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1

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

E-print Network

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 geometry the flow field influence on the local heat transfer distribution on an evenly cooled scraped heat

Boyer, Edmond

2

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

E-print Network

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

Paris-Sud XI, Université de

3

Heat transfer and power consumption in a scraped-surface heat exchanger while freezing aqueous solutions  

Microsoft Academic Search

The heat transfer coefficient and the power consumption of a laboratory scraped-surface heat exchanger (SSHE) were measured when it was used for freezing a 10wt.% sugar solution. Experimental results show that the heat transfer coefficient with phase change (ice formation) was about three to five times greater than that without phase change. Once onset of ice-growth occurred, the torque for

Frank Qin; Xiao Dong Chen; Shashini Ramachandra; Kevin Free

2006-01-01

4

Scrape  

MedlinePLUS

... soap and water. Large pieces of dirt or debris should be removed with tweezers. (Clean the tweezers ... provider if: The scrape contains dirt and other debris deep inside. The scrape is very large. The ...

5

Nest scrape design and clutch heat loss in Pectoral Sandpipers (Calidris melanotos)  

Microsoft Academic Search

Summary 1. The reasons why birds construct nest scrapes, and the extent to which scrape designs reflect functional optima, are poorly understood. Working on Pectoral Sandpipers (Calidris melanotos, Vieillot), we investigated whether scrapes function to insulate clutches and are efficiently designed to reduce heat loss rates. 2. Excavating a scrape and using lining material reduced the rate at which an

J. M. Reid; W. Cresswell; S. Holt; R. J. Mellanby; D. P. Whitfield; G. D. Ruxton

2002-01-01

6

Corrosive resistant heat exchanger  

DOEpatents

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

Richlen, Scott L. (Annandale, VA)

1989-01-01

7

Heat exchanger  

DOEpatents

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

Brackenbury, Phillip J. (Richland, WA)

1986-01-01

8

Heat exchanger  

DOEpatents

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

Brackenbury, P.J.

1983-12-08

9

Segmented heat exchanger  

DOEpatents

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

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

2010-12-14

10

Heat pipe array heat exchanger  

DOEpatents

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

Reimann, Robert C. (Lafayette, NY)

1987-08-25

11

Woven heat exchanger  

DOEpatents

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

Piscitella, R.R.

1984-07-16

12

Woven heat exchanger  

DOEpatents

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

Piscitella, Roger R. (Idaho Falls, ID)

1987-01-01

13

Active microchannel heat exchanger  

Microsoft Academic Search

The present invention is an active microchannel heat exchanger with an active heat source and with microchannel architecture. The active microchannel heat exchanger has (a) an exothermic reaction chamber; (b) an exhaust chamber; and (c) a heat exchanger chamber in thermal contact with the exhaust chamber, wherein (d) heat from the exothermic reaction chamber is convected by an exothermic reaction

Anna Lee Y. Tonkovich; Gary L. Roberts; Charles J. Call; Robert S. Wegeng; Yong Wang

2001-01-01

14

Phase change heat exchanger  

Microsoft Academic Search

A heat exchanger for a phase change material having a solid density greater than its liquid density, the heat exchanger is described comprising a container holding the phase change material, a tube surrounding the container to define an annular space there between, means for connecting the tube in fluid communication with a first source of heat exchange fluid to allow

R. L. Longardner; W. J. Longardner

1993-01-01

15

Direct fired heat exchanger  

DOEpatents

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

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

1986-01-01

16

Wound tube heat exchanger  

DOEpatents

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

Ecker, Amir L. (Duncanville, TX)

1983-01-01

17

Heat exchange device  

SciTech Connect

A heat exchange device is adapted to recover heat from the fire box of a wood burning stove or the like for heating ambient air in a room or other enclosed space. The heat exchange device is adapted to mount in a recess in a stove top in place of a lid which is normally supplied with the stove. The device according to the invention includes heat exchange means which extend into the fire box of the stove below the top surface thereof. The heat from the heat exchange device is transmitted into a main cavity of the device where the heat is transferred to air forced through the main cavity by a blower mounted to an outside surface of the device. Air exit means are provided on a surface opposite to the surface on which the blower is mounted to provide a passage for heated air into the room or other enclosed space to be heated. The device may also include a top mounted isolated handle for ease in handling the device such as for moving from one area to another. In a second embodiment of the device, a high temperature heat exchange glass plate is mounted on the surface of the device which is in contact with the fire box. Heat is transmitted by heat exchange plate to the main cavity of the device where the air is heated and blown into the room as above.

Callison, G.

1984-01-17

18

Nature's Heat Exchangers.  

ERIC Educational Resources Information Center

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)

Barnes, George

1991-01-01

19

Active microchannel heat exchanger  

DOEpatents

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

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

2001-01-01

20

Heat and mass exchanger  

DOEpatents

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

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

2007-09-18

21

Heat and mass exchanger  

DOEpatents

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

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

2011-06-28

22

Modular Heat Exchanger With Integral Heat Pipe  

NASA Technical Reports Server (NTRS)

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.

Schreiber, Jeffrey G.

1992-01-01

23

A corrosive resistant heat exchanger  

DOEpatents

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

Richlen, S.L.

1987-08-10

24

Radial flow heat exchanger  

DOEpatents

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

Valenzuela, Javier (Hanover, NH)

2001-01-01

25

Counterflow Regolith Heat Exchanger  

NASA Technical Reports Server (NTRS)

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.

Zubrin, Robert; Jonscher, Peter

2013-01-01

26

Intermittency in the heat and particle transports in the SINP tokamak scrape-off layer  

SciTech Connect

The intermittent heat and particle transports have been studied in the scrape-off layer of the SINP tokamak. Properties of the plasma structures, responsible for the intermittency, have been measured by the conditional averaging technique. The probability distribution functions of the fluctuations, including temperature fluctuations, obey non-Gaussian statistics. Wavelet analysis has shown that the cross-correlation between two probes is also intermittent in time and is connected to the passage of plasma structures. The structures decay in density as they move radially outward but their temperature is found to decay more rapidly.

Saha, S. K.; Chowdhury, S. [Plasma Physics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata-700064 (India)

2008-01-15

27

Monogroove liquid heat exchanger  

NASA Technical Reports Server (NTRS)

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).

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

1990-01-01

28

Chimney heat exchanger  

SciTech Connect

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.

Whiteley, I.C.

1981-09-01

29

Microgravity condensing heat exchanger  

NASA Technical Reports Server (NTRS)

A heat exchanger having a plurality of heat exchanging aluminum fins with hydrophilic condensing surfaces which are stacked and clamped between two cold plates. The cold plates are aligned radially along a plane extending through the axis of a cylindrical duct and hold the stacked and clamped portions of the heat exchanging fins along the axis of the cylindrical duct. The fins extend outwardly from the clamped portions along approximately radial planes. The spacing between fins is symmetric about the cold plates, and are somewhat more closely spaced as the angle they make with the cold plates approaches 90.degree.. Passageways extend through the fins between vertex spaces which provide capillary storage and communicate with passageways formed in the stacked and clamped portions of the fins, which communicate with water drains connected to a pump externally to the duct. Water with no entrained air is drawn from the capillary spaces.

Thomas, Christopher M. (Inventor); Ma, Yonghui (Inventor); North, Andrew (Inventor); Weislogel, Mark M. (Inventor)

2011-01-01

30

Heat exchanger panel  

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

31

Heat transfer enhancement in heat exchangers  

Microsoft Academic Search

In the power generation industry, high performance heat exchangers are needed to promote substantial improvements in effective utilization of waste heat in low temperature heat recovery applications. High performance heat exchangers are also seriously needed in low temperature power and refrigeration cycles that operate on renewable base energy sources such as ocean thermal energy conversion, geothermal and solar energy systems.

Ohadi

1991-01-01

32

Heat exchanger-accumulator  

DOEpatents

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

Ecker, Amir L. (Dallas, TX)

1980-01-01

33

Heat-Exchanger/Heat-Pipe Interface  

NASA Technical Reports Server (NTRS)

Monolithic assembly reliable and light in weight. Heat exchanger and evaporator ends of heat pipes integrated in monolithic halves welded together. Interface assembly connects heat exchanger of furnace, reactor, or other power source with heat pipes carrying heat to radiator or power-consuming system. One of several concepts proposed for nuclear power supplies aboard spacecraft, interface useful on Earth in solar thermal power systems, heat engines, and lightweight cooling systems.

Snyder, H. J.; Van Hagan, T. H.

1987-01-01

34

Lightweight Long Life Heat Exchanger  

NASA Technical Reports Server (NTRS)

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.

Moore, E. K.

1976-01-01

35

Fault-Tolerant Heat Exchanger  

NASA Technical Reports Server (NTRS)

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.

Izenson, Michael G.; Crowley, Christopher J.

2005-01-01

36

Solar heat exchanger  

SciTech Connect

A solar heat exchanger comprising a frame having an inner surface area defined by upstanding walls, ends and bottom wherein an insulation layer of relatively uniform thickness is spread throughout the inner surface. A plurality of channels are spaced throughout the frame. The channels may be arranged in a serpentine or manifold design and may comprise an outer curved wall and an inner curved wall wherein water flows through the inner and outer curved wall and spaced between the inner and outer curved wall in a restricted manner. Additionally, the frame may include a top insulation layer comprising generally parallel panels spanning the frame and creating a greenhouse effect upon the channels. Inlet and outlet means are provided within the frame to allow cooler water to enter the exchanger and warmer water to exit.

Kitzmiller, G.

1982-08-31

37

Hybrid Heat Exchangers  

NASA Technical Reports Server (NTRS)

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.

Tu, Jianping Gene; Shih, Wei

2010-01-01

38

Oscillating-Coolant Heat Exchanger  

NASA Technical Reports Server (NTRS)

Devices useful in situations in which heat pipes inadequate. Conceptual oscillating-coolant heat exchanger (OCHEX) transports heat from its hotter portions to cooler portions. Heat transported by oscillation of single-phase fluid, called primary coolant, in coolant passages. No time-averaged flow in tubes, so either heat removed from end reservoirs on every cycle or heat removed indirectly by cooling sides of channels with another coolant. Devices include leading-edge cooling devices in hypersonic aircraft and "frost-free" heat exchangers. Also used in any situation in which heat pipe used and in other situations in which heat pipes not usable.

Scotti, Stephen J.; Blosser, Max L.; Camarda, Charles J.

1992-01-01

39

Matrix-type heat exchangers  

NASA Astrophysics Data System (ADS)

Problems related to the analysis, design, and fabrication of compact matrix-type heat exchangers are discussed. Particular attention is given to the general characteristics describing the intensity of heat transfer and the hydrodynamic resistance of the matrices, an analysis of the efficiency of perforated ribs, and an evaluation of the efficiency of the matrix heat exchange surfaces. The effect of longitudinal heat conduction on heat transfer in the heat exchanger is examined, and a method is proposed whereby this factor can be allowed for in the analysis.

Mikulin, E. I.; Shevich, Iu. A.

40

Heat pipes in modern heat exchangers  

Microsoft Academic Search

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

Leonard L. Vasiliev

2005-01-01

41

Optimization of Heat Exchanger Cleaning  

E-print Network

. Material is not only continuously deposited on the heat exchange surface but is also continuously removed. In order to predict the optimum cleaning time and calculate the TFRE, it is necessary to develop a mathematical relationship for the rate... OPTIMIZATION OF HEAT EXCHANGER CLEANING Jeffrey H. Siegell Exxon Research and Engineering Company Florham Park, New Jersey ABSTRACT The performance of heat integration systems is quantified in terms of the amount of heat that is recovered...

Siegell, J. H.

42

SP100 Heat Source Heat Exchanger Design  

Microsoft Academic Search

A conceptual design for a liquid metal to gas counterflow heat exchanger has been developed for use in the SP-100 Closed Brayton Cycle (CBC) Space Reactor Power System (SRPS). The Heat Source Heat Exchanger (HSHX) is required to transfer 80 kWt from the 1350 K lithium reactor coolant to the He\\/Xe working fluid of the Brayton Rotating Unit (BRU). Trade

T. Ted Fallas; Andrew W. Desepte; Robert J. Hill; Georgi B. Manjarrez; Enrique R. Solorzano; Samir A. Salamah; Raphael Yahalom

1994-01-01

43

Flow maldistribution in heat exchangers  

Microsoft Academic Search

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

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

1999-01-01

44

High Temperature Heat Exchanger Project  

SciTech Connect

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

Anthony E. Hechanova, Ph.D.

2008-09-30

45

Modular heat exchanger  

DOEpatents

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

Giardina, A.R.

1981-03-03

46

Modular heat exchanger  

DOEpatents

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

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

1981-03-03

47

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

SciTech Connect

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 [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 fully 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 versus emission are discussed.

Myra, J. R. [Lodestar Research Corporation; Russell, D. A. [Lodestar Research Corporation; D'Ippolito, D. A. [Lodestar Research Corporation; Ahn, Joon-Wook [Oak Ridge National Laboratory (ORNL); Maingi, Rajesh [ORNL; Maqueda, R. J. [Princeton Plasma Physics Laboratory (PPPL); Lundberg, D. P. [Princeton Plasma Physics Laboratory (PPPL); Stotler, D. P. [Princeton Plasma Physics Laboratory (PPPL); Zweben, S. J. [Princeton Plasma Physics Laboratory (PPPL); Boedo, J. [University of California, San Diego; Umansky, M.W. [Lawrence Livermore National Laboratory (LLNL)

2011-01-01

48

Heat exchanger with ceramic elements  

DOEpatents

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

Corey, John A. (North Troy, NY)

1986-01-01

49

Heat exchanger using graphite foam  

DOEpatents

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

Campagna, Michael Joseph; Callas, James John

2012-09-25

50

Wood burning stove heat exchanger  

SciTech Connect

A wood burning stove includes a water circulating grate within the stove fire chamber which includes horizontally extending, vertically spaced, first and second tubular manifolds. Fuel supporting pipes, including bottom portions which define a ''V'', physically and fluidly interconnect the manifolds. An inlet pipe extends throughout the majority of the length of the bottom manifold, and the top manifold is connected-through a container having a larger cross-sectional area than the cross-sectional area of the manifold-to an outlet. The inlet to and outlet from the manifold are connected up to a hydronic space heating system. The container supports a heat exchanger comprising a finned copper tube, so that the heat exchanger extends generally horizontally and within the first manifold. The heat exchanger is connected up to a domestic hot water supply. The container also supports one or more electric resistance heating coils, which heat liquid within the container in emergency situations.

Manno, J. T.

1985-08-13

51

Numerical simulation of heat exchanger  

SciTech Connect

Accurate and detailed knowledge of the fluid flow field and thermal distribution inside a heat exchanger becomes invaluable as a large, efficient, and reliable unit is sought. This information is needed to provide proper evaluation of the thermal and structural performance characteristics of a heat exchanger. It is to be noted that an analytical prediction method, when properly validated, will greatly reduce the need for model testing, facilitate interpolating and extrapolating test data, aid in optimizing heat-exchanger design and performance, and provide scaling capability. Thus tremendous savings of cost and time are realized. With the advent of large digital computers and advances in the development of computational fluid mechanics, it has become possible to predict analytically, through numerical solution, the conservation equations of mass, momentum, and energy for both the shellside and tubeside fluids. The numerical modeling technique will be a valuable, cost-effective design tool for development of advanced heat exchangers.

Sha, W.T.

1985-01-01

52

Waste heat recovery using heat pipe heat exchanger for heating automobile using exhaust gas  

Microsoft Academic Search

The feasibility of using heat pipe heat exchangers for heating applying automotive exhaust gas is studied and the calculation method is developed. Practical heat pipe heat exchanger is set up for heating HS663, a large bus. Simple experiments are carried out to examine the performance of the heat exchanger. It is shown that the experimental results, which indicate the benefit

Feng Yang; Xiugan Yuan; Guiping Lin

2003-01-01

53

Ceramic-heat-exchanger technology  

NASA Astrophysics Data System (ADS)

Technology for pressurized, high temperature, ceramic tube heat exchangers was established by environmental, design, and fabrication studies. The design study includes the finite element stress analysis of the ceramic components contained in the DOE ceramic heat exchanger test module. This test module contains 28, 4.56-m long ceramic tubes with a 11.43-cm dia ceramic header. It was operated successfully for 125 h up to firing temperatures of 17000K (26000F) and outlet air temperatures of 15330K (23000F) at 689.4 kPa (100 psia). This unit was then fired with a pulverized coal burner under EPRI sponsorship for 25 h.

Ward, M. E.; Kubasco, A. J.

1983-03-01

54

Lightweight long life heat exchanger  

NASA Technical Reports Server (NTRS)

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.

Moore, E. K.

1975-01-01

55

Ceramic heat exchanger  

DOEpatents

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

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

1998-01-01

56

Ceramic heat exchanger  

DOEpatents

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

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

1998-06-16

57

Heat Exchanger Network Design, Monitoring and Optimization  

Microsoft Academic Search

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

Uma Maheshwar Kiran Ati

2009-01-01

58

Heat exchanger with oscillating flow  

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

59

Heat exchanger with oscillating flow  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

60

Operation Characteristics of Heat Pump Systems with Ground Heat Exchangers  

Microsoft Academic Search

This paper examines the merits of heating systems with a vapor compressor heat pump unit for small residential homes. In this case, the ground is assumed to serve as the low heat source, and the ground heat exchanger may be horizontal or vertical in form. A mathematical model for all vapor compressor heat pump (VCHP)-ground heat exchanger (GHE) systems is

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

2012-01-01

61

Second Law Optimization of Heat Exchangers  

E-print Network

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...

Witte, L. C.

62

Integrated Approach to Revamping Heat Exchangers Networks  

E-print Network

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...

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

63

Synergistic diffuser/heat-exchanger design  

E-print Network

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

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

2004-01-01

64

Pressurized bellows flat contact heat exchanger interface  

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

65

Improved Ceramic for Heat Exchangers  

NASA Technical Reports Server (NTRS)

Most promising composition developed in investigation consisted of mixed oxides described generically as ZrMAS. Has been commercially designated as GE-7808. Material was obtained from low-cost clay/talc mixture. Overall assessment of ZrMAS indicates it is a viable candidate for heat-exchanger application in automotive gas-turbine engines and possibly other areas that require dielectric materials of moderate refractoriness, good corrosion resistance, and excellent thermal-shock resistance.

Herbell, T. P.; Rauch, H. W.; Mccreeght, L. R.

1982-01-01

66

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

SciTech Connect

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

Culver, G.

1990-11-01

67

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

68

Cryogenic Heat Exchanger with Turbulent Flows  

ERIC Educational Resources Information Center

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…

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

2012-01-01

69

Scrape-off layer modeling of radiative divertor and high heat flux experiments on D3-D  

NASA Astrophysics Data System (ADS)

We use a new multispecies 1-D fluid code, NEWT-1D, to model DIII-D scrape-off layer (SOL) behavior during radiative divertor and high heat flux experiments. The separatrix location and the width of the SOL are uncertain, and affect the comparison of the data in important ways. The model agrees with many of the experimental measurements for a particular prescription for the separatrix location. The model cannot explain the recent data on the separatrix T(sub i) with a conventional picture of ion and electron power flows across the separatrix. Radial transport of particles and heat in some form is required to explain the peak heat flux data before and after gas puffing. For argon puffing in the private flux region, entrainment is poor in the steady state. The calculations suggest that strike point argon puffing in a slot divertor geometry results in substantially better entrainment. Self-consistent, steady-state solutions with radiated powers up to 80 percent of the SOL power input are obtained in 1-D. We discuss significant radial effects which warrant the development of a code which can treat strongly radiating impurities in 2-D geometries.

Campbell, R. B.; Petrie, T. W.; Hill, D. N.

1992-03-01

70

Scrape-off layer modeling of radiative divertor and high heat flux experiments on DIII-D  

NASA Astrophysics Data System (ADS)

We use a new multispecies 1D fluid code, NEWT-ID, to model DIII-D scrape-off layer (SOL) behavior during radiative divertor and high heat flux experiments. The separatrix location and the width of the SOL are uncertain, and affect the comparison of the data in important ways. The model agrees with many of the experimental measurements for a particular prescription for the separatrix location. The model cannot explain the recent data on the separatrix Ti with a conventional picture of ion and electron power flows across the separatrix. Radial transport of particles and heat in some form is required to explain the peak heat flux data before and after gas puffing. For argon puffing in the private flux region, entrainment is poor in the steady state. The calculations suggest that strike point argon puffing in a slot divertor geometry results in substantially better entrainment. Self-consistent, steady-state solutions with radiated powers up to 80% of the SOL power input are obtained in 1D. We discuss significant radial effects which warrant the development of a code which can treat strongly radiating impurities in 2D geometries.

Campbell, R. B.; Petrie, T. W.; Hill, D. N.

1992-12-01

71

SAFE gas turbine cycle primary heat exchangers  

NASA Astrophysics Data System (ADS)

Los Alamos National Laboratory and Marshall Space Flight Center are jointly developing two modular heat pipe heat exchangers, collectively named FIGMENT (Fission Inert Gas Metal Exchanger for Non-nuclear Testing). The FIGMENT heat exchangers are designed to transfer power from the SAFE nuclear reactor cores to gas turbine energy converters. A stainless steel prototype heat exchanger will be built during 2002 in preparation for the construction of a larger refractory metal version. Two promising FIGMENT stainless steel heat exchanger concepts are reviewed here. .

Reid, Robert S.; Kapernick, Richard J.

