heat exchanger concepts to couple the SP-100 nuclear reactor primary 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.

  15. Heating system with vapour compressor heat pump and vertical U-tube ground heat exchanger

    NASA Astrophysics Data System (ADS)

    Hanuszkiewicz-Drapa?a, Ma?gorzata; Sk?adzie?, Jan

    2010-10-01

    In the paper a heating system with a vapour compressor heat pump and vertical U-tube ground heat exchanger for small residential house is considered. A mathematical model of the system: heated object - vapour compressor heat pump - ground heat exchanger is presented shortly. The system investigated is equipped, apart from the heat pump, with the additional conventional source of heat. The processes taking place in the analyzed system are of unsteady character. The model consists of three elements; the first containing the calculation model of the space to be heated, the second - the vertical U-tube ground heat exchanger with the adjoining area of the ground. The equations for the elements of vapour compressor heat pump form the third element of the general model. The period of one heating season is taken into consideration. The results of calculations for two variants of the ground heat exchanger are presented and compared. These results concern variable in time parameters at particular points of the system and energy consumption during the heating season. This paper presents the mutual influence of the ground heat exchanger subsystem, elements of vapour compressor heat pump and heated space.

  16. Multi-Purpose Logistics Module (MPLM) Cargo Heat Exchanger

    NASA Technical Reports Server (NTRS)

    Zampiceni, John J.; Harper, Lon T.

    2002-01-01

    This paper describes the New Shuttle Orbiter's Multi- Purpose Logistics Modulo (MPLM) Cargo Heat Exchanger (HX) and associated MPLM cooling system. This paper presents Heat Exchanger (HX) design and performance characteristics of the system.

  17. Using Plate Heat Exchangers to Increase Energy Efficiency

    E-print Network

    Bailey, K.

    "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...

  18. Optimizing PT Arun LNG main heat exchanger

    SciTech Connect

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

    1995-12-01

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

  19. 40 CFR 63.1328 - Heat exchange systems provisions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2011-07-01 true Heat exchange systems provisions. 63.1328 ...63.1328 Heat exchange systems provisions. (a) Except...subpart, except for ethylene glycol which need not be considered...compliance date for heat exchange systems subject to the provisions...

  20. 40 CFR 63.1328 - Heat exchange systems provisions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Heat exchange systems provisions. 63.1328 ...63.1328 Heat exchange systems provisions. (a) Except...subpart, except for ethylene glycol which need not be considered...compliance date for heat exchange systems subject to the provisions...

  1. 40 CFR 63.1328 - Heat exchange systems provisions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Heat exchange systems provisions. 63.1328 ...63.1328 Heat exchange systems provisions. (a) Except...subpart, except for ethylene glycol which need not be considered...compliance date for heat exchange systems subject to the provisions...

  2. 40 CFR 63.1328 - Heat exchange systems provisions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Heat exchange systems provisions. 63.1328...IV Polymers and Resins § 63.1328 Heat exchange systems provisions. (a...subpart. (h) The compliance date for heat exchange systems subject to the...

  3. An automated approach for the optimal design of heat exchangers

    Microsoft Academic Search

    Prosenjit D. Chaudhuri; Urmila M. Diwekar; Jefferey S. Logsdon

    1997-01-01

    This paper presents an efficient strategy based on simulated annealing (SA), an algorithmic procedure for large-scale combinatorial optimization problems, for the optimal design of heat exchangers. The general heat exchanger design problem can be posed as a large-scale discrete optimization problem, and SA was found to be well suited for this type of heat exchanger design problem. A methodology based

  4. A survey of heat exchanger applications in New Zealand industries

    Microsoft Academic Search

    R. Steinhagen; H. Mueller-Steinhagen; K. Maani

    2009-01-01

    Stimulated by the increased need to operate thermal processes more efficiently, the installation of heat exchangers has increased over the past decades. Today heat exchangers play a crucial role in most chemical, food-processing, and power-generating processes. Despite the enormous practical and economical implications, little is known about numbers, sizes, and types of heat exchanger installations. All efforts to improve design

  5. Development of high effectiveness droplet heat exchangers. Final report

    Microsoft Academic Search

    W. J. Thayer; K. M. Sekins; A. P. Bruckner

    1985-01-01

    An experimental and analytical investigation has been carried out to assess the feasibility of developing high effectiveness, high temperature droplet heat exchangers and to identify practical applications for this type of direct contact heat exchanger. The droplet heat exchanger (DHX) concept studied uses a counterflowing gas and droplet configuration, uniformly sized droplets or particles, and a uniform dispersion of droplets

  6. Predictive Performance Assessment of Heat Exchangers for Proactive Remediation

    Microsoft Academic Search

    P. Vijaysai; M. D. Osborn; S. S. Au; K. R. C. Reddy; S. S. Shah; N. P. Vora; A. Gryscavage

    2006-01-01

    Efficiency of industrial heat exchangers degrades over time as a result of deposition of the extraneous matter present in the heat-exchanging medium. Many times the degradation is rapid enough to take a heavy toll on the overall plant economy. It is therefore important to keep a closer watch on heat exchanger performance so that a suitable corrective action can be

  7. PERFORMANCE OF FALLING FILM HEAT EXCHANGERS FOR SOLAR WATER HEATERS

    Microsoft Academic Search

    Graham Morrison; Masud Behnia

    The characteristics of a falling film heat exchanger for use on the collector loop heat exchanger in a pumped solar water heater have been assessed, and a TRNSYS model has been developed for evaluating long-term performance. The falling film heat exchanger is based on a conventional gas storage water heater tank with the gas combustion tube converted to a water

  8. The cost of heat exchanger fouling in the US industries

    Microsoft Academic Search

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

    1988-01-01

    Fouling of heat exchangers costs the US 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

  9. Numerical methods for thermal calculations of heat exchangers

    Microsoft Academic Search

    P. Mercier

    1991-01-01

    Global and analytical methods for the sizing of heat exchangers are described. Two thermal sizing methods used on a number of different types of heat exchangers are presented and illustrated. A hydraulic network method applied to the sizing of plate heat exchangers is presented. Multidimensional thermohydraulic calculation methods are discussed. They present a particular interest when flow patterns inside the

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

    E-print Network

    Michalski, Ryszard S.

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

  11. Deposition of Biological Aerosols on HVAC Heat Exchangers

    E-print Network

    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 heat exchangers. A model has been developed that incorporates the effects of several deposition

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

    E-print Network

    Schmidhuber, Juergen

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

  13. Heat exchanger support apparatus in a fluidized bed

    DOEpatents

    Lawton, Carl W. (West Hartford, CT)

    1982-01-01

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

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

    E-print Network

    Frandsen, Søren

    GEA Heat Exchangers GEA Searle Cooler and Condensing Unit Ranges Top-level engineering solutions,Eurovent verification and many more. GEA is one of the longest established and principal manufacturers of heat exchange range. GEA Heat Exchangers products are utilised across many industries. Applications include industrial

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

    E-print Network

    Boyer, Edmond

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

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

    E-print Network

    Kandlikar, Satish

    1 CORRELATING EVAPORATION HEAT TRANSFER COEFFICIENT OF REFRIGERANT R-134a IN A PLATE HEAT EXCHANGER for evaporation heat transfer coefficient of refrigerant R-134a flowing in a plate heat exchanger. Correlation heat exchanger are found to result in large discrepancies with their own experimental data

  17. Hydrotreater feed/effluent heat exchange

    SciTech Connect

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

    1991-08-13

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

  18. OXIDE DISPERSION-STRENGTHENED HEAT EXCHANGER TUBING

    SciTech Connect

    Harper, Mark A.

    2001-11-06

    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.

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

    E-print Network

    Kostic, Milivoje M.

    MEE 452: Example 3-2 ShellShell--andand--Tube Heat Exchanger Analysis:Tube Heat Exchanger Analysis-butyl alcohol @150oF. Two-tube-pass for illustration only COUNTER FLOW T PARALLEL FLOW T Heat Exchanger: [From B.K. Hodge and R.P. Taylor, Analysis and Design of Energy System, 3rd Ed., Prentice Hall, 1999

  20. Graphite Foam Heat Exchangers for Thermal Management

    SciTech Connect

    Klett, J.W.

    2004-06-07

    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.

  1. Thermal and hydrodynamic considerations of ice slurry in heat exchangers

    Microsoft Academic Search

    Jean-Pierre Bédécarrats; Françoise Strub; Christophe Peuvrel

    2009-01-01

    This article focuses on the behavior in heat exchangers of an ice slurry composed of fine ice particles inside an ethanol–water solution. The heat transfer and friction characteristics were studied in two double pipe heat exchangers, one with a smooth surface and another with an improved surface. Heat transfer coefficients and pressure drops were experimentally investigated for the slurry flowing

  2. Improving the thermal performance of coaxial borehole heat exchangers

    Microsoft Academic Search

    E. Zanchini; S. Lazzari; A. Priarone

    2010-01-01

    Borehole heat exchangers are the fundamental component of ground coupled heat pumps, which are now widely employed for energy saving in building heating and cooling. The improvement of the thermal efficiency of Coaxial Borehole Heat Exchangers (CBHEs) is pursued in this paper by investigating the effects of thermal short-circuiting and of flow rate, as well as of the constituent materials

  3. Shell-and-tube heat exchangers in refrigeration. Part 1

    Microsoft Academic Search

    1996-01-01

    This article covers the basics of sizing and selecting shell-and-tube heat exchangers for refrigeration applications. The heat exchanger is an indispensable device in many instances where heat must be transferred from one fluid to another. Its use is necessary in many applications involving thermal energy transfer in both heating and cooling processes, and there are a variety of designs on

  4. Microchannel Heat Exchangers with Carbon Dioxide

    SciTech Connect

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

    2001-09-15

    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.

  5. Design and Development of a Plastic Film Heat Exchanger

    E-print Network

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

    DESIGN AND DEVELOPMENT OF A PLASTIC FILM HEAT EXCHANGER Eric C. Guyer, Sc.D., David L. Brownell, and Martin K. Gollin Dynatech RID Company Cambridge, Massachusetts ABSTRACT A plastic film heat exchang.er (PFHX) utilizes the low cost.... The problems associated with the design of elements and manifolds are described together with an analysis of the thermal and hydraulic factors affecting the operation of the unit. INTRODUCTION The concept for the plastic film heat exchanger (PFHX...

  6. High-temperature self-circulating thermoacoustic heat exchanger

    NASA Astrophysics Data System (ADS)

    Backhaus, S.; Swift, G. W.; Reid, R. S.

    2005-07-01

    Thermoacoustic and Stirling engines and refrigerators use heat exchangers to transfer heat between the oscillating flow of their thermodynamic working fluids and external heat sources and sinks. An acoustically driven heat-exchange loop uses an engine's own pressure oscillations to steadily circulate its own thermodynamic working fluid through a physically remote high-temperature heat source without using moving parts, allowing for a significant reduction in the cost and complexity of thermoacoustic and Stirling heat exchangers. The simplicity and flexibility of such heat-exchanger loops will allow thermoacoustic and Stirling machines to access diverse heat sources and sinks. Measurements of the temperatures at the interface between such a heat-exchange loop and the hot end of a thermoacoustic-Stirling engine are presented. When the steady flow is too small to flush out the mixing chamber in one acoustic cycle, the heat transfer to the regenerator is excellent, with important implications for practical use.

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

    SciTech Connect

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

    2008-11-01

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

  8. Condensation in horizontal heat exchanger tubes

    SciTech Connect

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

    2012-07-01

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

  9. Analysis of thermosyphon heat exchangers for use in solar domestic hot water heating systems

    Microsoft Academic Search

    Scott David Dahl

    1998-01-01

    A recent innovation in the solar industry is the use of thermosyphon heat exchangers. Determining the performance of these systems requires knowledge of how thermosyphon flow rate and heat exchanger performance vary with operating conditions. This study demonstrates that several thermosyphon heat exchanger designs operate in the laminar mixed convection regime. Empirical heat transfer and pressure drop correlations are obtained

  10. Optimization of cross flow heat exchangers for thermoelectric waste heat recovery

    Microsoft Academic Search

    Douglas T. Crane; Gregory S. Jackson

    2004-01-01

    Thermoelectric waste heat recovery is investigated for current thermoelectric materials with advanced heat exchangers. Numerical heat exchanger models integrated with models for Bi2Te3 thermoelectric modules are validated against experimental data from previous cross flow heat exchanger studies as well as experiments using thermoelectrics between counterflow hot water and cooling air flow channels. The models are used in optimization studies of

  11. Numerical investigation of fouling on cross-flow heat exchanger tubes with conjugated heat transfer approach

    Microsoft Academic Search

    Y. Kaptan; E. Buyruk; A. Ecder

    2008-01-01

    Although fouling on heat exchanger tubes is extensively investigated, due to the lack of energy resources, the effects of fouling on heat exchangers is still an important area of study and gaining more and more attention every day. In this study we investigated the effects of fouling on heat transfer and flow structures numerically for cross-flow heat exchanger tube geometry.

  12. Industrial applications for LIGA-fabricated micro heat exchangers

    Microsoft Academic Search

    Kevin W. Kelly; Chad Harris; Lyndon S. Stephens; Christophe Marques; Dan Foley

    2001-01-01

    One of the well-known benefits of micro scale is enhanced heat transfer. This fact provides the motivation for fabricating a variety of micro heat exchangers using derivatives of the LIGA micromachining process. These heat exchangers can be made of polymers, nickel (electroplated or electroless), or ceramics (Si3N4 and alumina are presently being investigated). These heat exchangers are envisioned for applications

  13. Shell-and-double concentric-tube heat exchangers

    Microsoft Academic Search

    Chérif Bougriou; Khireddine Baadache

    2010-01-01

    This study concerns a new type of heat exchangers, which is that of shell-and-double concentric-tube heat exchangers. These\\u000a heat exchangers can be used in many specific applications such as air conditioning, waste heat recovery, chemical processing,\\u000a pharmaceutical industries, power production, transport, distillation, food processing, cryogenics, etc. The case studies include\\u000a both design calculations and performance calculations. It is demonstrated that

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

    E-print Network

    Gonzalez, Jose Antonio

    1993-01-01

    temperature, ground density, ground thermal conductivity and indoor air temperature were presented. Soil density was not found to be a significant contributor to the performance of ground coupled heat pump (GCHP) heat exchangers. Soil temperature and soil... thermal conductivity were found to be the most important parameters for sizing GCHP heat exchangers. The effects of oversizing or undersizing the heat exchanger were investigated. Oversized heat exchangers provide lower entering water temperatures (EWTs...

  15. Heat exchanger for a Stirling engine

    SciTech Connect

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

    1987-05-05

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

  16. Aerodynamics of heat exchangers for high-altitude aircraft

    NASA Technical Reports Server (NTRS)

    Drela, Mark

    1996-01-01

    Reduction of convective beat transfer with altitude dictates unusually large beat exchangers for piston- engined high-altitude aircraft The relatively large aircraft drag fraction associated with cooling at high altitudes makes the efficient design of the entire heat exchanger installation an essential part of the aircraft's aerodynamic design. The parameters that directly influence cooling drag are developed in the context of high-altitude flight Candidate wing airfoils that incorporate heat exchangers are examined. Such integrated wing-airfoil/heat-exchanger installations appear to be attractive alternatives to isolated heat.exchanger installations. Examples are drawn from integrated installations on existing or planned high-altitude aircraft.

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

    E-print Network

    Shawabkeh, Reyad A.

    of tubes, exchanger length and diameter, heat duty and other design specification. Otherwise, useSteps for design of Heat Exchanger By Dr. Reyad Shawabkeh Department of Chemical Engineering King the Temperature correction factor. #12;For 1 shell-2 tube pass exchanger For other configurations use

  18. Temperature profile of the infrared image Heat exchange between

    E-print Network

    Jaehne, Bernd

    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

  19. Shell-and-double concentric-tube heat exchangers

    NASA Astrophysics Data System (ADS)

    Bougriou, Chérif; Baadache, Khireddine

    2010-03-01

    This study concerns a new type of heat exchangers, which is that of shell-and-double concentric-tube heat exchangers. These heat exchangers can be used in many specific applications such as air conditioning, waste heat recovery, chemical processing, pharmaceutical industries, power production, transport, distillation, food processing, cryogenics, etc. The case studies include both design calculations and performance calculations. It is demonstrated that the relative diameter sizes of the two tubes with respect to each other are the most important parameters that influence the heat exchanger size.

  20. Diffusion-Welded Microchannel Heat Exchanger for Industrial Processes

    SciTech Connect

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

    2013-03-01

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

  1. Gas and solid particulate material heat exchanger

    SciTech Connect

    Kreisberg, A.J.; Warshawsky, J.

