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1

TRNSYS model of a thermosiphon solar domestic water heater with a horizontal store and mantle heat exchanger  

Microsoft Academic Search

A new TRNSYS model of a solar domestic water heater is presented. It describes a thermosiphon system with a horizontal store and a mantle heat exchanger. The fluid inlet is placed at the top of the annular gap. This new TRNSYS ‘Type’ is developed from the standard Types 45 and 38, with some new features. Results of the new type

A. Carrillo Andrés; J. M. Cejudo López

2002-01-01

2

Heat exchanger  

DOEpatents

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

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

1979-01-01

3

Heat exchanger  

Microsoft Academic Search

A heat exchanger is described in which the main component is formed of a plurality of elongated strips of rigid heat conductive material. Each of the strips has a cross-sectional configuration which is elongated in a direction transverse to the elongated extent of the strip so as to provide a pair of spaced relatively thin end edges and a pair

1982-01-01

4

Heat exchanger  

DOEpatents

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

Wolowodiuk, Walter (New Providence, NJ)

1976-01-06

5

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

6

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

7

Constraints on Thermochemical Mantle Convection From Plume Excess Temperature, Plume Heat Flux and Upper Mantle Temperature  

Microsoft Academic Search

Mantle convection is responsible for releasing about 36 TW heat from the mantle. However, how much of the 36 TW mantle heat flux is from the core (i.e., Qcmb), mantle radiogenic heating and mantle secular cooling remains poorly understood. This question is further complicated if the mantle is compositionally heterogeneous or layered as suggested by seismic and geochemical observations. The

S. Zhong

2005-01-01

8

Segmented heat exchanger  

SciTech Connect

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

9

High temperature heat exchangers  

SciTech Connect

This book contains the proceedings from the XVII Symposium of the International Center for Heat and Mass Transfer on High Temperature Heat Exchangers, held August 1985 in Yugoslavia. Papers were presented under the following topics: High Temperature Heat Exchangers Development; Basic Problem in High Temperature Heat Exchangers; Heat Exchangers for High Temperature Recovery; and High Temperature Heat Exchangers for Future Power Plants and Industrial Process Application. Some of the papers' titles are: Future Development of High Temperature Heat Exchangers; Regenerative and Direct Contact High Temperature Heat Exchangers; Heat Exchangers for Heat Recovery; High Temeprature Heat Transfer Augmentation; and Development of a BOF Slag Granulating and Heat Recovering System.

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

1986-01-01

10

Heat exchanger sourcebook  

SciTech Connect

This book covers techniques brought about by economical computing capabilities. It is divided into the following sections: general design information; shell-and-tube heat exchangers; reboilers and condensers; plate heat exchangers; heat exchange enhancement; techniques; and fouling.

Palen, J.W.

1986-01-01

11

Industrial heat exchangers  

Microsoft Academic Search

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

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

1985-01-01

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

Sizing plate heat exchangers  

SciTech Connect

Since their commercial debut in the 1930s, plate heat exchangers have found widespread use in the chemical process industries (CPI). Today, more than two dozen firms market this space-saving and highly efficient type of heat exchanger. One reason for the popularity of plate heat exchangers is that their overall heat-transfer coefficient (U) is superior to that of shell-and-tube heat exchangers [1,2,3,4]. In clean water-to-water service, for example, a shell-and-tube heat exchanger has a U value of 350 Btu/ft[sup 2]-h-F, much lower than the 1,000 of a plate design at the same pressure drop. However, the plate heat exchanger's much higher U values also mean that fouling factors have a much greater effect on calculations of exchanger surface area. The right fouling factor is the key to specifying plate heat exchanger areas correctly.

Kerner, J. (Alberts and Associates, Inc., Philadelphia, PA (United States))

1993-11-01

15

Microtube strip heat exchanger  

Microsoft Academic Search

The purpose of this contract has been to explore the limits of miniaturization of heat exchangers with the goals of (1) improving the theoretical understanding of laminar heat exchangers, (2) evaluating various manufacturing difficulties, and (3) identifying major applications for the technology. A low-cost, ultra-compact heat exchanger could have an enormous impact on industry in the areas of cryocoolers and

F. D. Doty

1992-01-01

16

Constraints on thermochemical convection of the mantle from plume heat flux, plume excess temperature, and upper mantle temperature  

Microsoft Academic Search

Seismic and geochemical observations indicate a compositionally heterogeneous mantle in the lower mantle, suggesting a layered mantle. The volume and composition of each layer, however, remain poorly constrained. This study seeks to constrain the layered mantle model from observed plume excess temperature, plume heat flux, and upper mantle temperature. Three-dimensional spherical models of whole mantle and layered mantle convection are

Shijie Zhong

2006-01-01

17

Heat exchanger antifoulant  

SciTech Connect

Disclosed is a process for reducing the fouling in a heat exchanger in which a hydrocarbon stream is heated or cooled as it passes through the heat exchanger. From 1 to 500 parts per million of a saturated sulfoxide is added to the stream to reduce fouling.

Ferm, R.L.

1984-09-04

18

Heat exchanger antifoulant  

SciTech Connect

Disclosed is a process for reducing the fouling in a heat exchanger in which a hydrocarbon stream is heated or cooled as it passes through the heat exchanger. From 1 to 500 parts per million of an alkylamino alkylphenol is added to the stream to reduce fouling.

Ferm, R.L.; Kray, L.R.

1984-03-06

19

Heat exchanger antifoulant  

SciTech Connect

Disclosed is a process for reducing the fouling in a heat exchanger in which a hydrocarbon stream is heated or cooled as it passes through the heat exchanger. From 1 to 500 parts per million of the reaction product of a polyalkylene amine and a hydroxy fatty acid are added to the stream to reduce fouling.

Ferm, R.L.

1984-02-14

20

Heat exchanger antifoulant  

SciTech Connect

Disclosed is a process for reducing the fouling in a heat exchanger in which a hydrocarbon stream is heated or cooled as it passes through the heat exchanger. From 1 to 500 parts per million of an organic hydroxylamine is added to the stream to reduce fouling.

Ferm, R. L.

1985-11-05

21

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

22

Microtube strip heat exchanger  

SciTech Connect

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

Doty, F.D.

1991-07-08

23

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

24

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

25

Heat pipe array heat exchanger  

Microsoft Academic Search

A heat exchanger is described for transferring heat between a first fluid and a second fluid in an absorption refrigeration system comprising: a first shell having an inlet for receiving the first fluid at a first elevated temperature and an outlet for discharging the first fluid at a first reduced temperature with the shell defining a free flow path for

Reimann

1987-01-01

26

Heat and mass exchanger  

SciTech Connect

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

27

Lightweight long life heat exchanger  

Microsoft Academic Search

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),

E. K. Moore

1976-01-01

28

Constraints on thermochemical convection of the mantle from plume heat flux, plume excess temperature, and upper mantle temperature  

Microsoft Academic Search

This study seeks to constrain the layered mantle model from observed plume excess temperature, plume heat flux, and upper mantle temperature. 3-D spherical models of whole- mantle and layered mantle convection are computed for different Rayleigh number, internal heat generation, buoyancy number, and bottom layer thickness for layered mantle models. The model results show that these observations are controlled by

Shijie Zhong; W. Leng

2006-01-01

29

Thermoelectric heat exchange element  

DOEpatents

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

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

2007-08-14

30

Vacuum powered heat exchanger  

SciTech Connect

In an internal combustion engine including an oil lubrication system, a liquid cooling system, and an improved air intake system is described. The improved air intake system comprises: a housing including a first opening in one end, which opening is open to the atmosphere and a second opening comprising an air outlet opening in the other end open to the air intake manifold of the engine, a heat exchanger positioned in the first opening. The heat exchanger consists of a series of coils positioned in the flow path of the atmospheric air as it enters the housing, the heat exchanger being fluidly connected to either the engine lubrication system or the cooling system to provide a warm heat source for the incoming air to the housing, acceleration means positioned in the housing downstream of the heat exchanger, the acceleration means comprising a honeycomb structure positioned across the air intake flow path. The honey-comb structure includes a multitude of honey combed mini-venturi cells through which the heated air flows in an accelerated mode, a removable air filter positioned between the heat exchanger and the acceleration means and a single opening provided in the housing through which the air filter can be passed and removed, and additional openings in the housing positioned downstream of the heat exchanger and upstream of the air filter, the additional openings including removable flaps for opening and closing the openings to control the temperature of the air flowing through the housing.