2002-01-01

72

Manufacture of aluminum plate heat exchangers  

Microsoft Academic Search

Plate heat exchangers (Fig. 1) are widely used as regenerators for gas turbine plants, heat exchangers in plants for the fractionating of air, etc. They have a number of advantages over other types of this equipment: high efficiency, low heat capacity, compactness of the surface, relatively small overall dimensions, etc. [1-3]. The use of plate heat exhcangers in the chemical,

N. S. Baranov; G. A. Stepanov

1966-01-01

73

Fluid to fluid contact heat exchanger  

NASA Technical Reports Server (NTRS)

Heat transfer and pressure drop test results for a fluid to fluid contact heat exchanger are reported. The heat exchanger, fabricated and tested to demonstrate one method of transferring heat between structures in space, had a total contact area of 0.18 sq m. It utilized contact surfaces which were flexible and conformed to the mating contact surfaces upon pressurization of the fluid circulating within the heat exchanger. During proof-of-concept performance tests, the heat exchanger was operated in a typical earth environment. It demonstrated a contact conductance of 3.8 kW/sq m C at contact pressures in the 15 to 70 kPa range.

Clark, W. E.

1986-01-01

74

Heat-Exchanger Method of Crystal Growth  

NASA Technical Reports Server (NTRS)

Large crystals of silicon are grown from melt, in either vacuum or pressurized atmosphere, without moving crucible, furnace, or anything else. Seed crystal is mounted on helium-cooled heat exchanger, which prevents seed from melting when furnace melts rest of silicon material in crucible; heat exchanger draws off heat from melt so that a solid ingot grows outward from seed in a regular crystal structure. Bottom of crucible is insulated so that heat exchanger cools only seed.

Khattak, C. P.; Schmid, F.

1982-01-01

75

NGNP Process Heat Utilization: Liquid Metal Phase Change Heat Exchanger  

SciTech Connect

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

Piyush Sabharwall; Mike Patterson; Vivek Utgikar; Fred Gunnerson

2008-09-01

76

Improved ceramic heat exchange material  

NASA Technical Reports Server (NTRS)

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.

Mccollister, H. L.

1977-01-01

77

Solar energy collector and heat exchanger  

Microsoft Academic Search

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

Pyle

1979-01-01

78

Heat Transfer Characteristics of a Generalized Divided Flow Heat Exchanger  

E-print Network

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

Singh, K. P.

1979-01-01

79

Innovative heat exchangers for solar water heaters.  

E-print Network

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

Soo Too, Yen Chean

2007-01-01

80

Modular tube bundle heat exchanger and geothermal heat pump system  

Microsoft Academic Search

An improved ground source heat pump system is described, comprising: an in-ground heat exchanger and a building heat exchanger coupled via conduits for refrigerant to at least one compressor and at least one expander, the compressor having at least one intake line and at least one discharge line, the compressor and the expander being coupled to the conduits such that

M. J. Galiyano; B. R. Wiggs; J. T. Aspacher

1993-01-01

81

AP600 passive residual heat removal heat exchanger test  

Microsoft Academic Search

The AP600 reactor is a pressurized water reactor being designed to utilize a passive residual heat removal (PRHR) heat exchanger as the safety grade means for residual heat removal. The PRHR heat exchanger is utilized during many design basis events and is especially important in mitigating non-loss-of-coolant accidents such as loss of normal feedwater and feedwater line break. The PRHR

M. M. Corletti; L. E. Hochreiter; D. Squarer

1990-01-01

82

Fuel delivery system including heat exchanger means  

NASA Technical Reports Server (NTRS)

A fuel delivery system is presented wherein first and second heat exchanger means are each adapted to provide the transfer of heat between the fuel and a second fluid such as lubricating oil associated with the gas turbine engine. Valve means are included which are operative in a first mode to provide for flow of the second fluid through both first and second heat exchange means and further operative in a second mode for bypassing the second fluid around the second heat exchanger means.

Coffinberry, G. A. (inventor)

1978-01-01

83

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

84

Direct contact heat exchanger with phase change of working fluid  

Microsoft Academic Search

A direct contact thermal storage heat exchanger is disclosed which utilizes the liquid-vapor phase change of a working fluid within the heat exchanger, and energy generation systems incorporating the heat exchanger. The heat exchanger is particularly useful in combination with a solar energy receiver. The heat exchanger includes an insulated pressure vessel packed with pebbles or spheres. Working fluid in

Pierce

1980-01-01

85

Heat exchanger device and method for heat removal or transfer  

SciTech Connect

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

Koplow, Jeffrey P. (San Ramon, CA)

2012-07-24

86

Heat transfer in ground heat exchangers with groundwater advection  

Microsoft Academic Search

In order to estimate the impact of groundwater flow on performance of geothermal heat exchangers in ground source heat pump systems, an equation of conduction–advection is established for heat transfer in porous media, and an analytical transient solution is obtained for a line heat source in an infinite medium by means of the Green function analysis. An explicit expression has

Nairen Diao; Qinyun Li; Zhaohong Fang

2004-01-01

87

Improved ceramic heat exchanger materials  

NASA Technical Reports Server (NTRS)

The development and evaluation of materials for potential application as heat exchanger structures in automotive gas turbine engines is discussed. Test specimens in the form of small monolithic bars were evaluated for thermal expansion and dimensional stability before and after exposure to sea salt and sulfuric acid, followed by short and long term cycling at temperatures up to 1200 C. The material finally selected, GE-7808, consists of the oxides, ZrO2-MgO-Al2O3-S1O2, and is described generically as ZrMAS. The original version was based on a commercially available cordierite (MAS) frit. However, a clay/talc mixture was demonstrated to be a satisfactory very low cost source of the cordierite (MAS) phase. Several full size honeycomb regenerator cores, about 10.2 cm thick and 55 cm diameter were fabricated from both the frit and mineral versions of GE-7808. The honeycomb cells in these cores had rectangular dimensions of about 0.5 mm x 2.5 mm and a wall thickness of approximately 0.2 mm. The test data show that GE-7808 is significantly more stable at 1100 C in the presence of sodium than the aluminosilicate reference materials. In addition, thermal exposure up to 1100 C, with and without sodium present, results in essentially no change in thermal expansion of GE-7808.

Rauch, H. W.

1980-01-01

88

Predicting particle deposition on HVAC heat exchangers  

Microsoft Academic Search

Particles in indoor environments may deposit on the surfaces of heat exchangers that are used in heating, ventilation and air conditioning (HVAC) systems. Such deposits can lead to performance degradation and indoor air quality problems. We present a model of fin-and-tube heat-exchanger fouling that deterministically simulates particle impaction, gravitational settling, and Brownian diffusion and uses a Monte Carlo simulation to

Jeffrey A. Siegel; William W Nazaroff

2003-01-01

89

Phase Change Material Heat Exchanger Life Test  

NASA Technical Reports Server (NTRS)

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.

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

2008-01-01

90

Heat exchanger, head and shell acceptance criteria  

SciTech Connect

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.

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

1992-09-01

91

21 CFR 870.4240 - Cardiopulmonary bypass heat exchanger.  

...2014-04-01 false Cardiopulmonary bypass heat exchanger. 870.4240 Section 870... § 870.4240 Cardiopulmonary bypass heat exchanger. (a) Identification. A cardiopulmonary bypass heat exchanger is a device, consisting of...

2014-04-01

92

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... § 870.4240 Cardiopulmonary bypass heat exchanger. (a) Identification. A cardiopulmonary bypass heat exchanger is a device, consisting of...

2012-04-01

93

14 CFR 25.1125 - Exhaust heat exchangers.  

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

2014-01-01

94

40 CFR 63.104 - Heat exchange system requirements.  

...2014-07-01 2014-07-01 false Heat exchange system requirements. 63.104...Chemical Manufacturing Industry § 63.104 Heat exchange system requirements. ...subject to this subpart shall monitor each heat exchange system used to cool...

2014-07-01

95

40 CFR 63.104 - Heat exchange system requirements.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Heat exchange system requirements. 63.104...Chemical Manufacturing Industry § 63.104 Heat exchange system requirements. ...subject to this subpart shall monitor each heat exchange system used to cool...

2010-07-01

96

14 CFR 29.1125 - Exhaust heat exchangers.  

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

2014-01-01

97

40 CFR 63.104 - Heat exchange system requirements.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Heat exchange system requirements. 63.104...Chemical Manufacturing Industry § 63.104 Heat exchange system requirements. ...subject to this subpart shall monitor each heat exchange system used to cool...

2013-07-01

98

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... § 870.4240 Cardiopulmonary bypass heat exchanger. (a) Identification. A cardiopulmonary bypass heat exchanger is a device, consisting of...

2010-04-01

99

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... Exhaust System § 23.1125 Exhaust heat exchangers. For reciprocating engine...following apply: (a) Each exhaust heat exchanger must be constructed and...

2011-01-01

100

40 CFR 63.104 - Heat exchange system requirements.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Heat exchange system requirements. 63.104...Chemical Manufacturing Industry § 63.104 Heat exchange system requirements. ...subject to this subpart shall monitor each heat exchange system used to cool...

2012-07-01

101

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... Exhaust System § 25.1125 Exhaust heat exchangers. For reciprocating engine...following apply: (a) Each exhaust heat exchanger must be constructed and...

2010-01-01

102

40 CFR 63.1328 - Heat exchange systems provisions.  

Code of Federal Regulations, 2010 CFR

...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...

2010-07-01

103

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... Exhaust System § 25.1125 Exhaust heat exchangers. For reciprocating engine...following apply: (a) Each exhaust heat exchanger must be constructed and...

2011-01-01

104

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... Exhaust System § 29.1125 Exhaust heat exchangers. For reciprocating engine...following apply: (a) Each exhaust heat exchanger must be constructed and...

2013-01-01

105

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... § 870.4240 Cardiopulmonary bypass heat exchanger. (a) Identification. A cardiopulmonary bypass heat exchanger is a device, consisting of...

2011-04-01

106

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

2012-07-01

107

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... Exhaust System § 29.1125 Exhaust heat exchangers. For reciprocating engine...following apply: (a) Each exhaust heat exchanger must be constructed and...

2012-01-01

108

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... Exhaust System § 23.1125 Exhaust heat exchangers. For reciprocating engine...following apply: (a) Each exhaust heat exchanger must be constructed and...

2013-01-01

109

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... Exhaust System § 29.1125 Exhaust heat exchangers. For reciprocating engine...following apply: (a) Each exhaust heat exchanger must be constructed and...

2010-01-01

110

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... § 870.4240 Cardiopulmonary bypass heat exchanger. (a) Identification. A cardiopulmonary bypass heat exchanger is a device, consisting of...

2013-04-01

111

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... Exhaust System § 25.1125 Exhaust heat exchangers. For reciprocating engine...following apply: (a) Each exhaust heat exchanger must be constructed and...

2013-01-01

112

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... Exhaust System § 29.1125 Exhaust heat exchangers. For reciprocating engine...following apply: (a) Each exhaust heat exchanger must be constructed and...

2011-01-01

113

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... Exhaust System § 23.1125 Exhaust heat exchangers. For reciprocating engine...following apply: (a) Each exhaust heat exchanger must be constructed and...

2012-01-01

114

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... Exhaust System § 25.1125 Exhaust heat exchangers. For reciprocating engine...following apply: (a) Each exhaust heat exchanger must be constructed and...

2012-01-01

115

40 CFR 63.104 - Heat exchange system requirements.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Heat exchange system requirements. 63.104...Chemical Manufacturing Industry § 63.104 Heat exchange system requirements. ...subject to this subpart shall monitor each heat exchange system used to cool...

2011-07-01

116

14 CFR 23.1125 - Exhaust heat exchangers.  

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

2014-01-01

117

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... Exhaust System § 23.1125 Exhaust heat exchangers. For reciprocating engine...following apply: (a) Each exhaust heat exchanger must be constructed and...

2010-01-01

118

Design study of plastic film heat exchanger  

NASA Astrophysics Data System (ADS)

This report presents the results of an effort to develop and design a unique thermoplastic film heat exchanger for use in an industrial heat pump evaporator system and other energy recovery applications. The concept for the exchanger is that of individual heat exchange elements formed by two adjoining and freely hanging plastic films. Liquid flows downward in a regulated fashion between the films due to the balance of hydrostatic and frictional forces. The fluid stream on the outside of film may be a free-falling liquid film, a condensing gas, or a noncondensing gas. The flow and structural principles are similar to those embodied in an earlier heat exchange system developed for use in waste water treatment systems (Sanderson). The design allows for high heat transfer rates while working within the thermal and structural limitations of thermoplastic materials. The potential of this new heat exchanger design lies in the relatively low cost of plastic film and the high inherent corrosion and fouling resistance. This report addresses the selection of materials, the potential heat transf er performance, the mechanical design and operation of a unit applied in a low pressure steam recovery system, and the expected selling price in comparison to conventional metallic shell and tube heat exchangers.

Guyer, E. C.; Brownell, D. L.

1986-02-01

119

Heat exchanger with transpired, highly porous fins  

DOEpatents

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

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

2002-01-01

120

Acceptance criteria for heat exchanger head staybolts  

SciTech Connect

Each of the six primary coolant loop systems of the Savannah River Site production reactors contains two parallel single-pass heat exchangers to transfer heat from the primary coolant (D{sub 2}O) to the secondary cooling water (H{sub 2}O). The configuration of the heat exchangers includes a plenary space defined by the heat exchanger tubesheet and the heat exchanger head at both the heat exchanger inlet and outlet to the primary piping. The primary restraint of the heat exchanger head (Type 304 stainless steel) is provided by 84 staybolts (Type 303 stainless steel) which attach to the tubesheet. The staybolts were cap seal-welded in the mid-1960`s and are immersed in moderator. Access to inspect the staybolts is limited to a recently-developed ultrasonic technique shooting a beam through the staybolt assembly. Acceptance Criteria to allow disposition of flaws detected by UT inspection have been developed. The structural adequacy to protect against collapse loading of the head is demonstrated by finite element analysis of the head assembly and fracture analysis of flaw postulates in the staybolts. Both normal operation and normal operation plus seismic loading conditions were considered. Several bounding cases containing various configurations of nonactive (exceeding critical flaw size) staybolts were analyzed. The model of the head assembly can be applied to evaluate any active staybolt configurations based on the results from future inspections. 9 refs.

Sindelar, R.L.; Lam, P.S.; Barnes, D.M.; Placr, A.; Morrison, J.M.

1991-12-31

121

Acceptance criteria for heat exchanger head staybolts  

SciTech Connect

Each of the six primary coolant loop systems of the Savannah River Site production reactors contains two parallel single-pass heat exchangers to transfer heat from the primary coolant (D{sub 2}O) to the secondary cooling water (H{sub 2}O). The configuration of the heat exchangers includes a plenary space defined by the heat exchanger tubesheet and the heat exchanger head at both the heat exchanger inlet and outlet to the primary piping. The primary restraint of the heat exchanger head (Type 304 stainless steel) is provided by 84 staybolts (Type 303 stainless steel) which attach to the tubesheet. The staybolts were cap seal-welded in the mid-1960's and are immersed in moderator. Access to inspect the staybolts is limited to a recently-developed ultrasonic technique shooting a beam through the staybolt assembly. Acceptance Criteria to allow disposition of flaws detected by UT inspection have been developed. The structural adequacy to protect against collapse loading of the head is demonstrated by finite element analysis of the head assembly and fracture analysis of flaw postulates in the staybolts. Both normal operation and normal operation plus seismic loading conditions were considered. Several bounding cases containing various configurations of nonactive (exceeding critical flaw size) staybolts were analyzed. The model of the head assembly can be applied to evaluate any active staybolt configurations based on the results from future inspections. 9 refs.

Sindelar, R.L.; Lam, P.S.; Barnes, D.M.; Placr, A.; Morrison, J.M.

1991-01-01

122

NRBP kicks off Clean Heat Woodstove Exchange  

SciTech Connect

The NRBP has created the Celan Heat Woodstove exchange with the goal of increasing public awareness and interest in the new generation EPA-certified woodstoves, equipping them with tools to promote the new stoves.

Handley, R. [CONEG Policy Research Center, Inc., Washington, DC (United States)

1994-12-31

123

Condensing Heat Exchangers Optimize Steam Boilers  

E-print Network

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

Sullivan, B.; Sullivan, P. A.

1983-01-01

124

Modelling and simulation of a heat exchanger  

NASA Technical Reports Server (NTRS)

Two models for two different control systems are developed for a parallel heat exchanger. First by spatially lumping a heat exchanger model, a good approximate model which has a high system order is produced. Model reduction techniques are applied to these to obtain low order models that are suitable for dynamic analysis and control design. The simulation method is discussed to ensure a valid simulation result.

Xia, Lei; Deabreu-Garcia, J. Alex; Hartley, Tom T.

1991-01-01

125

Joule-Thomson expander and heat exchanger  

NASA Technical Reports Server (NTRS)

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.

Norman, R. H.

1976-01-01

126

Brayton-cycle heat exchanger technology program  

NASA Technical Reports Server (NTRS)

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.

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

1976-01-01

127

Performance of a counterflow heat exchanger with heat loss through the wall at the cold end  

Microsoft Academic Search

The performance of high effectiveness heat exchangers used in cryogenic systems is strongly controlled by irreversibilities such as longitudinal heat conduction and heat leak from ambient. In all heat exchanger analyses, it is assumed that no heat is lost through the heat exchanger walls. In the case of small J-T refrigerators such as microminiature refrigerators, the heat exchanger cold end

S Pradeep Narayanan; G Venkatarathnam

1999-01-01

128

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

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.

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

2009-01-05

129

Phase Change Material Heat Exchanger Life Test  

NASA Technical Reports Server (NTRS)

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.

Lillibridge, Sean; Stephan, Ryan

2009-01-01

130

Heat Exchanger With Internal Pin Elements  

DOEpatents

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.

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

2004-01-13

131

Screen heat exchanger performance comparison  

Microsoft Academic Search

The performance of stainless steel screen regenerator stacks (500 mesh) has been investigated at relatively small flow rates in comparison to conventional operation close to the laminar-turbulent transition range. A modified 'single blow' technique was used initially, and an additional comparative procedure is employed to deduce heat transfer rate ratios with respect to a single-wire reference case of heat transfer.

J. Luna; K. V. Ravikumar; T. H. K. Frederking

1992-01-01

132

Heat exchanger analysis for nonazeotropic refrigerant mixtures  

SciTech Connect

A fundamental method for analyzing heat exchangers using pure refrigerants and nonazeotropic refrigerant mixtures is presented. The method allows for calculation of heat and mass transfer between moist air and nonazeotropic refrigerant mixtures and predicts local parameters of air and mixtures. Both single and two phase refrigerants can be analyzed with this method. Algorithms for the use of this model are presented. Data and calculated thermal performance for two conventional types of air-side geometries are also presented. The algorithms to calculate thermal performance of heat exchangers can be used for either conventional or enhanced geometries. A comparison of crossflow, cross-counterflow, and counterflow heat exchangers is given. The algorithms are sufficient for design and development of equipment using pure and mixed refrigerants.

Poz, M.Y. [Russian Association of Engineers for Heating, Ventilation, Air Conditioning, Heat Supply and Building Thermal Physics (ABOK), Moscow (Russian Federation); Conklin, J.C. [Oak Ridge National Lab., TN (United States)

1994-02-01

133

Heat exchanger with auxiliary cooling system  

DOEpatents

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

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

1980-01-01

134

Multiple Sensor Fault Detection in Heat Exchanger Systems  

E-print Network

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

Paris-Sud XI, Université de

135

Package embedded heat exchanger for stacked multi-chip module  

Microsoft Academic Search

This paper described a polymer type micro heat exchanger for stacked multi-chip module (MCM). Usually, heat exchanger was fabricated by high thermal conductive substrate such as metal, silicon etc. Of course it showed efficient heat exchange ability. However, there was packaging problem when it was integrated in a package, because the heat exchanger became too huge to accommodate in present

Haehyung Lee; Yongwon Jeong; Joonghan Shin; Songyi Kim; Minha Kim; Moonkoo Kang; Kukjin Chun

2003-01-01

136

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

137

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

Microsoft Academic Search

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

M. Rodriguez Pascual

2009-01-01

138

Study of frost melting on a heat pump heat exchanger  

SciTech Connect

This experimental work was carried out to obtain basic information on frost melting on a heat exchanger used as a heat pump air conditioner. The heat exchanger working fluid used in this experiment was a 50 wt% propylene glycol aqueous solution. The flow amount G and the temperature T{sub b} of the working fluid were 0.1 {lt} G m{sup 3}/hour {lt} 0.2 and 10 {lt} T{sub b}0{degrees}C {lt} 34, respectively. A melting thermal efficiency {eta} is defined in this paper as the ratio of the net heat for melting to the heat supplied to the heat exchanger until the critical time for melting t{sub c}. {eta} strongly depends on t{sub c}, and t{sub c} is strongly affected by G and T{sub b}. In conclusion, it was found that the heat supplied to the heat exchanger can be utilized with a high {eta} when t{sub c} becomes small.

Sugawara, M.; Kirihoshi, C.; Fujita, T. (Dept. of Mechanical Engineering, Akita Univ. (JP)); Uemura, S.; Yajima, R. (Daikin Industries, Ltd. (JP))

1990-01-01

139

HEAT AND MASS TRANSFER MODEL OF A GROUND HEAT EXCHANGER  

Microsoft Academic Search

A new approach to the simulation of a horizontal type Ground Heat Exchanger is proposed resulting in a better accuracy and at the same time a reduced computational effort. These results come from the concentration of the computational effort at the locations with the largest temperature and moisture gradients, i.e. the pipe-soil interface. The model takes into account heat and

Mirek Piechowski

140

Screen heat exchanger performance comparison  

NASA Astrophysics Data System (ADS)

The performance of stainless steel screen regenerator stacks (500 mesh) has been investigated at relatively small flow rates in comparison to conventional operation close to the laminar-turbulent transition range. A modified 'single blow' technique was used initially, and an additional comparative procedure is employed to deduce heat transfer rate ratios with respect to a single-wire reference case of heat transfer. The data obtained are two orders of magnitude below 'classical' room temperature values at low Reynolds number (Re); (Re based on the Darcy law-related characteristic length; Re less than 1). The fluid is cold nitrogen from a liquid bath at atmospheric pressure.