    1986-12-16

    This patent describes an apparatus for carrying out heat exchange between a gas and solid particulate material comprising a casing having an upper inlet for particulate material and a lower outlet for particulate material and a lower grate mounted in the casing extending from the upper inlet to the lower outlet for supporting a bed of particulate material for movement from the inlet to the outlet along the lower grate. A means defines an upper grate mounted in the casing and is spaced from the lower grate including generally vertically oriented slats, each spaced from and positioned below a preceding slat in the direction from the inlet toward the outlet for defining the top of the bed of material while permitting the bed of material to expand. The casing includes an inlet for gas on one side of the casing and an outlet for gas on the other side of the casing whereby gas flows from the inlet through the lower grate, the bed of material and through the upper grate to the outlet for gas for carrying out heat exchange between the gas and the solid particulate material. Each of the slats is perforated to permit gas and fine material to pass therethrough while retaining the bed of material on the lower grate.

  2. Developing an educational software for heat exchangers and heat exchanger networks projects

    Microsoft Academic Search

    L. M. F. Lona; F. A. N. Fernandes; M. C. Roque; S. Rodrigues

    2000-01-01

    The shell and tube heat exchanger is an equipment largely used at chemical industries. The most known methods used for its design are the methods of Kern, Bell-Delaware and Tinker, for what a lot of equations are necessary. In this way, the calculation without using any computer aid takes a lot of time. This paper present a didactical software developed

  3. Simulation Studies on A Cross Flow Plate Fin Heat Exchanger

    Microsoft Academic Search

    M. Thirumarimurugan; T. Kannadasan; E. Ramasamy

    Compact heat exchangers which were initially developed for the aerospace industries in the 1940s have been considerably improved in the past few years. The main reasons for the good performance of compact heat exchangers are their special design which includes turbulent which in turn use high heat transfer coefficient and resists fouling, and maximum temperature driving force between the hot

  4. COMPACT HEAT EXCHANGERS FOR MOBILE CO2 SYSTEMS

    Microsoft Academic Search

    A. Hafner

    The natural refrigerant carbon dioxide (CO2) with all its advantages offers new possibilities of efficient heating and cooling at different climates. In reversible air conditioning systems the capacity and efficiency in cooling mode is seen to be most important. The efficiency of the reversible interior heat exchanger depends on the design of the heat exchanger. Efficiency reduction is among other

  5. The catalytic heat exchanger using catalytic fin tubes

    Microsoft Academic Search

    Yong-Seog Seo; Sang-Pil Yu; Sung-June Cho; Kwang-Sup Song

    2003-01-01

    The characteristics of a catalytic heat exchanger which integrates heat generation and heat exchange into one equipment have been investigated by the experiment and numerical simulation. The surface of the fin tubes was catalyzed by the formation of the oxide layer and the subsequent washcoating of ZrO2, followed by the impregnation of Pd catalyst. The experimental results showed that the

  6. Heat exchanger's shell and tube modeling for intelligent control design

    Microsoft Academic Search

    Dirman Hanafi; Mohd Nor Mohd Than; Abdulrahman A. A. Emhemed; Tatang Mulyana; Amran Mohd Zaid; Ayob Hj. Johari

    2011-01-01

    my Abstract- The shell and tube of heat exchanger is a medium where heat transfer process occurred. The accuracy of the heat exchanger depends on the performance of both elements. Therefore, both components need to be controlled in order to achieve a substantial result in the process. For this purpose, the actual dynamics of both shell and tube of the

  7. Heat transfer of horizontal parallel pipe ground heat exchanger and experimental verification

    Microsoft Academic Search

    Hakan Demir; Ahmet Koyun; Galip Temir

    2009-01-01

    The ground heat exchangers (GHE) consist of pipes buried in the soil and is used for transferring heat between the soil and the heat exchanger pipes of the ground source heat pump (GSHP). Because of the complexity of the boundary conditions, the heat conduction equation has been solved numerically using alternating direction implicit finite difference formulation. A software was developed

  8. Optimal allocation of a heat-exchanger inventory in heat driven refrigerators

    Microsoft Academic Search

    M. Sokolov

    1995-01-01

    This paper reports the thermodynamic optimization (or entropy generation minimization) of a heat-driven refrigeration plant, that is, a refrigerator without work input, which is driven by a heat source. The treatment accounts for the heat transfer irreversibilities of the three heat exchangers, and for the finiteness of the total heat-exchanger inventory. The operating conditions for maximum refrigeration rate are determined.

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

    E-print Network

    Chen, Y.; Zhao, J.

    2006-01-01

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

  10. Heat exchanger for fuel cell power plant reformer

    DOEpatents

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

    1988-01-01

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

  11. Control Dewar Subcooler Heat Exchanger Calculations

    SciTech Connect

    Rucinski, R.; /Fermilab

    1993-10-04

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

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

    SciTech Connect

    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)

    2010-09-15

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

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

    DOEpatents

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

    1993-01-01

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

  14. Heat exchanger development at Reaction Engines Ltd.

    NASA Astrophysics Data System (ADS)

    Varvill, Richard

    2010-05-01

    The SABRE engine for SKYLON has a sophisticated thermodynamic cycle with heat transfer between the fluid streams. The intake airflow is cooled in an efficient counterflow precooler, consisting of many thousand small bore thin wall tubes. Precooler manufacturing technology has been under investigation at REL for a number of years with the result that flightweight matrix modules can now be produced. A major difficulty with cooling the airflow to sub-zero temperatures at low altitude is the problem of frost formation. Frost control technology has been developed which enables steady state operation. The helium loop requires a top cycle heat exchanger (HX3) to deliver a constant inlet temperature to the main turbine. This is constructed in silicon carbide and the feasibility of manufacturing various matrix geometries has been investigated along with suitable joining techniques. A demonstration precooler will be made to run in front of a Viper jet engine at REL's B9 test facility in 2011. This precooler will incorporate full frost control and be built from full size SABRE engine modules. The facility will incorporate a high pressure helium loop that rejects the absorbed heat to a bath of liquid nitrogen.

  15. 40 CFR 63.11920 - What are my initial and continuous compliance requirements for heat exchange systems?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...exposure to air for each heat exchange system in HAP service. (ii) Selected heat exchanger exit line(s) so that each heat exchanger or group of heat exchangers within a heat exchange system is covered by the selected monitoring...

  16. 40 CFR 63.11920 - What are my initial and continuous compliance requirements for heat exchange systems?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...exposure to air for each heat exchange system in HAP service. (ii) Selected heat exchanger exit line(s) so that each heat exchanger or group of heat exchangers within a heat exchange system is covered by the selected monitoring...

  17. 40 CFR 63.11920 - What are my initial and continuous compliance requirements for heat exchange systems?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...exposure to air for each heat exchange system in HAP service. (ii) Selected heat exchanger exit line(s) so that each heat exchanger or group of heat exchangers within a heat exchange system is covered by the selected monitoring...

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

    Microsoft Academic Search

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

    2010-01-01

    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 7.0m2 and a depth of 1.5m was built at Khon Kaen in North-Eastern Thailand (16°27?N102°E). Heat was successfully extracted

  19. Heat exchanger for geothermal heating and cooling systems

    SciTech Connect

    Rawlings, J.P.; Partin, J.R.

    1986-03-11

    This patent describes an apparatus for achieving heat exchange between a liquid medium and the earth in a vertical borehole in the earth. This apparatus consists of: a casing adapted to be positioned in a vertical borehole in the earth, the exterior surface of the casing being in thermal contact with the earth; a cap closing the casing lower end; a dip tube of external diameter smaller than the interior diameter of the casing, the dip tube being positioned within the casing providing an annular area between the interior of the casing and the exterior of the dip tube, the bottom end of the dip tube being open and spaced above the cap; a top manifold providing a first part connected to the upper end of the casing, a second part connected to the upper end of the dip tube, the second part having a vertical vent hole therein, a third part providing means to connect an outlet conduit, and a fourth part providing means to connect a supply conduit, the first and third parts and the second and fourth parts respectively communicating with each other within the manifold. The fluid exchanges heat with the earth as it flows in the casing. The manifold provides the connection to the casing, dip tube, output conduit and supply conduit in a common vertical plane; and means to close the hole to prevent the passage of fluid therethrough.

  20. Thermal energy storage heat exchanger: Molten salt heat exchanger design for utility power plants

    NASA Technical Reports Server (NTRS)

    Ferarra, A.; Yenetchi, G.; Haslett, R.; Kosson, R.

    1977-01-01

    The use of thermal energy storage (TES) in the latent heat of molten salts as a means of conserving fossil fuels and lowering the cost of electric power was evaluated. Public utility systems provided electric power on demand. This demand is generally maximum during late weekday afternoons, with considerably lower overnight and weekend loads. Typically, the average demand is only 60% to 80% of peak load. As peak load increases, the present practice is to purchase power from other grid facilities or to bring older less efficient fossil-fuel plants on line which increase the cost of electric power. The widespread use of oil-fired boilers, gas turbine and diesel equipment to meet peaking loads depletes our oil-based energy resources. Heat exchangers utilizing molten salts can be used to level the energy consumption curve. The study begins with a demand analysis and the consideration of several existing modern fossil-fuel and nuclear power plants for use as models. Salts are evaluated for thermodynamic, economic, corrosive, and safety characteristics. Heat exchanger concepts are explored and heat exchanger designs are conceived. Finally, the economics of TES conversions in existing plants and new construction is analyzed. The study concluded that TES is feasible in electric power generation. Substantial data are presented for TES design, and reference material for further investigation of techniques is included.

  1. Condensing Heat Exchanger with Hydrophilic Antimicrobial Coating

    NASA Technical Reports Server (NTRS)

    Thomas, Christopher M. (Inventor); Ma, Yonghui (Inventor)

    2014-01-01

    A multi-layer antimicrobial hydrophilic coating is applied to a substrate of anodized aluminum, although other materials may form the substrate. A silver layer is sputtered onto a thoroughly clean anodized surface of the aluminum to about 400 nm thickness. A layer of crosslinked, silicon-based macromolecular structure about 10 nm thickness overlies the silver layer, and the outermost surface of the layer of crosslinked, silicon-based macromolecular structure is hydroxide terminated to produce a hydrophilic surface with a water drop contact angle of less than 10.degree.. The coated substrate may be one of multiple fins in a condensing heat exchanger for use in the microgravity of space, which has narrow channels defined between angled fins such that the surface tension of condensed water moves water by capillary flow to a central location where it is pumped to storage. The antimicrobial coating prevents obstruction of the capillary passages.

  2. DEVELOPMENT OF ODS HEAT EXCHANGER TUBING

    SciTech Connect

    Mark A. Harper, Ph.D.

    2001-01-01

    The Vision 21 project titled ''Development of ODS Heat Exchanger Tubing'' has been initiated. A project kick-off meeting was held in Huntington, WV, the MA956 powder that will be used in the extrusion campaign has been obtained, and some of the MA956 tubing and rod required for joining trials has been shipped to the appropriate subcontractors. Acquisition of the MA956 alloy powder will allow the extrusion campaign to begin during the month of February. Also, tubing shipped to Edison Welding Institute and rod shipped to Michigan Technological University will allow joining trials to begin. In addition to these technical aspects, negotiations with all the subcontractors have been completed and the Project Management Plan and Project Work Plan have been prepared and submitted for approval.

  3. Global optimization algorithm for heat exchanger networks

    SciTech Connect

    Quesada, I.; Grossmann, I.E. (Carnegie Mellon Univ., Pittsburgh, PA (United States))

    1993-03-01

    This paper deals with the global optimization of heat exchanger networks with fixed topology. It is shown that if linear area cost functions are assumed, as well as arithmetic mean driving force temperature differences in networks with isothermal mixing, the corresponding nonlinear programming (NLP) optimization problem involves linear constraints and a sum of linear fractional functions in the objective which are nonconvex. A rigorous algorithm is proposed that is based on a convex NLP underestimator that involves linear and nonlinear estimators for fractional and bilinear terms which provide a tight lower bound to the global optimum. This NLP problem is used within a spatial branch and bound method for which branching rules are given. Basic properties of the proposed method are presented, and its application is illustrated with several example problems. The results show that the proposed method only requires few nodes in the branch and bound search.

  4. Predict the temperature distribution in gas-to-gas heat pipe heat exchanger

    NASA Astrophysics Data System (ADS)

    Azad, E.

    2012-07-01

    A theoretical model has been developed to investigate the thermal performance of a continuous finned circular tubing of an air-to-air thermosyphon-based heat pipe heat exchanger. The model has been used to determine the heat transfer capacity, which expresses the thermal performance of heat pipe heat exchanger. The model predicts the temperature distribution in the flow direction for both evaporator and condenser sections and also the saturation temperature of the heat pipes. The approach used for the present study considers row-by-row heat-transfer in evaporator and condenser sections of the heat pipe heat exchanger.

  5. Entropy resistance analyses of a two-stream parallel flow heat exchanger with viscous heating

    NASA Astrophysics Data System (ADS)

    Cheng, Xue-Tao; Liang, Xin-Gang

    2013-08-01

    Heat exchangers are widely used in industry, and analyses and optimizations of the performance of heat exchangers are important topics. In this paper, we define the concept of entropy resistance based on the entropy generation analyses of a one-dimensional heat transfer process. With this concept, a two-stream parallel flow heat exchanger with viscous heating is analyzed and discussed. It is found that the minimization of entropy resistance always leads to the maximum heat transfer rate for the discussed two-stream parallel flow heat exchanger, while the minimizations of entropy generation rate, entropy generation numbers, and revised entropy generation number do not always.

  6. Industrial utilization of heat exchangers for waste-heat recovery in New York State. Final report

    Microsoft Academic Search

    Caron

    1984-01-01

    Waste-heat recovery has not been achieved to its fullest potential although its technology has been well-established for two decades. However, recent developments in heat-exchanger technology coupled with higher fuel costs have further increased energy-conservation possibilities and enhanced the incentive for waste-heat recovery. This report is designed to encourage use of new heat-exchanger designs by examining the heat-exchanger technologies that have

  7. Thermal and economic analysis of plastic heat exchangers for solar water heating

    SciTech Connect

    Liu, W.; Davidson, J.; Raman, R.; Mantell, S.

    1999-07-01

    The feasibility of polymer heat exchangers for solar water heaters is examined in terms of thermal performance and cost of tube-in-shell and immersed designs. High temperature nylon and cross-linked polyethylene were identified as suitable polymers for this application. These materials can meet the high temperature and pressure requirements of a domestic potable hot water system. The heat exchanger designs are compared for heat transfer area required to provide 3,000 and 6,000 W. A nylon tube-in-shell heat exchanger, sized for a 3,000 W load, is approximately 80% of the cost of a copper tube-in-shell heat exchanger. For an immersed heat exchanger, a high temperature nylon tube bank design has the lowest cost. The nylon tube bank heat exchanger, sized for a 3,000 W load, is approximately 80% the cost of an immersed coiled copper tube heat exchanger.

  8. Protective coating for copper in aluminum heat exchangers

    NASA Technical Reports Server (NTRS)

    Avazian, R.

    1978-01-01

    Application of ultrathin layer of molybdenum disulfied coating to copper tubing permits utilization of tubing in cast-aluminum heat exchangers. Coating prevents formation of copper/aluminum eutectic, but does not impede heat transfer.

  9. Automatic Tube Cleaning Systems for Condensers & Heat Exchangers

    E-print Network

    Someah, K.

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

  10. Biofouling monitors for noncylindrical OTEC heat exchanger tubes

    Microsoft Academic Search

    T. M. Kuzay; A. P. Gavin; C. B. Panchal

    1982-01-01

    Heat-transfer monitors (HTMs) have been used to measure the reduction in the seawater heat-transfer coefficient due to buildup of biofouling and corrosion products inside circular tubes of shell-and-tube heat exchangers being developed for ocean thermal energy conversion (OTEC) plants. For OTEC heat exchangers (HXs) with other tube geometries, special, modified HTMs, which we call STMs, are being sought. The analytical

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

    E-print Network

    of the heat flow in the ground is used to predict the temperature rise and fall over time of the fluidLimitations of Using Uniform Heat Flux Assumptions in Sizing Vertical Borehole Heat Exchanger heat exchangers and the surrounding ground are essential for design, optimization and energy analysis

  12. Heat Recovery Ventilation for Housing: Air-to-Air Heat Exchangers.

    ERIC Educational Resources Information Center

    Corbett, Robert J.; Miller, Barbara

    The air-to-air heat exchanger (a fan powered ventilation device that recovers heat from stale outgoing air) is explained in this six-part publication. Topic areas addressed are: (1) the nature of air-to-air heat exchangers and how they work; (2) choosing and sizing the system; (3) installation, control, and maintenance of the system; (4) heat

  13. Compact Tube and Plate-Finned Heat Exchangers

    Microsoft Academic Search

    ELWIN KONSTANTINOVICH KALININ; GENRIKH ALEKSANDROVICH DREITSER; EUGENII VLADIMIROVICH DUBROVSKY

    1985-01-01

    A highly effective method for heat transfer enhancement in tube and plate-finned heat exchangers through artificial flow turbulization is proposed. Heat transfer surfaces of different design and their production are developed. A correlation for the increase in heat transfer is found as a function of increasing hydraulic resistance for channels of various cross sections. Results are compared with similar smooth

  14. Combined Steady-State and Dynamic Heat Exchanger Experiment

    ERIC Educational Resources Information Center

    Luyben, William L.; Tuzla, Kemal; Bader, Paul N.