Ruffolo, R.F.

1986-06-24

31

Understanding heat exchanger systems  

SciTech Connect

Many of the complaints heard about steam heat exchangers--water hammer, corrosion, and freezing--often are not caused by the unit itself but, rather, are problems within the system. Diagnosing and overcoming problems in existing systems or designing new ones properly requires a thorough understanding not only of the heat exchanger, but all of the components that make up the overall system. Many types of heat exchangers are available today (shell-and-tube, plate-and-frame, coil, tank heaters, and plate coils). The same basic principles and similar controls apply to all. Although the examples in this article consider the shell-and-tube style, the concepts apply to all types of steam heat exchangers.

Hughes, B. [ITT Fluid Technology, Guelph, Ontario (Canada)

1997-04-01

32

Greywater Heat Exchanger.  

National Technical Information Service (NTIS)

A kilowatt meter and water meter were installed to monitor pregreywater usage. The design considerations, the heat exchanger construction and installation, and the monitoring of usage levels are described. (ERA citation 09:040361)

D. Holmberg

1983-01-01

33

Greywater heat exchanger  

SciTech Connect

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

Holmberg, D.

1983-11-21

34

Energetics of mantle convection and the fate of fossil heat  

NASA Astrophysics Data System (ADS)

Reconstructing the thermal history of the Earth, consistent with the low concentration of heat-producing elements in convecting mantle as well as with modest secular cooling required by geological records, has been a major challenge in geophysics and geochemistry. By developing the self-consistent energetics of plate-tectonic mantle convection, we show that the low Urey ratio of convecting mantle can yield a geologically reasonable solution in the thermal evolution model of the Earth. The effect of dehydration on mantle rheology during plate formation with mantle melting results in more sluggish plate tectonics (i.e., lower heat flow) for hotter mantle. This inverse relationship between mantle temperature and surface heat flux leads to the efficient storage of fossil heat, preventing the drastic secular cooling of the Earth.

Korenaga, Jun

2003-04-01

35

Microtube Strip Heat Exchanger  

SciTech Connect

Doty Scientific (DSI) believes their Microtube-Strip Heat Exchanger will contribute significantly to (a) the closed Brayton cycles being pursued at MIT, NASA, and elsewhere; (b) reverse Brayton cycle cryocoolers, currently being investigated by NASA for space missions, being applied to MRI superconducting magnets; and (c) high-efficiency cryogenic gas separation schemes for CO{sub 2} removal from exhaust stacks. The goal of this current study is to show the potential for substantial progress in high-effectiveness, low-cost, gas-to-gas heat exchangers for diverse applications at temperatures from below 100 K to above 1000 K. To date, the highest effectiveness measured is about 98%, and relative pressure drops below 0.1% with a specific conductance of about 45 W/kgK are reported. During the pre-award period DSI built and tested a 3-module heat exchanger bank using 103-tube microtube strip (MTS) modules. To add to their analytical capabilities, DSI has acquired computational fluid dynamics (CFD) software. This report describes the pre-award work and the status of the ten tasks of the current project, which are: analyze flow distribution and thermal stresses within individual modules; design a heat exchanger bank of ten modules with 400 microtube per module; obtain production quality tubestrip die and AISI 304 tubestrips; obtain production quality microtubing; construct revised MTS heat exchanger; construct dies and fixtures for prototype heat exchanger; construct 100 MTS modules; assemble 8-10 prototype MTS heat exchangers; test prototype MTS heat exchanger; and verify test through independent means. 7 refs., 9 figs. 1 tab. (CK)

Doty, F.D.

1990-12-27

36

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

37

High Flux Heat Exchanger.  

National Technical Information Service (NTIS)

This interim report documents the results of the first two phases of a four-phase program to develop a high flux heat exchanger for cooling future high performance aircraft electronics. Phase I defines future needs for high flux heat removal in advanced m...

E. M. Flynn M. J. Mackowski

1993-01-01

38

Understand spiral heat exchangers  

SciTech Connect

Shell-and-tube heat exchangers are standard in most chemical process industries (CPI) applications. However, they do have limitations related to thermal efficiency, mechanical design, and maintenance requirements that will not allow the standard straight-tube fixed-tubesheet shell-and-tube (S and T) heat exchanger to work properly in certain applications. It is in these problem areas that spiral heat exchangers (SHEs) have been used successfully worldwide for over 60 years. The SHE can be a viable alternative to the complex and often expensive shell-and-tube heat exchanger. The SHEs' unique spiral countercurrent monochannel design gives them exceptionally high heat-transfer rates and low fouling tendencies. The mechanical configuration of the SHE also allows full access to all heat-transfer surfaces for simplified inspection, maintenance, and cleaning. This article describes how SHEs operate, discusses their advantages in terms of thermal efficiency, fouling, mechanical design, and maintenance characteristics, and provides guidance on choosing between spiral and tubular exchangers.

Bailey, K.M.

1994-05-01

39

Microtube strip heat exchanger  

SciTech Connect

The purpose of this contract has been to explore the limits of miniaturization of heat exchangers with the goals of (1) improving the theoretical understanding of laminar heat exchangers, (2) evaluating various manufacturing difficulties, and (3) identifying major applications for the technology. A low-cost, ultra-compact heat exchanger could have an enormous impact on industry in the areas of cryocoolers and energy conversion. Compact cryocoolers based on the reverse Brayton cycle (RBC) would become practical with the availability of compact heat exchangers. Many experts believe that hardware advances in personal computer technology will rapidly slow down in four to six years unless lowcost, portable cryocoolers suitable for the desktop supercomputer can be developed. Compact refrigeration systems would permit dramatic advances in high-performance computer work stations with conventional'' microprocessors operating at 150 K, and especially with low-cost cryocoolers below 77 K. NASA has also expressed strong interest in our MTS exchanger for space-based RBC cryocoolers for sensor cooling. We have demonstrated feasibility of higher specific conductance by a factor of five than any other work in high-temperature gas-to-gas exchangers. These laminar-flow, microtube exchangers exhibit extremely low pressure drop compared to alternative compact designs under similar conditions because of their much shorter flow length and larger total flow area for lower flow velocities. The design appears to be amenable to mass production techniques, but considerable process development remains. The reduction in materials usage and the improved heat exchanger performance promise to be of enormous significance in advanced engine designs and in cryogenics.

Doty, F.D.

1992-07-09

40

Microtube strip heat exchanger  

NASA Astrophysics Data System (ADS)

The purpose of this contract has been to explore the limits of miniaturization of heat exchangers with the goals of (1) improving the theoretical understanding of laminar heat exchangers, (2) evaluating various manufacturing difficulties, and (3) identifying major applications for the technology. A low-cost, ultra-compact heat exchanger could have an enormous impact on industry in the areas of cryocoolers and energy conversion. Compact cryocoolers based on the reverse Brayton cycle (RBC) would become practical with the availability of compact heat exchangers. Many experts believe that hardware advances in personal computer technology will rapidly slow down in four to six years unless lowcost, portable cryocoolers suitable for the desktop supercomputer can be developed. Compact refrigeration systems would permit dramatic advances in high-performance computer work stations with 'conventional' microprocessors operating at 150 K, and especially with low-cost cryocoolers below 77 K. NASA has also expressed strong interest in our MTS exchanger for space-based RBC cryocoolers for sensor cooling. We have demonstrated feasibility of higher specific conductance by a factor of five than any other work in high-temperature gas-to-gas exchangers. These laminar-flow, microtube exchangers exhibit extremely low pressure drop compared to alternative compact designs under similar conditions because of their much shorter flow length and larger total flow area for lower flow velocities. The design appears to be amenable to mass production techniques, but considerable process development remains. The reduction in materials usage and the improved heat exchanger performance promise to be of enormous significance in advanced engine designs and in cryogenics.

Doty, F. D.