Luna, J.; Ravikumar, K. V.; Frederking, T. H. K.

141

Heat exchanger for coal gasification process  

DOEpatents

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

Blasiole, George A. (Greensburg, PA)

1984-06-19

142

Analysis of compact heat exchanger performance  

NASA Astrophysics Data System (ADS)

Many cryogenic heat exchangers employ high-conductance metallic screens or perforated plates separated by insulating spacers normal to the fluid flow direction. Packed-bed regenerators employing wire screens, perforated plates, or granular particles also have a similar structure. The temperature profile along the length consists of many steps. The ineffectiveness due to axial conduction adds to that due to finite number of plates and finite heat transfer coefficient. A closed form expression is derived for the efficiency of a compact heat exchanger with given design N sub tu where the exchanger consists of layers of metallic screens, plates, or particle layers. It is observed that the effect of discrete temperature profile becomes significant when the per stage design N sub tu exceeds about 0.5.

Sarangi, S.; Barclay, J. A.

1984-12-01

143

Heat exchanger containing a component capable of discontinuous movement  

DOEpatents

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

Wilson, David G. (Winchester, MA)

1993-01-01

144

Heat exchanger containing a component capable of discontinuous movement  

DOEpatents

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

Wilson, David Gordon (Winchester, MA)

2002-01-01

145

Multidimensional numerical modeling of heat exchangers. [LMFBR  

SciTech Connect

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

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

1982-01-01

146

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

SciTech Connect

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.

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

147

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

E-print Network

Effects of winglets to augment tube wall heat transfer in louvered fin heat exchangers Paul A Abstract The louvered fin heat exchanger, a type of compact heat exchanger, has been used heavily transfer along the tube wall of the compact heat exchanger through the use of winglets placed

Thole, Karen A.

148

Simulation of compact heat exchanger performance  

Microsoft Academic Search

Purpose – The purpose of this paper is to present some methods to analyse and determine the performance of compact heat exchangers; show the applicability of various computational approaches and their limitations, provide examples to demonstrate the methods, and present results to highlight the opportunities and limitations of the considered methods. Design\\/methodology\\/approach – Engineering methods based on thermal balances and

Bengt Sunden

2010-01-01

149

Measurement of heat and moisture exchanger efficiency.  

PubMed

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

Chandler, M

2013-09-01

150

Mathematical modelling of PCM air heat exchanger  

Microsoft Academic Search

In order to cool a room with a cold night air phase change material, PCM, is stored in an air heat exchanger. During night the PCM crystallises, energy is released. During daytime air is circulated in the unit, energy is absorbed and the indoor air is cooled. The characteristic of PCM is that there is an increase of the specific

G. Hed; R. Bellander

2006-01-01

151

Optimization of heat exchangers for solar concentrators  

Microsoft Academic Search

A parametric study is done on heat exchangers to be used for cylindrical fixed mirror concentrators. The operational parameters, such as inlet fluid temperature, solar insolation, fluid flow rate, ambient temperature and wind velocities, are varied. The geometrical parameters, the absorber plate width and the diameter of the embedded copper tubes are also varied. The results of variation of these

P. R. Damshala; J. R. Williams

1978-01-01

152

Comparative Studies on Micro Heat Exchanger Optimisation Tatsuya Okabe  

E-print Network

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

Coello, Carlos A. Coello

153

Heat transfer in counterflow heat exchangers with helical turbulators  

NASA Astrophysics Data System (ADS)

A 3D mathematical model has been developed to investigate the heat transfer augmentation in a circular tube with a helical turbulator. Glycol-water blends of various concentrations were used in the inner tube, and pure water was used in the outer tube. Changes in fluid physical properties with temperature were taken into account, and k-?,k-?, and large eddy simulations were developed for turbulence modeling. The simulation results showed a nonlinear variation in Reynolds and Prandtl numbers for a long model of a heat exchanger even in the absence of a turbulator. The presence of the turbulator was found to increase the heat transfer, sometimes without inducing turbulence, but also increased the pressure drop. The results demonstrate that the model could be used as a useful tool for optimization of heat exchanger performance in the presence of a turbulator. Comparisons with experimental data showed reasonably agreement with large eddy simulation results.

Zamankhan, Piroz

2010-10-01

154

Brayton heat exchange unit development program  

NASA Technical Reports Server (NTRS)

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.

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

1971-01-01

155

Heat transfer analysis of boreholes in vertical ground heat exchangers  

Microsoft Academic Search

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

Heyi Zeng; Nairen Diao; Zhaohong Fang

2003-01-01

156

Heat transfer analysis of ground heat exchangers with inclined boreholes  

Microsoft Academic Search

Consisting of closed-loop of pipes buried in boreholes, ground heat exchangers (GHEs) are devised for extraction or injection of thermal energy from\\/into the ground. Evolved from the vertical borehole systems, the configuration of inclined boreholes is considered in order to reduce the land plots required to install the GHEs in densely populated areas. A transient three-dimensional heat conduction model has

Ping Cui; Hongxing Yang; Zhaohong Fang

2006-01-01

157

Triple loop heat exchanger for an absorption refrigeration system  

DOEpatents

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

Reimann, Robert C. (Lafayette, NY)

1984-01-01

158

Preliminary SP-100/Stirling heat exchanger designs  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

159

A modular phase change heat exchanger for a solar oven  

Microsoft Academic Search

A modular energy storing heat exchanger designed to use pentaerythritol for thermal storage (solid-solid phase change at 182 C) is tested in an oven by circulating heat transfer oil which is electrically heated in a manner to simulate a concentrating solar collector. Three efficiencies for heating the system under controlled and measured power input are determined - the heat exchanger

D. L. Bushnell; M. Sohi

1992-01-01

160

Analytical model of a PCM-air heat exchanger  

Microsoft Academic Search

This paper presents an analysis of a tubular heat exchanger which utilizes the latent heat of a phase-change material (PCM). In the heat exchanger, the PCM melts inside tubes while air flows across the tube banks. The sensible heat capacity of the liquid PCM and the tubes’ material is considered small in comparison with the latent heat of melting. This

Vadim Dubovsky; Gennady Ziskind; Ruth Letan

2011-01-01

161

Multi-Purpose Logistics Module (MPLM) Cargo Heat Exchanger  

NASA Technical Reports Server (NTRS)

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.

Zampiceni, John J.; Harper, Lon T.

2002-01-01

162

Innovative, counterflow gas/fine solids, direct contact heat exchanger  

NASA Astrophysics Data System (ADS)

The Aerojet Energy Conversion Company has completed the first phase of study for development of a heat exchanger. The heat exchanger, a highly efficient, low cost concept, is a candidate for application in process manufacturing industries such as cement, lime, or glass. The analytical effort was to establish the heat exchanger performance via computer modeling and analysis; the experimental effort was to demonstrate the heat exchanger performance.

Mah, C. S.

1987-10-01

163

Heat exchanger support apparatus in a fluidized bed  

DOEpatents

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

Lawton, Carl W. (West Hartford, CT)

1982-01-01

164

ISHED1: Applying the LEM Methodology to Heat Exchanger Design  

E-print Network

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

Michalski, Ryszard S.

165

GEA Heat Exchangers GEA Searle Cooler and Condensing Unit Ranges  

E-print Network

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

Frandsen, Søren

166

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

E-print Network

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

Schmidhuber, Juergen

167

40 CFR 63.654 - Heat exchange systems.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Heat exchange systems. 63.654 Section...From Petroleum Refineries § 63.654 Heat exchange systems. (a) Except as...this section, the owner or operator of a heat exchange system that meets the...

2013-07-01

168

40 CFR 63.1435 - Heat exchanger provisions.  

Code of Federal Regulations, 2010 CFR

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

2010-07-01

169

40 CFR 63.654 - Heat exchange systems.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Heat exchange systems. 63.654 Section...From Petroleum Refineries § 63.654 Heat exchange systems. (a) Except as...this section, the owner or operator of a heat exchange system that meets the...

2011-07-01

170

40 CFR 63.1435 - Heat exchanger provisions.  

Code of Federal Regulations, 2012 CFR

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

2012-07-01

171

40 CFR 63.654 - Heat exchange systems.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Heat exchange systems. 63.654 Section...From Petroleum Refineries § 63.654 Heat exchange systems. Link to an amendment...this section, the owner or operator of a heat exchange system that meets the...

2010-07-01

172

40 CFR 63.1328 - Heat exchange systems provisions.  

Code of Federal Regulations, 2011 CFR

...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...

2011-07-01

173

40 CFR 63.654 - Heat exchange systems.  

...2014-07-01 2014-07-01 false Heat exchange systems. 63.654 Section...From Petroleum Refineries § 63.654 Heat exchange systems. (a) Except as...this section, the owner or operator of a heat exchange system that meets the...

2014-07-01

174

40 CFR 63.1435 - Heat exchanger provisions.  

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

2014-07-01

175

40 CFR 63.1409 - Heat exchange system provisions.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Heat exchange system provisions. 63.1409...Amino/Phenolic Resins § 63.1409 Heat exchange system provisions. (a...subject to this subpart shall monitor each heat exchange system used to cool...

2013-07-01

176

40 CFR 63.1435 - Heat exchanger provisions.  

Code of Federal Regulations, 2011 CFR

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

2011-07-01

177

40 CFR 63.1409 - Heat exchange system provisions.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Heat exchange system provisions. 63.1409...Amino/Phenolic Resins § 63.1409 Heat exchange system provisions. (a...subject to this subpart shall monitor each heat exchange system used to cool...

2011-07-01

178

40 CFR 63.1409 - Heat exchange system provisions.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2011-07-01 true Heat exchange system provisions. 63.1409...Amino/Phenolic Resins § 63.1409 Heat exchange system provisions. (a...subject to this subpart shall monitor each heat exchange system used to cool...

2012-07-01

179

40 CFR 63.654 - Heat exchange systems.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Heat exchange systems. 63.654 Section...From Petroleum Refineries § 63.654 Heat exchange systems. (a) Except as...this section, the owner or operator of a heat exchange system that meets the...

2012-07-01

180

40 CFR 63.1409 - Heat exchange system provisions.  

...2014-07-01 2014-07-01 false Heat exchange system provisions. 63.1409...Amino/Phenolic Resins § 63.1409 Heat exchange system provisions. (a...subject to this subpart shall monitor each heat exchange system used to cool...

2014-07-01

181

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

2013-07-01

182

40 CFR 63.1328 - Heat exchange systems provisions.  

...2014-07-01 2014-07-01 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...

2014-07-01

183

40 CFR 63.1435 - Heat exchanger provisions.  

Code of Federal Regulations, 2013 CFR

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

2013-07-01

184

Liquid-metal heat transfer in a cocurrent- flow, double-pipe heat exchanger is investigated  

NASA Technical Reports Server (NTRS)

Analysis of liquid-metal heat transfer in cocurrent-flow, double-pipe heat exchangers shows that heat-transfer coefficients depend upon the operating conditions of the heat exchanger and that use of the customary design equation to predict heat-exchanger performance leads to significant errors.

Merriam, R. L.

1969-01-01

185

Preliminary design package for maxi-therm heat exchanger module  

NASA Technical Reports Server (NTRS)

Heat exchangers were developed for use in a solar heating and cooling system installed in a single family dwelling. Each of the three exchangers consisted of a heating and cooling module and a submersed electric water heating element. Information necessary to evaluate the preliminary design of the heat exchanger is presented in terms of the development and verification plans, performance specifications, installation and maintenance, and hazard analysis.

1978-01-01

186

OXIDE DISPERSION-STRENGTHENED HEAT EXCHANGER TUBING  

SciTech Connect

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

Harper, Mark A.

2001-11-06

187

Comparison of different kinds of compact cross flow heat exchangers  

NASA Astrophysics Data System (ADS)

A computer program for the calculation of compact heat exchangers for gas turbines was developed. The most important coefficients, pressure drops, and effectiveness of different kinds of exchangers were calculated as a function of Mach number, the dimensions of the exchanger, and the compactness. From the aerothermodynamic point of view, the plate exchanger is best, closely followed by the lancet heat exchanger. The ribs of the plate version have no significant effect on the characteristics, but are required for stiffness and uniform channel height. The tube heat exchanger can only compete as far as the transferable heat is concerned.

Siemens, Werner

1986-09-01

188

Comparison of different kinds of compact crossflow heat exchangers  

NASA Astrophysics Data System (ADS)

A computer program for the calculation of compact heat exchangers for gas turbines was developed. The most important coefficients, pressure drops, and effectiveness of different kinds of exchangers were calculated as a function of Mach number, the dimensions of the exchanger, and the compactness. From the aerothermodynamic point of view, the plate exchanger is best, closely followed by the lancet heat exchanger. The ribs of the plate version have no significant effect on the characteristics, but are required for stiffness and uniform channel height. The tube heat exchanger can only compete as far as the transferable heat is concerned.

Siemens, Werner

1988-03-01

189

The Conduction of Heat through Cryogenic Regenerative Heat Exchangers  

NASA Astrophysics Data System (ADS)

The need for improved regenerative cryocooler efficiency may require the replacement of conventional matrices with ducts. The ducts can not be continuous in the direction of temperature gradient when using conventional materials to prevent unacceptable conduction losses. However, this discontinuity creates a complex geometry to model and determine conduction losses. Chesapeake Cryogenics, Inc. has designed, fabricated and tested an apparatus for measuring the heat conduction through regenerative heat exchangers implementing different matrices. Data is presented for stainless steel photo etched disk, phophorus-bronze embossed ribbon coils and screens made of both stainless steel and phosphorus-bronze. The heat conduction was measured with the regenerators evacuated and pressurized with helium gas. In this test apparatus, helium gas presence increased the heat leak significantly. A description of the test apparatus, instrumentation, experimental methods and data analysis are presented.

Superczynski, W. F.; Green, G. F.

2006-04-01

190

Heat exchange following atropine injection before and after heat acclimation.  

PubMed

The effect of saline and atropine injection (2 mg, im) on eight healthy male subjects before and after heat acclimation was studied while each subject walked on a treadmill (1.34 m X s-1) in a hot-dry environment (ambient temperature = 48.4 degrees C, dew-point temperature = 20.5 degrees C). Partitional calorimetric analysis was done for the periods in which maximum sweat inhibition occurred (30 min). Mean skin temperature, rectal temperature, and heart rate were continuously observed. Evaporative loss from the skin was calculated by changes in body weight (Sauter balance); heat transfer coefficients were defined by Nishi equations. A prediction of sweat inhibition based on an analysis of heat storage and its effect on a theoretical temperature, which can be graphed on a psychrometric chart, was developed. A rational effective temperature (ET) defined as the operative temperature at the intersection of the 50% rh, which encompasses total heat exchange, was used to compare the effects of atropine before and after heat acclimation. The results show that heat acclimation reduced ET by approximately 2.5 degrees C when compared with the unacclimated state after atropine injection. Thus heat acclimation reduces the hazards of heatstroke caused by exercise in the heat with atropine injection. PMID:6725067

Kolka, M A; Holden, W L; Gonzalez, R R

1984-04-01

191

A hybrid genetic algorithm for synthesis of heat exchanger networks  

Microsoft Academic Search

A new hybrid genetic algorithm for optimal design of heat exchanger networks is developed. The mathematical model used in the algorithm is based on an explicit solution of stream temperatures of heat exchanger networks with the stage-wise superstructure. By taking heat transfer areas and heat capacity flow rates as genes in the genetic algorithm, the thermal performance and total cost

Xing Luo; Qing-Yun Wen; Georg Fieg

2009-01-01

192

Microchannel Heat Exchangers with Carbon Dioxide  

SciTech Connect

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

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

2001-09-15

193

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

E-print Network

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

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

2012-01-01

194

Turbulent heat exchanger {Delta}T and {Delta}P  

SciTech Connect

Optimum pressure drop ({Delta}P) and temperature difference ({Delta}T) in turbulent flow heat exchangers are presented in three frameworks: as quantitatively defined by fluid properties, the value of energy and the cost of heat exchange surface (with a little help from a relationship between [power/mass] and heat transfer); as the energy cost for heat recovery (with the {Delta}T cost being about equal to the heat exchanger cost and the {Delta}P cost being about 1/3 as great); and as the second law lost work inherent in heat exchange (with the {Delta}T loss being {approximately}3 times the {Delta}T loss).

Steinmeyer, D. [Monsanto Co., St. Louis, MO (United States)

1996-12-31

195

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

SciTech Connect

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

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

2008-11-01

196

Condensation in horizontal heat exchanger tubes  

SciTech Connect

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

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

2012-07-01

197

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

Microsoft Academic Search

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.

Y. Kaptan; E. Buyruk; A. Ecder

2008-01-01

198

Heat exchanger for a Stirling engine  

SciTech Connect

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

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

1987-05-05

199

Characterization of various losses in a cryogenic counterflow heat exchanger  

NASA Astrophysics Data System (ADS)

A detailed assessment of irreversibility, predominantly heat in-leak and axial wall conduction, is essential in accurately predicting the performance of high effectiveness heat exchangers employed in cryogenic applications. Integration into a refrigeration system as well requires consideration of parasitic heat loss by conduction from exchanger cold end to the adjacent components. Governing equations incorporating these effects in a counterflow exchanger are solved numerically and the model predictions evaluated for heat exchanger ineffectiveness and heat loss by conduction. The optimum performance mandates minimization of both. Although ineffectiveness decreases at higher longitudinal conduction, cold end loss increases with deterioration of the overall performance. Utilizing lower heat capacity rate hot fluid, nevertheless, reduces the cold end loss. Heat in-leak is relatively high with concurrent consideration of axial wall conduction and has adverse consequence on heat exchanger effectiveness. Analysis of the net heat transferred to lower stages of refrigeration reveals a critical NTU.

Aminuddin, Mohammad; Zubair, Syed M.

2014-11-01

200

Diffusion-Welded Microchannel Heat Exchanger for Industrial Processes  

SciTech Connect

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

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

2013-03-01

201

Condensate removal device for heat exchanger  

NASA Technical Reports Server (NTRS)

A set of perforated tubes disposed at the gas output side of a heat exchanger, in a position not to affect the rate of flow of the air or other gas is described. The tubes are connected to a common manifold which is connected to a sucking device. Where it is necessary to conserve and recirculate the air sucked through the tubes, the output of the manifold is run through a separator to remove the condensate from the gas. The perforations in the slurper tubes are small, lying in the range of 0.010 inch to 0.100 inch. The tubes are disposed in contact with the surfaces of the heat exchanger on which the condensate is precipitated, whether fins or plates, so that the water may be directed to the tube openings by means of surface effects, together with the assistance of the air flow. Only about 5 percent of the air output need be thus diverted, and it effectively removes virtually all of the condensate.

Trusch, R. B.; Oconnor, E. W. (inventors)

1975-01-01

202

Direct contact heat exchanger for phase change thermal storage  

Microsoft Academic Search

A molten salt-to-liquid metal direct contact heat exchanger is being developed for phase change thermal storage in central receiver solar thermal plants. The heat exchanger consists of a column of liquid metal into which molten salt is injected. Salt droplets that form at the injector orifices rise through the column and solidify as they transfer heat to the liquid metal.

W. Luft; J. W. Leach; T. Lowry

1984-01-01

203

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

Microsoft Academic Search

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.

M. Sokolov

1995-01-01

204

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

Microsoft Academic Search

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

Hakan Demir; Ahmet Koyun; Galip Temir

2009-01-01

205

Thermal performance analysis for heat exchangers having a variable overall heat transfer coefficient  

Microsoft Academic Search

The classic, conventional analysis for the thermal performance of heat exchangers is based on three assumptions: constant fluid flow rate, constant specific heat fluids, and constant overall heat transfer coefficient. Our analysis describes a general approach for analyzing the thermal performance of heat exchangers in which the overall heat transfer coefficient varies as a function of enthalpy, with the other

J. C. Conklin; E. Granryd

1991-01-01

206

Study of hydraulic resistance and heat transfer in perforated-plate heat exchangers  

NASA Astrophysics Data System (ADS)

An experimental study is made of the hydraulic resistance and heat transfer in heat exchangers made of perforated plates with different internal geometries. Generalizing theoretical relations are obtained.

Shevyakova, S. A.; Orlov, V. K.

1983-07-01

207

Heat exchanger for fuel cell power plant reformer  

DOEpatents

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

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

1988-01-01

208

Heat transfer with phase change in plate-fin heat exchangers  

NASA Astrophysics Data System (ADS)

A theoretical and experimental study was conducted for convective evaporation and condensation in plate-fin compact heat exchangers. The overall performance of a brazed-aluminum heat exchanger in the evaporation mode with ammonia and in the condensation mode with both ammonia and refrigerant R-22 as working fluids. The heat exchanger has straight perforated fins on the working-fluid side and extruded rectangular channels on the single-phase (water) side. The two-phase flow in narrow channels of the heat exchanger is modeled using a triangular relationship between pressure gradient, liquid film flow rate, and film thickness. The overall performance of the heat exchanger is calculated by employing local heat-transfer analysis and integrating mass- and heat-balance equations along the heat-exchanger length. Theoretical predictions are found to agree favorably with experimental results for a prototypical heat exchanger unit.

Panchal, C. B.