    2009-01-01

    This paper describes a heat-transfer experiment that combines steady-state analysis and dynamic control. A process-water stream is circulated through two tube-in-shell heat exchangers in series. In the first, the process water is heated by steam. In the second, it is cooled by cooling water. The equipment is pilot-plant size: heat-transfer areas…

  15. A modified entropy generation number for heat exchangers

    NASA Astrophysics Data System (ADS)

    Xu, Z. M.; Yang, S. R.; Chen, Z. Q.

    1996-12-01

    This paper demonstrates the difference between the entropy generation number method proposed by Bejan and the method of entropy generation per unit amount of heat transferred in analyzing the thermodynamic performance of heat exchangers, points out the reason for leading to the above difference. A modified entropy generation number for evaluating the irreversibility of heat exchangers is proposed which is in consistent with the entropy generation per unit amount of heat transferred in entropy generation analysis. The entropy generated by friction is also investigated. Results show that when the entropy generated by friction in heat exchangers is taken into account, there is a minimum total entropy generation number while the NTU and the ratio of heat capacity rates vary. The existence of this minimum is the prerequisite of heat exchanger optimization.

  16. Two dimensional model for multistream plate fin heat exchangers

    NASA Astrophysics Data System (ADS)

    Goyal, Mukesh; Chakravarty, Anindya; Atrey, M. D.

    2014-05-01

    A model based on finite volume analysis is presented here for multistream plate fin heat exchangers for cryogenic applications. The heat exchanger core is discretised in both the axial and transverse directions. The model accounts for effects of secondary parameters like axial heat conduction through the heat exchanger metal matrix, parasitic heat in-leak from surroundings, and effects of variable fluid properties/metal matrix conductivity. Since the fins are discretised in the transverse direction, the use of a fin efficiency is eliminated and the effects of transverse heat conduction/stacking pattern can be taken care of. The model is validated against results obtained using commercially available software and a good agreement is observed. Results from the developed code are discussed for sample heat exchangers.

  17. The impact of heat exchanger fouling on the optimum operation and maintenance of the Stirling engine

    Microsoft Academic Search

    M. Kuosa; J. Kaikko; L. Koskelainen

    2007-01-01

    This paper focuses on the effect of heat exchanger fouling on the performance of the Stirling engine in combined heat and power (CHP) application. Fouling results from using biomass fuels and affects the heat exchanger that transfers heat into the engine. This heat exchanger is referred to as the heater. The heat exchanger that recovers heat from the flue gases

  18. Effectively design shell-and-tube heat exchangers

    Microsoft Academic Search

    1998-01-01

    Thermal design of shell-and-tube heat exchangers (STHEs) is done by sophisticated computer software. However, a good understanding of the underlying principles of exchanger design is needed to use this software effectively. This article explains the basics of exchanger thermal design, covering such topics as: STHE components; classification of STHEs according to construction and according to service; data needed for thermal

  19. Thermohydraulic Simulation of Heat Exchanger Networks Subjected to Fouling

    Microsoft Academic Search

    Viviane B. G. Tavares; André L. H. Costa; Eduardo M. Queiroz; Fernando L. P. Pessoa; Fábios S. Liporace; Sérgio G. Oliveira

    2009-01-01

    Fouling is a complex problem which affects thermal equipment. The deposits over the heat exchanger surface diminish the thermal effectiveness and increase flow resistances. The consequences of fouling are related to important economic penalties, such as, more expensive equipment with larger thermal surfaces, higher energy consumption costs (heat\\/power), shutdown costs for exchanger cleaning, fluid treatment costs, etc. Despite the considerable

  20. Numerical computation of sapphire crystal growth using heat exchanger method

    Microsoft Academic Search

    Chung-Wei Lu; Jyh-Chen Chen

    2001-01-01

    The finite element software FIDAP is employed to study the temperature and velocity distribution and the interface shape during a large sapphire crystal growth process using a heat exchanger method (HEM). In the present study, the energy input to the crucible by the radiation and convection inside the furnace and the energy output through the heat exchanger is modeled by

  1. Multi-objective optimization of shell and tube heat exchangers

    Microsoft Academic Search

    Sepehr Sanaye; Hassan Hajabdollahi

    2010-01-01

    The effectiveness and cost are two important parameters in heat exchanger design. The total cost includes the capital investment for equipment (heat exchanger surface area) and operating cost (for energy expenditures related to pumping). Tube arrangement, tube diameter, tube pitch ratio, tube length, tube number, baffle spacing ratio as well as baffle cut ratio were considered as seven design parameters.

  2. Use of phosphoric acid to remove heat exchanger deposits

    Microsoft Academic Search

    T. M. Idrisova; Yu. M. Avyzgil'din; G. G. Telyashev; F. G. Gataullin; Yu. I. Kir'yanov

    1979-01-01

    removing these deposits. The deposits that foul heat exchangers usually consist of inorganic compounds cemented by tarry poly- merized products (1); they are formed in heat exchangers through the oxidation of hydrocarbons at high tem- peratures. Operating experience at the Novo-Ufa refinery has indicated that the initial processing of mixed West Siberian crudes in the unit was accompanied by a

  3. Circulating heat exchangers for oscillating wave engines and refrigerators

    DOEpatents

    Swift, Gregory W.; Backhaus, Scott N.

    2003-10-28

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

  4. The heat exchanger of small pellet boiler for phytomass

    NASA Astrophysics Data System (ADS)

    Mi?ieta, Jozef; Lenhard, Richard; Janda?ka, Jozef

    2014-08-01

    Combustion of pellets from plant biomass (phytomass) causes various troubles. Main problem is slagging ash because of low melting temperature of ash from phytomass. This problem is possible to solve either improving energetic properties of phytomass by additives or modification of boiler construction. A small-scale boiler for phytomass is different in construction of heat exchanger and furnace mainly. We solve major problem - slagging ash, by decreasing combustion temperature via redesign of pellet burner and boiler body. Consequence of lower combustion temperature is also lower temperature gradient of combustion gas. It means that is necessary to design larger heat exchanging surface. We plane to use underfed burner, so we would utilize circle symmetry heat exchanger. Paper deals design of heat exchanger construction with help of CFD simulation. Our purpose is to keep uniform water flux and combustion gas flux in heat exchanger without zone of local overheating and excess cooling.

  5. Reactor safety research section probability of heat exchanger leaks

    SciTech Connect

    Cramer, D.S.; Shine, E.P.; Copeland, W.J.

    1992-02-01

    Three heat exchangers (HXs) were changed out after the December 1991 leak of Process Water to the Savannah River. This leaves 6 of the original 304 stainless steel heat exchangers which will remain in K-Reactor for restart. This report discusses SRS site specific data which were used to estimate the probability of a leak within a one-year period as a function of leak rate and root cause in these six heat exchangers in conjunction with six new heat exchangers presently in service in K-Reactor. Based on several assumptions and statistical models, SRS data indicate that the total probability of a leak occurring during a one-year period in K-Reactor with 6 original (304 stainless steel) and 6 new (316-L or SEA-CURE) heat exchangers, with a leak rate greater than 20, 40 or 90 pounds/hr, is 0.013, 0.004 or 0.0005, respectively.

  6. Dynamic Simulation of Shell-and-Tube Heat Exchangers

    Microsoft Academic Search

    DANIEL J. CORREA; JACINTO L. MARCHETTI

    1987-01-01

    The transient operation of a multipass shell-and-tube heat exchanger with baffles is described by a multicell dynamic model where every cell represents a specific part of the exchanger. The proposed modeling technique can be used in a digital computer for the dynamic simulation of almost any type of shell-and-tube heat exchanger. The model includes time-dependent inlet conditions for both the

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

    E-print Network

    Witte, L. C.

    THE INFLUENCE OF AVAILABILITY COSTS ON OPTIMAL H~ EXCHANGER SIZE Larry C. Witte Professor of Mechanical Engineering University of Houston Houston, TX 77004 examples of such a process. I I Optimizing heat exchangers based on se cond law... rather than first law co~idera? tions e~ures that the most efficient use of available energy is being made. ~chnique8 for second-law optimising heat exchangers have been developed recently that are straightforward and simple. The main diffi culty...

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

    DOEpatents

    Drake, Richard L. (Delmar, NY)

    1993-01-01

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

  9. Development of a New Type Heat Exchanger for Natural Refrigerant CO2 Heat Pump Water Heaters

    Microsoft Academic Search

    Kazushige KASAI; Yutaka SHIBATA

    2005-01-01

    The hot-water supply heat exchanger installed in CO2 heat pump water heater was developed. In order to use for the design of the heat exchanger, precise performance simulation was developed and the dimension was optimized. This heat exchanger can supply 90 degrees C hot-water, and the counter flow style is employed in order to use the characteristic of CO2 refrigerant.

  10. Heat transfer characteristics of a new helically coiled crimped spiral finned tube heat exchanger

    Microsoft Academic Search

    Kwanchanok Srisawad; Somchai Wongwises

    2009-01-01

    In the present study, the heat transfer characteristics in dry surface conditions of a new type of heat exchanger, namely\\u000a a helically coiled finned tube heat exchanger, is experimentally investigated. The test section, which is a helically coiled\\u000a fined tube heat exchanger, consists of a shell and a helical coil unit. The helical coil unit consists of four concentric\\u000a helically

  11. Performance testing of a two-phase interface heat exchanger

    NASA Technical Reports Server (NTRS)

    Mccabe, M. E., Jr.; Swanson, T. D.

    1989-01-01

    This paper describes the design and performance testing of a heat exchanger which interfaces separate two-phase ammonia thermal loops. The basic design involves a tube-in-tube concept, with boiling occurring in the inner tube and condensation in the outer tube. Eight such tubes are arranged in parallel. Testing has demonstrated that up to 8.2 kW of heat may be transferred across the heat exchanger when the saturation temperature difference between the systems is 5 C. Performance of the heat exchanger is affected primarily by the mass flow rate of ammonia in the liquid supply loop.

  12. The Design on the Refrigerant Circuit of Heat Exchanger

    NASA Astrophysics Data System (ADS)

    Wang, Kaijian; Fukaya, Masaharu; Ding, Guoliang; Liu, Jian

    The efficient design method for plate fin-and-tube heat exchanger has been developed with the directed graph(graph-based traversal method) in graph theory and the distribution model of refrigerant flow rate. According to the experimental results of heat exchanger which is carried out under 98 experimental conditions of the changes of air velocity and the refrigerant flow rates and so on, by using the refrigerant R 22 and R 410A, we conclude the following deviations of analysis: the heat transfer rate is within ±10% and the pressure drop is within ±20%. Now this design method has being used for designing plate fin-and-tube heat exchangers efficiently.

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

    SciTech Connect

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

    1993-04-01

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

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

    NASA Technical Reports Server (NTRS)

    Skupinski, Robert C.; Tower, Leonard K.; Madi, Frank J.; Brusk, Kevin D.

    1993-01-01

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

  15. Heat exchanger header with parallel edges

    SciTech Connect

    Smith, D.M.

    1993-08-24

    A heat exchanger is described, comprising: a pair of fluid tank units supporting a plurality of parallel tube passes extending in fluid communication therebetween; each of the tank units having a separate tank member and header secured to one another to form the tank unit, the tank member having parallel walls including grooves at the base of each of which is formed a protrusion that is curved in cross section and which runs the length of each respective groove, the header having an arcuate interior surface including perimeter side flanges that fit into the grooves and against the curved protrusions, the header also having a plurality of slots and surrounding wells through which the ends of the tube passes are receivable, the edges of the wells terminating short of the side flanges and having a curvature that blends into the arcuate shape of the side flanges as well as complementing the cross sectional curvature of the protrusions, whereby, when the tank member and header are secured, the protrusions, side flange interior surfaces, and well edges mate together so as to provide complete sealing contact and reinforcement for the securement.

  16. Peltier cooling system utilizing liquid heat exchanger combined with pump

    Microsoft Academic Search

    H. Nishihata; O. Kido; T. Ueno

    2002-01-01

    Peltier cooling systems utilizing liquid heat transfer directly with thermoelectric modules are adopted in fridges for hotel-use, home-bar and so forth. This paper reports the development of a highly efficient, high capacity liquid heat exchanger in which a thermoelectric module is installed to minimize electric power consumption and reduce cost. In the heat exchanger, a highly efficient 62-mm diameter round

  17. Heat exchangers for use in the culturing of marine organisms

    Microsoft Academic Search

    John E. Huguenin

    1976-01-01

    Marine Biological experiments often require controlling the seawater temperature in flowing culture systems. This heating\\u000a or cooling of seawater is generally accomplished with a heat exchanger and an intermediary fluid. The major consideration\\u000a in the choice of a heat exchanger is often finding a unit whose material is compatible with seawater, with the culture organisms\\u000a and with the objectives of

  18. Experimental Study on Heat Transfer of Plate Heat Exchanger and Application to Waste Heat Power Generation

    NASA Astrophysics Data System (ADS)

    Tang, X. Y.; Zhu, D. S.; Guo, C. Q.

    2010-03-01

    According to investigation on the steel plant, a large amount of low thermal energy is emitted directly to the environment without any utilization. It is apparent that energy cogeneration and energy conversion become a problem concerned by all countries. At present, the utilization of thermal energy stored in slag washing water is mainly confined to transformation to heating rather than electricity generation. The working mechanism of electricity generation using slag washing water and experimental study on heat transfer characteristics of plate heat exchanger are presented in this paper. The experimental results show the non-linear relationship between heat transfer coefficient of plate heat exchanger made by different materials and different flow velocity of clean water in the pipe. When the flow velocity is greater than 1 m/s, K retains a certain value while the resistance coefficient increases dramatically. By comparison of experimental data, it is found that the heat resistance outside plate heat exchanger is the main factor that influences performance of plate heat transfer.

  19. Temperature distribution in internally heated walls of heat exchangers composed of nonnuclear flow passages

    NASA Technical Reports Server (NTRS)

    Eckert, E R G; Low, George M

    1951-01-01

    In the walls of heat exchangers composed of noncircular passages, the temperature varies in the circumferential direction because of local variations of the heat-transfer coefficients. A prediction of the magnitude of this variation is necessary in order to determine the region of highest temperature and in order to determine the admissible operating temperatures. A method for the determination of these temperature distributions and of the heat-transfer characteristics of a special type of heat exchanger is developed. The heat exchanger is composed of polygonal flow passages and the passage walls are uniformly heated by internal heat sources. The coolant flow within the passages is assumed to be turbulent. The circumferential variation of the local heat-transfer coefficients is estimated from flow measurements made by Nikuradse, postulating similarity between velocity and temperature fields. Calculations of temperature distributions based on these heat-transfer coefficients are carried out and results for heat exchangers with triangular and rectangular passages are presented.

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

    DOEpatents

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

    1994-11-29

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

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

    E-print Network

    Chen, Y.; Zhang, J.

    2006-01-01

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

  2. Heat transfer of high thermal energy storage with heat exchanger for solar trough power plant

    Microsoft Academic Search

    Sarayooth Vaivudh; Wattanapong Rakwichian; Sirinuch Chindaruksa

    2008-01-01

    High temperature thermal energy storage was studied by a lab-scale cylindrical storage tank experiment. A heat exchanger of thermal energy storage is used for separating two fluids, storage medium, and heat transfer fluid (HTF). There are two types of pipe in the heat exchanger, a vertical straight pipe and a helical coiled pipe. The experimental results were validated with the

  3. Heat transfer characteristics of flat plate finned-tube heat exchangers with large fin pitch

    Microsoft Academic Search

    Yonghan Kim; Yongchan Kim

    2005-01-01

    The objective of this study is to provide experimental data that can be used in the optimal design of flat plate finned-tube heat exchangers with large fin pitch. In this study, 22 heat exchangers were tested with a variation of fin pitch, number of tube row, and tube alignment. The air-side heat transfer coefficient decreased with a reduction of the

  4. Evaporation heat transfer and pressure drop of refrigerant R-134a in a plate heat exchanger

    Microsoft Academic Search

    Y.-Y. Yan; T.-F. Lin

    1999-01-01

    Plate heat exchangers (PHE) have been widely used in food processing, chemical reaction processes, and other industrial applications for many years. Particularly, in the last 20 years plate heat exchangers have been introduced to the refrigeration and air conditioning systems as evaporators or condensers for their high efficiency and compactness. Here, the evaporation heat transfer coefficient and pressure drop for

  5. Solar power plant equipped with high efficiency heat exchangers

    Microsoft Academic Search

    Moisdon

    1981-01-01

    This is a description of solar power plant having a plurality of modular units, which form improved heat exchangers by enhancement of heat transfer surfaces, through the action of wipers and the draining down of transfer surfaces. The whole structure is insulated by a film of lubricant, and a solar heater booster provides additional heating capabilities.