1992-07-01

41

Heat exchanger restart evaluation  

SciTech Connect

On December 24, 1991, the K-Reactor was in the shutdown mode with full AC process water flow and full cooling water flow. Safety rod testing was being performed as part of the power ascension testing program. The results of cooling water samples indicated tritium concentrations higher than allowable. Further sampling and testing confirmed a Process Water System to Cooling Water System leak in heat exchanger 4A (HX 4A). The heat exchanger was isolated and the plant shutdown. Heat exchanger 4A was removed from the plant and moved to C-Area prior to performing examinations and diagnostic testing. This included locating and identifying the leaking tube or tubes, eddy current examination of the leaking tube and a number of adjacent tubes, visually inspecting the leaking tube from both the inside as well as the area surrounding the identified tube. The leaking tube was removed and examined metallurgically to determine the failure mechanism. In addition ten other tubes that either exhibited eddy current indications or would represent a baseline condition were removed from heat exchanger 4A for metallurgical examination. Additional analysis and review of heat exchanger leakage history was performed to determine if there are any patterns which can be used for predictive purposes. Compensatory actions have been taken to improve the sensitivity and response time to any future events of this type. The results of these actions are summary herein.

Morrison, J.M.; Hirst, C.W.; Lentz, T.F.

1992-03-18

42

Scraped surface heat exchangers.  

PubMed

Scraped surface heat exchangers (SSHEs) are commonly used in the food, chemical, and pharmaceutical industries for heat transfer, crystallization, and other continuous processes. They are ideally suited for products that are viscous, sticky, that contain particulate matter, or that need some degree of crystallization. Since these characteristics describe a vast majority of processed foods, SSHEs are especially suited for pumpable food products. During operation, the product is brought in contact with a heat transfer surface that is rapidly and continuously scraped, thereby exposing the surface to the passage of untreated product. In addition to maintaining high and uniform heat exchange, the scraper blades also provide simultaneous mixing and agitation. Heat exchange for sticky and viscous foods such as heavy salad dressings, margarine, chocolate, peanut butter, fondant, ice cream, and shortenings is possible only by using SSHEs. High heat transfer coefficients are achieved because the boundary layer is continuously replaced by fresh material. Moreover, the product is in contact with the heating surface for only a few seconds and high temperature gradients can be used without the danger of causing undesirable reactions. SSHEs are versatile in the use of heat transfer medium and the various unit operations that can be carried out simultaneously. This article critically reviews the current understanding of the operations and applications of SSHEs. PMID:16527753

Rao, Chetan S; Hartel, Richard W

2006-01-01

43

Heat exchanger support  

SciTech Connect

This patent describes a support structure for in-bed heat exchanger tubes of a fluidzed bed boiler having wall means defining a fluidized bed region and a freeboard region above the fluidized bed region, the wall means including tubular means disposed near a transition zone between the fluidized bed and freeboard regions, the structure comprising support tubes having opposite ends extending respectively through the wall means and over the tubular means for support thereby, each support tube having at least one upright portion disposed in the fluidized bed region, and at least one heat exchanger tube being supportingly secured to the upright portion.

McDonald, D.K.; Weitzel, P.S.

1988-09-13

44

Conquer heat exchanger fouling  

SciTech Connect

Fouling plays a dominant role in heat exchanger performance. It is extremely important to choose the most appropriate type of heat exchanger for a particular application and adopt proper values for fouling resistance. A design practice for shell-and-tube heat exchangers that will limit fouling to a minimum and thus ensure trouble-free operation is essential. Due to the availability of specialized software, the thermal design of heat exchangers has become precise and scientific. The results occasionally have to be tempered with practical experience and engineering judgment, but generally these computer programs are very reliable and authentic. However, the above is true only for determining heat-transfer coefficients and pressure drop. One important area that cannot possibly be addressed by design software is fouling. While a proper selection of fouling resistance is extremely difficult due to the numerous factors involved, a sound design practice will minimize any errors. However, it is important to first understand the phenomenon of fouling. The paper describes what fouling is, types of fouling, factors affecting fouling, providing a fouling allowance, selecting a fouling resistance, and overcoming fouling through better design.

Mukherjee, R. [Engineers India Ltd., New Delhi (India)

1996-01-01

45

Two-stage heat exchanger  

SciTech Connect

Improved furnaces are described in which secondary and tertiary heat exchanges are incorporated into new and existing hot-air furnace systems for controlled cooling of hot combustion products by co-current and countercurrent heat exchanges. Hot combustion products are cooled to a temperature at which latent heat of water vapor contained in combustion gases are substantially recovered. In one embodiment of our invention, a secondary heat exchanger comprises inter alia a closed hollow annular drum concentric with and spaced from a cylindrical combustion chamber, said annular drum having an upper annulus preferably filled with randomly packed refractory material. A second embodiment of our invention comprises a closed double annuli drum heat exchanger concentric with and spaced from a cylindrical combustion chamber. Finned tube or thermosiphon heat exchangers can be arranged sequentially with the primary heat exchanger combustion chamber to function as a secondary heat exchanger or as a tertiary heat exchanger.

Overall, J.C.; Schaus, O.O.

1981-06-30

46

Compact heat exchangers  

SciTech Connect

This report aims to increase the market penetration of compact heat exchangers (CHEs) in industry by detailing current experience of their use. CHEs are characterized by having a comparatively large amount of surface area in a given volume, compared to traditional heat exchangers, in particular the shell-and-tube type. The most basic CHEs have volumes of less than 50% of that of a comparable shell-and-tube heat exchanger, for a given duty. Some new designs can, under appropriate process conditions, have only 5% of the volume of traditional equivalents. An essential component of many of these compact concepts is heat (and mass) transfer enhancement. This report also details some of the main enhancement methods which are used in the implementation of compact systems. CHEs are of interest for a number of reasons. As well as being, in general, highly efficient, allowing greater amounts of energy to be recovered between process streams, they are more versatile in terms of the number of process streams that can be handled. Some CHEs can handle only two streams. Others can handle four or more with ease. That, coupled with the availability of units to cater for most operating temperatures and pressures, makes them of interest to operators of complex thermal processing plants. Of even greater long-term importance to the process industries is the ability to use CHE manufacturing technology to integrate effective heat transfer with other unit operations, such as reactors, in one unit. This radical approach to process plant design has fostered many exciting concepts for combined unit operations, some of which are discussed in this report. Topics covered are: types of CHE; (2) the role of heat transfer enhancement; (3) benefits and perceived limitations of CHEs; (4) costs; (5) fouling; (6) specification, installation and operating procedures; (7) the new opportunities; and (8) conclusions.

NONE

1999-11-01

47

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

48

Plug for heat exchanger tubes  

Microsoft Academic Search

A heat exchanger tube plug is described for sealing the ends of heat exchanger tubes, comprising a cylindrical housing member sized for insertion within the end portion of one of the heat exchanger tubes, the housing member having a longitudinal blind bore comprising a smooth portion communicating with a threaded portion. An eccentric locking means is mounted on the housing

Epstein

1987-01-01

49

Heat pipe heat exchanger design considerations  

Microsoft Academic Search

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

K. T. Feldman; D. C. Lu

1976-01-01

50

Preliminary analysis of heat pipe heat exchangers for heat recovery  

Microsoft Academic Search

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

J. O. Amode; K. T. Feldman

1975-01-01

51

DHE (Downhole Heat Exchangers)  

NASA Astrophysics Data System (ADS)

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.

Culver, G.

1990-11-01

52

Heat exchanger performance monitoring guidelines  

SciTech Connect

Fouling can occur in many heat exchanger applications in a way that impedes heat transfer and fluid flow and reduces the heat transfer or performance capability of the heat exchanger. Fouling may be significant for heat exchanger surfaces and flow paths in contact with plant service water. This report presents guidelines for performance monitoring of heat exchangers subject to fouling. Guidelines include selection of heat exchangers to monitor based on system function, safety function and system configuration. Five monitoring methods are discussed: the heat transfer, temperature monitoring, temperature effectiveness, delta P and periodic maintenance methods. Guidelines are included for selecting the appropriate monitoring methods and for implementing the selected methods. The report also includes a bibliography, example calculations, and technical notes applicable to the heat transfer method.