1984-08-01

209

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

SciTech Connect

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

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

2010-09-15

210

Simulation and Analysis of Influence Factors on Performance of Vertical Ground Heat Exchanger for Ground Coupled Heat Pump  

Microsoft Academic Search

A numerical heat transfer model of vertical ground heat exchanger was developed based on finite volume method, and the influence factors on performance of ground heat exchanger was investigated. Simulation results indicate that higher conductivity of pipe material is more benefit to enhance the performance of ground heat exchanger. The heat transfer of ground heat exchanger increases with the augment

Tian Bai; Jian-Li Zhang; Mao-Yu Zheng

2010-01-01

211

Investigation of local heat transfer in compact heat exchangers by holographic interferometry  

Microsoft Academic Search

Compact heat exchangers are key components for the development of future aircraft devices. An enhancement of the heat transfer results in a decrease in the heat exchanger size and thus in lower weight and lower investment costs. Exact knowledge of the temperature distribution in the boundary layer is necessary for a specific augmentation of heat transfer. Holographic interferometry was applied

R. Fehle; J. Klas; F. Mayinger

1995-01-01

212

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

ERIC Educational Resources Information Center

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

Corbett, Robert J.; Miller, Barbara

213

Initial characterization of a modular heat exchanger with an integral heat pipe  

Microsoft Academic Search

A conceptual design for a Stirling space engine for future NASA missions uses 40 modular heat exchangers, each with its own integral heat pipe to transport heat to the engine. An existing free-piston Stirling engine was modified to serve as a testbed for evaluating the heat-exchanger modules. The design and fabrication of the modules and the engine used for these

Jeffrey G. Schreiber

1989-01-01

214

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

E-print Network

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 water-to-water experiment and a two-phase evaporation experiment with refrigerant R- 134a in a plate

Kandlikar, Satish

215

Combined Steady-State and Dynamic Heat Exchanger Experiment  

ERIC Educational Resources Information Center

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…

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

2009-01-01

216

Oil refinery saves $5500\\/wk cleaning own heat exchanger bundles  

Microsoft Academic Search

Hydrodrills supplied by Global Heat Exchanger, Inc. saves an oil refinery in California $5500 per week by enabling the refinery to do all their tube and shell heat exchanger cleaning. The refinery is so satisfied with the hydrodrills, which have been in operation for three years, that they plan to purchase another in the near future.

Regan

1983-01-01

217

Evaluation and design of downhole heat exchangers for direct application  

Microsoft Academic Search

Over 400 wells with downhole heat exchangers are in use in Klamath Falls, Oregon. Some have been in use for nearly 30 years. Despite the large number and the long experience, the exact nature of the mechanism of heat exchange and, therefore, the maximum output was not known, except that it had been theorized that convection cells were established in

Gene Culver; Gordon M. Reistad

1974-01-01

218

Failure analysis of heat exchanger tubes of four gas coolers  

Microsoft Academic Search

A Number of leaks occurred on four heat exchangers used on an off-shore platform in the south of Iran. As a result heat exchanger tubes made of Inconel 625 failed after only two years in operation. The failure was caused by pitting corrosion in two contact regions, tubes and baffles as well as in tube sheet and shell contact regions

S. R. Allahkaram; P. Zakersafaee; S. A. M. Haghgoo

2011-01-01

219

Velocity distribution and vibration excitation in tube bundle heat exchangers  

Microsoft Academic Search

Design criteria for tube bundle heat exchangers, to avoid fluidelastic instability, are based on stability criteria for ideal bundles and uniform flow conditions along the tube length. In real heat exchangers, a non-uniform flow distribution is caused by inlet nozzles, impingement plates, baffles and bypass gaps. The calculation of the equivalent velocities, according to the extended stability equation of Connors,

Ulrich Mohr; Horst Gelbe

2000-01-01

220

The heat exchanger of small pellet boiler for phytomass  

NASA Astrophysics Data System (ADS)

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.

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

2014-08-01

221

Reactor safety research section probability of heat exchanger leaks  

SciTech Connect

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.

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

1992-02-01

222

A simplified method of calculating heat flow through a two-phase heat exchanger  

Microsoft Academic Search

A simplified method of calculating the heat flow through a heat exchanger in which one or both heat carrying media are undergoing a phase change is proposed. It is based on enthalpies of the heat carrying media rather than their temperatures. The method enables the determination of the maximum rate of heat flow provided the thermodynamic properties of both heat-carrying

Y. G. Yohanis; O. S. Popel; S. E. Frid

2005-01-01

223

The Influence of Availability Costs on Optimal Heat Exchanger Size  

E-print Network

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...

Witte, L. C.

224

Self-defrosting recuperative air-to-air heat exchanger  

DOEpatents

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

Drake, Richard L. (Delmar, NY)

1993-01-01

225

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

Microsoft Academic Search

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

Kwanchanok Srisawad; Somchai Wongwises

2009-01-01

226

Optimized heat exchanger unit in a thermoacoustic refrigerator  

NASA Astrophysics Data System (ADS)

Due to concern over the environmental impact caused by hazardous refrigerants, the last ten years or so has seen increasing research into thermoacoustic refrigeration. A thermoacoustic refrigerator is a device which uses acoustic power to pump heat. It holds the merits of simple mechanical design, absence of harmful refrigerants and having no or few moving parts. However, the performance of the thermoacoustic refrigerator, particularly the standing wave types, is currently not competitive compared to its counterpart conventional vapor-compression refrigerator. Thermoacoustic refrigeration prototypes, built up-to-date, achieved 0.1-0.2 relative coefficient of performance (COPR) compared with that of 0.33-0.5 for the conventional vapor-compression refrigerators. The poor heat exchanger design is one of the reasons for this poor efficiency. This paper discussed the influence of the thermoacoustic refrigerator heat exchanger's parameters on its design and the optimization of the performance of the system using the Lagrange multiplier method. The results showed that, the dissipated power is less than the published value by about 49% in the cold heat exchanger and about 38.5% in the hot heat exchanger. Furthermore, the increase of the cold heat exchanger effectiveness is found to be 3%. Thus, the decrease in the dissipated power in both heat exchangers with effective cold heat exchanger increases the performance of the thermoacoustic refrigerator.

El-Fawal, Mawahib Hassan; Mohd-Ghazali, Normah

2012-06-01

227

Direct-contact closed-loop heat exchanger  

DOEpatents

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

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

1984-01-01

228

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

DOEpatents

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

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

1994-11-29

229

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

Microsoft Academic Search

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

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

1999-01-01

230

Design method for sizing a latent heat store\\/heat exchanger in a thermal system  

Microsoft Academic Search

The sizing of a latent heat storage device in a thermal system is studied under thermodynamic and economic stress (for example, power rates to or from the store). Another such stress is the effect of phase change on the heat exchanger performance. This paper presents a method of determining the surface of a shell-and-tube heat exchanger and the volume of

D. Lecomte; D. Mayer

1985-01-01

231

The Experimental Study on Heat Transfer Characteristics of The External Heat Exchanger  

Microsoft Academic Search

Using the external heat exchanger in large-scale CFB boilers can control combustion and heat transfer separately, make the adjustments of bed temperature and steam temperature convenient. The state of gas-solid two phase flow in the external heat exchanger is bubbling fluidized bed, but differs from the regular one as there is a directional flow in it. Consequently, the temperature distribution

X. Y. Ji; X. F. Lu; L. Yang; H. Z. Liu

2010-01-01

232

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

E-print Network

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

Chen, Y.; Zhang, J.

2006-01-01

233

Solar power plant equipped with high efficiency heat exchangers  

Microsoft Academic Search

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.

Moisdon

1981-01-01

234

Condensing Heat Exchanger for Optimization of Energy Efficiency  

E-print Network

? conder:sing heat exchangers are arranged in parallel and accept a slipstream of about one third of the plant flue gas flow from multiple boilers. The recovered heat is transferred to boiler make-up water. The cooled flue gas leaving the heat...

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

235

Model Based Controller Design for Shell and Tube Heat Exchanger  

Microsoft Academic Search

In all the process industries the process variables like flow, pressure, level and temperature are the main parameters that need to be controlled in both set point and load changes. The transfer of heat is one of the main important operation in the heat exchanger .The transfer of heat may be fluid to fluid, gas to gas i.e. in the

S. Nithya; Abhay Singh Gour; N. Sivakumaran; T. K. Radhakrishnan; N. Anantharaman

236

Microchannel crossflow fluid heat exchanger and method for its fabrication  

DOEpatents

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

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

1985-05-14

237

Microchannel crossflow fluid heat exchanger and method for its fabrication  

DOEpatents

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

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

1985-01-01

238

Microchannel crossflow fluid heat exchanger and method for its fabrication  

DOEpatents

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

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

1982-08-31

239

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

...standards and compliance requirements for heat exchange systems? 63.11499 Section...standards and compliance requirements for heat exchange systems? (a) If the cooling water flow rate in your heat exchange system is equal to or...

2014-07-01

240

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

Code of Federal Regulations, 2011 CFR

...standards and compliance requirements for heat exchange systems? 63.11499 Section...standards and compliance requirements for heat exchange systems? (a) If the cooling water flow rate in your heat exchange system is equal to or...

2011-07-01

241

40 CFR 63.502 - Equipment leak and heat exchange system provisions.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Equipment leak and heat exchange system provisions. 63.502...Resins § 63.502 Equipment leak and heat exchange system provisions. (a) Equipment...the purposes of this subpart. (n) Heat exchange system provisions. The...

2010-07-01

242

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

Code of Federal Regulations, 2010 CFR

...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...

2010-07-01

243

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

Code of Federal Regulations, 2013 CFR

...standards and compliance requirements for heat exchange systems? 63.11499 Section...standards and compliance requirements for heat exchange systems? (a) If the cooling water flow rate in your heat exchange system is equal to or...

2013-07-01

244

40 CFR 63.502 - Equipment leak and heat exchange system provisions.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Equipment leak and heat exchange system provisions. 63.502...Resins § 63.502 Equipment leak and heat exchange system provisions. (a) Equipment...the purposes of this subpart. (n) Heat exchange system provisions. The...

2012-07-01

245

40 CFR 63.502 - Equipment leak and heat exchange system provisions.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Equipment leak and heat exchange system provisions. 63.502...Resins § 63.502 Equipment leak and heat exchange system provisions. (a) Equipment...the purposes of this subpart. (n) Heat exchange system provisions. The...

2013-07-01

246

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

... 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...

2014-07-01

247

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

Code of Federal Regulations, 2013 CFR

... 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...

2013-07-01

248

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

Code of Federal Regulations, 2012 CFR

...standards and compliance requirements for heat exchange systems? 63.11499 Section...standards and compliance requirements for heat exchange systems? (a) If the cooling water flow rate in your heat exchange system is equal to or...

2012-07-01

249

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

...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...

2014-07-01

250

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

Code of Federal Regulations, 2011 CFR

... 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...

2011-07-01

251

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

Code of Federal Regulations, 2010 CFR

... 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...

2010-07-01

252

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

Code of Federal Regulations, 2013 CFR

...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...

2013-07-01

253

40 CFR 63.502 - Equipment leak and heat exchange system provisions.  

...2014-07-01 false Equipment leak and heat exchange system provisions. 63.502...Resins § 63.502 Equipment leak and heat exchange system provisions. (a) Equipment...the purposes of this subpart. (n) Heat exchange system provisions. The...

2014-07-01

254

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

Code of Federal Regulations, 2012 CFR

... 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...

2012-07-01

255

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

Code of Federal Regulations, 2011 CFR

...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...

2011-07-01

256

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

Code of Federal Regulations, 2012 CFR

...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...

2012-07-01

257

40 CFR 63.502 - Equipment leak and heat exchange system provisions.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Equipment leak and heat exchange system provisions. 63.502...Resins § 63.502 Equipment leak and heat exchange system provisions. (a) Equipment...the purposes of this subpart. (n) Heat exchange system provisions. The...

2011-07-01

258

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

Code of Federal Regulations, 2010 CFR

...and compliance requirements for heat exchange systems? 63.11499 Section 63...and compliance requirements for heat exchange systems? (a) If the cooling water flow rate in your heat exchange system is equal to or greater...

2010-07-01

259

Heat Transfer and Energy Diffusion Analysis of Cannula Ground Heat Exchanger  

Microsoft Academic Search

A heat transfer model about fluid flow and heat conduct in cannula ground heat exchanger were given in this article. The heat transfer characteristics were analyzed by means of numerical method of finite element. Affect of difference size of buried tubes and the velocity of flow in the tube, on fluid outlet temperature and unit heat transfer of burned pipe

Jiang Yan; Gao Qing; Li Ming

2010-01-01

260

Study of transient behavior of finned coil heat exchangers  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

261

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

SciTech Connect

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.

Panchal, C.B.

1993-07-01

262

Heat transfer with phase change in plate-fin heat exchangers  

Microsoft Academic Search

A theoretical and experimental study was conducted for convective evaporation and condensation in plate-fin compact heat exchangers. The overall performance of a brazed-aluminum heat exchanger in the evaporation mode with ammonia and in the condensation mode with both ammonia and refrigerant R-22 as working fluids. The heat exchanger has straight perforated fins on the working-fluid side and extruded rectangular channels

C. B. Panchal

1984-01-01

263

Slotting Fins of Heat Exchangers to Provide Thermal Breaks  

NASA Technical Reports Server (NTRS)

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.

Scull, Timothy D.

2003-01-01

264

Acoustically enhanced heat exchange and drying apparatus  

DOEpatents

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

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

1987-07-10

265

SILICON CARBIDE CERAMICS FOR COMPACT HEAT EXCHANGERS  

SciTech Connect

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

DR. DENNIS NAGLE; DR. DAJIE ZHANG

2009-03-26

266

Heat exchanger for reactor core and the like  

DOEpatents

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

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

1986-01-01

267

Evaluation of fluid bed heat exchanger optimization parameters. Final report  

SciTech Connect

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

Not Available

1980-03-01

268

Process Heat Exchanger Options for Fluoride Salt High Temperature Reactor  

SciTech Connect

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

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

2011-04-01

269

Process Heat Exchanger Options for the Advanced High Temperature Reactor  

SciTech Connect

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

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

2011-06-01

270

Energy effectiveness of simultaneous heat and mass exchange devices  

E-print Network

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

Narayan, G. Prakash

2010-01-01

271

A Plastic-Core Compact Heat Exchanger for Energy Conservation  

E-print Network

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...

Lazaridis, A.; Rafailidis, E.

272

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

E-print Network

ICEBO2006, Shenzhen, China HVAC Technologies for Energy Efficiency, Vol. IV-6-3 Applications of the Strong Heat Transformation by Pulse Flow in the Shell and Tube Heat Exchanger Yu Chen Jingye Zhao Beijing Institute...

Chen, Y.; Zhao, J.

2006-01-01

273

Two-phase/two-phase heat exchanger analysis  

NASA Technical Reports Server (NTRS)

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.

Kim, Rhyn H.

1992-01-01

274

Transient response of perforated plate matrix heat exchangers  

NASA Astrophysics Data System (ADS)

Perforated plate matrix heat exchangers are used in a number of applications such as helium liquefiers, Joule-Thompson cryocoolers operating with pure fluids and mixtures, etc. The time taken for cool down of cryocoolers is very critical in many applications, for example, those used in mobile applications (e.g. missiles). In this paper we study the effect of different parameters on the transient response of perforated plate matrix heat exchangers.

Ramesh, P.; Venkatarathnam, G.

275

Fin Distance Effect at Tube-Fin Heat Exchanger  

NASA Astrophysics Data System (ADS)

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.

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

2013-04-01

276

Modeling of plate heat exchangers with generalized configurations  

Microsoft Academic Search

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

Jorge A. W. Gut; José M. Pinto

2003-01-01

277

DOE/ANL/HTRI heat exchanger tube vibration data bank  

SciTech Connect

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.

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

1981-01-01

278

Improvement in Modeling of Heat Transfer in Vertical Ground Heat Exchangers  

Microsoft Academic Search

The heat transfer model of vertical ground heat exchangers for ground-source heat pump systems is discussed. An explicit solution of a finite line-source model has been derived to better describe temperature response of boreholes for long time steps, which can be easily incorporated into computer programs for thermal analysis of ground heat exchangers. A quasi-three-dimensional model is also presented for

N. R. Diao; H. Y. Zeng; Z. H. Fang

2004-01-01

279

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

E-print Network

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

Gonzalez, Jose Antonio

1993-01-01

280

CTOD-based acceptance criteria for heat exchanger head staybolts  

SciTech Connect

The primary coolant piping system of the Savannah River Site (SRS) reactors contains twelve heat exchangers to remove the waste heat from the nuclear materials production. A large break at the inlet or outlet heads of the heat exchangers would occur if the restraint members of the heads become inactive. The heat exchanger head is attached to the tubesheet by 84 staybolts. The structural integrity of the heads is demonstrated by showing the redundant capacity of the staybolts to restrain the head at design conditions and under seismic loadings. The beat exchanger head is analyzed with a three- dimensional finite element model. The restraint provided by the staybolts is evaluated for several postulated cases of inactive or missing staybolts, that is, bolts that have a flaw exceeding the ultrasonic testing (UT) threshold depth of 25% of the bolt diameter. A limit of 6 inactive staybolts is reached with a fracture criterion based on the maximum allowable local displacement at the active staybolts which corresponds to the crack tip opening displacement (CTOD) of 0.032 inches. An acceptance criteria methodology has been developed to disposition flaws reported in the staybolt inspections while ensuring adequate restraint capacity of the staybolts to maintain integrity of the heat exchanger heads against collapse. The methodology includes an approach for the baseline and periodic inspections of the staybolts. A total of up to 6 staybolts, reported as containing flaws with depths at or exceeding 25% would be acceptable in the heat exchanger.

Lam, P.S.; Sindelar, R.L.; Barnes, D.M.; Awadalla, N.G.

1992-11-01

281

The Experimental Study on Heat Transfer Characteristics of The External Heat Exchanger  

NASA Astrophysics Data System (ADS)

Using the external heat exchanger in large-scale CFB boilers can control combustion and heat transfer separately, make the adjustments of bed temperature and steam temperature convenient. The state of gas-solid two phase flow in the external heat exchanger is bubbling fluidized bed, but differs from the regular one as there is a directional flow in it. Consequently, the temperature distribution changes along the flow direction. In order to study the heat transfer characteristics of the water cooled tubes in the bubbling fluidized bed and ensure the uniformity of heat transfer in the external heat exchanger, a physical model was set up according to the similarity principle and at the geometric ratio of 1?28 to an external heat exchanger of a 300MW CFB boiler. The model was connected with an electrically heated CFB test-bed which provides the circulating particles. The influencing factors and the distribution rule of the particles' heat transfer coefficient in the external heat exchanger were assessed by measuring the temperature changes of the water in the tubes and different parts of particles flow along the flow direction. At the end, an empirical correlation of particles' heat transfer coefficient in external heat exchanger was given by modifying the Veedendery empirical correlation.

Ji, X. Y.; Lu, X. F.; Yang, L.; Liu, H. Z.

282

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

E-print Network

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

Thole, Karen A.

283

Heat capacity of vertical ground heat exchangers with single U-tube in stallation in the function of time  

Microsoft Academic Search

O ne of the major problems of ensuring optimal working of ground source heat pump systems is a heat transfer around vertical ground heat exchanger. The working of vertical U-tube can be understood as a heat exchanger between the ground and the heat carrying medium. In our case this heat carrying medium is fluid, which transfers the extracted heat from

LÁSZLÓ GARBAI; SZABOLCS MÉHES

284

Heat Exchangers for the Next Generation of Nuclear Reactors  

SciTech Connect

The realisation that fossil fuel resources are finite, the associated rising price and a growing concern about greenhouse gas emissions, has resulted in renewed interest in nuclear energy. Generation IV and other programmes are looking at a variety of new reactors. These reactors vary in type from Very High Temperature Gas Cooled Reactors (VHTR) to Liquid Metal Fast Reactors (LFR and SFR) with cooling mediums that include: - Helium, - Supercritical carbon dioxide, - Sodium, - Lead, - Molten salts. In addition interest is not just focused on production of electrical power with an efficiency greater than that associated with the Rankine Cycle (typically 30 -35%); there is now genuine interest in nuclear energy as a heat source for hydrogen production, via the Sulphur Iodine Process (SI) or high temperature electrolysis. The production of electrical power at higher efficiency via a Brayton Cycle, and hydrogen production requires both heat at higher temperatures, up to 1000 deg C and high effectiveness heat exchange to transfer the heat to either the power or process cycle. This presents new challenges for the heat exchangers. If plant efficiencies are to be improved there is a need for: - High effectiveness heat exchange at minimal pressure drop; - Compact heat exchange to improve safety and economics; - An ability to build coded heat exchangers in a variety of nickel based alloys, oxide dispersion strengthened alloys (ODS) and ceramic materials to address the temperature, life and corrosion issues associated with these demanding duties. Heatric has already given consideration to many of these challenges. Their Print Circuit Heat Exchanger (PCHE) and Formed Plate Heat Exchanger (FPHE) technology which are commercially available today, will fulfill all of the duties up to temperatures of 950 deg C. In addition products currently under development will further increase the temperature and pressure range, while offering greater corrosion resistance and operational life. This paper outlines the challenges for the heat exchangers and the development required, with particular attention given to material selection. It is further the objective of this study to demonstrate that heat exchangers such as PCHE and FPHE are able to meet the above challenges. (authors)

Xiuqing, Li; Le Pierres, Renaud; Dewson, Stephen John [Heatric Division of Meggitt (UK) Ltd., 46 Holton Road, Holton Heath, Poole, Dorset BH16 6LT (United Kingdom)

2006-07-01

285

Design and Development of a Plastic Film Heat Exchanger  

E-print Network

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... and high resistance to corrosion and fouling which are. offered by plastics. The PFHX consists of elements, each formed by a pair of clo sely spaced plas tic films, with liquid flowing' bet ween the films. The fluid on the other side of the film could...

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

286

Self-defrosting recuperative air-to-air heat exchanger  

DOEpatents

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.

Drake, R.L.