  6. Analytical modeling of water condensation in condensing heat exchanger

    Microsoft Academic Search

    Kwangkook Jeong; Michael J. Kessen; Harun Bilirgen; Edward K. Levy

    2010-01-01

    An analytical model of heat and mass transfer processes in a flue gas condensing heat exchanger system was developed to predict the heat transferred from flue gas to cooling water and the condensation rate of water vapor in the flue gas. Flue gas exit temperature, cooling water outlet temperature, water vapor mole fraction, and condensation rate of water vapor were

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

    DOEpatents

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

    1982-08-31

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

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

    DOEpatents

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

    1985-05-14

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

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

    DOEpatents

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

    1985-01-01

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

  10. Geothermal application of heat exchanger design for desalination plants

    SciTech Connect

    Fritzler, E.A.; Coury, G.E.

    1980-09-01

    Heat exchangers can be a very costly part of modern geothermal plants for either electric or direct heat applications. To make maximum use of technology transfer from other industries, and to minimize as much as possible the need to duplicate previous work, this report has been prepared to provide an analytical review of the very extensive literature on heat exchangers developed by the Office of Saline Water (OSW). The OSW accomplished a very large amount of significant work related to the design and performance of large heat exchanger bundles and enhanced heat transfer surfaces. The exchanger design configurations that were studied include multistage flash plant condensers, vertical tube falling film and upward flow evaporators, and horizontal tube spray film evaporators.

  11. 40 CFR 63.1083 - Does this subpart apply to my heat exchange system?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... false Does this subpart apply to my heat exchange system? 63.1083 Section...for Ethylene Manufacturing Process Units: Heat Exchange Systems and Waste Operations Applicability for Heat Exchange Systems § 63.1083 Does...

  12. 40 CFR 63.1083 - Does this subpart apply to my heat exchange system?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... false Does this subpart apply to my heat exchange system? 63.1083 Section...for Ethylene Manufacturing Process Units: Heat Exchange Systems and Waste Operations Applicability for Heat Exchange Systems § 63.1083 Does...

  13. 40 CFR 63.1085 - What are the general requirements for heat exchange systems?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...false What are the general requirements for heat exchange systems? 63.1085 Section 63...Standards for Ethylene Manufacturing Process Units: Heat Exchange Systems and Waste Operations Heat Exchange System Requirements § 63.1085...

  14. 40 CFR 63.1085 - What are the general requirements for heat exchange systems?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...false What are the general requirements for heat exchange systems? 63.1085 Section 63...Standards for Ethylene Manufacturing Process Units: Heat Exchange Systems and Waste Operations Heat Exchange System Requirements § 63.1085...

  15. Obtaining Closure for Fin-and-Tube Heat Exchanger Modeling Based on Volume Averaging Theory (VAT)

    E-print Network

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

    2011-01-01

    in fin-and-tube heat exchangers for design and optimizationtube heat exchangers based on volume averaging theory with the help of designdesign of experiments (DOE), the performance of a fin-and-tube heat exchanger

  16. 40 CFR 63.11499 - What are the standards and compliance requirements for heat exchange systems?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...standards and compliance requirements for heat exchange systems? (a) If the cooling water flow rate in your heat exchange system is equal to or...reactor as the surrogate indicator of heat exchanger system leaks when complying...

  17. 40 CFR 63.11499 - What are the standards and compliance requirements for heat exchange systems?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...standards and compliance requirements for heat exchange systems? (a) If the cooling water flow rate in your heat exchange system is equal to or...reactor as the surrogate indicator of heat exchanger system leaks when complying...

  18. 40 CFR 63.11499 - What are the standards and compliance requirements for heat exchange systems?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...standards and compliance requirements for heat exchange systems? (a) If the cooling water flow rate in your heat exchange system is equal to or...reactor as the surrogate indicator of heat exchanger system leaks when complying...

  19. 40 CFR 63.11499 - What are the standards and compliance requirements for heat exchange systems?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...standards and compliance requirements for heat exchange systems? (a) If the cooling water flow rate in your heat exchange system is equal to or...reactor as the surrogate indicator of heat exchanger system leaks when complying...

  20. 40 CFR 63.11499 - What are the standards and compliance requirements for heat exchange systems?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...standards and compliance requirements for heat exchange systems? (a) If the cooling water flow rate in your heat exchange system is equal to or...reactor as the surrogate indicator of heat exchanger system leaks when complying...

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

    SciTech Connect

    Panchal, C.B.

    1993-07-01

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

  2. Study of transient behavior of finned coil heat exchangers

    NASA Astrophysics Data System (ADS)

    Rooke, S. P.; Elissa, M. G.

    1993-11-01

    The status of research on the transient behavior of finned coil cross-flow heat exchangers using single phase fluids is reviewed. Applications with available analytical or numerical solutions are discussed. Investigation of water-to-air type cross-flow finned tube heat exchangers is examined through the use of simplified governing equations and an up-wind finite difference scheme. The degenerate case of zero air-side capacitance rate is compared with available exact solution. Generalization of the numerical model is discussed for application to multi-row multi-circuit heat exchangers.

  3. Study of transient behavior of finned coil heat exchangers

    NASA Technical Reports Server (NTRS)

    Rooke, S. P.; Elissa, M. G.

    1993-01-01

    The status of research on the transient behavior of finned coil cross-flow heat exchangers using single phase fluids is reviewed. Applications with available analytical or numerical solutions are discussed. Investigation of water-to-air type cross-flow finned tube heat exchangers is examined through the use of simplified governing equations and an up-wind finite difference scheme. The degenerate case of zero air-side capacitance rate is compared with available exact solution. Generalization of the numerical model is discussed for application to multi-row multi-circuit heat exchangers.

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

    DOEpatents

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

    1993-11-30

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

  5. Slotting Fins of Heat Exchangers to Provide Thermal Breaks

    NASA Technical Reports Server (NTRS)

    Scull, Timothy D.

    2003-01-01

    Heat exchangers that include slotted fins (in contradistinction to continuous fins) have been invented. The slotting of the fins provides thermal breaks that reduce thermal conduction along flow paths (longitudinal thermal conduction), which reduces heat-transfer efficiency. By increasing the ratio between transverse thermal conduction (the desired heat-transfer conduction) and longitudinal thermal conduction, slotting of the fins can be exploited to (1) increase heat-transfer efficiency (thereby reducing operating cost) for a given heat-exchanger length or to (2) reduce the length (thereby reducing the weight and/or cost) of the heat exchanger needed to obtain a given heat transfer efficiency. By reducing the length of a heat exchanger, one can reduce the pressure drop associated with the flow through it. In a case in which slotting enables the use of fins with thermal conductivity greater than could otherwise be tolerated on the basis of longitudinal thermal conduction, one can exploit the conductivity to make the fins longer (in the transverse direction) than they otherwise could be, thereby making it possible to make a heat exchanger that contains fewer channels and therefore, that weighs less, contains fewer potential leak paths, and can be constructed from fewer parts and, hence, reduced cost.

  6. Experimental determination of correlations for average heat transfer coefficients in heat exchangers on both fluid sides

    NASA Astrophysics Data System (ADS)

    Taler, Dawid

    2013-08-01

    This paper presents an experimental-numerical method for determining heat transfer coefficients in cross-flow heat exchangers with extended heat exchange surfaces. Coefficients in the correlations defining heat transfer on the liquid- and air-side were determined based on experimental data using a non-linear regression method. Correlation coefficients were determined from the condition that the weighted sum of squared liquid and air temperature differences at the heat exchanger outlet, obtained by measurements and those calculated, achieved minimum. Minimum of the sum of the squares was found using the Levenberg-Marquardt method. The uncertainty in estimated parameters was determined using the error propagation rule by Gauss. The outlet temperature of the liquid and air leaving the heat exchanger was calculated using an analytical model of the heat exchanger.

  7. Acoustically enhanced heat exchange and drying apparatus

    DOEpatents

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

    1987-07-10

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

  8. SILICON CARBIDE CERAMICS FOR COMPACT HEAT EXCHANGERS

    SciTech Connect

    DR. DENNIS NAGLE; DR. DAJIE ZHANG

    2009-03-26

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

  9. Heat exchanger for reactor core and the like

    DOEpatents

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

    1986-01-01

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

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

    SciTech Connect

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

    2011-06-01

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

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

    SciTech Connect

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

    2011-04-01

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

  12. Oscillating side-branch enhancements of thermoacoustic heat exchangers

    DOEpatents

    Swift, Gregory W.

    2003-05-13

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

  13. 40 CFR 63.1409 - Heat exchange system provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...FOR SOURCE CATEGORIES National Emission Standards for Hazardous Air Pollutant Emissions: Manufacture of Amino/Phenolic Resins § 63.1409 Heat exchange system provisions. (a) Unless one or more of the conditions specified...

  14. Energy effectiveness of simultaneous heat and mass exchange devices

    E-print Network

    Narayan, G. Prakash

    2010-01-01

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

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

    E-print Network

    Lazaridis, A.; Rafailidis, E.

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

  16. Prototype solar-heated hot water systems and double-walled heat exchangers

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Development progress made on two solar-heated hot water systems and two heat exchangers is reported. The development, manufacture, installation, maintenance, problem resolution, and system evaluation are described.

  17. Tube vibration in industrial size test heat exchanger

    Microsoft Academic Search

    H. Halle; M. W. Wambsganss

    1980-01-01

    Tube vibration data from tests of a specially built and instrumented, industrial-type, shell-and-tube heat exchanger are reported. The heat exchanger is nominally 0.6 m (2 ft) in dia and 3.7 m (12 ft) long. Both full tube and no-tubes-in-window bundles were tested for inlet\\/outlet nozzles of different sizes and with the tubes supported by seven, equally-spaced, single-segmental baffles. Prior to

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

    E-print Network

    Lovelady, Jeffery Paul

    1988-01-01

    THE DESIGN, CONSTRUCTION, AND CALIBRATION OF A HEAT EXCHANGER CALORIMETER A Thesis by JEFFERY PAUL LOVELADY Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE December 1988 Major Subject: Mechanical Engineering THE DESIGN, CONSTRUCTION, AND CALIBRATION OF A HEAT EXCHANGER CALORIMETER A Thesis by JEFFERY PAUL LOVELADY Approved as to style and content by: N. K. Anand (Chairman...

  19. Two-phase/two-phase heat exchanger analysis

    NASA Technical Reports Server (NTRS)

    Kim, Rhyn H.

    1992-01-01

    A capillary pumped loop (CPL) system with a condenser linked to a double two-phase heat exchanger is analyzed numerically to simulate the performance of the system from different starting conditions to a steady state condition based on a simplified model. Results of the investigation are compared with those of similar apparatus available in the Space Station applications of the CPL system with a double two-phase heat exchanger.

  20. Large eddy simulation of turbulence within heat exchangers

    E-print Network

    Pruitt, John Myron

    1992-01-01

    LARGE EDDY SIMULATION OF TURBULENCE WITHIN HEAT EXCHANGERS A Thesis by JOHN MYRON PRUITI' Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May... 1992 Major Subject: Nuclear Engineering LARGE EDDY SIMULATION OF TURBULENCE WITHIN HEAT EXCHANGERS A Thesis by JOHN MYRON PRUIIT Approved as to style and content by: in A. assan (Chair of Committee) /dred'fed'p, Erian A. Baskharone (Member...

  1. Fin Distance Effect at Tube-Fin Heat Exchanger

    NASA Astrophysics Data System (ADS)

    Lemfeld, F.; Muller, M.; Frana, K.

    2013-04-01

    Article deals with numerical simulation of the Tube-Fin heat exchanger. Several distances between fins are examined with intence of increasing the cooling output of the heat exchanger. Geometrical model consists of set of 2 fins with input and output area. Calculations covers the area of the gap from 2.25 mm to 4 mm with new fin geometry. For the numerical silumation was used software Ansys Fluent.

  2. Analysis of Spray-Cooled Finned-Tube Heat Exchangers

    Microsoft Academic Search

    A. A. DREYER; D. E. KRIEL; P. J. ERENS

    1992-01-01

    A mathematical model has been developed for the analysis of spray-cooled finned-tube heat exchangers. An experimental study was conducted on a four-pass, finned-tube heat exchanger in a vertical air\\/water mist flow to validate the model, and the results compared well with the predicted performance.Significant performance enhancement (up to 3.5 times the dry performance) was found by spraying relatively small amounts

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

    SciTech Connect

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

    1981-01-01

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

  4. Modeling of plate heat exchangers with generalized configurations

    Microsoft Academic Search

    Jorge A. W. Gut; José M. Pinto

    2003-01-01

    A mathematical model is developed in algorithmic form for the steady-state simulation of gasketed plate heat exchangers with generalized configurations. The configuration is defined by the number of channels, number of passes at each side, fluid locations, feed connection locations and type of channel-flow. The main purposes of this model are to study the configuration influence on the exchanger performance

  5. In - line determination of heat transfer coefficients in a plate heat exchanger

    Microsoft Academic Search

    S. Silva Sotelo; R. J. Romero Domínguez

    2008-01-01

    \\u000a This paper shows an in – line determination of heat transfer coefficients in a plate heat exchanger. Water and aqueous working\\u000a solution of lithium bromide + ethylene glycol are considered. Heat transfer coefficients are calculated for both fluids. “Type\\u000a T” thermocouples were used for monitoring the wall temperature in a plate heat exchanger, which is one of the main components

  6. Acoustically enhanced heat exchange and drying apparatus

    DOEpatents

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

    1989-01-01

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

  7. Heat Exchanger Design Studies for AN Lhc Inner Triplet Upgrade

    NASA Astrophysics Data System (ADS)

    Rabehl, R. J.; Huang, Y.

    2008-03-01

    A luminosity upgrade of the CERN Large Hadron Collider (LHC) is planned to coincide with the expected end of life of the existing inner triplet quadrupole magnets. The upgraded inner triplet will have much larger heat loads to be removed from the magnets by the cryogenics system. A number of cryogenics design studies have been completed under the LHC Accelerator Research Program (LARP), including investigations of required heat exchanger characteristics to transfer this heat from the pressurized He II bath to the saturated He II system. This paper discusses heat exchangers both external to the magnet cold mass and internal to the magnet cold mass. A possible design for a heat exchanger external to the magnet cold mass is also presented.

  8. HEAT EXCHANGER DESIGN STUDIES FOR AN LHC INNER TRIPLET UPGRADE

    SciTech Connect

    Rabehl, R. J.; Huang, Y. [Fermi National Accelerator Laboratory Batavia, Illinois, 60510 (United States)

    2008-03-16

    A luminosity upgrade of the CERN Large Hadron Collider (LHC) is planned to coincide with the expected end of life of the existing inner triplet quadrupole magnets. The upgraded inner triplet will have much larger heat loads to be removed from the magnets by the cryogenics system. A number of cryogenics design studies have been completed under the LHC Accelerator Research Program (LARP), including investigations of required heat exchanger characteristics to transfer this heat from the pressurized He II bath to the saturated He II system. This paper discusses heat exchangers both external to the magnet cold mass and internal to the magnet cold mass. A possible design for a heat exchanger external to the magnet cold mass is also presented.

  9. Review of Heat Transfer and Pressure Drop Correlations for Evaporation of Fluid Flow in Plate Heat Exchangers (RP1352)

    Microsoft Academic Search

    Tariq S. Khan; Mohammad S. Khan; Ming-C. Chyu; Zahid H. Ayub; Javed A. Chattha

    2009-01-01

    Plate heat exchangers have been widely used in dairy, food processing, paper\\/pulp, heating, ventilating, and other related industry. While single-phase flow in plate heat exchangers has been studied extensively, the industry lacks basic information on fluid flow evaporating in plate heat exchangers. This paper provides a review of heat transfer and pressure drop correlations for fluid flow evaporating in plate

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

    E-print Network

    Fernández de Córdoba, Pedro

    Optimized design of a heat exchanger for an air-to-water reversible heat pump working with propane-to-water reversible heat pump unit was carried out using two different fin-and-tube heat exchanger ``coil'' designs of Performance; Heat exchangers 1. Introduction Due to ozone depletion that leads to global warming effects

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

    E-print Network

    Thole, Karen A.

    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

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

    E-print Network

    Gaskill, Travis

    2012-02-14

    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...

  13. Fan-less heat exchanger concept for CO 2 heat pump systems

    Microsoft Academic Search

    Petter Nekså; Rune L. Hoggen; Kåre Aflekt; Arne Jakobsen; Geir Skaugen

    2005-01-01

    A novel system for space heating has been developed taking advantage of the favourable characteristics of the transcritical CO2 cycle, where heat is rejected by cooling of supercritical gas at gliding temperature. By a proper design of a counter flow heat exchanger it is possible to heat air to high temperatures and thereby giving the driving force for circulation of

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

    DOEpatents

    Drake, R.L.

    1993-12-28

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

  15. Pressure drop across spined heat exchangers in crossflow

    E-print Network

    Carranza, Richard Guy

    1987-01-01

    . 792-inch tube spacings; and 1/8-inch nominal diameter spined tubes were set at 0. 896-inch, 0. 643-inch, and 0. 522-inch tube spacings. Rows were added one at a time ranging from 1 to 8, and air velocities ranged from 200 ft/min to 1100 ft... exchangers at 1. 125- inch tube spacing and one row of tubes. Figure of merit, 4q, for four heat exchangers at 0. 792- inch tube spacing and one row of tubes. Figure of merit, 4q, for four heat exchangers at 0. 897- inch tube spacing and one row of tubes...