Stambaugh, N. (Duke Power Co., Charlotte, NC (United States)); Closser, W. Jr. (Toledo Edison Co., Oak Harbor,OH (United States)); Mollerus, F.J. (Mollerus Engineering Corp., Los Gatos, CA (United States))

1991-12-01

53

The heat pipe exchanger with controllable heat exchanging area  

NASA Astrophysics Data System (ADS)

The heat transfer rate through the heat exchanger in an industrial boiler that burns heavy oils must be controlled so as not to decrease the exhaust gas temperature below the dew point of sulfuric acid. Two systems of heat pipe exchangers are examined: one controls the heat exchange area of the condenser section of the heat pipes and the other uses the variable conductance heat pipes. The characteristics of these two systems are described. The temperatures at various points and the gas quantity are plotted against the boiler loads. The maintainability and operational reliability of both systems are demonstrated.

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

1984-03-01

54

The Microtube Strip Heat Exchanger  

Microsoft Academic Search

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

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

1991-01-01

55

Heat pipe heat exchanger for heat recovery in air conditioning  

Microsoft Academic Search

The heat pipe heat exchangers are used in heat recovery applications to cool the incoming fresh air in air conditioning applications. Two streams of fresh and return air have been connected with heat pipe heat exchanger to investigate the thermal performance and effectiveness of heat recovery system. Ratios of mass flow rate between return and fresh air of 1, 1.5

Mostafa A. Abd El-Baky; Mousa M. Mohamed

2007-01-01

56

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

57

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

58

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

59

Rotating fluidized bed heat exchanger  

Microsoft Academic Search

A rotating fluidized bed heat exchanger particularly adaptable as a heat exchange unit in the recuperator section of conventional gas turbine engines is disclosed comprising an annular fluidized bed, defined by inner and outer spaced apart coaxial cylindrical, perforated walls, which rotates about the longitudinal axis of the cylinders. The bed is comprised of pulverulent inert particulate material and includes

W. H. Belke; A. Goloff; G. B. Grim

1982-01-01

60

Troubleshooting problems with heat exchangers  

SciTech Connect

Problems encountered during routine use of shell and tube heat exchangers are identified and discussed. Most problems which affect unit performance fall into two basic categories: thermal design and mechanical design. This article approaches the troubleshooting of heat exchangers using this categorization.

Mehra, D.K.

1985-08-01

61

Heat transfer enhancement in heat exchangers  

SciTech Connect

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. Presently, the excessively large heat transfer surface area requirements prohibit cost-effective use of these systems. This paper reports on the new and promising electrohydrodynamic (EHD) technique which has demonstrated impressive potential for enhancing heat transfer in heat exchangers involving single-phase or phase-change processes. This article provides a brief description of EHD operational principles, research advancements in EHD during the past decade, and potential future EHD applications of specific interest to the HVAC and R industry.

Ohadi, M.M.

1991-12-01

62

Influence of heating mode in three-dimensional mantle convection  

SciTech Connect

Numerical models of three-dimensional, thermal convection in highly viscous spherical shells with different combinations of internal and basal heating consistently have upwelling concentrations in the form of cylindrical plumes and downwelling in planar sheets. As the proportion of internal heating increases, the number of upwelling plumes increases, and downwelling sheets become more vigorous and time-dependent. With any amount of basal heating, the entire convective pattern, during its evolution, is anchored to the upwelling plumes. As the proportion of internal heating increases, the heat flow carried by the upwelling plumes remains a large fraction of the basal heat flow. Downwelling sheets carry only a minor fraction (approximately 30%) of the basal heat flow (even when the shell is entirely heated from below), but they advect almost all of the internally generated heat. The relatively large number of plumes in the Earth's mantle (inferred from hotspots), the possibility that downwelling slabs are vigorous enough to penetrate the lower mantle, and the small fraction of terrestrial surface heat flow carried by plumes all suggest that the mantle is predominantly heated from within. /copyright/ American Geophysical Union 1989

Bercovici, D.; Schubert, G.; Glatzmaier, G. A.

1989-07-01

63

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

64

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

65

Compact heat exchanger  

SciTech Connect

A compact heat exchanger apparatus is described which consists of: a cluster of hollow shells, the shell having an outer surface and an inner surface, the shells being clustered to connect portions of their outer surfaces with portions of the outer surfaces of adjacent the shells to form a substantially contiguous interstitial space between the unconnected portions of the outer surfaces, the inner surfaces forming cavities which are interconnected by inner passages through the connecting portions of the shells' outer furfaces to cavaties in adjacent shells, at least some of the cavities and inner passages comprising a contiguous inner space within the inner surfaces of the cluster, fluid communication between the interstitial space and the inner space being prevented by the shells; a first side of the cluster bonded to a first bonding layer which seals the interstitial space on the first side of the cluster, the first side of the cluster being open to the exterior side of the first bonding layer to make the inner space accessible to a first manifold connected to the exterior side of the first bonding layer; a second side of the cluster bonded to a second bonding layer which seals the interstitial space on the second side of the cluster, the second side of the cluster being open to the exterior side of the second bonding layer.

Wood, C.D. III; Benson, H.S.

1986-07-15

66

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)

1981-01-01

67

Optimal design of the separate type heat pipe heat exchanger  

Microsoft Academic Search

Separate type heat pipe heat exchangers are often used for large-scale heat exchanging. The arrangement of such a heat exchanger\\u000a conveniently allows heat input to and output from the heat exchanger at remote locations. The traditional method of designing\\u000a an ordinary HPHE (heat pipe heat exchanger) is commonly applied in the separate type exchanger design, but the calculations\\u000a have to

Zi-tao Yu; Ya-cai Hu; Ke-fa Cen

2005-01-01

68

Ceramic heat pipe heat exchangers  

Microsoft Academic Search

High-temperature strength, resistance to corrosive atmospheres, and moderate cost combine to make ceramic materials an obvious choice for construction of high-temperature thermal energy recuperator systems. Despite these advantages, ceramic recuperators are steadily being replaced by metallic units at considerable sacrifice in maximum air or fuel preheat temperatures and hence in recovery efficiency. By constructing a recuperator from ceramic heat pipes,

W. A. Ranken

1976-01-01

69

Heat exchanger using graphite foam  

SciTech Connect

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

70

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

71

Designing heat exchangers by computer  

SciTech Connect

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

Palen, J.W.

1986-07-01

72

Radiative heat transfer in a hydrous mantle transition zone  

NASA Astrophysics Data System (ADS)

The structure and dynamics of Earth's interior depend crucially upon heat flow and thus upon the thermal conductivity of its constituents. We measured optical absorbance spectra of hydrous wadsleyite and hydrous ringwoodite at simultaneous high-pressure and high-temperature conditions up to 26 GPa and 823 K in order to determine their radiative conductivities and to study the potential influence of hydration in the transition zone on thermal conductivity of the mantle. We report radiative thermal conductivities of 1.5±0.2 Wm-1 K-1 for hydrous wadsleyite and 1.2±0.1 Wm-1 K-1 for hydrous ringwoodite at transition zone conditions. The analytically derived radiative thermal conductivities of anhydrous wadsleyite and ringwoodite are 40% and 33% higher, respectively. The total thermal conductivities, calculated from temperature- and pressure-dependent optical absorption measurements, maintain an energy transmission window in the infrared and visible spectral range at high pressures and temperatures. The results indicate that the mantle transition zone may contribute significantly to heat transfer in the mantle and demonstrate the importance of radiative heat transfer in controlling geodynamic processes in Earth's mantle.

Thomas, Sylvia-Monique; Bina, Craig R.; Jacobsen, Steven D.; Goncharov, Alexander F.

2012-12-01

73

The heat pipe heat exchangers: Design, technology and applications  

Microsoft Academic Search

The Heat Pipe Heat Exchanger (HPHE) is a relatively new and very attractice heat exchanger type. For a good understanding of this very special heat exchanger, a minimum knowledge of the heat pipes is required. The heat pipe and thermosyphon basic theory (including the calculation of the thermal limits) is summarized. Some information concerning the heat pipe technological aspects is

S. Chadourne

1991-01-01

74

Heat exchanger with oscillating flow  

Microsoft Academic Search

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

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

1992-01-01

75

Heat exchanger with oscillating flow  

Microsoft Academic Search

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

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

1990-01-01

76

Heat exchanger with oscillating flow  

Microsoft Academic Search

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

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

1993-01-01

77

Earth-air heat exchanger  

SciTech Connect

Optimizing the thermal environment of a livestock building is beneficial to the growth and production of the animal. Minimizing temperature extremes of inlet ventilation air to the livestock building by passing the air through underground ducts would accomplish this goal. Providing this optimum environment by reducing heating and cooling loads would reduce energy costs and increase profits for the producer. The heat transfer in an earth-air heat exchanger was studied in two phases to develop design criteria for these systems. The experimental phase consisted of an earth-air exchanger installation from which data were collected during hot weather (cooling effect), cold weather (heating effect), and mild weather performances. The analytical phase developed a finite element program for simulating the earth-air heat exchanger and studying the effects of important parameters on the heat transfer rate and the air temperature. Results of the first phase were used to verify the computer model. Design criteria for the earth-air heat exchanger were determined based on the information obtained in the two phases of this study.