1993-12-28

287

PS1 satellite refrigerator heat exchanger: Failure of the LN2 heat exchanger to low pressure helium  

SciTech Connect

The PS1 heat exchanger is one of three prototype heat exchangers built by Atomic Welders before Meyer was given the contract to build the Satellite Refrigerator Heat Exchanger components. This heat exchanger was first put into operation in July 1983. In November 1991, this heat exchanger experienced a failure in the shell of heat exchanger 1 causing nitrogen to contaminate the helium in the refrigerator. The resulting contamination plugged heat exchanger 3. The break occurred at a weld that connects a 0.25 inch thick ring to heat exchanger 1. The failure appears to be a fatigue of the shell due to temperature oscillations. The flow rate through the break was measured to be 1.0 scfm for a pressure drop over the crack of 50 psi. An ANSYS analysis of the failure area indicates that the stress would be 83,000 psi if the metal did not yield. This is based on cooling down the shell to 80K from 300K with the shell side helium on the outside of the shell at 300K. This is the largest change in temperature that occurs during operation. During normal operations, the temperature swings are not nearly this large, however temperatures down to 80K are not unusual (LN2 overflowing pot). The highest temperatures are typically 260K. The analysis makes no attempt to estimate the stress concentration factor at this weld but there is no doubt that it is greater than 1. No estimate as to the number of cycles to cause failure was calculated nor any estimate as to the actual number of cycles was made.

Squires, B.

1992-11-01

288

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

Microsoft Academic Search

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,

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

2012-01-01

289

Optimal design of a plate heat exchanger with undulated surfaces  

Microsoft Academic Search

The purpose of this study is to suggest a general method for the optimal design of a plate heat exchanger (PHE) with undulated surfaces that complies with the principles of sustainability. A previously validated CFD code is employed to predict the heat transfer rate and pressure drop in this type of equipment. The computational model is a three-dimensional narrow channel

A. G. Kanaris; A. A. Mouza; S. V. Paras

2009-01-01

290

Fouling on the suction side of 5058 heat exchangers  

Microsoft Academic Search

Just as in the recirculating lines, salt deposits had been observed for years on the suction side of the heat exchangers behind the converters. They consisted of ammonium carbonate formed at one molecule each of NHâ, COâ, and HâO. The corresponding hydrogen-sulfide combination was never found. By means of occasional, later continuous, water injections on the suction side of heat

1941-01-01

291

A Freezable Heat Exchanger for Space Suit Radiator Systems  

NASA Technical Reports Server (NTRS)

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.

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

2008-01-01

292

Air Circulation and Heat Exchange Under Reduced Pressures  

NASA Technical Reports Server (NTRS)

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.

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

2010-01-01

293

Numerical studies on flow and heat transfer in membrane helical-coil heat exchanger and membrane serpentine-tube heat exchanger  

Microsoft Academic Search

The flow and heat transfer characteristics of synthesis gas (syngas) in membrane helical-coil heat exchanger and membrane serpentine-tube heat exchanger under different operating pressures, inlet velocities and pitches are investigated numerically. The three-dimensional governing equations for mass, momentum and heat transfer are solved using a control volume finite difference method. The realizable k-? model is adopted to simulate the turbulent

Zhenxing Zhao; Xiangyu Wang; Defu Che; Zidong Cao

2011-01-01

294

Fast reactor power plant design having heat pipe heat exchanger  

DOEpatents

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

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

1984-08-30

295

Fast reactor power plant design having heat pipe heat exchanger  

DOEpatents

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

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

1985-01-01

296

Fast reactor power plant design having heat pipe heat exchanger  

Microsoft Academic Search

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

Paul R. Huebotter; George A. McLennan

1985-01-01

297

Fast reactor power plant design having heat pipe heat exchanger  

Microsoft Academic Search

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

P. R. Huebotter; G. A. McLennan

1984-01-01

298

Wall mounted heat exchanger characterization. [cryogenic propellant tanks  

NASA Technical Reports Server (NTRS)

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.

Bullard, B. R.

1975-01-01

299

Matrix heat exchangers and their application in cryogenic systems  

NASA Astrophysics Data System (ADS)

The necessity of high effectiveness in a small volume has led to the development of perforated plate matrix heat exchangers (MHE) for cryogenic applications. Although the basic principles have remained the same, the techniques of fabrication and bonding have changed considerably during the last four decades. With the introduction of all metal construction, these exchangers are finding increasing use in cryogenic refrigerators. The mechanism of heat transfer in a matrix heat exchanger is complex. Convection in three different surfaces and conduction in two different directions are coupled together in determining the temperature profiles. While early analyses were based on simple empirical correlations and approximate analytical solutions, they have given way to accurate numerical models. This paper traces the chronological development of the MHE and different methods of fabrication, heat transfer and fluid flow characteristics and design and simulation procedures.

Venkatarathnam, G.; Sarangi, Sunil

300

Design and fabrication of a Stirling engine heat exchanger module with an integral heat pipe  

SciTech Connect

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.

Schreiber, J.G.

1988-01-01

301

Direct-contact closed-loop heat exchanger  

DOEpatents

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

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

1981-11-02

302

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

PubMed

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

Khaled, A-R A

2014-01-01

303

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

E-print Network

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

Skogestad, Sigurd

304

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

E-print Network

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

Skogestad, Sigurd

305

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

E-print Network

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

Al-Shayea, Naser Abdul-Rahman

306

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

NASA Technical Reports Server (NTRS)

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.

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

2009-01-01

307

Carbon-Fiber Brush Heat Exchangers  

NASA Technical Reports Server (NTRS)

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.

Knowles, Timothy R.

2004-01-01

308

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

SciTech Connect

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

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

2011-04-01

309

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

Microsoft Academic Search

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

W. L. Fu; C. T. Chang

1997-01-01

310

Finite Element Analysis for the Heat Transfer of Ground Heat Exchanger  

Microsoft Academic Search

A review of the analytical conduction models for ground heat exchangers was presented first, followed with the developed 3D finite element model based on the ANSYS. The developed model was constructed using a conduction-advection element and meshing trick that enabled the cost-effective simulation for complex heat transfer around ground buried heat exchangers. The validation of the developed model was performed

Xianlei Zong; Xiaohui Cheng

2010-01-01

311

The Experimental Study on Heat Transfer Characteristics of The External Heat Exchanger  

Microsoft Academic Search

\\u000a Using the external heat exchanger in large-scale CFB boilers can control combustion and heat transfer separately, make the\\u000a adjustments of bed temperature and steam temperature convenient. The state of gas-solid two phase flow in the external heat\\u000a exchanger is bubbling fluidized bed, but differs from the regular one as there is a directional flow in it. Consequently,\\u000a the temperature distribution

X. Y. Ji; X. F. Lu; L. Yang; H. Z. Liu

312

Dealing with Uncertainties During Heat Exchanger Design  

E-print Network

heat capacity flow rate of 30 kW/K. The cold stream flowing through E I bas a heat capacity flow rate of 55 kW/K and that flowing through E2 a value of 35 kW/K. 123 ESL-IE-01-05-20 Proceedings from the Twenty-third National Industrial Energy...) Flowrate kg}s 100 87.5 Heat capacity Jlkl/:.K 2000 2000 Heat capacity flowrate, CP kW/K 200 175 Inlet Temperature ?C 220 80 Outlet Temperature ?C 180.7 125 Foulinl/: Resistance m 2 KIW 0.0005 0.0001 Min. Vel. '", ":"'~ ," TwesIdeP.o. -Shelside p...

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

313

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

DOEpatents

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

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

1996-12-03

314

Power and refrigeration plants for minimum heat exchanger inventory  

SciTech Connect

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 al.'s conclusions for fixed power and minimum UA (total heat exchanger inventory). The second objective is to consider the reverse of the refrigeration problem, and to minimize the total UA while holding the refrigeration load fixed. It will be shown analytically that (UA)[sub H] = (UA)[sub L] is once again a feature of the optimal design, the H and L referring to hot and cold ends of the heat exchanger. The third objective is to minimize the total heat exchanger inventory while holding the refrigerator power input fixed, and to show analytically that (UA)[sub H] = (UA)[sub L]. The overriding objective of this note is to demonstrate in the simplest analytical way possible that power plants and refrigeration plants share a common optimization principle. That principle is that the needed heat exchanger inventory is minimum when it is divided evenly between the two ends of the cycle.

Bejan, A. (Duke Univ., Durham, NC (United States))

1993-06-01

315

Assessment of next generation nuclear plant intermediate heat exchanger design.  

SciTech Connect

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

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

2008-10-17

316

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

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

317

Design of Heat Exchanger for Heat Recovery in CHP Systems  

E-print Network

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

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

318

SIMULATION OF COMPACT HEAT EXCHANGERS USING GLOBAL REGRESSION AND SOFT COMPUTING  

E-print Network

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

Sen, Mihir

319

Materials, Turbomachinery and Heat Exchangers for Supercritical CO2 Systems  

SciTech Connect

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.

Anderson, Mark; Nellis, Greg; Corradini, Michael

2012-10-19

320

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

NASA Technical Reports Server (NTRS)

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.

1977-01-01

321

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

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

322

B. Gallego P. Cessi Exchange of heat and momentum between the atmosphere  

E-print Network

exchanger design, multiphase heat transfer), energy modelling Mechanical Design (design methodol- ogy THE FACULTY AND THEIR RESEARCH Allen, P., Solar Energy Utilisation, Heat Exchangers, Heat Transfer, Energy, Phase Change and multiphase process, Renewable energy (Solan, Tidal), Energy Storage, Conversion

Cessi, Paola

323

Industrial Plate Exchangers Heat Recovery and Fouling  

E-print Network

. ,. \\ 4) Very close temperature approaches ,.( possible(i.e. ideal for heat recovery) 1 I I} Max.working temperature 130 to 150lc with elastomer gaskets and 200 to I 250 0 C with C.A.F.gaskets. 2} Max working pressure 25 Bars. I FOULING...

Cross, P. H.

1981-01-01

324

Magnetic confinement experiments: plasma-material interactions, divertors, limiters, scrape-off layer (EX/D), stability (EX/S), wave-plasma interactions, current drive, heating, energetic particles (EX/W)  

NASA Astrophysics Data System (ADS)

This paper summarizes the results presented at the 24th IAEA Fusion Energy Conference in the categories of plasma-material interactions, divertors, limiters, scrape-off layer (EX/D), stability (EX/S), wave-plasma interactions, current drive, heating, energetic particles (EX/W) in magnetic confinement experiments. In total, 149 papers including post-deadline papers have contributed to these categories. Several closely related papers, which are actually categorized in confinement (EX/C), have also been included. The understanding of experimental results has progressed remarkably, in particular, in the topics of resonant magnetic perturbation and ITER-like wall, which are the highlight of this conference. At the same time, identification of the bridging mechanism between the actuator and the consequence still requires further dedicated efforts so as to provide more accurate and reliable extrapolations to ITER and DEMO.

Yamada, H.

2013-10-01

325

Prefabricated heat-exchanging fireplace. Final technical report  

SciTech Connect

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.

Schleper, M.A.

1981-06-15

326

A modular phase change heat exchanger for a solar oven  

SciTech Connect

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

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

1992-10-01

327

Development of corrosion resistant heat exchangers for flue gas desulfurization  

NASA Astrophysics Data System (ADS)

A glass lining as protection against corrosion in flue gas desulfurization plants was developed. Glasses were evaluated under corrosive attack of fluoride-containing acids. The corrosion properties of one-layer and two-layer glass enamels are optimized. Two-layer systems always show better resistance and longer life. The optimized glass linings were tested in a power plant. Manufacturing principles for glass-lined heat exchanger elements are derived. The optimized glasses may be used as protective lining design for heat exchangers or parts of them.

Ernst, E.; Lorentz, R.

1984-12-01

328

Internal dust recirculation system for a fluidized bed heat exchanger  

DOEpatents

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

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

1981-01-01

329

Heat Pump Cycle with Solution Circuit and Internal Heat Exchange  

E-print Network

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

Radermacher, R.

330

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

SciTech Connect

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

Mittereder, N.; Poerschke, A.

2013-11-01

331

An experimental study on the heat transfer characteristics of a heat pipe heat exchanger with latent heat storage. Part II: Simultaneous charging\\/discharging modes  

Microsoft Academic Search

In this part of the paper, the performance of the simultaneous charging\\/discharging operation modes of the heat pipe heat exchanger with latent heat storage is experimentally studied. The experimental results show that the device may operate under either the fluid to fluid heat transfer with charging heat to the phase change material (PCM) or the fluid to fluid heat transfer

Zhongliang Liu; Zengyi Wang; Chongfang Ma

2006-01-01

332

Physics of tokamak scrape-off layer confinement  

NASA Astrophysics Data System (ADS)

Confinement in the scrape-off layer (SOL) of a tokamak is believed to be governed by classical flows along magnetic field lines terminated by sheaths, and turbulent transport across field lines. In this paper, we review how these two effects conspire to establish the width of the SOL, and survey recent and ongoing work on mechanisms for turbulence in SOL's. The beneficial relationship between scrape-off layer turbulence in mitigating the heat flux density on divertors is noted, and tactics for actively altering SOL confinement so as to reduce the heat flux density are discussed.

Cohen, R. H.

1993-03-01

333

Spacecraft Radiator Freeze Protection Using a Regenerative Heat Exchanger  

NASA Technical Reports Server (NTRS)

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.

Ungar, Eugene K.; Schunk, Richard G.

2011-01-01

334

Time resolved heat exchange in driven quantum systems  

NASA Astrophysics Data System (ADS)

We study time-dependent heat transport in systems composed of a resonant level periodically forced with an external power source and coupled to a fermionic continuum. This simple model contains the basic ingredients to understand time resolved energy exchange in quantum capacitors that behave as single particle emitters. We analyse the behaviour of the dynamic heat current for driving frequencies within the non-adiabatic regime, showing that it does not obey a Joule dissipation law.

Florencia Ludovico, María; Lim, Jong Soo; Moskalets, Michael; Arrachea, Liliana; Sánchez, David

2014-12-01

335

Metal foams as compact high performance heat exchangers  

Microsoft Academic Search

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

K. Boomsma; D. Poulikakos; F. Zwick

2003-01-01

336

A Zero Emission Mechanical Seal with Integral Micro Heat Exchanger  

E-print Network

/689,406) with an internal heat exchanger within the body of the mating ring that channels a coolant toward the interface to effectively cool the seal faces. The coolant may be either liquid or gas, such as instrument air. This research is in part supported by a...An Industrial Zero Emission Seal with Improved Heat Transfer Characteristics Michael Khonsari Dow Chemical Endowed Chair in Rotating Machinery and Professor Center for Rotating Machinery Department of Mechanical Engineering Louisiana State...

Khonsari, M.

2005-01-01

337

Analysis of an Ultrathin Graphite-Based Compact Heat Exchanger  

Microsoft Academic Search

The emerging production of ultrathin graphite material is applied to thermal management in a numerical comparison of aluminum and graphite-based plate-fin heat exchangers. Considering anisotropic thermal conductivity in which out-of-plane transport is about two orders of magnitude lower than in-plane values, the ultrathin graphite-based solution outperforms aluminum by rejecting up to twenty percent more heat on a volumetric basis. Thermal

Alex Heltzel; Columbia Mishra; Rodney S. Ruoff; Andrew Fleming

2012-01-01

338

Metal-Based Microchannel Heat Exchangers: Manufacturing and Heat Transfer Testing.  

E-print Network

??This dissertation focuses on improving the functionality of metal-based microchannel heat exchangers (MHEs), as well as pushing this technology toward real-world applications. Design optimization was… (more)

Lu, Bin

2013-01-01

339

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

E-print Network

.R. Salimpour [16] presents the first known analysis of the effects of temperature dependent fluid properties on a shell and helical coil heat exchanger. The fluid used in the coils was Behran Hararat oil and had temperature dependent properties correlated...

Gaskill, Travis

2012-02-14

340

High Performance Trays and Heat Exchangers in Heat Pumped Distillation Columns  

E-print Network

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

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

1981-01-01

341

Investigation of Condensing Ice Heat Exchangers for MTSA Technology Development  

NASA Technical Reports Server (NTRS)

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.

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

2009-01-01

342

Xenon Recirculation-Purification with a Heat Exchanger  

E-print Network

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

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

2011-03-04

343

Analysis of performance of heat exchangers used in practical micro miniature refrigerators  

NASA Astrophysics Data System (ADS)

Micro miniature refrigerators are employed to cool small infra-red sensors and other electronic devices in a number of applications. In a micro miniature refrigerator the heat exchanger, expansion valve and evaporator are all machined on a thin glass or stainless steel sheet (typically about 1 mm thick). Unlike normal heat exchangers, the volume of the flow channels of the heat exchanger is much smaller than that of the walls of the heat exchanger. Also, a large temperature gradient (up to 200 K) is sustained between the two ends of the exchanger which are typically 50-100 mm long. The performance of the heat exchanger is therefore largely controlled by the heat conduction that takes place through the walls of the heat exchanger. In this paper the governing equations of practical micro miniature refrigerator heat exchanger are solved numerically to understand the complex convection-conduction interactions. Some guidelines are presented for the design of these heat exchangers.

Narayanan, S. Pradeep; Venkatarathnam, G.

1999-09-01

344

High temperature heat exchangers for gas turbines and future hypersonic air breathing propulsion  

NASA Astrophysics Data System (ADS)

After surveying the results of ONERA's investigations to date of metallic and ceramic heat exchangers applicable to automotive and aircraft powerplants, which are primarily of finned-tube counterflow configuration, attention is given to the influence of heat-exchanger effectiveness on fuel consumption and exchanger dimensions and weight. Emphasis is placed on the results of studies of cryogenic heat exchangers used by airbreathing hypersonic propulsion systems. The numerical codes developed by ONERA for the modeling of heat exchanger thermodynamics are evaluated.

Avran, Patrick; Bernard, Pierre

345

Initial characterization of a modular heat exchanger with an integral heat pipe  

SciTech Connect

As part of the Civil Space Technology Initiative (CSTI) Advanced Technology program, a conceptual design of the Stirling space engine (SSE) was generated. The overall goal of the CSTI high capacity power element is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space missions. The free-piston Stirling engine (FPSE) was chosen as the growth option in the CSTI program. A major goal during the conceptual design of the SSE was to reduce the number of critical joints. One area of concern was the heat exchanger assemblies that typically have the majority of critical joints. The solution proposed in the SSE conceptual design used 40 modular heat exchangers. Each module has its own integral heat pipe to transport heat from the heat source to the engine. A demonstration of the modular concept was undertaken before committing to the detailed design of the SSE heat exchangers. An existing FPSE was modified as a test bed for modular heat exchanger evaluation. The engine incorporated three heat exchanger modules, each having a sodium filled heat pipe. The thermal loading of these modules was intended to be similar to the conditions projected for the SSE modules. The engine was assembled and tests are underway. The design and fabrication of the heat exchanger modules and the engine used for these tests were described. Evaluation of the individual heat pipes before installation in the engine is described. The initial test results with the modules in operation on the engine were presented. Future tests involving the engine were outlined.

Schreiber, J.G.

1989-01-01

346

Web Scraping for Astronomy  

NASA Astrophysics Data System (ADS)

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.

Derriere, S.; Boch, T.

2012-09-01

347

NGNP Process Heat Utilization: Liquid Metal Phase Change Heat Exchanger  

Microsoft Academic Search

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

Piyush Sabharwall; Mike Patterson; Vivek Utgikar; Fred Gunnerson

2008-01-01

348

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

DOEpatents

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

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

1998-07-21

349

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

DOEpatents

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

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

1998-07-21

350

Heat exchanger with leak detecting double wall tubes  

DOEpatents

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

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

1981-01-01

351

Heat-Exchange Fluids for Sulfuric Acid Vaporizers  

NASA Technical Reports Server (NTRS)

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.

Lawson, D. D.; Petersen, G. R.

1982-01-01

352

Potential heat exchange fluids for use in sulfuric acid vaporizers  

NASA Technical Reports Server (NTRS)

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.

Lawson, D. D.; Petersen, G. R.

1979-01-01

353

Potential heat exchange fluids for use in sulfuric acid vaporizers  

NASA Technical Reports Server (NTRS)

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.

Lawson, D. D.; Petersen, G. R.

1981-01-01

354

Heat exchanger efficiently operable alternatively as evaporator or condenser  

Microsoft Academic Search

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

Amir L

1981-01-01

355

Power and refrigeration plants for minimum heat exchanger inventory  

Microsoft Academic Search

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

A. Bejan

1993-01-01

356

Teaching Heat Exchanger Network Synthesis Using Interactive Microcomputer Graphics.  

ERIC Educational Resources Information Center

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)

Dixon, Anthony G.

1987-01-01

357

Finned Tube With Vortex Generators For A Heat Exchanger.  

DOEpatents

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

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

2004-09-14

358

Understand ÎP and ÎT in turbulent flow heat exchangers  

Microsoft Academic Search

This article attempts to lead the reader down a clear path to the approximate optimum pressure drop (ÎP) and temperature difference (ÎT) for the most important class of heat exchangers--those with turbulent flow, no phase change, and fluids and flow rates that are similar on both the hot and cold sides. The optimum ÎP and ÎT are presented in two

1996-01-01

359

Thermodynamic optimal design of heat exchangers for an irreversible refrigerator  

Microsoft Academic Search

Thermodynamic optimisation of energy systems is essential in reducing the environmental impact of energy utilisation. Yet, the refrigerators commonly used for this purpose have improvable efficiency levels. Their performance, as shown by the literature, is highly influenced by the size of the heat exchangers and by internal irreversibilities. In this paper the maximum coefficient of performance (COP) is obtained for

Giuseppe Grazzini; Rinaldo Rinaldi

2001-01-01

360

Air Circulation and Heat Exchange under Reduced Pressures  

NASA Astrophysics Data System (ADS)

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.