  16. Advanced heat-pipe heat exchanger and microprocessor-based modulating burner controls development

    NASA Astrophysics Data System (ADS)

    Lowenstein, A.; Cohen, B.; Feldman, S.; Spatz, M.; Smith, E.

    1986-03-01

    The development of a novel condensing heat exchanger, a modulating gas burner, and a zone-controlled residential warm-air heating system is described. The condensing heat exchanger uses ten thermosyphons which are manifolded at both the condenser and evaporator ends to achieve a compact low-cost design. Initial tests have demonstrated a + 92 percent steady-state efficiency for a conventional clamshell furnace operating with the thermosyphon heat exchanger located outside the furnace cabinet. A 100,000 -Btu/hr modulating burner has also been developed. Comprehensive study of the burner's operating characteristics has produced guidelines for the design and application of the device. Finally, the modulating burner has been incorporated into a zone-controlled heating system. In parallel with the development of the preceding heating system components, the performance of thermosyphons over a wide range of operating conditions is being explored with the objective of improving design procedures for incorporating these devices into heat exchangers.

  17. A Proposal of a Nonlinear Observer Applied to the Heat Exchange Phenomena in a Double Pipe Heat Exchanger

    Microsoft Academic Search

    J. F. Briones; M. A. Paz; J. L. Gallegos; J. I. O. Rodriguez; S. C. Garibo

    \\u000a The aim of this paper is to show the heat exchange phenomena applied in a double pipe heat exchanger pilot plant scale, by\\u000a considering a macroscopic dynamic model, that describes the evolution of the temperature of hot and cold fluids in the equipment.\\u000a The proposed dynamic model is function of mean effective temperature difference and of the thermodynamic and transport

  18. A review of metal foam and metal matrix composites for heat exchangers and heat sinks

    Microsoft Academic Search

    Xiao-hong Han; Qin Wang; Young-Gil Park; Christophe T’Joen; Andrew Sommers; Anthony Jacobi

    2012-01-01

    Recent advances in manufacturing methods open the possibility for broader use of metal foams and metal matrix composites (MMCs) for heat exchangers, and these materials can have tailored material properties. Metal foams in particular combine a number of interesting properties from a heat exchanger's point of view. In this paper, the material properties of metal foams and MMCs are surveyed,

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

    E-print Network

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

    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...

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

    Microsoft Academic Search

    S. Somasundaram; M. M. Ohadi; S. Richlen

    1992-01-01

    An assessment is make of selected currently available heat exchanger enhancement techniques for single- and two-phase heat transfer mechanisms to determine their practicality and commercialization potential for different industrial applications. The assessment includes a screening review of the major techniques being investigated in the research community, and identification of selected passive techniques and determine their potential limitations with respect to

  1. GAS COOLED, MOLTEN SALT HEAT EXCHANGER--DESIGN STUDY

    Microsoft Academic Search

    MacPherson

    1958-01-01

    BS> One of the major problems in the economic evaluation of the ; application of forced circulation, gas cooling to high temperature, molten salt ; power reactor systems is the definition of the required heat transfer equipment, ; its size and operating cost. A design study of the saltto-gas heat exchangers ; for such a gas-cooled system has recently been

  2. A Freezable Heat Exchanger for Space Suit Radiator Systems

    NASA Technical Reports Server (NTRS)

    Nabity, James A.; Mason, Georgia R.; Copeland, Robert J.; Trevino, Luis a.

    2008-01-01

    During an ExtraVehicular Activity (EVA), both the heat generated by the astronaut s metabolism and that produced by the Portable Life Support System (PLSS) must be rejected to space. The heat sources include the heat of adsorption of metabolic CO2, the heat of condensation of water, the heat removed from the body by the liquid cooling garment and the load from the electrical components. Although the sublimator hardware to reject this load weighs only 1.58 kg (3.48 lbm), an additional 3.6 kg (8 lbm) of water are loaded into the unit, most of which is sublimated and lost to space, thus becoming the single largest expendable during an eight-hour EVA. Using a radiator to reject heat from the astronaut during an EVA can reduce the amount of expendable water consumed in the sublimator. Radiators have no moving parts and are thus highly reliable. Past freezable radiators have been too heavy, but the weight can be greatly reduced by placing a small and freeze tolerant heat exchanger between the astronaut and radiator, instead of making the very large radiator freeze tolerant. Therefore, the key technological innovation to improve space suit radiator performance was the development of a lightweight and freezable heat exchanger that accommodates the variable heat load generated by the astronaut. Herein, we present the heat transfer performance of a newly designed heat exchanger that endured several freeze / thaw cycles without any apparent damage. The heat exchanger was also able to continuously turn down or turn up the heat rejection to follow the variable load.

  3. Analysis of thermosyphon heat exchangers for use in solar domestic hot water heating systems

    NASA Astrophysics Data System (ADS)

    Dahl, Scott David

    1998-11-01

    A recent innovation in the solar industry is the use of thermosyphon heat exchangers. Determining the performance of these systems requires knowledge of how thermosyphon flow rate and heat exchanger performance vary with operating conditions. This study demonstrates that several thermosyphon heat exchanger designs operate in the laminar mixed convection regime. Empirical heat transfer and pressure drop correlations are obtained for three tube-in-shell heat exchangers (four, seven, and nine tube). Thermosyphon flow is on the shell side. Correlations are obtained with uniform heat flux on the tube walls and with a mixture of glycol and water circulating inside the tubes. Ranges of Reynolds, Prandtl, and Grashof numbers are 50 to 1800, 2.5 and 6.0, and 4×105 to 1×108, respectively. Nusselt number correlations are presented in a form that combines the contributions of forced and natural convection, Nu4Mixed=Nu4Forced+Nu4Natural. The Nusselt number is influenced by natural convection when the term Raq0.25/(Re0.5Pr0.33) is greater than unity. Pressure drop through these three designs is not significantly affected by mixed convection because most pressure drop losses are at the heat exchanger inlet and outlet. A comparison and discussion of the performance of several other heat exchanger designs (tube-in-shell and coil-in- shell designs) are presented. Generally, the coil-in- shell heat exchangers perform better than the tube-in- shell heat exchangers. Data from all heat exchanger designs is used to develop a new one-dimensional model for thermosyphon heat exchangers in solar water heating systems. The model requires two empirically determined relationships, pressure drop as a function of water mass flow rate and the overall heat transfer coefficient-area product (UA) as a function of Reynolds, Prandtl, and Grashof number. A testing protocol is presented that describes the procedure to obtain the data for the correlations. Two new TRNSYS component models are presented, for the thermosyphon heat exchanger and thermosyphon loop. Unlike previous models, which are based on forced flow relationships, the new heat exchanger model accounts for mixed convection heat transfer and accurately predicts pressure drop in the connecting piping around the thermosyphon loop. Comparison between the model and experimental data shows excellent agreement. Daily and annual ratings for a sample thermosyphon system are presented.

  4. Air Circulation and Heat Exchange Under Reduced Pressures

    NASA Technical Reports Server (NTRS)

    Rygalov, V.; Wheeler, R.; Dixon, M.; Fowler, P.; Hillhouse, L.

    2010-01-01

    Heat exchange rates decrease non-linearly with reductions in atmospheric pressure. This decrease creates risk of thermal stress (elevated leaf temperatures) for plants under reduced pressures. Forced convection (fans) significantly increases heat exchange rate under almost all pressures except below 10 kPa. Plant cultivation techniques under reduced pressures will require forced convection. The cooling curve technique is a reliable means of assessing the influence of environmental variables like pressure and gravity on gas exchange of plant. These results represent the extremes of gas exchange conditions for simple systems under variable pressures. In reality, dense plant canopies will exhibit responses in between these extremes. More research is needed to understand the dependence of forced convection on atmospheric pressure. The overall thermal balance model should include latent and radiative exchange components.

  5. In - line determination of heat transfer coefficients in a plate heat exchanger

    NASA Astrophysics Data System (ADS)

    Sotelo, S. Silva; Domínguez, R. J. Romero

    This paper shows an in - line determination of heat transfer coefficients in a plate heat exchanger. Water and aqueous working solution of lithium bromide + ethylene glycol are considered. Heat transfer coefficients are calculated for both fluids. "Type T" thermocouples were used for monitoring the wall temperature in a plate heat exchanger, which is one of the main components in an absorption system. Commercial software Agilent HP Vee Pro 7.5 was used for monitoring the temperatures and for the determination of the heat transfer coefficients. There are not previous works for heat transfer coefficients for the working solution used in this work.

  6. Direct use geothermal applications for brazed plate heat exchangers

    NASA Astrophysics Data System (ADS)

    Rafferty, K.

    1993-02-01

    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 H2S 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 H2S 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 deg or greater. Size limitations restrict applications to 100 gpm and/or 200 sq ft heat transfer surface area.

  7. Direct use geothermal applications for brazed plate heat exchangers

    SciTech Connect

    Rafferty, K.

    1992-01-01

    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.

  8. Direct use geothermal applications for brazed plate heat exchangers

    SciTech Connect

    Rafferty, K.

    1993-02-01

    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.

  9. Direct use geothermal applications for brazed plate heat exchangers

    SciTech Connect

    Rafferty, K.

    1992-12-31

    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.

  10. Direct use geothermal applications for brazed plate heat exchangers

    SciTech Connect

    Rafferty, K.

    1993-02-01

    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.

  11. Industrial Plate Exchangers Heat Recovery and Fouling

    E-print Network

    Cross, P. H.

    1981-01-01

    by choosing a more suitable material of construction. Plate exchangers being economic on surface area are able to use materials such as stainless steels, titanium,hastelloy,incolloy etc.without excessive cost. Normally the more e~pensive the material... was available for cooling then the spirals were cooled by a closed circuit of fresh water which was in turn cooled by a titanium plate exchanger using the brackish water as a coolant.This eliminated fouling from the acid coolers and restricted...

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

    DOEpatents

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

    1984-08-30

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

  13. Enhanced heat transfer techniques for industrial heat exchangers

    Microsoft Academic Search

    A. E. Bergles

    1991-01-01

    An introductory lecture on the enhancement of convective heat transfer which provides background for the many applications of this 'second generation heat transfer technology' is presented. The many available enhancement techniques are described, and some representative performance data and correlations are given for the popular passive techniques. The discussion is organized according to the modes of heat transfer ranging from

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

    DOEpatents

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

    1985-01-01

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

  15. Capillary pumped loop body heat exchanger

    NASA Technical Reports Server (NTRS)

    Swanson, Theodore D. (Inventor); Wren, deceased, Paul (Inventor)

    1998-01-01

    A capillary pumped loop for transferring heat from one body part to another body part, the capillary pumped loop comprising a capillary evaporator for vaporizing a liquid refrigerant by absorbing heat from a warm body part, a condenser for turning a vaporized refrigerant into a liquid by transferring heat from the vaporized liquid to a cool body part, a first tube section connecting an output port of the capillary evaporator to an input of the condenser, and a second tube section connecting an output of the condenser to an input port of the capillary evaporator. A wick may be provided within the condenser. A pump may be provided between the second tube section and the input port of the capillary evaporator. Additionally, an esternal heat source or heat sink may be utilized.

  16. Wall mounted heat exchanger characterization. [cryogenic propellant tanks

    NASA Technical Reports Server (NTRS)

    Bullard, B. R.

    1975-01-01

    Analytical models are presented for describing the heat and mass transfer and the energy distribution in the contents of a cryogenic propellant tank, under varying gravity levels. These models are used to analytically evaluate the effectiveness of a wall heat exchanger as a means of controlling the pressure in the tank during flight and during fill operations. Pressure and temperature histories are presented for tanks varying in size from 4 to 22.5 feet in diameter and gravity levels from 0-1. Results from the subscale test program, utilizing both non-cryogenic and cryogenic fluid, designed to evaluate a tank wall heat exchanger are described and compared with the analytical models. Both the model and test results indicate that a passive tank wall heat exchanger can effectively control tank pressure. However, the weight of such a system is considerably higher than that of an active mixer system.

  17. The design and fabrication of a Stirling engine heat exchanger module with an integral heat pipe

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey G.

    1988-01-01

    The conceptual design of a free-piston Stirling Space Engine (SSE) intended for space power applications has been generated. The engine was designed to produce 25 kW of electric power with heat supplied by a nuclear reactor. A novel heat exchanger module was designed to reduce the number of critical joints in the heat exchanger assembly while also incorporating a heat pipe as the link between the engine and the heat source. Two inexpensive verification tests are proposed. The SSE heat exchanger module is described and the operating conditions for the module are outlined. The design process of the heat exchanger modules, including the sodium heat pipe, is briefly described. Similarities between the proposed SSE heat exchanger modules and the LeRC test modules for two test engines are presented. The benefits and weaknesses of using a sodium heat pipe to transport heat to a Stirling engine are discussed. Similarly, the problems encountered when using a true heat pipe, as opposed to a more simple reflux boiler, are described. The instruments incorporated into the modules and the test program are also outlined.

  18. Active heat exchange thermal storage unit with pentaerythritol

    Microsoft Academic Search

    Y. Abe; M. Kamimoto; K. Kanari; T. Ozawa; R. Sakamoto; Y. Takahashi

    1984-01-01

    A latent thermal energy storage unit with pentaerythritol was developed, and in the storage unit an active heat transfer enhancement was performed. The phase change material, pentaerythritol, was mixed with a hydrocarbon heat transfer oil and this two-phase storage medium was stirred in a shell-coil type heat exchanger. Through the preliminary experiments in a glass vessel, a lab-scale storage unit

  19. Modeling for industrial heat exchanger type steam reformer

    Microsoft Academic Search

    Yong Ho Yu; Mihail H. Sosna

    2001-01-01

    In a heat exchanger type steam methane reformer, the temperature profiles and mole fractions along the axial distance from\\u000a the top of the reformer can be predicted by using the channel model, considering radiation heat transfer. The cross-section\\u000a of the reformer tube was divided into several channels as concentric circles and then heat transfer and mass transfer at the\\u000a interfaces

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

    E-print Network

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

    number of different points. In the jargon of pinch technology, these heating and cooling duties are associated with streams moving from "supply" to "target" temperatures. The heating and cooling require ments can always be met by using external... Technology Conference, Houston, TX, September 16-18, 1987 removed from one part of the process can be absorbed in another part. For example, Figure 1 illustrates the simple case of a feed/effluent heat exchanger, in which a hot reactor effluent stream...

  1. Development, Fabrication, and Testing of a Liquid/Liquid Microchannel Heat Exchanger for Constellation Spacecrafts

    NASA Technical Reports Server (NTRS)

    Hawkins-Reynolds, Ebony; Le,Hung; Stephans, Ryan A.

    2009-01-01

    Minimizing mass and volume is critically important for space hardware. Microchannel technology can be used to decrease both of these parameters for heat exchangers. Working in concert with NASA, Pacific Northwest National Laboratories (PNNL) has developed a microchannel liquid/liquid heat exchanger that has resulted in significant mass and volume savings. The microchannel heat exchanger delivers these improvements without sacrificing thermal and pressure drop performance. A conventional heat exchanger has been tested and the performance of it recorded to compare it to the microchannel heat exchanger that PNNL has fabricated. The microchannel heat exchanger was designed to meet all of the requirements of the baseline heat exchanger, while reducing the heat exchanger mass and volume. The baseline heat exchanger was designed to have an transfer approximately 3.1 kW for a specific set of inlet conditions. The baseline heat exchanger mass was 2.7 kg while the microchannel mass was only 2.0 kg. More impressive, however, was the volumetric savings associated with the microchannel heat exchanger. The microchannel heat exchanger was an order of magnitude smaller than the baseline heat exchanger (2180cm3 vs. 311 cm3). This paper will describe the test apparatus designed to complete performance tests for both heat exchangers. Also described in this paper will be the performance specifications for the microchannel heat exchanger and how they compare to the baseline heat exchanger.

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

    E-print Network

    Al-Shayea, Naser Abdul-Rahman

    1 Energy, Exergy and Uncertainty Analyses of the Thermal Response Test for a Ground Heat Exchanger response test of a ground heat exchanger. In this study, a vertical U-shaped ground heat exchanger with 80 of the ground heat exchanger. The thermal response test was carried out four times at different thermal loads

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

    E-print Network

    Skogestad, Sigurd

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

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

    E-print Network

    McCarthy, John E.

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

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

    E-print Network

    Skogestad, Sigurd

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

  6. Analysis of Heat Transfers inside Counterflow Plate Heat Exchanger Augmented by an Auxiliary Fluid Flow

    PubMed Central

    Khaled, A.-R. A.