Kammel, D.W.

1985-01-01

78

Internal heating induced subadiabaticity in the lower mantle  

NASA Astrophysics Data System (ADS)

It has been known for some time that the geotherm calculated in models of convection in Earth's mantle is subadiabatic when internal heat sources, used to model the effects of radioactive decay, are present. It has been argued that such subadiabaticity arises because of a balance in the energy equation between vertical advection and internal heating in the slow upward return flow region that takes up most of the convective domain in strongly internally heated convection. In this submission, we analyze a large number of simple convection models with mixed basal and internal heating to determine the dominant balances in the energy equation in regions of subadiabaticity. We find that in addition to the previously mentioned mechanism, subadiabaticity also arises in the lower mantle where cold sinking material is forced to turn sideways by the lower boundary and the dominant balance is between vertical and horizontal advection. This latter mechanism makes the largest contribution to the subadiabatic gradient in most cases. Subadiabatic gradients also occur in the vicinity of time-dependent plumes but these do not contribute significantly to the mean subadiabaticity in the mantle.

Sinha, G.; Butler, S. L.

2006-12-01

79

Heating fireplace and heat exchanger for a heating fireplace  

Microsoft Academic Search

The floor of the furnace space (fire chamber) of the heating fireplace is constituted by a horizontal, flat part and the rear wall of the furnace space is constituted in part by a vertical, flat part of a heat exchanger serving for heating water for a hot water heater. Heat is transferred to the water on the sides of the

H. A. Burger; W. Gehrig

1984-01-01

80

Fluidized bed heat exchanger utilizing angularly extending heat exchange tubes  

Microsoft Academic Search

A fluidized bed heat exchanger in which air is passed through a bed of particulate material containing fuel disposed in a housing. A steam\\/water natural circulation system is provided and includes a steam drum disposed adjacent the fluidized bed and a series of tubes connected at one end to the steam drum. A portion of the tubes are connected to

Fred M. Talmud; Juan-Antonio Garcia-Mallol

1980-01-01

81

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

82

Preliminary design study of heat pipe heat exchangers  

Microsoft Academic Search

A preliminary design study was conducted in order to identify the important design parameters which can be varied to optimize overall performance of heat pipe heat exchangers. A computer program was developed to analyze the heat exchanger performance using conventional design procedures for finned tube heat exchangers and using conventional design procedures for three-puddle-artery heat pipes.

K. T. Feldman; D. C. Lu

1976-01-01

83

Accelerated heat exchanger core testing  

Microsoft Academic Search

A program has been started at Argonne National Laboratory to test high performance evaporators and condensers being considered for the 1-MWe ocean test of OTEC heat exchangers. The experimental part of the program will be carried out in a test facility containing three loops - warm water, cold water, and ammonia. The test units will be about 1\\/40th the size

N. F. Sather

1977-01-01

84

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

85

Heat exchanger for concentrating solar collectors and method for making the heat exchanger  

SciTech Connect

nment of the flow passages with the A heat exchanger assembly is disclosed for use with concentrating solar collectors of the type employing an elongated conduit for transporting a heat exchange fluid, the heat exchanger being positioned within an opening in the upper surface of the conduit and operating to transfer heat to the heat exchange fluid. The heat exchanger includes a plurality of stacked heat conducting heat exchanger plates having grooves oriented to form flow passage extending in the direction of fluid flow. The heat direction of heat exchange fluid flow. The grooved heat exchange plates may be fabricated by stamp from a sheet of heat conducting material to facilitate manufacturing of the heat exchanger. In another embodiment, the plates are positioned normal to the fluid flow direction with openings in the plates serving to form flow channels. The heat exchanger is usuable with collectors employing either photovoltaic cells or a solar radiation absorbing flat plate collector.

Stultz, R.A.

1983-08-09

86

Multiple heat pipe heat exchanger and method for making  

Microsoft Academic Search

A heat pipe heat exchanger has a plurality of heat pipes which are interconnected so as to permit fluid communication between the pipes at least during charging so that the heat pipes may be simultaneously filled with heat transfer fluid.

Maxson

1979-01-01

87

Heat exchangers: Selection, rating, and thermal design  

SciTech Connect

This book takes a systematic approach to the subject, focusing on the selection, design, rating, and operational challenges of various types of heat exchangers. Written by well-known authors in the field of heat transfer, this book covers all the most commonly used types of heat exchangers, including condensers and evaporators. The text begins with the classification of the different types of heat exchangers and discusses methods for their sizing and rating. Single phase forced convection correlations in ducts and pressure drop and pumping power analysis are also covered. A chapter is devoted to the special problem of fouling. Thermal design methods and processes, including designs for condensers and evaporators, complete this thorough introduction to the subject. The appendix provides information on the thermophysical properties of fluids, including the new refrigerants. Every topic features worked examples to illustrate the methods and procedures presented, and additional problems are included at the end of each chapter, with examples to be used as a student design project. An instructor's manual is available, including complete solutions to selected problems in the text. The contents include: classification of heat exchangers; basic design methods of heat exchangers; forced convection correlations for single-phase side of heat exchangers; heat exchanger pressure drop and pumping power; fouling of heat exchangers; double-pipe heat exchangers; design correlations for condensers and evaporators; shell-and-tube heat exchangers; compact heat exchangers; gasketed-plate heat exchangers; and condensers and evaporators.

Kakac, S.; Liu, H.

1998-01-01

88

A New Design of Heat Exchanger  

Microsoft Academic Search

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

D. L. Astanovskii; L. Z. Astanovskii

2003-01-01

89

21 CFR 870.4240 - Cardiopulmonary bypass heat exchanger.  

Code of Federal Regulations, 2010 CFR

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

2009-04-01

90

21 CFR 870.4240 - Cardiopulmonary bypass heat exchanger.  

Code of Federal Regulations, 2010 CFR

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

2010-04-01

91

21 CFR 870.4240 - Cardiopulmonary bypass heat exchanger.  

Code of Federal Regulations, 2013 CFR

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

2013-04-01

92

Heat exchanger expert system logic  

NASA Astrophysics Data System (ADS)

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

Cormier, R.

1988-08-01

93

Hydrogen absorption indirect heat exchanger  

US Patent & Trademark Office Database

A case for a hydrogen absorption indirect heat exchanger of the present invention includes a square cylindrical portion 11 having each portion thereof formed integrally by die-casting or extrusion molding. The corners 11a of this square cylindrical portion 11 and the center portion of its side 11b are shaped to a greater thickness than that of other portions. The weight of the case can be reduced while the case powder capacity is secured.

Toh; Keiji (Kariya, JP); Kubo; Hidehito (Kariya, JP); Fujita; Nobuo (Toyota, JP); Mitsui; Hiroyuki (Aichi-ken, JP)

2002-03-26

94

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

95

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…

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

2012-01-01

96

Heat exchangers for sea solar power plants  

Microsoft Academic Search

The most obvious problems in the design of heat exchangers for ocean thermal power plants are summarized and some of the solutions suggested for them are discussed. Modular construction of heat exchangers is examined, with emphasis on reliability, availability, and maintainability of components. A drawing is presented showing the most important characteristics of heat exchangers for ocean power plants. The

B. King

1975-01-01

97

Microtube strip heat exchanger. Final technical report  

Microsoft Academic Search

The purpose of this contract has been to explore the limits of miniaturization of heat exchangers with the goals of (1) improving the theoretical understanding of laminar heat exchangers, (2) evaluating various manufacturing difficulties, and (3) identifying major applications for the technology. A low-cost, ultra-compact heat exchanger could have an enormous impact on industry in the areas of cryocoolers and

Doty

1992-01-01

98

Analysis and application of the heat pipe heat exchanger  

Microsoft Academic Search

Heat pipe heat exchangers offer many advantages over more conventional heat exchangers, particularly for gas-to-gas application. Proper application of these devices depends on the conditions imposed by the process from which waste heat is to be recovered, and some of the more common constraints are analyzed. The overall operation of heat pipe heat exchangers is best studied using effectiveness-NTU calculations,

T. H. Sun; R. C. Prager

1978-01-01

99

Performance of a variable conductance heat pipe heat exchanger  

Microsoft Academic Search

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

P. D. Chancelor

1983-01-01

100

Heat pipe heat exchangers as energy recovery devices  

Microsoft Academic Search

Counterflow heat exchangers comprised of a bundle of heat pipes with secondary finned surfaces attached offer attractive advantages as energy recovery units. With no moving parts and wide design flexibility, these heat pipe heat exchangers are finding ever increasing usage in air-to-air heat recovery. Three general classes of applications can be identified: using energy recovery from process exhaust to regenerate

Ruch

1976-01-01

101

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

102

Biofouling Countermeasure Evaluations for OTEC Heat Exchangers.  