Rygalov, Vadim; Wheeler, Raymond; Dixon, Mike; Hillhouse, Len; Fowler, Philip

361

Dual Expander Cycle Rocket Engine with an Intermediate, Closed-cycle Heat Exchanger  

NASA Technical Reports Server (NTRS)

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.

Greene, William D. (Inventor)

2008-01-01

362

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

E-print Network

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

Salamon, Peter

363

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

E-print Network

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

Yu, Lisan

364

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

E-print Network

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

Wirtz, Richard A.

365

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

366

Plate Heat Exchangers: Calculation Methods for Singleand Two-Phase Flow  

Microsoft Academic Search

Plate heat exchangers were first developed about 100 years ago but have won increasing interest during the last two decades, primarily due to the development of methods of manufacturing brazed plate heat exchangers. This type of heat exchanger offers very good heat transfer performance in single-phase flow as well as in evaporation and condensation. Part of the reason is the

Björn Palm; Joachim Claesson

2006-01-01

367

Optimal Shape Design of Compact Heat Exchangers Based on Adjoint Analysis of Momentum and Heat Transfer  

NASA Astrophysics Data System (ADS)

An adjoint-based shape optimization method of heat exchangers, which takes into account the heat transfer performance with the pressure loss penalty, is proposed, and its effectiveness is examined through a series of numerical simulation. Undulated heat transfer surface is optimized under an isothermal heated condition based on the variational method with the first derivative of the cost function, which is determined by an adjoint analysis of momentum and heat transfer. When applied to a modeled heat-exchanger passage with a pair of oblique wavy walls, the present optimization method refines the duct shape so as to enhance the heat transfer while suppressing the flow separation. It is shown that the j/f factor is further increased by 4% from the best value of the initial obliquely wavy duct. The effects of the initial wave amplitude upon the shape evolution process are also investigated.

Morimoto, Kenichi; Suzuki, Yuji; Kasagi, Nobuhide

368

Concepts and realization of microstructure heat exchangers for enhanced heat transfer  

SciTech Connect

Microstructure heat exchangers have unique properties that make them useful for numerous scientific and industrial applications. The power transferred per unit volume is mainly a function of the distance between heat source and heat sink-the smaller this distance, the better the heat transfer. Another parameter governing for the heat transfer is the lateral characteristic dimension of the heat transfer structure; in the case of microchannels, this is the hydraulic diameter. Decreasing this characteristic dimension into the range of several 10s of micrometers leads to very high values for the heat transfer rate. Another possible way of increasing the heat transfer rate of a heat exchanger is changing the flow regime. Microchannel devices usually operate within the laminar flow regime. By changing from microchannels to three dimensional structures, or to planar geometries with microcolumn arrays, a significant increase of the heat transfer rate can be achieved. Microheat exchangers in the form of both microchannel devices (with different hydraulic diameters) and microcolumn array devices (with different microcolumn layouts) are presented and compared. Electrically heated microchannel devices are presented, and industrial applications are briefly described. (author)

Brandner, J.J.; Anurjew, E.; Bohn, L.; Hansjosten, E.; Henning, T.; Schygulla, U.; Wenka, A.; Schubert, K. [Forschungszentrum Karlsruhe, Institute for Micro Process Engineering IMVT, P.O. Box 3640, DE-76021 Karlsruhe (Germany)

2006-08-15

369

Novel Power Electronics Three-Dimensional Heat Exchanger: Preprint  

SciTech Connect

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

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

2014-08-01

370

A survey of oscillating flow in Stirling engine heat exchangers  

NASA Technical Reports Server (NTRS)

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.

Simon, Terrence W.; Seume, Jorge R.

1988-01-01

371

Feasibility and design studies for heat recovery from a refrigeration system with a canopus heat exchanger  

Microsoft Academic Search

This paper presents an investigation of the feasibility of heat recovery from the condenser of a vapour compression refrigeration (VCR) system through a Canopus heat exchanger (CHE) between the compressor and condenser components. The presence of the CHE makes it possible to recover the superheat of the discharged vapour and utilize it for increasing the temperature of the external fluid

S. C. Kaushik; M. Singh

1995-01-01

372

Enhancement of heat transfer in compact heat exchanger by different type of rib with holographic interferometry  

Microsoft Academic Search

An experimental study was carried out to investigate enhancement of heat transfer in compact heat exchanger by keeping pressure drop constant in a given range. Two different test matrices, cylindrical and triangular, used to find the optimum ribs were compared with a smooth channel. The investigation was performed with both laminar and turbulent forced flow for Reynolds numbers from 250

Ibrahim Kilicaslan; H. Ibrahim Sarac

1998-01-01

373

Heat transfer and friction correlation for compact louvered fin-and-tube heat exchangers  

Microsoft Academic Search

General heat transfer and friction correlations for louver fin geometry having round tube configuration were proposed in the present study. A total of 49 samples of louvered fin-and-tube heat exchangers with different geometrical parameters, including louver pitch, louver height, longitudinal tube pitch, transverse tube pitch, tube diameter, and fin pitch were used to develop the correlations. The proposed correlation describes

C.-C. Wang; C.-J. Lee; C.-T. Chang; S.-P. Lin

1998-01-01

374

Local heat transfer measurements of plate finned-tube heat exchangers by infrared thermography  

Microsoft Academic Search

An experimental study is performed using an infrared thermovision to monitor temperature distribution over a plate-fin surface inside the plate finned-tube heat exchangers. The differentiation of the temperature function is derived to determine the local convective heat transfer coefficients on the tested fin, using a local element lumped conduction equation included the convective effect on the boundaries with experimental data.

Herchang Ay; JiinYuh Jang; Jer-Nan Yeh

2002-01-01

375

Heat transfer and pressure drop of ice slurries in plate heat exchangers  

Microsoft Academic Search

Ice slurries can be used both for cold storage in place of chilled water or ice and as a secondary refrigerant since, up to certain concentrations, they can be pumped directly through distribution pipeworks and heat exchangers. For ice slurries to become more widely accepted, however, more engineering information is required on fluid flow and heat transfer characteristics.This paper reports

J. Bellas; I. Chaer; S. A. Tassou

2002-01-01

376

Computer simulation of borehole ground heat exchangers for geothermal heat pump systems  

Microsoft Academic Search

Computer simulation of borehole ground heat exchangers used in geothermal heat pump systems was conducted using three-dimensional implicit finite difference method with rectangular coordinate system. Each borehole was approximated by a square column circumscribed by the borehole radius. Borehole loading profile calculated numerically based on the prescribed borehole temperature profile under quasi-steady state conditions was used to determine the ground

C. K. Lee; H. N. Lam

2008-01-01

377

Development of spiral heat source model for novel pile ground heat exchangers  

Microsoft Academic Search

The extensive application of ground coupled heat pump system (GCHP) is restricted by the installation cost of conventional borehole ground heat exchangers (GHE), which is not only expensive but also requires additional ground area. The idea of combining the GHE with building foundation piles, i.e., the “energy pile,” has arisen in recent years. The novel pile GHEs consisting of vertical

Yi Man; Hongxing Yang; Nairen Diao; Ping Cui; Lin Lu; Zhaohong Fang

2011-01-01

378

Direct contact heat exchange for latent heat-of-fusion energy storage systems  

Microsoft Academic Search

Rudimentary computational and experimental results are presented for a thermal energy storage process based on a novel counter current, direct contact heat exchange concept, the shot tower. The process uses a phase change material and a mutually immiscible heat transfer fluid. A two-tank storage system is used, one each for cool and hot phase change material, respectively. In use, the

M. C. Nichols; R. M. Green

1977-01-01

379

A review of hydrocarbon two-phase heat transfer in compact heat exchangers and enhanced geometries  

Microsoft Academic Search

Hydrocarbons are considered as alternative fluids for refrigeration, air-conditioning and heat pump applications. Pure butane, propane or their mixtures can be adopted, but due to their flammable properties, the systems have to be designed in such a way that the refrigerant charge is minimized. Therefore, compact heat exchangers and enhanced geometries are adopted in such systems. In this paper, the

Bernard Thonon

2008-01-01

380

Secondary Heat Exchanger Design and Comparison for Advanced High Temperature Reactor  

SciTech Connect

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

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

2012-06-01

381

Intensification of heat and mass transfer by ultrasound: Application to heat exchangers and membrane separation processes.  

PubMed

This paper aims to illustrate the interest of ultrasound technology as an efficient technique for both heat and mass transfer intensification. It is demonstrated that the use of ultrasound results in an increase of heat exchanger performances and in a possible fouling monitoring in heat exchangers. Mass transfer intensification was observed in the case of cross-flow ultrafiltration. It is shown that the enhancement of the membrane separation process strongly depends on the physico-chemical properties of the filtered suspensions. PMID:25216897

Gondrexon, N; Cheze, L; Jin, Y; Legay, M; Tissot, Q; Hengl, N; Baup, S; Boldo, P; Pignon, F; Talansier, E

2014-08-30

382

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

E-print Network

STUDY OF FROST GROWTH ON HEAT EXCHANGERS USED AS OUTDOOR COILS IN AIR SOURCE HEAT PUMP SYSTEMS OF FROST GROWTH ON HEAT EXCHANGERS USED AS OUTDOOR COILS IN AIR SOURCE HEAT PUMP SYSTEMS Dissertation of Frost Growth . . . . . . . . . . . . . . . . . . . . . 7 2.2 Frost Growth on Simple Geometries

383

Experimental Investigation of Ice Phase Change Material Heat Exchangers  

NASA Technical Reports Server (NTRS)

Phase change materials (PCM) may be useful for spacecraft thermal control systems that involve cyclical heat loads or cyclical thermal environments. Thermal energy can be stored in the PCM during peak heat loads or in adverse thermal environments. The stored thermal energy can then be released later during minimum heat loads or in more favorable thermal environments. This can result in a decreased turndown ratio for the radiator and a reduced system mass. The use of water as a PCM rather than the more traditional paraffin wax has the potential for significant mass reduction since the latent heat of formation of water is approximately 70% greater than that of wax. One of the potential drawbacks of using ice as a PCM is its potential to rupture its container as water expands upon freezing. In order to develop a space qualified ice PCM heat exchanger, failure mechanisms must first be understood. Therefore, a methodical experimental investigation has been undertaken to demonstrate and document specific failure mechanisms due to ice expansion in the PCM. A number of ice PCM heat exchangers were fabricated and tested. Additionally, methods for controlling void location in order to reduce the risk of damage due to ice expansion were investigated. This paper presents an overview of the results of this investigation from the past three years.

Leimkuehler, Thomas O.; Stephan, Ryan A.

2011-01-01

384

Heat-transfer and friction factor design data for all-metal compact heat exchangers  

NASA Astrophysics Data System (ADS)

To improve system life, an effort was undertaken to develop all-metal compact heat exchangers to replace existing heat exchangers which contain organic materials. Eliminating organic materials increases system life because outgassing organics can contaminate the helium working fluid and reduce system life. Perforated plate heat exchangers were found to have inherently low axial conduction and are therefore excellent candidates for cryogenic applications where an all-metal design is required. A total of 11 plate cores were tested; 2 were chemically etched, 1 was mechanically punched, and 8 were manufactured using electron beam drilling. Hole size, percent open area, and plate thickness parameters were varied among the plates. Experimental results were compared to analytical projections and found to differ significantly. The single-blow transient test technique was used to determine the heat transfer coefficients and the isothermal pressure drop test was used to determine friction factors, as a function of Reynolds number.

Cain, Christina L.

1989-03-01

385

Heat transfer and friction characteristics of plain fin-and-tube heat exchangers, part II: Correlation  

Microsoft Academic Search

A correlation for fin-and-tube heat exchanger having plain fin geometry is proposed in this study. A total of 74 samples were used to develop the correlation. For practical considerations, the proposed heat transfer correlation had absorbed the contact conductance in the development of correlation. The proposed heat transfer correlation can describe 88.6% of the database within ±15%, while the proposed

Chi-Chuan Wang; Kuan-Yu Chi; Chun-Jung Chang

2000-01-01

386

Heat transfer enhancement in fin-tube heat exchangers by winglet type vortex generators  

Microsoft Academic Search

Numerical investigations of the flow structure and heat transfer enhancement in a channel with a built-in-circular tube and a winglet type vortex generator are presented. The geometrical configuration represents an element of a gas-liquid fin-tube crossflow heat exchanger. In the absence of the winglet type vortex generator, relatively little heat transfer takes place in the downstream of the circular tube

G. Biswas; N. K. Mitra; M. Fiebig

1994-01-01

387

A Local Heat Flux Measurement Technique for Inclined Heat Exchanger Tubes  

Microsoft Academic Search

This article presents the design, fabrication, and calibration of thermocouple pairs for local heat flux measurement. The intended application of the thermocouple pairs is on the tubes of phase-change heat exchangers experiencing heat fluxes on the order of 10 W\\/m. Particular advantages of this technique are that it is accurate even for thin-wall tubes, there are no restrictions on the

T. Wu; K. Vierow

2006-01-01

388

Fabrication of Wire Mesh Heat Exchangers for Waste Heat Recovery Using Wire-Arc Spraying  

NASA Astrophysics Data System (ADS)

Waste heat can be recovered from hot combustion gases using water-cooled heat exchangers. Adding fins to the external surfaces of the water pipes inserted into the hot gases increases their surface area and enhances heat transfer, increasing the efficiency of heat recovery. A method of increasing the heat transfer surface area has been developed using a twin wire-arc thermal spray system to generate a dense, high-strength coating that bonds wire mesh to the outside surfaces of stainless steel pipes through which water passes. At the optimum spray distance of 150 mm, the oxide content, coating porosity, and the adhesion strength of the coating were measured to be 7%, 2%, and 24 MPa, respectively. Experiments were done in which heat exchangers were placed inside a high-temperature oven with temperature varying from 300 to 900 °C. Several different heat exchanger designs were tested to estimate the total heat transfer in each case. The efficiency of heat transfer was found to depend strongly on the quality of the bond between the wire meshes and pipes and the size of openings in the wire mesh.

Rezaey, R.; Salavati, S.; Pershin, L.; Coyle, T.; Chandra, S.; Mostaghimi, J.

2014-04-01

389

Preliminary evaluation of a heat pipe heat exchanger on a regenerative turbofan  

NASA Technical Reports Server (NTRS)

A preliminary evaluation was made of a regenerative turbofan engine using a heat pipe heat exchanger. The heat exchanger had an effectiveness of 0.70, a pressure drop of 3 percent on each side, and used sodium for the working fluid in the stainless steel heat pipes. The engine was compared to a reference turbofan engine originally designed for service in 1979. Both engines had a bypass ratio of 4.5 and a fan pressure ratio of 2.0. The design thrust of the engines was in the 4000 N range at a cruise condition of Mach 0.98 and 11.6 km. It is shown that heat pipe heat exchangers of this type cause a large weight and size problem for the engine. The penalties were too severe to be overcome by the small uninstalled fuel consumption advantage. The type of heat exchanger should only be considered for small airflow engines in flight applications. Ground applications might prove more suitable and flexible.

Kraft, G. A.

1975-01-01

390

Heat exchanger sizing for vertical closed-loop ground-source heat pumps  

SciTech Connect

A building energy simulation program has been used in conjunction with a ground heat exchanger sizing algorithm to develop general guidelines on how to size vertical ground heat exchangers for closed-loop ground-source heat pump systems in large buildings. The analysis considered three commercial building types of varying size with different internal loads and heat pump efficiencies. Each building variation was simulated in seven cities, three in the US and four in Canada. The ground heat exchanger sizing algorithm has been previously validated against actual system data. The analysis results showed a strong correlation between heat exchanger length required and annual energy rejected to the ground, if the building was cooling-dominated, or annual energy extracted from the ground, if the building was heating-dominated. The resulting sizing guidelines recommend hour-by-hour energy analysis to determine the energy extracted from and rejected to the building water loop. Using this information the designer will have available easy-to-use, accurate sizing guidelines that should result in more economical installations than those based on previous ``rule of thumb`` guidelines.

Cane, R.L.D.; Clemes, S.B.; Morrison, A. [Caneta Research, Inc., Mississauga, Ontario (Canada); Hughes, P.J. [Oak Ridge National Lab., TN (United States)

1995-12-31

391

Design of compact intermediate heat exchangers for gas cooled fast reactors  

E-print Network

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

Gezelius, Knut, 1978-

2004-01-01

392

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

E-print Network

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

Skogestad, Sigurd

393

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

E-print Network

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

Skogestad, Sigurd

394

Interpretive 2-D treatment of scrape-off-layer plasmas  

SciTech Connect

The width of the scrape-off-layer in a tokamak is determined by cross field transport. In Alcator C-mod the plasma parameters in the scrape-off-layer are measured at upstream and divertor plate locations. We solve a 2-D scrape-off-layer heat conduction equation in the flux geometry (as determined by EFIT) of the C-mod experiment. Bolometric measurements are utilized for the radiative loss term. We use the end wall probe measurements of electron temperature as a boundary condition and the fast scanning probe measurements of upstream temperature are treated as constraints to determine the cross field transport and thermal conductivity. Results are compared with 1-D onion-skin-model predictions.

Umansky, M.; Allen, A.; Daughton, W. [MIT Plasma Fusion Center, Cambridge, MA (United States)] [and others

1996-12-31

395

Thermal performance of direct contact heat exchangers for mixed hydrocarbons  

SciTech Connect

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

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

1985-01-01

396

Innovative, counterflow gas/fine solids, direct contact heat exchanger: Final report  

SciTech Connect

The Aerojet Energy Conversion Company has completed the first phase of study for development of a heat exchanger. The heat exchanger, a highly efficient, low cost concept, is a candidate for application in process manufacturing industries such as cement, lime, or glass. The analytical effort was to establish the heat exchanger performance via computer modeling and analysis; the experimental effort was to demonstrate the heat exchanger performance.

Mah, C.S.

1987-10-01

397

An investigation of the performance of compact heat exchanger for latent heat recovery from exhaust flue gases  

Microsoft Academic Search

An experimental and theoretical investigation of the utilization of finned tube compact heat exchanger for a heat recovery steam generator (HRSG) to recover both sensible and latent heat is presented in this paper. The heat transfer and pressure drop characteristics of the fin-and-tube heat exchanger are theoretically studied. A correlation of the combined convection–condensation heat transfer is derived by using

Xiaojun Shi; Defu Che; Brian Agnew; Jianmin Gao

2011-01-01

398

Thermal Performance Study of a Prototype Multiport Heat Exchanger  

NASA Astrophysics Data System (ADS)

Great efforts have been made to investigate the thermal performance and fluid flow behaviour in Minichannel Heat Exchangers (MICHX), however, the examination of air side in a multiport serpentine slab heat exchanger is rare. In the current investigation, experiments were conducted on air heating via a prototype multiport MICHX. Hot DI-water at different mass flow rates and a constant inlet temperature of 70°C was passed through the channels. The water side Reynolds numbers were varied from 255 to 411. The airside Reynolds numbers were calculated based on the free mean stream velocity and varied from 1750 to 5250, while, the air inlet temperatures were in the range of 22.5°C to 34.5°C. The effects of dimensional parameters, such as Reynolds number, Nusselt number, Prandtl number, Brinkman number, and Dean number on the heat transfer performance were investigated. The effect of the serpentine on the enhancement of DI water thermal performance behaviour was studied. Heat transfer correlations were established and compared to the results in the open literature.

Fotowat, Shahram

399

Gas Diodes for Thermoacoustic Self-circulating Heat Exchangers  

NASA Astrophysics Data System (ADS)

An asymmetrical constriction in a pipe functions as an imperfect gas diode for acoustic oscillations in the gas in the pipe. One or more gas diodes in a resonant loop of pipe create substantial steady flow, which can carry substantial heat between a remote heat exchanger and a thermoacoustic or Stirling engine or refrigerator; the flow is driven directly by the oscillations in the engine or refrigerator itself. This invention gives Stirling and thermoacoustic devices unprecedented flexibility, and may lead to Stirling engines of unprecedented power. We have built two of these resonant self-circulating heat exchangers, one as a fundamental test bed and the other as a demonstration of practical levels of heat transfer. Measurements of flow and heat transfer are in factor-of-two agreement with either of two simple calculation methods. One calculation method treats the oscillating and steady flows as independent and simply superimposed, except in the gas diodes. The other method accounts for the interaction between the oscillating and steady flow with the quasi-steady approximation. The mutual influence of superimposed turbulent oscillating and steady flows is a theoretical challenge.

Swift, Greg; Backhaus, Scott

2006-05-01

400

The Design, Fabrication, and Testing of Composite Heat Exchange Coupons  

NASA Technical Reports Server (NTRS)

Several heat exchanger (HX) test panels were designed, fabricated and tested at the NASA Glenn Research Center to explore the fabrication and performance of several designs for composite heat exchangers. The development of these light weight, high efficiency air-liquid test panels was attempted using polymer composites and carbon foam materials. The fundamental goal of this effort was to demonstrate the feasibility of the composite HX for various space exploration and thermal management applications including Orion CEV and Altair. The specific objectives of this work were to select optimum materials, designs, and to optimize fabrication procedures. After fabrication, the individual design concept prototypes were tested to determine their thermal performance and to guide the future development of full-size engineering development units (EDU). The overall test results suggested that the panel bonded with pre-cured composite laminates to KFOAM Grade L1 scored above the other designs in terms of ease of manufacture and performance.

Quade, Derek J.; Meador, Michael A.; Shin, Euy-Sik; Johnston, James C.; Kuczmarski, Maria A.