    2014-01-01

    Enhancement of heat transfers in counterflow plate heat exchanger due to presence of an intermediate auxiliary fluid flow is investigated. The intermediate auxiliary channel is supported by transverse conducting pins. The momentum and energy equations for the primary fluids are solved numerically and validated against a derived approximate analytical solution. A parametric study including the effect of the various plate heat exchanger, and auxiliary channel dimensionless parameters is conducted. Different enhancement performance indicators are computed. The various trends of parameters that can better enhance heat transfer rates above those for the conventional plate heat exchanger are identified. Large enhancement factors are obtained under fully developed flow conditions. The maximum enhancement factors can be increased by above 8.0- and 5.0-fold for the step and exponential distributions of the pins, respectively. Finally, counterflow plate heat exchangers with auxiliary fluid flows are recommended over the typical ones if these flows can be provided with the least cost. PMID:24719572

  7. Analysis of heat transfers inside counterflow plate heat exchanger augmented by an auxiliary fluid flow.

    PubMed

    Khaled, A-R A

    2014-01-01

    Enhancement of heat transfers in counterflow plate heat exchanger due to presence of an intermediate auxiliary fluid flow is investigated. The intermediate auxiliary channel is supported by transverse conducting pins. The momentum and energy equations for the primary fluids are solved numerically and validated against a derived approximate analytical solution. A parametric study including the effect of the various plate heat exchanger, and auxiliary channel dimensionless parameters is conducted. Different enhancement performance indicators are computed. The various trends of parameters that can better enhance heat transfer rates above those for the conventional plate heat exchanger are identified. Large enhancement factors are obtained under fully developed flow conditions. The maximum enhancement factors can be increased by above 8.0- and 5.0-fold for the step and exponential distributions of the pins, respectively. Finally, counterflow plate heat exchangers with auxiliary fluid flows are recommended over the typical ones if these flows can be provided with the least cost. PMID:24719572

  8. Carbon-Fiber Brush Heat Exchangers

    NASA Technical Reports Server (NTRS)

    Knowles, Timothy R.

    2004-01-01

    Velvetlike and brushlike pads of carbon fibers have been proposed for use as mechanically compliant, highly thermally conductive interfaces for transferring heat. A pad of this type would be formed by attaching short carbon fibers to either or both of two objects that one desires to place in thermal contact with each other. The purpose of using a thermal-contact pad of this or any other type is to reduce the thermal resistance of an interface between a heat source and a heat sink.

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

    SciTech Connect

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

    2011-04-01

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

  10. Optimal design of plate-and-frame heat exchangers for efficient heat recovery in process industries

    Microsoft Academic Search

    Olga P. Arsenyeva; Leonid L. Tovazhnyansky; Petro O. Kapustenko; Gennadiy L. Khavin

    2011-01-01

    The developments in design theory of plate heat exchangers, as a tool to increase heat recovery and efficiency of energy usage, are discussed. The optimal design of a multi-pass plate-and-frame heat exchanger with mixed grouping of plates is considered. The optimizing variables include the number of passes for both streams, the numbers of plates with different corrugation geometries in each

  11. Heat transfer and friction characteristics of typical wavy fin-and-tube heat exchangers

    Microsoft Academic Search

    W. L. Fu; C. T. Chang

    1997-01-01

    Extensive experiments on the heat transfer and pressure drop characteristics of typical wavy fin-and-tube heat exchangers were carried out. In the present study, 18 samples of wavy fin-and-tube heat exchangers with different geometrical parameters, including the number of tube rows, fin pitch, and flow arrangements, were tested in a wind tunnel. Results are presented as plots of the Fanning friction

  12. Three-Dimensional Numerical Simulation of Shell-And Heat Exchangers. Part II: Heat Transfer

    Microsoft Academic Search

    M. Prithiviraj; M. J. Andrews

    1998-01-01

    A three-dimensional, allocated, fully implicit control volume based calculation procedure HEATX [1] has been developed over the past 3 years to simulate flow and heat transfer in sheU-and-tube heat exchangers. The three-dimensional model uses the distributed resistance concept of Patankar and Spalding [2], in conjunction with surface permeabilities and volumetric porosities to model the tubes in the heat exchanger. Part

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

    DOEpatents

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

    1996-12-03

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

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

    SciTech Connect

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

    2008-10-17

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

  15. Effect of nanoparticles on heat transfer in mini double-pipe heat exchangers in turbulent flow

    NASA Astrophysics Data System (ADS)

    Aghayari, Reza; Maddah, Heydar; Ashori, Fatemeh; Hakiminejad, Afshin; Aghili, Mehdi

    2015-03-01

    In this work, heat transfer of a fluid containing nanoparticles of aluminum oxide with the water volume fraction (0.1-0.3) percent has been reported. Heat transfer of the fluid containing nano water aluminum oxide with a diameter of about 20 nm in a horizontal double pipe counter flow heat exchanger under turbulent flow conditions was studied. The results showed that the heat transfer of nanofluid in comparison with the heat transfer of fluid is slightly higher than 12 percent.

  16. A novel underground solar thermal heat storage unit cum heat exchanger for non air-conditioned buildings

    Microsoft Academic Search

    Rakesh Kumar; S. C. Kaushik

    2003-01-01

    A novel passive space conditioning configuration is presented, integrating a Solar Collector System, Underground Storage Tank and Novel Heat Exchanger. This Underground Solar Thermal Heat Exchanger (USTHE) provided improved sensible heating\\/cooling of air by employing a Novel Heat Exchanger (NHX). The dynamic performance of the storage tank in USTHE is modelled using the finite difference method accounting thermal stratification of

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

    E-print Network

    Thole, Karen A.

    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

  18. Liquid Salt Heat Exchanger Technology for VHTR Based Applications

    SciTech Connect

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

    2012-10-11

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

  19. Light bulb heat exchanger for magnetohydrodynamic generator applications - Preliminary evaluation

    NASA Technical Reports Server (NTRS)

    Smith, J. M.; Hwang, C. C.; Seikel, G. R.

    1974-01-01

    The light-bulb heat-exchanger concept is investigated as a possible means of using a combustion heat source to supply energy to an inert gas MHD power generator system. In this concept, combustion gases flow through a central passage which consists of a duct with transparent walls through which heat is transferred by radiation to a radiation receiver which in turn heats the inert gas by convection. The effects of combustion-gas emissivity, transparent-wall-transmissivity, radiation-receiver emissivity, and the use of fins in the inert gas coolant passage are studied. The results indicate that inert gas outlet temperatures of 2500 K are possible for combustion temperatures of 3200 K and that sufficient energy can be transferred from the combustion gas to reduce its temperature to approximately 2000 K. At this temperature more conventional heat exchangers can be used.

  20. Choose the best alloy for incinerator heat exchangers

    SciTech Connect

    Sorell, G. (G. Sorell Consulting Services, North Caldwell, NJ (United States))

    1994-03-01

    Growing emphasis on energy efficiency and conservation has led to increasing use of heat recovery equipment with incinerators. The most prominent energy recovery devices are the boilers in large municipal refuse incinerators, often referred to as waste-to-energy (WTE) or resource recovery plants, which generate steam to drive turbines for electric power generation. Heat extraction is also finding wider application in industrial incinerators used to dispose of chemical and other hazardous wastes. Boilers are by no means the only method for extracting energy from incinerator off-gases. Extensive use is made of gas/gas heat exchangers for preheating combustion air and waste streams, notably in sludge incinerators and thermal oxidizers. Other heat exchanger applications in incineration facilities include the coolers, condensers, and reheaters in air-pollution control gas trains and associated subsystems. This article addresses alloy selection for incinerator heat-transfer equipment. It discusses heat exchanger design configurations, construction materials, corrosion concerns, examples of material failures, and selection criteria for heat-resistant and corrosion-resistant alloys. The materials covered include stainless steels and nickel-based alloys. Nonmetallic materials (such as plastics, glass, graphite, and ceramics) are not covered because of their very limited use for incinerator heat-transfer applications.

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

    SciTech Connect

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

    2011-01-01

    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.

  2. Design optimization of shell-and-tube heat exchanger using particle swarm optimization technique

    Microsoft Academic Search

    V. K. Patel; R. V. Rao

    2010-01-01

    Shell-and-tube heat exchangers (STHEs) are the most common type of heat exchangers that find widespread use in numerous industrial applications. Cost minimization of these heat exchangers is a key objective for both designer and users. Heat exchanger design involves complex processes, including selection of geometrical parameters and operating parameters. The traditional design approach for shell-and-tube heat exchangers involves rating a

  3. Electrically enhanced fluidized bed heat exchanger

    SciTech Connect

    Lessor, D.L.; Robertus, R.J.; Roberts, G.L.

    1994-05-01

    The experiments have shown that a high level of electrical charging can be achieved in a fluidized bed of two resistive particle types; that bed stabilization rather than increased sensible heat transport dominates low frequency electric field effects on heat transfer with most bed loadings; and, hence, that applying an oscillatory potential difference between tubes or rods in a fluidized bed of two mutual contact-charging particle species gives reduced rather than improved heat transfer. Applying an oscillatory potential difference between rods in a bed of quartz particles fluidized alone did give improved heat transfer, however. With no electric field applied, most fluidized mixes were found to give higher heat transfer rates than the average of the values when each of the two species was fluidized alone. The high level of charging observed in some mixed beds may prove of interest for some air cleanup applications; the results show that simultaneous fluidization of pairs of bipolar charging materials of similar particle size is possible without excessive agglomeration. This would be important for air cleanup.

  4. Experimental comparison and analysis on silica gel and polymer coated fin-tube heat exchangers

    Microsoft Academic Search

    T. S. Ge; Y. J. Dai; R. Z. Wang; Z. Z. Peng

    2010-01-01

    In this paper, two desiccant-coated heat exchangers, which are actually fin-tube heat exchanging devices coated with silica gel and polymer materials respectively, are investigated experimentally. Due to the hygroscopic properties of the desiccant materials, both the sensible heat and the latent heat of the process air can be handled by using this kind of heat exchanger. An experimental setup was

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

    Microsoft Academic Search

    B. V. Babu; S. A. Munawar

    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

  6. Differential evolution strategies for optimal design of shell-and-tube heat exchangers

    Microsoft Academic Search

    B. V. Babu; S. A. Munawar

    2007-01-01

    Differential evolution (DE) and its various strategies are applied for the optimal design of shell-and-tube heat exchangers in this study. 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

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

    E-print Network

    Sen, Mihir

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

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

    SciTech Connect

    Anderson, Mark; Nellis, Greg; Corradini, Michael

    2012-10-19

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

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

    E-print Network

    Boyd, Sylke

    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

  10. Application of heat pipe heat exchangers to humidity control in air-conditioning systems

    Microsoft Academic Search

    Xiao Ping Wu; Peter Johnson; Aliakbar Akbarzadeh

    1997-01-01

    Relative humidity control in air-conditioning systems is an important aspect of the maintenance of good indoor air quality. However, considerable reheat energy is needed to control relative humidity using conventional reheating coils. For improved energy efficiency a thermosyphon heat pipe heat exchanger is under investigation using a Hilton Air-Conditioning Laboratory Unit in RMIT. The study involves aspects of the heat

  11. Heat transfer monitor for measurements of fouling of industrial heat exchangers

    Microsoft Academic Search

    C. B. Panchal

    1985-01-01

    A Heat Transfer Monitor (HTM) is a sensitive device that quantifies development of fouling on heat exchanger surfaces in terms of degradation in the heat transfer coefficient as fouling progresses. The Argonne HTM was originally developed by Carnegie-Mellon University for Ocean Thermal Energy Conversion (OTEC) applications and later modified by Argonne National Laboratory. The HTM has been used for the

  12. Thermal modeling for greenhouse heating by using thermal curtain and an earth–air heat exchanger

    Microsoft Academic Search

    Ashish Shukla; G. N. Tiwari; M. S. Sodha

    2006-01-01

    In this paper, a thermal model for heating of greenhouse by using different combinations of inner thermal curtain, an earth–air heat exchanger, and geothermal heating has been developed. The analysis incorporates the study of thermal performance of three-zone greenhouse. The calculations have been made for a typical production greenhouse in southern part of Argentina; available climatic data has been used.

  13. Heat exchanger for recovery of heat energy from dust-containing waste gases

    Microsoft Academic Search

    K. Berkestad; L. Danielsson; E. Henriksson; A. Ostlund; T. Svensson

    1982-01-01

    A heat exchanger for recovering the heat energy content in furnace waste gases and for recovering much of the dust entrained therewith includes a hollow duct through which the waste gases pass, and which contains first and second tube bundles arranged one after the other and a dust collection surface therebetween. The heat content in the waste gases is transferred

  14. System design package: Maxi-therm S-101 heating module, passive heat exchanger

    NASA Technical Reports Server (NTRS)

    1977-01-01

    This document is the specification which establishes the requirements for the design, installation, and performance of a passive heat exchanger module with auxiliary heaters for use with solar heating systems. It designates the Interim Performance Criteria applicable to the subsystem and defines any deviations. This document also includes the manufacturing instructions and required materials and parts for the Maxitherm S101 Heating Module.

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

    E-print Network

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

    1994-01-01

    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...

  16. Experimental investigation on heat transfer analysis of conical coil heat exchanger with 90° cone angle

    NASA Astrophysics Data System (ADS)

    Purandare, Pramod S.; Lele, Mandar M.; Gupta, Raj Kumar

    2015-03-01

    In the present study, an experimental investigation on thermal performance of the conical coil heat exchanger with 90° conical coil heat exchanger is reported. Three different conical coil heat exchangers of same mean coil diameter (Dm = 200 mm) with different tube diameters ( di = 8, 10, 12.5 mm) are analyzed under steady state condition. The analysis is carried out for the tube side hot fluid flow range of 10-100 lph ( Re = 500-5,000), while the shell side flow range of 30-90 lph. The data available from experimentation leads to evaluate heat transfer coefficients for inside and outside the tube of the conical coil heat exchanger by Wilsons plot method. The calculations are further extended to estimate Nusselt Number ( Nu) and effectiveness. The empirical correlations are proposed for predicting Nu and the outlet temperatures of hot and cold fluids. The predicted empirical correlations show reasonable agreement with the experimental results within the given range of parameters.

  17. A prototype heat pipe heat exchanger for the capillary pumped loop flight experiment

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Yun, Seokgeun; Kroliczek, Edward J.

    1992-01-01

    A Capillary Pumped Two-Phase Heat Transport Loop (CAPL) Flight Experiment, currently planned for 1993, will provide microgravity verification of the prototype capillary pumped loop (CPL) thermal control system for EOS. CAPL employs a heat pipe heat exchanger (HPHX) to couple the condenser section of the CPL to the radiator assembly. A prototype HPHX consisting of a heat exchanger (HX), a header heat pipe (HHP), a spreader heat pipe (SHP), and a flow regulator has been designed and tested. The HX transmits heat from the CPL condenser to the HHP, while the HHP and SHP transport heat to the radiator assembly. The flow regulator controls flow distribution among multiple parallel HPHX's. Test results indicated that the prototype HPHX could transport up to 800 watts with an overall heat transfer coefficient of more than 6000 watts/sq m-deg C. Flow regulation among parallel HPHX's was also demonstrated.

  18. Diffusion Welding of Compact Heat Exchangers for Nuclear Applications

    SciTech Connect

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

    2012-06-01

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

  19. Heat exchanger module for stirling engines

    SciTech Connect

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

    1985-02-12

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

  20. Prefabricated heat-exchanging fireplace. Final technical report

    SciTech Connect

    Schleper, M.A.

    1981-06-15

    A heat-exchanging fireplace was installed in a 2000 square foot home and the standard air distribution equipment was ducted directly to the forced-air heating system of the home. The standard air distribution equipment for the fireplace included two squirrel-cage blowers which were connected to a thermostat, allowing a choice of temperature ranges; and a snap disc thermostat was used to disconnect the blowers in order to avoid blowing cold air after the fire died out. Arranged in this manner, one is able to set the regular home thermostat a few degrees lower than the fireplace thermostat, and this will allow the regular heating system to turn on after the fire has gone out in the fireplace. Energy consumption in both the fireplace and the conventional heating system was monitored throughout a heating season and then compared with past heating seasons when only a conventional heating system was used.

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

    SciTech Connect

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

    1980-02-01

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

  2. Internal dust recirculation system for a fluidized bed heat exchanger

    DOEpatents

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

    1981-01-01

    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.

  3. Subsurface environment database for application of ground heat exchanger system

    NASA Astrophysics Data System (ADS)

    Hamamoto, H.; Hachinohe, S.; Shiraishi, H.; Takashi, I.; Sasaka, K.; Miyakoshi, A.; Goto, S.