National Technical Information Service (NTIS)

Several promising countermeasure methods for maintaining heat transfer efficiency in OTEC heat exchangers have been evaluated by the LaQue Center for Corrosion Technology, Inc., under contract to Argonne National Laboratory (ANL). Heat transfer monitors d...

R. O. Lewis

1981-01-01

103

Thermosiphon water heaters 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 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 reasonable performance can be attained with these systems compared to thermosiphons without heat exchangers.

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

1980-06-01

104

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

105

Influence of magmatism on mantle cooling, surface heat flow and Urey ratio  

NASA Astrophysics Data System (ADS)

Two-dimensional thermo-chemical mantle convection simulations are used to investigate the influence of melting-inducted differentiation on the thermal evolution of Earth's mantle, focussing on matching the present-day surface heat flow and the 'Urey ratio'. The influence of heat production rate, initial mantle temperature and partitioning of heat-producing elements into basaltic crust are studied. High initial mantle temperatures cause major differences in early mantle thermo-chemical structures but by the present day surface heat flux and internal structures are indistinguishable from cases with a low initial temperature. Assuming three different values of mantle heat production that vary by more than a factor of two results in small differences in present-day heat flow, as does assuming different partitioning ratios of heat-producing elements into crust. As a consequence of the model present-day surface heat flow varying only slightly with parameters, the Urey ratio is highly dependent on the amount of heat production, and due to the large uncertainty, the Urey ratio is considered to be a much poorer constraint on thermal evolution than the heat flow. The range of present-day Urey ratio observed in simulations here is about 0.3 to 0.5, which is consistent with observational and geochemical constraints [Jaupart et al., 2007]. Magmatic heat transport contributes about 10% to Earth's present-day heat loss but a much higher fraction at earlier times — often more than convective heat loss — so neglecting this causes an overestimation of the Urey ratio. Magmatic heat transport also plays an important role in mantle cooling. Considering these points, it is important to include magmatic effects when attempting to understand the thermal evolution of the Earth. In addition, we will show some preliminary results on thermal evolution of Earth's mantle and core including additional compositional anomalies at the base of mantle known as the BAsal Melange 'BAM' [Tackley, 2012].

Nakagawa, T.; Tackley, P.

2012-04-01

106

40 CFR 63.104 - Heat exchange system requirements.  

Code of Federal Regulations, 2010 CFR

...cooling water enters and exits each heat exchanger or any combination of heat exchangers...the entrance and exit of each heat exchanger or any combination of heat exchangers...cooling water enters the individual heat exchanger or group of heat exchangers...

2009-07-01

107

40 CFR 63.104 - Heat exchange system requirements.  

Code of Federal Regulations, 2010 CFR

...cooling water enters and exits each heat exchanger or any combination of heat exchangers...the entrance and exit of each heat exchanger or any combination of heat exchangers...cooling water enters the individual heat exchanger or group of heat exchangers...

2010-07-01

108

Heat Transfer Augmentation in a Compact Heat Exchange Pedestal Array.  

National Technical Information Service (NTIS)

A compact heat exchanger pedestal array for augmenting heat transfer in a machine is disclosed. The compact heat exchanger pedestal array includes a wall having first and second surfaces. The first surface faces a heated flow path and the second surface p...

C. R. Joe P. M. Lutjen

2004-01-01

109

Investigation of waste heat recovery utilizing fluidized bed heat exchangers  

Microsoft Academic Search

An experimental and analytical investigation was conducted to evaluate the economic potential of shallow fluidized bed heat exchangers to recover the waste heat in the exhaust gases from large diesel engines. The program involved: (1) experiments to measure the heat transfer, pressure loss, and fouling characteristics of a commercially available shallow fluidized bed heat exchanger, and (2) conceptual design of

1978-01-01

110

Testing and analysis of immersed heat exchangers  

SciTech Connect

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

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

1986-08-01

111

Analysis of a bayonet tube heat exchanger  

Microsoft Academic Search

This paper details the design, construction and testing of a bayonet tube heat exchanger for use in the process industry and potentially as part of an externally fired combined cycle. Detailed analysis of the system has been undertaken, in particular on the tube side. The data is reported in terms of temperature, pressure, heat gain and heat exchanger effectiveness, over

T O'Doherty; A. J Jolly; C. J Bates

2001-01-01

112

Analysis of Heat Exchangers for Dilution Refrigerators.  

National Technical Information Service (NTIS)

Numerical calculations of the behavior of dilution refrigerator heat exchangers are discussed and some results for both discrete and continuous exchangers are presented. It is shown that thermal conductance along the stream is negligible for a typical con...

J. D. Siegwarth R. Radebaugh

1971-01-01

113

Core Heat Flow and Suppression of Mantle Plumes by Plate-Scale Mantle Flow: Results From Laboratory Experiments  

NASA Astrophysics Data System (ADS)

Heat flow from the Earth's core to the mantle remains an unresolved quantity. Its value has implications for the core's thermal evolution and growth of the inner core, the geodynamo, and the relative abundance of radioactive elements in the core and mantle. Core heat flow is affected by dynamics of the lowermost mantle in three ways: (1) advection of heat by plume instabilities; (2) conductive heating of subducted material; and (3) suppression of plume instabilities, as well as advection of heat by plate-scale mantle flow. We present results from a boundary-layer analysis and laboratory experiments aimed at understanding the effects of an imposed large-scale circulation on thermal convection at high-Rayleigh number (106<=Ra<=109) in a fluid with a strongly temperature-dependent viscosity. The ultimate goal of this work is to better understand the effect of plate-scale mantle flow on heat flux across the CMB and on the dynamics of plume formation at the CMB. Our theoretical analysis is complemented by lab experiments, in which a layer of corn syrup is heated from below and a large-scale flow is induced in the fluid above the hot boundary. We identify 4 convective regions associated with high-Rayleigh number convection in the presence of a large-scale flow: (1) a subcritical TBL region (Domain I), where plume instabilities are suppressed by the advective thinning of the TBL and heat flux is increased relative to convection without large-scale flow; (2) a supercritical TBL region (Domain II), where plume instabilities are no longer suppressed and heat flux is equal to convection without large-scale flow; (3) a flow-dominated region (Domain III), which is free of plumes; and (4) a plume-dominated domain (Domain IV), where the interaction of hot buoyant plumes and imposed large-scale flow results in lateral advection and distortion of rising plumes. In addition, we present a boundary-layer analysis that predicts heat flux, Q, from a hot surface as a function of imposed large-scale velocity (U) or Peclet number (Pe=UL/? , where L is fluid depth and ? is thermal diffusivity) and horizontal position. Due to the strong temperature dependence of our working fluid, we observe a viscosity contrast of order 10 to 100 between ambient fluid and fluid near the hot boundary. We find a good match between boundary layer analysis for a free-slip boundary and experiments and obtain a heat-flux ratio ?=QPe>0/QPe=0 that scales with Pe1/2 Ra-0.28. Throughout Domain I values of ?>1 and TBL thickness increases, while ? decreases in the downstream direction. When applied to the Earth, our results indicate that the TBL at the CMB may locally be stabilized by plate-scale mantle flow (Domain I), thereby resulting in locally increased heat flux across the CMB. If the mantle above D" is 2-3 times more viscous than the upper mantle (Ra~106) and lower-mantle velocities are ~1 cm/y, then plume formation will be suppressed over a significant distance (~1000 km). This would have implications for the distribution of hotspots. Furthermore, the increased CMB heat flux could be of importance in terms of core evolution, the geodynamo and global heat-flow estimates. For smaller velocities and/or larger Ra, our analysis suggests that plume suppression and increased CMB heat flux remain localized and of limited importance.