2011-01-01

401

Condensing Heat Exchanger Concept Developed for Space Systems  

NASA Technical Reports Server (NTRS)

The current system for moisture removal and humidity control for the space shuttles and the International Space Station uses a two-stage process. Water first condenses onto fins and is pulled through "slurper bars." These bars take in a two-phase mixture of air and water that is then separated by the rotary separator. A more efficient design would remove the water directly from the air without the need of an additional water separator downstream. For the Condensing Heat Exchanger for Space Systems (CHESS) project, researchers at the NASA Glenn Research Center in collaboration with NASA Johnson Space Center are designing a condensing heat exchanger that utilizes capillary forces to collect and remove water and that can operate in varying gravitational conditions including microgravity, lunar gravity, and Martian gravity.

Hasan, Mohammad M.; Nayagam, Vedha

2005-01-01

402

Oscillating flow loss test results in Stirling engine heat exchangers  

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

403

High pressure ratio cryocooler with integral expander and heat exchanger  

NASA Astrophysics Data System (ADS)

A new 1 W, 4.2 K cryocooler is under development that is intended to miniaturize helium temperature refrigeration systems using a high-pressure-ratio Collins-type cycle. The configuration resulted from optimization studies of a saturated vapor compression (SCV) cycle that employs miniature parallel-plate heat exchangers. The basic configuration is a long displacer in a close-fitting, thin-walled cylinder. The displacer-to-cylinder gap is the high-pressure passage of the heat exchanger, and the low-pressure passage is formed by a thin tube over the OD of the cylinder. A solenoid-operated inlet valve admits 40 atm helium to the displacer-to-cylinder gap at room temperature, while the solenoid-operated exhaust valve operates at 4 atm. The single-stage cryocooler produces 1 W of refrigeration at 40 K without precooling and at 20 K with liquid nitrogen precooling.

Crunkleton, J. A.; Smith, J. L., Jr.; Iwasa, Y.

404

Experimental investigation of fluid flow and heat transfer in a single-phase liquid flow micro-heat exchanger  

Microsoft Academic Search

This work presents an experimental analysis of the hydrodynamic and thermal performance of micro-heat exchangers. Two micro-heat exchangers, characterized by microchannels of 100×100 and 200×200?m square cross-sections, were designed for that purpose. The fluid used was deionized water and there was no phase change along the fluid circuit. The fluid pressure drop along the heat exchanger and the heat transfer

N. García-Hernando; A. Acosta-Iborra; U. Ruiz-Rivas; M. Izquierdo

2009-01-01

405

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

Code of Federal Regulations, 2012 CFR

...and continuous compliance requirements for heat exchange systems? 63.11920 Section...and continuous compliance requirements for heat exchange systems? (a) Except as...of volatile organic compounds from each heat exchange system in HAP service...

2012-07-01

406

40 CFR 63.1084 - What heat exchange systems are exempt from the requirements of this subpart?  

...2014-07-01 2014-07-01 false What heat exchange systems are exempt from the requirements...for Ethylene Manufacturing Process Units: Heat Exchange Systems and Waste Operations Applicability for Heat Exchange Systems § 63.1084 What...

2014-07-01

407

46 CFR 54.15-15 - Relief devices for unfired steam boilers, evaporators, and heat exchangers (modifies UG-126).  

Code of Federal Regulations, 2013 CFR

...unfired steam boilers, evaporators, and heat exchangers (modifies UG-126). 54...unfired steam boilers, evaporators, and heat exchangers (modifies UG-126...above the safety valve setting. (f) A heat exchanger with liquid in the shell...

2013-10-01

408

40 CFR 63.1084 - What heat exchange systems are exempt from the requirements of this subpart?  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false What heat exchange systems are exempt from the requirements...for Ethylene Manufacturing Process Units: Heat Exchange Systems and Waste Operations Applicability for Heat Exchange Systems § 63.1084 What...

2013-07-01

409

46 CFR 54.15-15 - Relief devices for unfired steam boilers, evaporators, and heat exchangers (modifies UG-126).  

Code of Federal Regulations, 2012 CFR

...unfired steam boilers, evaporators, and heat exchangers (modifies UG-126). 54...unfired steam boilers, evaporators, and heat exchangers (modifies UG-126...above the safety valve setting. (f) A heat exchanger with liquid in the shell...

2012-10-01

410

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

Code of Federal Regulations, 2013 CFR

...and continuous compliance requirements for heat exchange systems? 63.11920 Section...and continuous compliance requirements for heat exchange systems? (a) Except as...of volatile organic compounds from each heat exchange system in HAP service...

2013-07-01

411

46 CFR 54.15-15 - Relief devices for unfired steam boilers, evaporators, and heat exchangers (modifies UG-126).  

Code of Federal Regulations, 2011 CFR

...unfired steam boilers, evaporators, and heat exchangers (modifies UG-126). 54...unfired steam boilers, evaporators, and heat exchangers (modifies UG-126...above the safety valve setting. (f) A heat exchanger with liquid in the shell...

2011-10-01

412

40 CFR 63.1084 - What heat exchange systems are exempt from the requirements of this subpart?  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false What heat exchange systems are exempt from the requirements...for Ethylene Manufacturing Process Units: Heat Exchange Systems and Waste Operations Applicability for Heat Exchange Systems § 63.1084 What...

2012-07-01

413

40 CFR 63.1084 - What heat exchange systems are exempt from the requirements of this subpart?  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false What heat exchange systems are exempt from the requirements...for Ethylene Manufacturing Process Units: Heat Exchange Systems and Waste Operations Applicability for Heat Exchange Systems § 63.1084 What...

2010-07-01

414

40 CFR 63.1084 - What heat exchange systems are exempt from the requirements of this subpart?  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false What heat exchange systems are exempt from the requirements...for Ethylene Manufacturing Process Units: Heat Exchange Systems and Waste Operations Applicability for Heat Exchange Systems § 63.1084 What...

2011-07-01

415

Development of corrosion resistant heat exchangers for flue gas desulfurization  

Microsoft Academic Search

A glass lining as protection against corrosion in flue gas desulfurization plants was developed. Glasses were evaluated under corrosive attack of fluoride-containing acids. The corrosion properties of one-layer and two-layer glass enamels are optimized. Two-layer systems always show better resistance and longer life. The optimized glass linings were tested in a power plant. Manufacturing principles for glass-lined heat exchanger elements

E. Ernst; R. Lorentz

1984-01-01

416

Performance of Plate Heat Exchangers for Evaporation of Ammonia  

Microsoft Academic Search

Measurements on a semi-welded plate heat exchanger (PHE) and on various versions of the nickel-brazed PHE were performed in a large experimental refrigeration rig. Experiments were carried out with the refrigerant ammonia, which was completely evaporated in vertical upward flow in PHEs connected in a U-type manner. A multiple linear regression analysis produced three Nusselt number correlations for the different

Dirk Sterner; Bengt Sunden

2006-01-01

417

Simulation of lakes and surface water heat exchangers for design of surface water heat pump systems  

NASA Astrophysics Data System (ADS)

Surface Water Heat Pump (SWHP) system utilize surface water bodies, such as ponds, lakes, rivers, and the sea, as heat sources and/or sinks. These systems may be open-loop, circulating water between the surface water body and a heat exchanger on dry land, or closed-loop, utilizing a submerged surface water heat exchanger (SWHE). Both types of SWHP systems have been widely used, but little in the way of design data, design procedures, or energy calculation procedures is available to aid engineers in the design and analysis of these systems. For either type of SWHP system, the ability to predict the evolution of lake temperature with time is an important aspect of needed design and energy analysis procedures. This thesis describes the development and validation of a lake model that is coupled with a surface water heat exchanger model to predict both the lake dynamics (temperature, stratification, ice/snow cover) and the heat transfer performance of different types of SWHE. This one-dimensional model utilizes a detailed surface heat balance model at the upper boundary, a sediment conduction heat transfer model at the lower boundary, and an eddy diffusion model to predict transport within the lake. The lake model is implemented as part of the developed software design tool, which can be used as an aid in the sizing of SWHE used in closed loop SWHP systems.

Conjeevaram Bashyam, Krishna

418

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

E-print Network

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

Paris-Sud XI, Université de

419

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

E-print Network

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

Skogestad, Sigurd

420

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

E-print Network

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

California at Los Angeles, University of

421

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

E-print Network

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

Sen, Mihir

422

Entry region of louvered n heat exchangers Marlow E. Springer, Karen A. Thole *,1  

E-print Network

Entry region of louvered ®n heat exchangers Marlow E. Springer, Karen A. Thole *,1 Mechanical for most compact heat exchangers occurs on the gas side and as such an understanding of the gas side ¯ow®eld is needed before improving current designs. Louvered ®ns are commonly used in many compact heat exchangers

Thole, Karen A.

423

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

E-print Network

Numerical computation of 3D heat transfer in complex parallel convective exchangers using convective heat exchangers that handles possibly complex input/output con- ditions as well as connection between pipes. It is based on a spectral method that allows to re-cast three-dimensional heat exchangers

Paris-Sud XI, Université de

424

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

E-print Network

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

Pacheco, Jose Rafael

425

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

E-print Network

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

Kasagi, Nobuhide

426

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

E-print Network

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

Michalski, Ryszard S.

427

Control Structure Selection for Optimal Operation of a Heat Exchanger Network  

E-print Network

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

Skogestad, Sigurd

428

TEMPERATURE CONTROLLABILITY IN CROSS-FLOW HEAT EXCHANGERS AND LONG DUCTS  

E-print Network

TEMPERATURE CONTROLLABILITY IN CROSS-FLOW HEAT EXCHANGERS AND LONG DUCTS A Dissertation Submitted-FLOW HEAT EXCHANGERS AND LONG DUCTS Abstract by Sorour Abdulhadi Alotaibi The performance of thermal control nature and delay due to fluid advection from one point to an- other. Two basic systems, heat exchangers

Sen, Mihir

429

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

E-print Network

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

Skogestad, Sigurd

430

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

E-print Network

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

Paris-Sud XI, Université de

431

40 CFR 63.2490 - What requirements must I meet for heat exchange systems?  

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2014-07-01

432

40 CFR Table 6 to Subpart Hhhhh of... - Requirements for Heat Exchange Systems  

Code of Federal Regulations, 2011 CFR

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2011-07-01

433

40 CFR 63.2490 - What requirements must I meet for heat exchange systems?  

Code of Federal Regulations, 2011 CFR

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2011-07-01

434

40 CFR Table 6 to Subpart Hhhhh of... - Requirements for Heat Exchange Systems  

Code of Federal Regulations, 2010 CFR

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2010-07-01

435

40 CFR Table 10 to Subpart Ffff of... - Work Practice Standards for Heat Exchange Systems  

Code of Federal Regulations, 2010 CFR

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2010-07-01

436

40 CFR 63.2490 - What requirements must I meet for heat exchange systems?  

Code of Federal Regulations, 2013 CFR

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2013-07-01

437

40 CFR 63.8030 - What requirements apply to my heat exchange systems?  

Code of Federal Regulations, 2011 CFR

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2011-07-01

438

40 CFR 63.8030 - What requirements apply to my heat exchange systems?  

Code of Federal Regulations, 2010 CFR

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2010-07-01

439

40 CFR Table 10 to Subpart Ffff of... - Work Practice Standards for Heat Exchange Systems  

Code of Federal Regulations, 2013 CFR

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2013-07-01

440

40 CFR 63.8030 - What requirements apply to my heat exchange systems?  

Code of Federal Regulations, 2012 CFR

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2012-07-01

441

40 CFR Table 10 to Subpart Ffff of... - Work Practice Standards for Heat Exchange Systems  

Code of Federal Regulations, 2012 CFR

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2012-07-01

442

40 CFR Table 6 to Subpart Hhhhh of... - Requirements for Heat Exchange Systems  

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2014-07-01

443

40 CFR Table 6 to Subpart Hhhhh of... - Requirements for Heat Exchange Systems  

Code of Federal Regulations, 2012 CFR

...2011-07-01 true Requirements for Heat Exchange Systems 6 Table 6 to Subpart...Subpart HHHHH of Part 63—Requirements for Heat Exchange Systems As required in § 63...the following table that applies to your heat exchange systems. For each . . ....

2012-07-01

444

40 CFR 63.2490 - What requirements must I meet for heat exchange systems?  

Code of Federal Regulations, 2012 CFR

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2012-07-01

445

40 CFR Table 10 to Subpart Ffff of... - Work Practice Standards for Heat Exchange Systems  

Code of Federal Regulations, 2011 CFR

...2009-07-01 true Work Practice Standards for Heat Exchange Systems 10 Table 10 to Subpart...Part 63—Work Practice Standards for Heat Exchange Systems As required in § 63...the following table that applies to your heat exchange systems: For each . . ....

2011-07-01

446

40 CFR 63.8030 - What requirements apply to my heat exchange systems?  

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2014-07-01

447

40 CFR 63.2490 - What requirements must I meet for heat exchange systems?  

Code of Federal Regulations, 2010 CFR

...true What requirements must I meet for heat exchange systems? 63.2490 Section...2490 What requirements must I meet for heat exchange systems? (a) You must comply...10 to this subpart that applies to your heat exchange systems, except as...

2010-07-01

448

40 CFR Table 10 to Subpart Ffff of... - Work Practice Standards for Heat Exchange Systems  

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2014-07-01

449

40 CFR Table 6 to Subpart Hhhhh of... - Requirements for Heat Exchange Systems  

Code of Federal Regulations, 2013 CFR

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2013-07-01

450

40 CFR 63.8030 - What requirements apply to my heat exchange systems?  

Code of Federal Regulations, 2013 CFR

... false What requirements apply to my heat exchange systems? 63.8030 Section...8030 What requirements apply to my heat exchange systems? (a) You must comply...Table 6 to this subpart that apply to your heat exchange systems, except as...

2013-07-01

451

All-metal, compact heat exchanger for space cryocoolers  

NASA Astrophysics Data System (ADS)

This report describes the development of a high performance, all metal compact heat exchanger. The device is designed for use in a reverse Brayton cryogenic cooler which provides five watts of refrigeration at 70 K. The heat exchanger consists of a stainless steel tube concentrically assembled within a second stainless steel tube. Approximately 300 pairs of slotted copper disks and matching annular slotted copper plates are positioned along the centerline axis of the concentric tubes. Each of the disks and plates has approximately 1200 precise slots machined by means of a special electric discharge process. Positioning of the disk and plate pairs is accomplished by means of dimples in the surface of the tubes. Mechanical and thermal connections between the tubes and plate/disk pairs are made by solder joints. The heat exchanger assembly is 9 cm in diameter by 50 cm in length and has a mass of 10 kg. The predicted thermal effectiveness is greater than 0.985 at design conditions. Pressure loss at design conditions is less than 5 kPa in both fluid passages. Tests were performed on a subassembly of plates integrally soldered to two end headers. The measured thermal effectiveness of the test article exceeded predicted levels. Pressure losses were negligibly higher than predictions.

Swift, Walter L.; Valenzuela, Javier; Sixsmith, Herbert

1990-11-01

452

All-metal, compact heat exchanger for space cryocoolers  

NASA Technical Reports Server (NTRS)

This report describes the development of a high performance, all metal compact heat exchanger. The device is designed for use in a reverse Brayton cryogenic cooler which provides five watts of refrigeration at 70 K. The heat exchanger consists of a stainless steel tube concentrically assembled within a second stainless steel tube. Approximately 300 pairs of slotted copper disks and matching annular slotted copper plates are positioned along the centerline axis of the concentric tubes. Each of the disks and plates has approximately 1200 precise slots machined by means of a special electric discharge process. Positioning of the disk and plate pairs is accomplished by means of dimples in the surface of the tubes. Mechanical and thermal connections between the tubes and plate/disk pairs are made by solder joints. The heat exchanger assembly is 9 cm in diameter by 50 cm in length and has a mass of 10 kg. The predicted thermal effectiveness is greater than 0.985 at design conditions. Pressure loss at design conditions is less than 5 kPa in both fluid passages. Tests were performed on a subassembly of plates integrally soldered to two end headers. The measured thermal effectiveness of the test article exceeded predicted levels. Pressure losses were negligibly higher than predictions.

Swift, Walter L.; Valenzuela, Javier; Sixsmith, Herbert

1990-01-01

453

Heat exchanger bypass system for an absorption refrigeration system  

DOEpatents

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

Reimann, Robert C. (Lafayette, NY)

1984-01-01

454

Fabrication, assembly and heat transfer testing of low-profile copper-based microchannel heat exchangers  

NASA Astrophysics Data System (ADS)

Low-profile, Cu-based microchannel heat exchangers (MHEs) with different geometric dimensions were fabricated, bonded and assembled. A transient liquid phase (TLP) process was used for bonding of Cu-based MHEs with total thicknesses ranging from 600 µm to 1700 µm. The structural integrity of TLP-bonded Cu MHEs was examined. Device-level heat transfer testing was performed on a series of Cu-based MHEs to study the influence of microchannel dimensions on overall heat transfer performance, corroborated by computational results from a simple 2D finite element analysis. The present results demonstrate the promise of low-profile metallic MHEs for high heat flux cooling applications.

Lu, Bin; Chen, Ke; Meng, W. J.; Mei, Fanghua

2010-11-01

455

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

NASA Technical Reports Server (NTRS)

Sizing procedures are presented for latent heat thermal energy storage systems that can be used for electric utility off-peak energy storage, solar power plants and other preliminary design applications.

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

1977-01-01

456

Negative Joule Heating in Ion-Exchange Membranes  

E-print Network

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

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

2014-02-06

457

Negative Joule Heating in Ion-Exchange Membranes  

E-print Network

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

Biesheuvel, P M; Hamelers, H V M

2014-01-01

458

Transient testing of perforated plate matrix heat exchangers  

NASA Astrophysics Data System (ADS)

Till recently, perforated plate matrix heat exchangers (MHEs) were used mainly in helium liquefaction systems and Brayton cycle refrigerators. Currently they are also being used in Kleemenko or J-T refrigerators operating with a mixture of gases. It is now well understood that the effectiveness of a MHE is strongly dependent on the number of plate-spacer pairs used. It has also been shown that the traditional methods used for reducing the transient single blow method to determine the heat transfer coefficients cannot be used for MHEs. In this paper we show that the traditional methods can indeed be used for determining the heat transfer coefficients using the transient testing methods, provided certain conditions are met.

Krishnakumar, K.; Venkatarathnam, G.

2003-02-01

459

Bibliography and analysis of calculation methods for heat exchangers. Part 3: Calculation methods including tube bending  

NASA Astrophysics Data System (ADS)

Membrane analogies applicable to the calculation of tube heat exchanger structural behavior are considered. Topics include: (1) the rational analysis of heat exchanger tube-sheet stresses, (2) axisymmetrical bending of circular plates under simultaneous action of lateral load, force in the middle plane and elastic foundations; (3) fixed tube sheet heat exchangers; (4) heat exchanger tube sheet design (three U-tube and bayonet-tube sheets); (5) a calculation method for tube sheets in straight tube heat exchangers; and (6) and analysis method for heterogeneous structures. The computer codes corresponding to these methods are listed in the bibliography.

Osweiller, F.

1980-01-01

460

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

SciTech Connect

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

Davidson, J.H.

1998-06-01

461

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

SciTech Connect

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

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

2010-10-15

462

Water Based Phase Change Material Heat Exchanger Development  

NASA Technical Reports Server (NTRS)

In a cyclical heat load environment such as low Lunar orbit, a spacecraft’s radiators are not sized to reject the full heat load requirement. Traditionally, a supplemental heat rejection device (SHReD) such as an evaporator or sublimator is used to act as a “topper” to meet the additional heat rejection demands. Utilizing a Phase Change Material (PCM) heat exchanger (HX) as a SHReD provides an attractive alternative to evaporators and sublimators as PCM HXs do not use a consumable, thereby leading to reduced launch mass and volume requirements. Studies conducted in this paper investigate utilizing water’s high latent heat of formation as a PCM, as opposed to traditional waxes, and corresponding complications surrounding freezing water in an enclosed volume. Work highlighted in this study is primarily visual and includes understanding ice formation, freeze front propagation, and the solidification process of water/ice. Various test coupons were constructed of copper to emulate the interstitial pin configuration (to aid in conduction) of the proposed water PCM HX design. Construction of a prototypic HX was also completed in which a flexible bladder material and interstitial pin configurations were tested. Additionally, a microgravity flight was conducted where three copper test articles were frozen continuously during microgravity and 2-g periods and individual water droplets were frozen during microgravity.

Hansen, Scott W.; Sheth, Ribik B.; Atwell, Matt; Cheek, Ann; Agarwal, Muskan; Hong, Steven; Patel, Aashini,; Nguyen, Lisa; Posada, Luciano

2014-01-01

463

Investigation of plasma potential enhancement in the scrape-off layer of ion cyclotron range of frequencies heated discharges on Alcator C-Mod  

E-print Network

ICRF-heated discharges on Alcator C-Mod are associated with enhanced sputtering of molybdenum plasma facing surfaces and increased levels of core impurity contents, which subsequently degrade the core plasma performance. ...

Ochoukov, Roman Igorevitch

2013-01-01

464

Experiment and simulation of temperature characteristics of intermittently-controlled ground heat exchanges  

Microsoft Academic Search

Because of poor heat transfer coefficients of soil\\/rock, ground source heat pumps (GSHP) or underground thermal energy storage (UTES) systems always occupy a large area and need many ground heat exchangers. This initial energy investment is so heavy that it cannot be used on a large-scale. Intermittent operation can reduce the extreme temperatures around the ground heat exchangers (GHEs) and

Qing Gao; Ming Li; Ming Yu

2010-01-01

465

Chaotic advection induced heat transfer enhancement in a chevron-type plate heat exchanger  

NASA Astrophysics Data System (ADS)

The present work examines the role of chaotic mixing as a means of heat transfer enhancement in plate heat exchangers. In order to demonstrate the chaotic behavior, sensitivity to initial conditions and horseshoe maps are visualized. The Nusselt number and the friction factor were computed in the range of reynolds number, 1 < Re < 10. The Nusselt number increases considerably in chaotic models whereas the friction factor increases only marginally.