    2010-12-01

    Ground heat exchanger system is economical and environmentally friendly technology and widely used in Europe and North America, while it is rarely used in Japan. One of the causes is relatively complex topography and geological structure in Japan in comparison with those in Europe and North America. Complex structures produce regional differences in subsurface thermal properties and temperature structure, leading to regional variation in efficiency of heat exchanger system. It is thus important to evaluate available subsurface heat energy through thermal response tests and/or numerical simulation and to design appropriate systems (depth and number of boreholes for heat exchange). Information on subsurface environment in target areas is necessary for evaluation of potential subsurface heat energy, but little information has been published. Center for Environmental Science in Saitama is a research institute established by a local government, Saitama prefecture, which is located on the north of Tokyo and has a population of over seven million. We have been collecting various subsurface environmental data in Saitama (e.g., lithological column data on over 10,000 boreholes). We have compiled the accumulated data and obtained new data (geological information, subsurface temperature distribution, and hydrogeological properties) to construct a database for application of ground heat exchanger systems in Saitama. It is important to estimate demand for heat energy in the target areas as well as available subsurface heat energy. We therefore compile meteorological data (air temperature and solar radiation) necessary for estimation for the demand and investigate regional variation in meteorological condition. We intend to disclose the database and research products using web GIS (geographic information system) in the future. It will assist spread of ground heat exchanger systems in the target areas. Investigation methods of subsurface environment survey and database construction can be applied to other areas. We present results of numerical simulation of ground heat exchanger system operation based on the database. The amount of available heat energy and influence on subsurface thermal environment vary by up to about 20 % within the study area depending on geological and meteorological conditions. Map of temperature measurement stations and numerical simulation considering with groundwater flow

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

    SciTech Connect

    Mittereder, N.; Poerschke, A.

    2013-11-01

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

  5. Spacecraft Radiator Freeze Protection Using a Regenerative Heat Exchanger

    NASA Technical Reports Server (NTRS)

    Ungar, Eugene K.; Schunk, Richard G.

    2011-01-01

    An active thermal control system architecture has been modified to include a regenerative heat exchanger (regenerator) inboard of the radiator. Rather than using a radiator bypass valve a regenerative heat exchanger is placed inboard of the radiators. A regenerator cold side bypass valve is used to set the return temperature. During operation, the regenerator bypass flow is varied, mixing cold radiator return fluid and warm regenerator outlet fluid to maintain the system setpoint. At the lowest heat load for stable operation, the bypass flow is closed off, sending all of the flow through the regenerator. This lowers the radiator inlet temperature well below the system set-point while maintaining full flow through the radiators. By using a regenerator bypass flow control to maintain system setpoint, the required minimum heat load to avoid radiator freezing can be reduced by more than half compared to a radiator bypass system.

  6. Web Scraping for Astronomy

    NASA Astrophysics Data System (ADS)

    Derriere, S.; Boch, T.

    2012-09-01

    Astronomical web sites and portals are used daily by astronomers, and are increasingly interactive and customizable, mainly through the use of JavaScript. In addition, information often arises from the linking of remotely distributed data and contents. All these potential links can not always be defined in advance and stored in a web document for at least two reasons: they could potentially increase the size of the document source by a large fraction; and sometimes only the user (and not the document creator) knows where relevant links should be provided. Web scraping is the process of automatically collecting Web information. In this context, we started developing a method allowing retrieval of remote information, and display of this information (including links to remote websites) in the current document, triggered by a very simple action from the user: the selection of a portion of text in the web document. Our first prototype deals with astronomical object names. It is written in JavaScript, and can easily be implemented in a web document, or used as a bookmarklet. Whenever the user selects a portion of text in a web document, a request to the Sesame name resolver is made to test if this is a valid object identifier. On success, information retrieved in JSON allows to display a tooltip with additional information on this object such as its coordinates, links to various CDS services, image thumbnails, etc. We present the current status of this work, and discuss how it could be extended in the future to other applications.

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

    NASA Astrophysics Data System (ADS)

    Pierre, Charles; Bouyssier, Julien; de Gournay, Frédéric; Plouraboué, Franck

    2014-07-01

    We propose and develop a variational formulation dedicated to the simulation of parallel convective heat exchangers that handles possibly complex input/output conditions as well as connection between pipes. It is based on a spectral method that allows to re-cast three-dimensional heat exchangers into a two-dimensional eigenvalue problem, named the generalized Graetz problem. Our formulation handles either convective, adiabatic, or prescribed temperature at the entrance or at the exit of the exchanger. This formulation is robust to mode truncation, offering a huge reduction in computational cost, and providing insights into the most contributing structure to exchanges and transfer. Several examples of heat exchangers are analyzed, their numerical convergence is tested and the numerical efficiency of the approach is illustrated in the case of Poiseuille flow in tubes.

  8. Unglazed selective absorber solar air collector: Heat exchange analysis

    Microsoft Academic Search

    D. Njomo

    2000-01-01

    Unglazed solar air collectors show promise for applications such as ventilation air heating or crop drying. In this paper\\u000a a mathematical model is developed to analyze the heat exchanges in an unglazed non-porous selective absorber air heater. It\\u000a is shown that at quasi-steady state the energy balance equations of the components of the collector cascade into a single\\u000a first order

  9. Modeling of Air to Air Enthalpy Heat Exchanger

    Microsoft Academic Search

    Mohammad Shakir Nasif; Ra’fat AL-Waked; Masud Behnia; Graham Morrison

    2012-01-01

    The thermal performance of a Z shaped enthalpy heat exchanger utilizing 45gsm Kraft paper as the heat and moisture transfer surface for HVAC energy recovery is experimentally investigated through temperature and moisture content measurements.A mathematical model is developed and validated against the experimental results using the effectiveness-NTU method. In this model the paper moisture transfer resistance is determined by paper

  10. Metal foams as compact high performance heat exchangers

    Microsoft Academic Search

    K. Boomsma; D. Poulikakos; F. Zwick

    2003-01-01

    Open-cell metal foams with an average cell diameter of 2.3 mm were manufactured from 6101-T6 aluminum alloy and were compressed and fashioned into compact heat exchangers measuring 40.0 mm×40.0 mm×2.0 mm high, possessing a surface area to volume ratio on the order of 10,000 m2\\/m3. They were placed into a forced convection arrangement using water as the coolant. Heat fluxes

  11. Most Frequently Used Heat Exchangers from Pioneering Research to Worldwide Applications

    Microsoft Academic Search

    B. I. Master; K. S. Chunangad; A. J. Boxma; D. Kral; P. Stehlík

    2006-01-01

    Heat exchangers contribute significantly to many energy conversion processes. Applications range from power production, petroleum refining and chemicals, paper and pharmaceutical production, to aviation and transportation industries. A large percentage of world market for heat exchangers is served by the industry workhorse, the shell-and-tube heat exchanger. Recent developments in other exchanger geometries have penetrated in various industry applications; however, the

  12. DESIGN, CONSTRUCTION, AND PERFORMANCE OF TWO COMPACT AIR COOLED SODIUM HEAT EXCHANGERS

    Microsoft Academic Search

    W. F. Brown; R. W. Fisher; H. M. Black

    1963-01-01

    A bare-tube crossflow heat exchanger and a finned-tube crossflow heat ; exchanger were designed, constructed, and tested. The exchangers have sodium as ; a tube side fluid and air as a shell side fluid and are constructed of Inconel. ; The bare-tube heat exchanger has three unmixed passes on the sodium side and one ; mixed pass on the air

  13. An experimental investigation of heat transfer enhancement for a shell-and-tube heat exchanger

    Microsoft Academic Search

    Simin Wang; Jian Wen; Yanzhong Li

    2009-01-01

    For the purpose of heat transfer enhancement, the configuration of a shell-and-tube heat exchanger was improved through the installation of sealers in the shell-side. The gaps between the baffle plates and shell is blocked by the sealers, which effectively decreases the short-circuit flow in the shell-side. The results of heat transfer experiments show that the shell-side heat transfer coefficient of

  14. Investigation of Condensing Ice Heat Exchangers for MTSA Technology Development

    NASA Technical Reports Server (NTRS)

    Padilla, Sebastian; Powers, Aaron; Ball, Tyler; Lacomini, Christie; Paul, Heather L.

    2009-01-01

    Metabolic heat regenerated Temperature Swing Adsorption (MTSA) technology is being developed for thermal, carbon dioxide (CO2) and humidity control for a Portable Life Support Subsystem (PLSS). Metabolically-produced CO2 present in the ventilation gas of a PLSS is collected using a CO2-selective adsorbent via temperature swing adsorption. The temperature swing is initiated through cooling to well below metabolic temperatures. Cooling is achieved with a sublimation heat exchanger using water or liquid carbon dioxide (L CO2) expanded below sublimation temperature when exposed to low pressure or vacuum. Subsequent super heated vapor, as well as additional coolant, is used to further cool the astronaut. The temperature swing on the adsorbent is then completed by warming the adsorbent with a separate condensing ice heat exchanger (CIHX) using metabolic heat from moist ventilation gas. The condensed humidity in the ventilation gas is recycled at the habitat. The water condensation from the ventilation gas represents a significant source of potential energy for the warming of the adsorbent bed as it represents as much as half of the energy potential in the moist ventilation gas. Designing a heat exchanger to efficiently transfer this energy to the adsorbent bed and allow the collection of the water is a challenge since the CIHX will operate in a temperature range from 210K to 280K. The ventilation gas moisture will first freeze and then thaw, sometimes existing in three phases simultaneously.

  15. Xenon Recirculation-Purification with a Heat Exchanger

    E-print Network

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

    2011-03-04

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

  16. Heat transfer characteristics of a new helically coiled crimped spiral finned tube heat exchanger

    NASA Astrophysics Data System (ADS)

    Srisawad, Kwanchanok; Wongwises, Somchai

    2009-02-01

    In the present study, the heat transfer characteristics in dry surface conditions of a new type of heat exchanger, namely a helically coiled finned tube heat exchanger, is experimentally investigated. The test section, which is a helically coiled fined tube heat exchanger, consists of a shell and a helical coil unit. The helical coil unit consists of four concentric helically coiled tubes of different diameters. Each tube is constructed by bending straight copper tube into a helical coil. Aluminium crimped spiral fins with thickness of 0.5 mm and outer diameter of 28.25 mm are placed around the tube. The edge of fin at the inner diameter is corrugated. Ambient air is used as a working fluid in the shell side while hot water is used for the tube-side. The test runs are done at air mass flow rates ranging between 0.04 and 0.13 kg/s. The water mass flow rates are between 0.2 and 0.4 kg/s. The water temperatures are between 40 and 50°C. The effects of the inlet conditions of both working fluids flowing through the heat exchanger on the heat transfer coefficients are discussed. The air-side heat transfer coefficient presented in term of the Colburn J factor is proportional to inlet-water temperature and water mass flow rate. The heat exchanger effectiveness tends to increase with increasing water mass flow rate and also slightly increases with increasing inlet water temperature.

  17. Active heat exchange system development for latent heat thermal energy storage

    NASA Technical Reports Server (NTRS)

    Lefrois, R. T.; Knowles, G. R.; Mathur, A. K.; Budimir, J.

    1979-01-01

    Active heat exchange concepts for use with thermal energy storage systems in the temperature range of 250 C to 350 C, using the heat of fusion of molten salts for storing thermal energy are described. Salt mixtures that freeze and melt in appropriate ranges are identified and are evaluated for physico-chemical, economic, corrosive and safety characteristics. Eight active heat exchange concepts for heat transfer during solidification are conceived and conceptually designed for use with selected storage media. The concepts are analyzed for their scalability, maintenance, safety, technological development and costs. A model for estimating and scaling storage system costs is developed and is used for economic evaluation of salt mixtures and heat exchange concepts for a large scale application. The importance of comparing salts and heat exchange concepts on a total system cost basis, rather than the component cost basis alone, is pointed out. The heat exchange concepts were sized and compared for 6.5 MPa/281 C steam conditions and a 1000 MW(t) heat rate for six hours. A cost sensitivity analysis for other design conditions is also carried out.

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

    SciTech Connect

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

    2012-07-01

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

  19. CACHE: an extended BASIC program which computes the performance of shell and tube heat exchangers. [HTGR

    Microsoft Academic Search

    Tallackson

    1976-01-01

    An extended BASIC program, CACHE, has been written to calculate steady state heat exchange rates in the core auxiliary heat exchangers, (CAHE), designed to remove afterheat from High-Temperature Gas-Cooled Reactors (HTGR). Computationally, these are unbaffled counterflow shell and tube heat exchangers. The computational method is straightforward. The exchanger is subdivided into a user-selected number of lengthwise segments; heat exchange in

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

    DOEpatents

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

    1998-07-21

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

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

    DOEpatents

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

    2005-12-20

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

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

    DOEpatents

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

    2004-09-14

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

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

    SciTech Connect

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

    1999-07-15

    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.

  4. Opportunities for heat exchanger applications in environmental systems

    Microsoft Academic Search

    R. K. Shah; B. Thonon; D. M. Benforado

    2000-01-01

    There is a worldwide interest in using pollution prevention methods to eliminate or lessen air, water, land and thermal pollution problems. Pollution prevention is designing processes that do not create pollution in the first place. Heat exchangers play an essential role in pollution prevention and in the reduction of environmental impact of industrial processes, by reducing energy consumption or recovering

  5. Air Circulation and Heat Exchange under Reduced Pressures

    NASA Astrophysics Data System (ADS)

    Rygalov, Vadim; Wheeler, Raymond; Dixon, Mike; Hillhouse, Len; Fowler, Philip

    Low pressure atmospheres were suggested for Space Greenhouses (SG) design to minimize sys-tem construction and re-supply materials, as well as system manufacturing and deployment costs. But rarified atmospheres modify heat exchange mechanisms what finally leads to alter-ations in thermal control for low pressure closed environments. Under low atmospheric pressures (e.g., lower than 25 kPa compare to 101.3 kPa for normal Earth atmosphere), convection is becoming replaced by diffusion and rate of heat exchange reduces significantly. During a period from 2001 to 2009, a series of hypobaric experiments were conducted at Space Life Sciences Lab (SLSLab) NASA's Kennedy Space Center and the Department of Space Studies, University of North Dakota. Findings from these experiments showed: -air circulation rate decreases non-linearly with lowering of total atmospheric pressure; -heat exchange slows down with pressure decrease creating risk of thermal stress (elevated leaf tem-peratures) for plants in closed environments; -low pressure-induced thermal stress could be reduced by either lowering system temperature set point or increasing forced convection rates (circulation fan power) within certain limits; Air circulation is an important constituent of controlled environments and plays crucial role in material and heat exchange. Theoretical schematics and mathematical models are developed from a series of observations. These models can be used to establish optimal control algorithms for low pressure environments, such as a space greenhouse, as well as assist in fundamental design concept developments for these or similar habitable structures.

  6. Heat-Exchange Fluids for Sulfuric Acid Vaporizers

    NASA Technical Reports Server (NTRS)

    Lawson, D. D.; Petersen, G. R.

    1982-01-01

    Some fluorine-substituted organic materials meet criteria for heat-exchange fluids in contact with sulfuric acid. Most promising of these are perfluoropropylene oxide polymers with degree of polymerization (DP) between 10 and 50. It is desirable to have DP in high range because vapor pressure of material decreases as DP increases, and high-DP liquids have lower loss due to vaporization.

  7. Potential heat exchange fluids for use in sulfuric acid vaporizers

    NASA Technical Reports Server (NTRS)

    Lawson, D. D.; Petersen, G. R.

    1981-01-01

    A series of liquids have been screened as candidate heat exchange fluids for service in thermochemical cycles that involve the vaporization of sulfuric acid. The required chemical and physical criteria of the liquids is described with the results of some preliminary high temperature test data presented.

  8. Potential heat exchange fluids for use in sulfuric acid vaporizers

    NASA Technical Reports Server (NTRS)

    Lawson, D. D.; Petersen, G. R.

    1979-01-01

    A series of perhalocarbons are proposed as candidate heat exchange fluids for service in thermochemical cycles for hydrogen production that involve direct contact of the fluid with sulfuric acid and vaporization of the acid. The required chemical and physical criteria of the liquids are described and the results of some preliminary high temperature test data are presented.

  9. Reliability, availability and maintenance optimisation of heat exchanger networks

    Microsoft Academic Search

    László Sikos; Ji?í Klemeš

    2010-01-01

    A new methodology is proposed to use comprehensive up-to-date commercial software tools for heat exchanger network (HEN) reliability modelling and optimisation. The idea behind this proposal is that to apply the combination of specific HEN optimisation and reliability software packages has several advantages over the commonly used approach. There is a variety of features that need to be taken into

  10. Qualification of stainless steel for OTEC heat exchanger tubes

    Microsoft Academic Search

    F. L. Laque

    1979-01-01

    The history of the AL-6X alloy was reviewed and its credentials as a candidate for use as tubing in ocean thermal energy conversion (OTEC) heat exchangers were examined. Qualification was based on results of accelerated tests using ferric chloride for resistance to crevice corrosion and pitting, long time crevice and pitting tests in natural sea water and anticipated resistance to

  11. Numerical Simulations of Particle Deposition in Metal Foam Heat Exchangers

    NASA Astrophysics Data System (ADS)

    Sauret, Emilie; Saha, Suvash C.; Gu, Yuantong

    2013-01-01

    Australia is a high-potential country for geothermal power with reserves currently estimated in the tens of millions of petajoules, enough to power the nation for at least 1000 years at current usage. However, these resources are mainly located in isolated arid regions where water is scarce. Therefore, wet cooling systems for geothermal plants in Australia are the least attractive solution and thus air-cooled heat exchangers are preferred. In order to increase the efficiency of such heat exchangers, metal foams have been used. One issue raised by this solution is the fouling caused by dust deposition. In this case, the heat transfer characteristics of the metal foam heat exchanger can dramatically deteriorate. Exploring the particle deposition property in the metal foam exchanger becomes crucial. This paper is a numerical investigation aimed to address this issue. Two-dimensional (2D) numerical simulations of a standard one-row tube bundle wrapped with metal foam in cross-flow are performed and highlight preferential particle deposition areas.