Gonnermann, H. M.; Jellinek, A. M.; Richards, M. A.; Manga, M.

2002-12-01

114

High temperature heat exchange: nuclear process heat applications  

SciTech Connect

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

Vrable, D.L.

1980-09-01

115

Performance of a Variable Conductance Heat Pipe Heat Exchanger.  

National Technical Information Service (NTIS)

The primary objective of the work is to evaluate the performance of an air to air variable conductance heat pipe heat exchanger (VCHPHX). This type of heat exchanger is of particular interest to the commercial aircraft industry because of its unique contr...

P. D. Chancelor

1983-01-01

116

40 CFR 63.1409 - Heat exchange system provisions.  

Code of Federal Regulations, 2010 CFR

...cooling water enters and exits each heat exchanger or any combination of heat exchangers...the entrance and exit of each heat exchanger or any combination of heat exchangers...cooling water enters the individual heat exchanger or group of heat...

2010-07-01

117

40 CFR 63.1409 - Heat exchange system provisions.  

Code of Federal Regulations, 2010 CFR

...cooling water enters and exits each heat exchanger or any combination of heat exchangers...the entrance and exit of each heat exchanger or any combination of heat exchangers...cooling water enters the individual heat exchanger or group of heat...

2009-07-01

118

14 CFR 25.1125 - Exhaust heat exchangers.  

Code of Federal Regulations, 2013 CFR

...following apply: (a) Each exhaust heat exchanger must be constructed and installed...gases; and (4) No exhaust heat exchanger or muff may have any stagnant...fluids. (b) If an exhaust heat exchanger is used for heating...

2013-01-01

119

Radiative heat exchange between a fluidized bed and heated surface  

Microsoft Academic Search

The radiative heat exchange between a fluidized bed and a heated surface was investigated via an optical experiment employing a He-Ne laser and numerical simulation analysis. A model for predicting the radiative heat transfer is proposed that considers the thermal boundary layer near the heated surface. The numerical results indicate that radiative heat transfer is enhanced when the penetration depth

Jun Yamada; Yasuo Kurosaki; Isao Satoh; Kazuhiko Shimada

1995-01-01

120

A method of analysis for heat pipe heat exchangers  

Microsoft Academic Search

A method of analysis for the thermal performance of heat pipe heat exchangers based on the conductance model was developed in the present study. In the analysis the specific heat conductance of the heat pipe was obtained from a performance test of a single heat pipe described in the present paper and the well-known universal correlations were used to calculate

B. J. Huang; J. T. Tsuei

1985-01-01

121

Experimental investigation of a manifold heat-pipe heat exchanger  

Microsoft Academic Search

Results of experimental investigations of a heat exchanger on a manifold water heat pipe are given. An analysis is made of the temperature distribution along the heat-transfer agent path as a function of the transferred heat power. The influence of the degree of filling with the heat transfer agent on the operating characteristics of the construction is considered.

S. V. Konev; Wang Tszin'lyan; I. I. D'Yakov

1995-01-01

122

Solar pond heat removal using a submerged heat exchanger  

SciTech Connect

The results of operating a submerged plastic-tube heat exchanger in the 1080 m/sup 2/ Research Salt Gradient Solar Pond at Argonne National Laboratory are presented. The heat exchange system simulates grain drying, in which the temperature of the ambient air is raised 8 to 15/sup 0/C when it passes through a liquid-to-air heat exchanger that is coupled to the submerged heat exchanger. Approximately 1.0 x 10/sup 11/ J (100 MMBtu) were extracted from the pond, and the operation had no adverse effects on the stability of the salt gradient.

Hull, J.R.; Scranton, A.B.; Kasza, K.E.

1985-01-01

123

Industrial heat exchangers: Types and functions  

NASA Astrophysics Data System (ADS)

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

Shah, R. K.

124

On line mechanical cleaning of heat exchangers  

Microsoft Academic Search

Discusses experiences with on line, continuous, mechanical cleaning of heat exchangers in a cat cracker and comparisons with other cleaning methods. Heat exchangers, including surface condensers, can be severely affected by waterside fouling and the insulating effect of the laminar layer of stagnant water next to the tube wall. Waterside fouling, which includes mineral scale, biofouling, silt and corrosion products,

A. F. Stegelman; R. Renfftlen

1983-01-01

125

Heat exchanger fouling and corrosion evaluation  

Microsoft Academic Search

The experimental determination of acid corrosion and fouling effects upon a series of tubular heat exchanger modules exposed to the exhaust gases from a large (8900-hp) diesel engine, with different fin geometries and materials was studied. A study of the exhaust gas analysis was undertaken and acid dew point temperatures were determined. Heat exchanger test modules were then operated with

E. Deanda

1981-01-01

126

Plastic heat exchangers for sea solar plants  

Microsoft Academic Search

A plastic heat exchanger for ocean thermal power plants whose design depends on the flow of the Gulf Stream across the tubes of the evaporator to give the necessary velocity to enhance heat transfer is described. Another plastic exchanger considered uses forced circulation of the warm seawater through enclosed boilers. The boilers are of the horizontal tube, spray film design

E. N. Sieder

1975-01-01

127

Particulate fouling in plate heat exchangers  

SciTech Connect

Particulate fouling in an Alfa-Laval P20 plate heat exchanger was investigated using a suspension of aluminum oxide particles in heptane. Process parameters such as flow velocity, heat flux, and particle concentration were varied over a considerable range. In this paper, the influence of the above parameters on the asymptotic fouling resistance is discussed. Measured values of fouling resistance are compared with results for a double-pipe heat exchanger and with the prediction of a fouling model from the literature.

Muller-Steinhagen; Middis, J. (Univ. of Auckland, Dept. of Chemical and Materials Engineering, Auckland (NZ))

1989-01-01

128

Heat exchangers for lumber dry kilns  

Microsoft Academic Search

An air-to-air, flat-plate heat exchanger was used to recover exhausted heat from an 80 MBF capacity commercial dry kiln. Heat exchanger efficiency averaged 46% and ranged from 20 to 90% on the charges studied. Energy consumption of the dry kiln was reduced by 18%. Natural gas savings at a cost of $5.65 per MCF were $1.76 per MBF for yellow-poplar

Toennisson

1985-01-01

129

Heat exchanger device and method for heat removal or transfer  

DOEpatents

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

130

Fluidized-Bed Heat Exchanger for a Residential Heat Pump.  

National Technical Information Service (NTIS)

The goal of this project was to design and test a fluidized-bed heat exchanger at the evaporator stage of the cycle. Its purpose was two-fold: (1) Eliminate the formation of frost and ice on the exchanger surfaces and thus increase the overall heat transf...

E. S. Grimmett J. R. Reindfleisch

1985-01-01

131

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

132

Brayton-cycle heat exchanger technology program  

Microsoft Academic Search

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

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

1976-01-01

133

Heat transfer characteristics of a gas-to-gas heat exchanger using heat pipes  

Microsoft Academic Search

The heat transfer characteristics of a gas-to-gas heat exchanger employing heat pipes as the heat transfer elements were examined. Experimental data obtained on the heat exchanger containing 66 finned heat pipes were compared with the values calculated by using various empirical and theoretical equations. A basic design procedure for gas-to-gas heat exchangers using heat pipes was then established. The results

Y. Wakiyama; K. Harada; S. Inoue; J. Fujita; H. Suematsu

1978-01-01

134

Increasing the Efficiency of Maple Sap Evaporators with Heat Exchangers.  

National Technical Information Service (NTIS)

A study of the engineering and economic effects of heat exchangers in conventional maple syrup evaporators indicated that: (1) Efficiency was increased by 15 to 17 percent with heat exchangers; (2) Syrup produced in evaporators with heat exchangers was si...