Tohidi, A.; Hosseinalipour, S. M.; Taheri, P.; Nouri, N. M.; Mujumdar, A. S.

2013-11-01

466

A heat transfer element of a high-temperature heat exchanger  

NASA Astrophysics Data System (ADS)

Results of an experimental study of the thermal and hydraulic characteristics of an element of a high-temperature heat exchanger with spiral wire fins are reported. The fins are made of a bimetal wire consisting of a copper core and a shell of stainless steel. It is found that the heat efficiency of the bimetal wire is practically the same as that of all-copper fins of the same geometrical characteristics.

Diuzhev, V. I.; Matveev, V. M.; Okhapkin, E. V.; Filippov, Iu. N.

467

Numerical characterization of heat transfer in closed-loop vertical ground heat exchanger  

Microsoft Academic Search

A series of numerical analyses has been performed on the characteristics of heat transfer in a closed-loop vertical ground heat exchanger (U-loop). A 2-D finite element analysis was conducted to evaluate the temperature distribution over the cross section of the U-loop system involving high-density polyethylene (HDPE) pipe\\/grout\\/soil to compare the sectional efficiency between the conventional U-loop and a new latticed

Chulho Lee; Hujeong Gil; Hangseok Choi; Shin-Hyung Kang

2010-01-01

468

Fully Coupled 3-D Conjugate Heat Transfer Algorithm for Borehole Heat Exchanger Performance Prediction  

Microsoft Academic Search

Quantitative three-dimensional prediction of the thermal performance of a vertical borehole heat exchanger (BHE) in a ground-source heat pump installation is sought. As BHE installation exhibits exceptionally disparate characteristic length scales, an alternative formation-fluid-thermal fully coupled algorithm is derived to quickly predict the 3-D temperature distributions. The time scale of the steady prediction is of order minutes. This simulation capability

Allen J. Baker; Cheng-Xian Lin; Joe A. Orzechowski; Cormack Gordon

2011-01-01

469

Numerical analysis and experimental validation of heat transfer in ground heat exchangers in alternative operation modes  

Microsoft Academic Search

A finite element numerical model has been developed for the simulation of the ground heat exchangers (GHEs) in alternative operation modes over a short time period for ground-coupled heat pump applications. Comparisons between the numerical and analytical results show that the finite line-source model is not capable of modeling the GHEs within a few hours because of the line-source assumption.

P. Cui; H. Yang; Z. Fang

2008-01-01

470

Flow-induced vibration analysis of conical rings used for heat transfer enhancement in heat exchangers  

Microsoft Academic Search

In the present work, flow-induced vibration characteristics of conical-ring turbulators used for heat transfer enhancement in heat exchangers are investigated experimentally. The conical-rings, having 10, 20 and 30 mm pitches, are inserted in a model pipe-line through which air is passed as the working fluid. Vortex-shedding frequencies and amplitude are determined and St-Re, Prms-Re variations are presented graphically. Flow-acoustic coupling

Kenan Yakut; Bayram Sahin

2004-01-01

471

High heat transfer oxidizer heat exchanger design and analysis. [RL10-2B engine  

NASA Technical Reports Server (NTRS)

The RL10-2B engine, a derivative of the RL10, is capable of multimode thrust operation. This engine operates at two low thrust levels: tank head idle (THI), which is approximately 1 to 2% of full thrust, and pumped idle (PI), which is 10% 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 low-g deployment. Stable combustion of the RL10-2B engine during the low thrust operating modes can be accomplished by using a heat exchanger to supply gaseous oxygen to the propellant injector. The oxidizer heat exchanger (OHE) vaporizes the liquid oxygen using hydrogen as the energy source. The design, concept verification testing and analysis for such a heat exchanger is discussed. The design presented uses a high efficiency compact core to vaporize the oxygen, and in the self-contained unit, attenuates any pressure and flow oscillations which result from unstable boiling in the core. This approach is referred to as the high heat transfer design. An alternative approach which prevents unstable boiling of the oxygen by limiting the heat transfer is referred to as the low heat transfer design and is reported in Pratt & Whitney report FR-19135-2.

Kmiec, Thomas D.; Kanic, Paul G.; Peckham, Richard J.

1987-01-01

472

MULTIPLE POLLUTANT REMOVAL USING THE CONDENSING HEAT EXCHANGER  

SciTech Connect

The Integrated Flue Gas Treatment (IFGT) system is a new concept whereby a Teflon ® covered condensing heat exchanger is adapted to remove certain flue gas constituents, both particulate and gaseous, while recovering low level heat. The pollutant removal performance and durability of this device is the subject of a USDOE sponsored program to develop this technology. The program was conducted under contract to the United States Department of Energy?s Fossil Energy Technology Center (DOE-FETC) and was supported by the Ohio Coal Development Office (OCDO) within the Ohio Department of Development, the Electric Power Research Institute?s Environmental Control Technology Center (EPRI-ECTC) and Babcock and Wilcox - a McDermott Company (B&W). This report covers the results of the first phase of this program. This Phase I project has been a two year effort. Phase I includes two experimental tasks. One task dealt principally with the pollutant removal capabilities of the IFGT at a scale of about 1.2MWt. The other task studied the durability of the Teflon ® covering to withstand the rigors of abrasive wear by fly ash emitted as a result of coal combustion. The pollutant removal characteristics of the IFGT system were measured over a wide range of operating conditions. The coals tested included high, medium and low-sulfur coals. The flue gas pollutants studied included ammonia, hydrogen chloride, hydrogen fluoride, particulate, sulfur dioxide, gas phase and particle phase mercury and gas phase and particle phase trace elements. The particulate removal efficiency and size distribution was investigated. These test results demonstrated that the IFGT system is an effective device for both acid gas absorption and fine particulate collection. Although soda ash was shown to be the most effective reagent for acid gas absorption, comparative cost analyses suggested that magnesium enhanced lime was the most promising avenue for future study. The durability of the Teflon ® covered heat exchanger tubes was studied on a pilot-scale single- stage condensing heat exchanger (CHX ® ). This device was operated under typical coal-fired flue gas conditions on a continuous basis for a period of approximately 10 months. Data from the test indicate that virtually no decrease in Teflon ® thickness was observed for the coating on the first two rows of heat exchanger tubes, even at high inlet particulate loadings. Evidence of wear was present only at the microscopic level, and even then was very minor in severity.

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

1998-06-01

473

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

E-print Network

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

Yu, Kun

2014-05-08

474

Xenon Recirculation-Purification with a Heat Exchanger  

E-print Network

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...

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

2011-01-01

475

Investigations on two-phase heat exchanger for mixed refrigerant Joule-Thomson cryocooler  

NASA Astrophysics Data System (ADS)

The design of the recuperative heat exchanger used to pre-cool the refrigerant mixture prior to J-T expansion is crucial for the efficient operation of the mixed refrigerant Joule- Thomson (MR J-T) cryocooler. The multi-component non-azeotropic refrigerant mixture undergoes boiling and condensation heat transfer simultaneously in the heat exchanger. Therefore, it is important to analyze the performance of the heat exchanger in terms of temperature distribution with respect to the mixture of gases used. In the present work, temperature measurements are carried out at the ends of the heat exchanger for high pressure stream, while eight sensors are installed at equal distance along the length of heat exchanger to measure temperature of low pressure stream. The paper reports variation in heat transfer coefficient along the length of the heat exchanger. The variation is discussed with respect to temperature distribution across the length and changes in thermo-physical properties of the gas mixture.

Ardhapurkar, Purushottam; Sridharan, Arunkumar; Atrey, Milind

2012-06-01

476

Heat-exchange statistics in driven open quantum systems  

E-print Network

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

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

2014-07-29

477

Heat-exchange statistics in driven open quantum systems  

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

478

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

Microsoft Academic Search

The development of thermal-hydraulic design tools for rectangular offset strip fin compact heat exchangers and the associated convection process are delineated. On the basis of current understanding of the physical phenomena and enhancement mechanisms, existing empirical f and j data for actual cores are reanalyzed. The asymptotic behavior of the data in the deep laminar and fully turbulent flow regimes

Arthur E. Bergles

1995-01-01

479

Sensible heat and friction characteristics of plate fin-and-tube heat exchangers having plane fins  

Microsoft Academic Search

In the present study, 15 samples of plate fin heat exchangers with different geometrical parameters, including the number of tube rows, fin spacing and fin thickness are tested and compared in an induced flow open wind tunnel. Results are presented in the form of friction factor and Colburn j-factor against Reynolds number based on the tube collar diameter in the

Yi-Chung Hsieh; Yur-Tsai Lin

1996-01-01

480

New heat transfer and friction factor design data for perforated plate heat exchangers  

Microsoft Academic Search

Perforated plate heat exchangers have been found to have inherently low axial conduction and are therefore excellent candidates for cryogenic applications where an all-metal design is required. A total of three plate cores were tested; two were chemically etched and the other mechanically punched. Hole size, percent open area and plate thickness parameters were varied among the plates. Experimental results

Richard H. Hubbell; Christina L. Cain

1988-01-01

481

Retrofitting Crude Oil Refinery Heat Exchanger Networks to Minimize Fouling While Maximizing Heat Recovery  

Microsoft Academic Search

The use of fouling factors in heat exchanger design and the lack of appreciation of fouling in traditional pinch approaches have often resulted in crude preheat networks that are subject to extensive fouling. The development of thermal and pressure drop models for crude oil fouling has allowed its effects to be quantified so that techno-economic analyses can be performed and

B. L. Yeap; D. Wilson; G. Polley; S. Pugh

2005-01-01

482

Design of heat exchanger for Ericsson-Brayton piston engine.  

PubMed

Combined power generation or cogeneration is a highly effective technology that produces heat and electricity in one device more efficiently than separate production. Overall effectiveness is growing by use of combined technologies of energy extraction, taking heat from flue gases and coolants of machines. Another problem is the dependence of such devices on fossil fuels as fuel. For the combustion turbine is mostly used as fuel natural gas, kerosene and as fuel for heating power plants is mostly used coal. It is therefore necessary to seek for compensation today, which confirms the assumption in the future. At first glance, the obvious efforts are to restrict the use of largely oil and change the type of energy used in transport. Another significant change is the increase in renewable energy--energy that is produced from renewable sources. Among machines gaining energy by unconventional way belong mainly the steam engine, Stirling engine, and Ericsson engine. In these machines, the energy is obtained by external combustion and engine performs work in a medium that receives and transmits energy from combustion or flue gases indirectly. The paper deals with the principle of hot-air engines, and their use in combined heat and electricity production from biomass and with heat exchangers as primary energy transforming element. PMID:24977174

Durcansky, Peter; Papucik, Stefan; Jandacka, Jozef; Holubcik, Michal; Nosek, Radovan

2014-01-01

483

Continued Water-Based Phase Change Material Heat Exchanger Development  

NASA Technical Reports Server (NTRS)

In a cyclical heat load environment such as low Lunar orbit, a spacecraft's radiators are not sized to reject the full heat load requirement. Traditionally, a supplemental heat rejection device (SHReD) such as an evaporator or sublimator is used to act as a "topper" to meet the additional heat rejection demands. Utilizing a Phase Change Material (PCM) heat exchanger (HX) as a SHReD provides an attractive alternative to evaporators and sublimators as PCM HXs do not use a consumable, thereby leading to reduced launch mass and volume requirements. In continued pursuit of water PCM HX development two full-scale, Orion sized water-based PCM HX's were constructed by Mezzo Technologies. These HX's were designed by applying prior research and experimentation to the full scale design. Design options considered included bladder restraint and clamping mechanisms, bladder manufacturing, tube patterns, fill/drain methods, manifold dimensions, weight optimization, and midplate designs. Design and construction of these HX's led to successful testing of both PCM HX's.

Hansen, Scott; Poynot, Joe

2014-01-01

484

Design of Heat Exchanger for Ericsson-Brayton Piston Engine  

PubMed Central

Combined power generation or cogeneration is a highly effective technology that produces heat and electricity in one device more efficiently than separate production. Overall effectiveness is growing by use of combined technologies of energy extraction, taking heat from flue gases and coolants of machines. Another problem is the dependence of such devices on fossil fuels as fuel. For the combustion turbine is mostly used as fuel natural gas, kerosene and as fuel for heating power plants is mostly used coal. It is therefore necessary to seek for compensation today, which confirms the assumption in the future. At first glance, the obvious efforts are to restrict the use of largely oil and change the type of energy used in transport. Another significant change is the increase in renewable energy—energy that is produced from renewable sources. Among machines gaining energy by unconventional way belong mainly the steam engine, Stirling engine, and Ericsson engine. In these machines, the energy is obtained by external combustion and engine performs work in a medium that receives and transmits energy from combustion or flue gases indirectly. The paper deals with the principle of hot-air engines, and their use in combined heat and electricity production from biomass and with heat exchangers as primary energy transforming element. PMID:24977174

Durcansky, Peter; Papucik, Stefan; Jandacka, Jozef

2014-01-01

485

Development of Passive Fuel Cell Thermal Management Heat Exchanger  

NASA Technical Reports Server (NTRS)

The NASA Glenn Research Center is developing advanced passive thermal management technology to reduce the mass and improve the reliability of space fuel cell systems for the NASA Exploration program. The passive thermal management system relies on heat conduction within highly thermally conductive cooling plates to move the heat from the central portion of the cell stack out to the edges of the fuel cell stack. Using the passive approach eliminates the need for a coolant pump and other cooling loop components within the fuel cell system which reduces mass and improves overall system reliability. Previous development demonstrated the performance of suitable highly thermally conductive cooling plates that could conduct the heat, provide a sufficiently uniform temperature heat sink for each cell of the fuel cell stack, and be substantially lighter than the conventional thermal management approach. Tests were run with different materials to evaluate the design approach to a heat exchanger that could interface with the edges of the passive cooling plates. Measurements were made during fuel cell operation to determine the temperature of individual cooling plates and also to determine the temperature uniformity from one cooling plate to another.

Burke, Kenneth A.; Jakupca, Ian J.; Colozza, Anthony J.

2010-01-01

486

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

SciTech Connect

An analytical Detailed Loop Model (DLM) has been developed to analyze the performance of solar thermosiphon water heaters with heat exchangers in storage tanks. The model has been used to study the performance of thermosiphons as a function of heat exchanger characteristics, heat transfer fluids, flow resistances, tank stratification, and tank elevation relative to the collector. The results indicate that good performance can be attained with these systems compared to thermosiphons without heat exchangers.

Mertol, A.; Place, W.; Webster, T.; Greif, R.

1981-06-01

487

Application of nanofluids in heat transfer enhancement of compact heat exchanger  

NASA Astrophysics Data System (ADS)

In this paper, numerical investigation using ethylene glycol (EG) as a base fluid with diamond and SiO2 as the coolants with nanoparticle volume fractions (?) ranged from 0.1 % to 2 % on automobile flat tube plain fin compact heat exchanger (CHE) is conducted. The convective heat transfer coefficient in the developing regions along the flat tubes with the nanofluid flow showed marked improvement over the base fluid (0 %). Quantitative results of the heat transfer enhancement of CHE with increasing volumetric concentrations of nanofluids at various Reynolds numbers are presented.

Gunnasegaran, P.; Shuaib, N. H.; Jalal, M. F. Abdul; Sandhita, E.

2012-11-01

488

Localized corrosion of aluminum alloys for OTEC heat exchangers  

SciTech Connect

The effects of dissolved oxygen, pH and temperature on the rate of initiation and growth of pitting and crevice corrosion of aluminum alloy 5052 and pure aluminum have been determined. Variations in pH and temperature rather than dissolved oxygen are shown to account for increased corrosion rates of 5000 series aluminum alloys that have been reported for deep ocean exposures. The impact of these results on the use of aluminum for heat exchanger tubing and on possible approaches to corrosion control are discussed. 31 refs.

Dexter, S.C.

1981-01-01

489

Aging management guideline for commercial nuclear power plants - heat exchangers  

SciTech Connect

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

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

1994-06-01

490

A micro heat exchanger microfabricated from bulk aluminium  

NASA Astrophysics Data System (ADS)

We report a micro heat exchanger microfabricated from a bulk aluminium alloy substrate. The device is comprised of two 18 cm long microchannels, one on each side of an aluminium chip, capped on both sides with a thin self-adhesive polymer film. In spite of a cheap and facile fabrication method, initial experiments with the device show promising results. Area densities from 25000 m?1 to 45000 m?1 have been achieved. Compared to our previous work on aluminium microfluidic devices produced with a similar technology but from a different, less pure alloy, in this study the etched surfaces are significantly smoother, and present less photoresist delamination.

Scotti, G.; Franssila, S.

2014-11-01

491

Permeation Barrier Coatings for the Helical Heat Exchanger  

SciTech Connect

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

Korinko, P.S.

1999-05-26

492

Heat transfer in thin, compact heat exchangers with circular, rectangular, or pin-fin flow passages  

NASA Technical Reports Server (NTRS)

Heat transfer and pressure drop have been measured of three thin, compact heat exchangers in helium gas at 3.5 MPa and higher, with Reynolds numbers of 450 to 36,000. The flow geometries for the three heat exchanger specimens were: circular tube, rectangular channel, and staggered pin fin with tapered pins. The specimens were heated radiatively at heat fluxes up to 77 W/sq cm. Correlations were developed for the isothermal friction factor as a function of Reynolds number, and for the Nusselt number as a function of Reynolds number and the ratio of wall temperature to fluid temperature. The specimen with the pin fin internal geometry had significantly better heat transfer than the other specimens, but it also had higher pressure drop. For certain conditions of helium flow and heating, the temperature more than doubled from the inlet to the outlet of the specimens, producing large changes in gas velocity, density, viscosity, and thermal conductivity. These changes in properties did not affect the correlations for friction factor and Nusselt number in turbulent flow.

Olson, D. A.

1992-01-01

493

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

SciTech Connect

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

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

2009-07-15

494

An experimental study on heat transfer characteristics of heat pipe heat exchanger with latent heat storage. Part I: Charging only and discharging only modes  

Microsoft Academic Search

A new thermal storage system, a heat pipe heat exchanger with latent heat storage, is reported. The new system may operate in three basic different operation modes, the charging only, the discharging only and the simultaneous charging\\/discharging modes, which makes the system suitable for various time and\\/or weather dependent energy systems. In this part of the paper, the basic structure,

Zhongliang Liu; Zengyi Wang; Chongfang Ma

2006-01-01

495

Vapor Compression and Thermoelectric Heat Pump Heat Exchangers for a Condensate Distillation System: Design and Experiment  

NASA Technical Reports Server (NTRS)

Maximizing the reuse of wastewater while minimizing the use of consumables is critical in long duration space exploration. One of the more promising methods of reclaiming urine is the distillation/condensation process used in the cascade distillation system (CDS). This system accepts a mixture of urine and toxic stabilizing agents, heats it to vaporize the water and condenses and cools the resulting water vapor. The CDS wastewater flow requires heating and its condensate flow requires cooling. Performing the heating and cooling processes separately requires two separate units, each of which would require large amounts of electrical power. By heating the wastewater and cooling the condensate in a single heat pump unit, mass, volume, and power efficiencies can be obtained. The present work describes and compares two competing heat pump methodologies that meet the needs of the CDS: 1) a series of mini compressor vapor compression cycles and 2) a thermoelectric heat exchanger. In the paper, the system level requirements are outlined, the designs of the two heat pumps are described in detail, and the results of heat pump performance tests are provided. A summary is provided of the heat pump mass, volume and power trades and a selection recommendation is made.

Erickson, Lisa R.; Ungar, Eugene K.

2013-01-01

496

Experimental Study on Heat Transfer and Flow Characteristics of Air Cooling through Cross-flow Microchannel Heat Exchanger.  

E-print Network

??Air-side heat transfer and flow characteristics were studied through an air-to-deionized water cross-flow serpentine microchannel heat exchanger during air cooling. In the single phase, twenty… (more)

Dasgupta, Engr Sarbadaman

2011-01-01

497

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

E-print Network

Statistical properties of the energy exchanged between two heat baths coupled by thermal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.2 Stochastic equations for work and heat exchanged between the two circuits Abstract We study both experimentally and theoretically the statistical properties of the energy exchanged

Paris-Sud XI, Université de

498

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

E-print Network

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

Li, Baowen

499

Study of thermal energy storage using fluidized bed heat exchangers  

SciTech Connect

The technical and economic feasibility of fluid bed heat exchangers (FBHX) for thermal energy storage (TES) in waste heat recovery applications is assessed by analysis of two selected conceptual systems, the rotary cement kiln and the electric arc furnace. It is shown that the inclusion of TES in the energy recovery system requires that the difference in off-peak and on-peak energy rates be large enough so that the value of the recovered energy exceeds the value of the stored energy by a wide enough margin to offset parasitic power and thermal losses. Escalation of on-peak energy rates due to fuel shortages could make the FBHX/TES applications economically attractive in the future.

Weast, T.E.; Shannon, L.J.; Ananth, K.P.

1980-01-01

500

Two-phase/two-phase heat exchanger simulation analysis  

NASA Technical Reports Server (NTRS)

The capillary pumped loop (CPL) system is one of the most desirable devices to dissipate heat energy in the radiation environment of the Space Station providing a relatively easy control of the temperature. A condenser, a component of the CPL system, is linked with a buffer evaporator in the form of an annulus section of a double tube heat exchanger arrangement: the concentric core of the double tube is the condenser; the annulus section is used as a buffer between the conditioned space and the radiation surrounding but works as an evaporator. A CPL system with this type of condenser is modeled to simulate its function numerically. Preliminary results for temperature variations of the system are shown and more investigations are suggested for further improvement.

Kim, Rhyn H.

1992-01-01