  12. Control of marine biofouling in heat exchanger systems

    SciTech Connect

    Mitchell, R.; Benson, P.

    1981-01-01

    A critical review is provided of biofouling hazards associated with heat exchanger surfaces in contact with seawater; mechanisms of biofouling formation, environmental factors affecting fouling and control measures. Available antifoulants include elastomer or plastic-based toxic coatings, copper alloys, and the application of chemicals, principally chlorine. 29 refs.

  13. Development of plastic heat exchangers for sea solar power plants

    Microsoft Academic Search

    W. B. Suratt; G. K. Hart; E. N. Sieder

    1975-01-01

    Conceptual designs of heat exchangers for the sea solar power plant using lost cost plastic surfaces are evaluated. Composite walls of conductive, filled high density polyethylene and multilayered thin films of impermeable plastics are used as the reference material. Plate surfaces using thin falling films for evaporation and condensation of ammonia are identified as the least expensive concept. Horizontal tubular

  14. Integral collector storage system with heat exchange apparatus

    DOEpatents

    Rhodes, Richard O.

    2004-04-20

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

  15. Condensing Heat Exchanger for Optimization of Energy Efficiency

    E-print Network

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

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

  16. Power and refrigeration plants for minimum heat exchanger inventory

    Microsoft Academic Search

    A. Bejan

    1993-01-01

    What has been accomplished to date on the question of how to minimize and allocate the heat exchanger inventory in power plants and refrigeration plants is summarized in a table. This table also highlights the three objectives of the present study. The first objective is to devise a much simpler model and analysis to reproduce in closed form Ibrahim et

  17. Teaching Heat Exchanger Network Synthesis Using Interactive Microcomputer Graphics.

    ERIC Educational Resources Information Center

    Dixon, Anthony G.

    1987-01-01

    Describes the Heat Exchanger Network Synthesis (HENS) program used at Worcester Polytechnic Institute (Massachusetts) as an aid to teaching the energy integration step in process design. Focuses on the benefits of the computer graphics used in the program to increase the speed of generating and changing networks. (TW)

  18. Calculation of radiant heat exchange in tunnel kilns

    Microsoft Academic Search

    B. G. Abbakumov; S. I. Bel'skii

    1982-01-01

    Conclusions A new program for calculating the error when a two-dimensional model of heat exchange in tunnel kilns of various sizes and with different temperature gradients along the axis of the channel is used, has been developed. It is established that the use of a two-dimensional model is valid in the calculations of large tunnel kilns but may lead to

  19. A novel compact heat exchanger using gap flow mechanism.

    PubMed

    Liang, J S; Zhang, Y; Wang, D Z; Luo, T P; Ren, T Q

    2015-02-01

    A novel, compact gap-flow heat exchanger (GFHE) using heat-transfer fluid (HTF) was developed in this paper. The detail design of the GFHE coaxial structure which forms the annular gap passage for HTF is presented. Computational fluid dynamics simulations were introduced into the design to determine the impacts of the gap width and the HTF flow rate on the GFHE performance. A comparative study on the GFHE heating rate, with the gap widths ranged from 0.1 to 1.0 mm and the HTF flow rates ranged from 100 to 500 ml/min, was carried out. Results show that a narrower gap passage and a higher HTF flow rate can yield a higher average heating rate in GFHE. However, considering the compromise between the GFHE heating rate and the HTF pressure drop along the gap, a 0.4 mm gap width is preferred. A testing loop was also set up to experimentally evaluate the GFHE capability. The testing results show that, by using 0.4 mm gap width and 500 ml/min HTF flow rate, the maximum heating rate in the working chamber of the as-made GFHE can reach 18?°C/min, and the average temperature change rates in the heating and cooling processes of the thermal cycle test were recorded as 6.5 and 5.4?°C/min, respectively. These temperature change rates can well satisfy the standard of IEC 60068-2-14:2009 and show that the GFHE developed in this work has sufficient heat exchange capacity and can be used as an ideal compact heat exchanger in small volume desktop thermal fatigue test apparatus. PMID:25725874

  20. A novel compact heat exchanger using gap flow mechanism

    NASA Astrophysics Data System (ADS)

    Liang, J. S.; Zhang, Y.; Wang, D. Z.; Luo, T. P.; Ren, T. Q.

    2015-02-01

    A novel, compact gap-flow heat exchanger (GFHE) using heat-transfer fluid (HTF) was developed in this paper. The detail design of the GFHE coaxial structure which forms the annular gap passage for HTF is presented. Computational fluid dynamics simulations were introduced into the design to determine the impacts of the gap width and the HTF flow rate on the GFHE performance. A comparative study on the GFHE heating rate, with the gap widths ranged from 0.1 to 1.0 mm and the HTF flow rates ranged from 100 to 500 ml/min, was carried out. Results show that a narrower gap passage and a higher HTF flow rate can yield a higher average heating rate in GFHE. However, considering the compromise between the GFHE heating rate and the HTF pressure drop along the gap, a 0.4 mm gap width is preferred. A testing loop was also set up to experimentally evaluate the GFHE capability. The testing results show that, by using 0.4 mm gap width and 500 ml/min HTF flow rate, the maximum heating rate in the working chamber of the as-made GFHE can reach 18 °C/min, and the average temperature change rates in the heating and cooling processes of the thermal cycle test were recorded as 6.5 and 5.4 °C/min, respectively. These temperature change rates can well satisfy the standard of IEC 60068-2-14:2009 and show that the GFHE developed in this work has sufficient heat exchange capacity and can be used as an ideal compact heat exchanger in small volume desktop thermal fatigue test apparatus.

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

    E-print Network

    Oak Ridge National Laboratory

    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

  2. Research on heat-exchanger corrosion

    NASA Astrophysics Data System (ADS)

    Razgaitis, R.; Payer, J. H.; Stickford, G. H.; White, E. L.; Talbert, S. G.; Cudnick, R. A.; Locklin, D. W.; Farnsworth, C. A.

    1984-09-01

    Research conducted to develop technology for selecting corrosion resistant materials in high efficiency, gas fired, residential space heating equipment is reported. The methodology and results of sampling in over 500 homes to statistically characterize the corrosivity of flue gas condensate are described. The corrosion resistance of over 40 metal alloys was evaluated in accelerated laboratory tests with specimens exposed to an alternate wet/dry environment using chloride spiked condensate. A wide range of corrosion was observed, fron no corrosion to severe attack. Some stainless steels exhibited essentially complete resistance to attack in all corrosion modes evaluated. The results to date provide interim guidance to equipment manufacturers in the selection of materials for condensing equipment.

  3. Simulation of multistream plate–fin heat exchangers of an air separation unit

    Microsoft Academic Search

    R. Boehme; J. A. R. Parise; R. Pitanga Marques

    2003-01-01

    Hot and cold reversible heat exchangers of an air separation unit are simulated. Five fluid streams exchange heat with six fluid streams in parallel and counter flow. The numerical method employed divides the heat exchanger in a number of sections, for which fluid properties, capacity rates and heat transfer coefficients are considered constant. Single and two-phase streams are taken into

  4. Dual Expander Cycle Rocket Engine with an Intermediate, Closed-cycle Heat Exchanger

    NASA Technical Reports Server (NTRS)

    Greene, William D. (Inventor)

    2008-01-01

    A dual expander cycle (DEC) rocket engine with an intermediate closed-cycle heat exchanger is provided. A conventional DEC rocket engine has a closed-cycle heat exchanger thermally coupled thereto. The heat exchanger utilizes heat extracted from the engine's fuel circuit to drive the engine's oxidizer turbomachinery.

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

    E-print Network

    Salamon, Peter

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

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

    E-print Network

    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

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

    E-print Network

    Yu, Lisan

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

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

    E-print Network

    Wirtz, Richard A.

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

  9. Active heat exchange thermal storage unit with pentaerythritol

    SciTech Connect

    Abe, Y.; Kamimoto, M.; Kanari, K.; Ozawa, T.; Sakamoto, R.; Takahashi, Y.

    1984-08-01

    A latent thermal energy storage unit with pentaerythritol was developed, and in the storage unit an active heat transfer enhancement was performed. The phase change material, pentaerythritol, was mixed with a hydrocarbon heat transfer oil and this two-phase storage medium was stirred in a shell-coil type heat exchanger. Through the preliminary experiments in a glass vessel, a lab-scale storage unit of 1 kWh storage capacity was developed. The storage unit demonstrated the feature of latent thermal energy storage; constant-temperature output in both charge and discharge periods was observed.

  10. Performance and modeling of thermosyphon heat exchangers for solar water heaters

    Microsoft Academic Search

    S. D. Dahl; J. H. Davidson

    1997-01-01

    Determining the performance of indirect solar heating systems that use thermosyphon heat exchangers requires knowledge of how thermosyphon flow rate and heat exchanger performance vary with operating conditions. In this paper, measured performance of a two-pass, tube-in-shell, double-wall heat exchanger is discussed in terms of modeling issues. Thermosyphon heat exchangers may operate in the developing, mixed convection regime where natural

  11. Experiment and economic analysis of an air/molten salt direct-contact heat exchanger

    SciTech Connect

    Bohn, M S

    1983-08-01

    Direct-contact heat exchange (DCHX) has several advantages over conventional finned-tube heat exchangers. Without the intervening tube wall, thermal resistance is lower and fouling of the heat-exchange surface is not a problem. Intimate mixing of the two fluid streams can produce very high rates of heat transfer. The heat exchanger design can be simpler, require less construction material, and provide more flexibility in choice of materials.

  12. Thermal performance of a geofluid direct-contact heat exchanger

    SciTech Connect

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

    1983-01-01

    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.

  13. Heat exchanger efficiently operable alternatively as evaporator or condenser

    DOEpatents

    Ecker, Amir L. (Dallas, TX)

    1981-01-01

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

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

    SciTech Connect

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

    2014-08-01

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

  15. A survey of oscillating flow in Stirling engine heat exchangers

    NASA Technical Reports Server (NTRS)

    Simon, Terrence W.; Seume, Jorge R.

    1988-01-01

    Similarity parameters for characterizing the effect of flow oscillation on wall shear stress, viscous dissipation, pressure drop and heat transfer rates are proposed. They are based on physical agruments and are derived by normalizing the governing equations. The literature on oscillating duct flows, regenerator and porous media flows is surveyed. The operating characteristics of the heat exchanger of eleven Stirling engines are discribed in terms of the similarity parameters. Previous experimental and analytical results are discussed in terms of these parameters and used to estimate the nature of the oscillating flow under engine operating conditions. The operating points for many of the modern Stirling engines are in or near the laminar to turbulent transition region. In several engines, working fluid does not pass entirely through heat exchangers during a cycle. Questions that need to be addressed by further research are identified.

  16. Flow induced acoustic resonance in tubular heat exchangers

    NASA Astrophysics Data System (ADS)

    1988-12-01

    This Data Item 88028, an addition to the Sub-series on Heat Transfer, and complements ESDU 87019, which provides prediction methods for vibration of heat exchanger bundles. After outlining the nature of acoustic resonance, calculation methods are given for the acoustic frequency in both rectangular and cylindrical ducts. Procedures, based on a correlation of all the available acoustic data (all data on periodic wake shedding derived from measurements in the flow field were discarded because of their inapplicability), are given for the prediction of resonance. Possible damage caused by accoustic resonance is considered, and the means by which a design can be modified, before or after fabrication, are discussed. The methods apply to bundles in a rectangular cross-section duct, to shell-and-tube heat exchangers and to helical coil arrangements.

  17. Investigation of Condensing Ice Heat Exchangers for MTSA Technology Development

    NASA Technical Reports Server (NTRS)

    Padilla, Sebastian; Powers, Aaron; Ball, Tyler; Iacomini, Christie; Paul, Heather, L.

    2008-01-01

    Metabolic heat regenerated Temperature Swing Adsorption (MTSA) technology is being developed for thermal, carbon dioxide (CO2) and humidity control for a Portable Life Support Subsystem (PLSS). Metabolically-produced CO2 present in the ventilation gas of a PLSS is collected using a CO2selective adsorbent via temperature swing adsorption. The temperature swing is initiated through cooling to well below metabolic temperatures. Cooling is achieved with a sublimation heat exchanger using water or liquid carbon dioxide (LCO2) expanded below sublimation temperature when exposed to low pressure or vacuum. Subsequent super heated vapor, as well as additional coolant, is used to further cool the astronaut. The temperature swing on the adsorbent is then completed by warming the adsorbent with a separate condensing ice heat exchanger (CIHX) using metabolic heat from moist ventilation gas. The condensed humidity in the ventilation gas is recycled at the habitat. The water condensation from the ventilation gas is a significant heat transfer mechanism for the warming of the adsorbent bed because it represents as much as half of the energy potential in the moist ventilation gas. Designing a heat exchanger to efficiently transfer this energy to the adsorbent bed and allow the collection of the water is a challenge since the CIHX will operate in a temperature range from 210K to 280K. The ventilation gas moisture will first freeze and then thaw, sometimes existing in three phases simultaneously. A NASA Small Business Innovative Research (SBIR) Phase 1 contract was performed to investigate condensing and icing as applied to MTSA to enable higher fidelity modeling and assess the impact of geometry variables on CIHX performance for future CIHX design optimization. Specifically, a design tool was created using analytical relations to explore the complex, interdependent design space of a condensing ice heat exchanger. Numerous variables were identified as having nontrivial contributions to performance such as hydraulic diameter, heat exchanger effectiveness, ventilation gas mass flow rate and surface roughness. Using this tool, four test articles were designed and manufactured to map to a full MTSA subassembly (the adsorbent bed, the sublimation heat exchanger for cooling and the condensing ice heat exchanger for warming). The design mapping considered impacts due to CIHX geometry as well as subassembly impacts such as thermal mass and thermal resistance through the adsorbent bed. The test articles were tested at simulated PLSS ventilation loop temperature, moisture content and subambient pressure. Ice accumulation and melting were observed. Data and test observations were analyzed to identify drivers of the condensing ice heat exchanger performance. This paper will discuss the analytical models, the test article designs, and testing procedures. Testing issues will be discussed to better describe data and share lessons learned. Data analysis and subsequent conclusions will be presented.

  18. Mixed convection heat transfer and pressure drop correlations for tube-in-shell thermosyphon heat exchangers with uniform heat flux

    SciTech Connect

    Dahl, S.D.; Davidson, J.H. [Univ. of Minnesota, Minneapolis, MN (United States). Mechanical Engineering Dept.

    1998-11-01

    An important issue arising from prior studies of thermosyphon heat exchangers for use in solar water heaters is the need for heat transfer and pressure drop correlations for the laminar, mixed-convection regime in which these many of these heat exchangers operate. In this paper, the authors present empirical correlations for tube-in-shell heat exchangers with the thermosyphon flow on the shell side. The correlations are determined for uniform heat flux on the tube walls. Ranges of Reynolds and Grashof numbers are 130 to 2,000 and 4 {times} 10{sup 5} to 8 {times} 10{sup 7}, respectively. Nusselt number correlations are presented in a form that combines the contributions of forced and natural convection. Mixed convection dominates forced convection heat transfer in these geometries. Pressure drop is not significantly affected by mixed convection.

  19. Buoyancy driven flow in counter flow heat exchangers

    NASA Astrophysics Data System (ADS)

    Olsson, C. O.

    2012-11-01

    The temperature distribution, the buoyancy head and the flow rate have been studied in a counter flow heat exchanger having buoyancy driven flow on at least one side. The assumptions made for heat flux distribution are varied and the resulting effects on the flow rate and fluid temperatures are studied. A network model is used to simulate the temperature distribution and oil flow rates in an oil-filled power transformer cooled by radiators. It is found that for operating conditions normally found for mineral oil the counter flow assumptions for heat flux distribution gives approximately the same results as assuming uniform heat flux. When a more viscous oil type is used or the radiators are placed lower than normal relative to the heat generating parts, the counter flow assumptions give more reliable results.

  20. Experiment on a continuous heat regenerative adsorption refrigerator using spiral plate heat exchanger as adsorbers

    Microsoft Academic Search

    R. Z. Wang; J. Y. Wu; Y. X. Xu; Y. Teng; W. Shi

    1998-01-01

    Spiral plate heat exchangers were proposed to be used as adsorbers, and a prototype heat regenerative adsorption refrigerator using the activated carbon-methanol pair was developed and tested. The adsorption system using 12 kg activated carbon has a cycle time of 40 min., meanwhile 14 kg ice per day was made.