L. D. Garrett H. Duchacek M. Morselli F. M. Laing N. K. Huyler

1977-01-01

135

40 CFR 63.1409 - Heat exchange system provisions.  

Code of Federal Regulations, 2013 CFR

...which the cooling water exits the heat exchanger or group of heat exchangers. (5) A minimum...using a surrogate indicator of heat exchange system leaks shall comply...acceptable monitoring program are ion specific electrode monitoring, pH,...

2013-07-01

136

40 CFR 63.104 - Heat exchange system requirements.  

Code of Federal Regulations, 2013 CFR

...which the cooling water exits the heat exchanger or group of heat exchangers. (5) A minimum...using a surrogate indicator of heat exchange system leaks shall comply...acceptable monitoring program are ion specific electrode monitoring, pH,...

2013-07-01

137

14 CFR 25.1125 - Exhaust heat exchangers.  

Code of Federal Regulations, 2010 CFR

...2009-01-01 false Exhaust heat exchangers. 25.1125 Section 25...System § 25.1125 Exhaust heat exchangers. For reciprocating engine...apply: (a) Each exhaust heat exchanger must be constructed and...

2009-01-01

138

14 CFR 23.1125 - Exhaust heat exchangers.  

Code of Federal Regulations, 2010 CFR

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

2010-01-01

139

14 CFR 29.1125 - Exhaust heat exchangers.  

Code of Federal Regulations, 2010 CFR

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

2010-01-01

140

14 CFR 23.1125 - Exhaust heat exchangers.  

Code of Federal Regulations, 2010 CFR

...2009-01-01 false Exhaust heat exchangers. 23.1125 Section 23...System § 23.1125 Exhaust heat exchangers. For reciprocating engine...apply: (a) Each exhaust heat exchanger must be constructed and...

2009-01-01

141

14 CFR 29.1125 - Exhaust heat exchangers.  

Code of Federal Regulations, 2010 CFR

...2009-01-01 false Exhaust heat exchangers. 29.1125 Section 29...System § 29.1125 Exhaust heat exchangers. For reciprocating engine...apply: (a) Each exhaust heat exchanger must be constructed and...

2009-01-01

142

14 CFR 25.1125 - Exhaust heat exchangers.  

Code of Federal Regulations, 2010 CFR

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

2010-01-01

143

Influence of magmatism on mantle cooling, surface heat flow and Urey ratio  

NASA Astrophysics Data System (ADS)

Two-dimensional thermo-chemical mantle convection simulations are used to investigate the influence of melting-inducted differentiation on the thermal evolution of Earth's mantle, focussing in particular on matching the present-day surface heat flow and the 'Urey ratio'. The influence of internal heating rate, initial mantle temperature and partitioning of heat-producing elements into basaltic crust are studied. High initial mantle temperatures, which are expected following Earth's accretion, cause major differences in early mantle thermo-chemical structures, but by the present-day surface heat flux and internal structures are indistinguishable from cases with a low initial temperature. Assuming three different values of mantle heat production that vary by more than a factor of two results in small differences in present-day heat flow, as does assuming different partitioning ratios of heat-producing elements into crust. Indeed, all of the cases presented here, regardless of exact parameters, have approximately Earth's present-day heat flow, with substantial fractions coming from the core and from mantle cooling. As a consequence of the model present-day surface heat flow varying only slightly with parameters, the Urey ratio (the ratio of total heat production to the total surface heat flow) is highly dependent on the amount of internal heat production, and due to the large uncertainty in this, the Urey ratio is considered to be a much poorer constraint on thermal evolution than the heat flow. The range of present-day Urey ratio observed in simulations here is about 0.3 to 0.5, which is consistent with observational and geochemical constraints (Jaupart et al., 2007). Magmatic heat transport contributes an upper bound of 9% to Earth's present-day heat loss but a much higher fraction at earlier times—often more than convective heat loss—so neglecting this causes an overestimation of the Urey ratio. Magmatic heat transport also plays an important role in mantle cooling. Considering these points, it is important to include magmatic effects when attempting to understand the thermal evolution of the Earth.

Nakagawa, Takashi; Tackley, Paul J.

2012-05-01

144

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

145

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

146

Heat-exchange crisis in thermosiphon circuits  

NASA Astrophysics Data System (ADS)

The article discusses the analogy and distinguishing features of heat-exchange crises in steam-generating channels of thermosiphon circuits. A chart of the crisis phenomena in channels with natural and forced circulation is presented.

Bezrodnyi, M. K.; Volkov, S. S.; Khavin, S. A.

1985-05-01

147

Silicon Carbide Ceramics for Compact Heat Exchangers.  

National Technical Information Service (NTIS)

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 demonstratin...

D. Zhang D. C. Nagle

2009-01-01

148

High Efficiency Flat Panel Microchannel Heat Exchanger.  

National Technical Information Service (NTIS)

An apparatus providing high efficiency heat exchange between two fluids is disclosed. The apparatus most commonly comprises a flat panel with microchannels directing the flow of the two fluids, specifically: with a small hydraulic diameter in order to inc...

K. W. Kelly A. McCandless

2005-01-01

149

A laminar-flow heat exchanger  

NASA Astrophysics Data System (ADS)

The advantages of designing heat exchangers in the laminar flow regime are discussed from a theoretical standpoint. It is argued that laminar flow designs have the advantages of reducing thermodynamic and hydrodynamic irreversibilities and hence increasing system efficiency. More concretely, laminar flow heat exchangers are free from the turbulence-induced vibration common in conventional heat exchangers and can thus offer longer life and greater reliability. The problems of manufacturing heat exchangers suited to laminar flow are discussed. A method of manufacture which allows compact, modular design is outlined. Experience with this method of manufacture is described, and experimental results are presented. The problems of fouling and flow maldistribution are briefly discussed, and some possible applications are mentioned.

Doty, F. D.; Hosford, G.; Jones, J. D.; Spitzmesser, J. B.

150

Heat exchanger fouling: Prediction, measurement and mitigation  

SciTech Connect

The US Department of Energy (DOE), Office of Industrial Programs (OIP) sponsors the development of innovative heat exchange systems. Fouling is a major and persistent cost associated with most industrial heat exchangers and nationally wastes an estimated 2.9 Quads per year. To predict and control fouling, three OIP projects are currently exploring heat exchanger fouling in specific industrial applications. A fouling probe has been developed to determine empirically the fouling potential of an industrial gas stream and to derive the fouling thermal resistance. The probe is a hollow metal cylinder capable of measuring the average heat flux along the length of the tube. The local heat flux is also measured by a heat flux meter embedded in the probe wall. The fouling probe has been successfully tested in the laboratory at flue gas temperatures up to 2200 F and a local heat flux up to 41,000 BTU/hr-ft{sup 2}. The probe has been field tested at a coal-fired boiler plant. Future tests at a municipal waste incinerator are planned. Two other projects study enhanced heat exchanger tubes, specifically the effect of enhanced surface geometries on the tube bundle performance. Both projects include fouling in a liquid heat transfer fluid. Identifying and quantifying the factors affecting fouling in these enhanced heat transfer tubes will lead to techniques to mitigate fouling. 1 tab.

Not Available

1989-01-01

151

Heat exchanger fouling: Prediction, measurement, and mitigation  

NASA Astrophysics Data System (ADS)

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

152

Study on dynamic characteristics of heat exchanger  

NASA Astrophysics Data System (ADS)

Temperature regulation in aircraft air conditioning systems is considered. The structural form of a dynamic mathematical model for a heat exchanger with the form of lumped parameter model is theoretically deduced. An experimental way to obtain the model parameters is proposed and the appropriate calculation formulas are deduced. A method for calculating the dynamic characteristics of a heat exchanger is pointed out. An example is given.

Ying, Wenjiang

1993-04-01

153

Heat exchanger effectiveness in unsteady state  

NASA Astrophysics Data System (ADS)

A method is proposed to determine the thermal effectiveness of heat exchangers in situ, when one of the fluids is submitted to any kind of flow rate variations. It leads to the definition of the average effectiveness in unsteady state, which forms an extension of the classical effectiveness used in steady state. It requires an unsophisticated equipment of measurement and should lead to an easy and continuous control of the fouling of heat exchangers.

Mai, T. H.; Chitou, N.; Padet, J.

1999-10-01

154

Plastic Film Heat Exchanger Development Project  

NASA Astrophysics Data System (ADS)

This report presents the progress that has been achieved in the development of the plastic film heat exchanger system (PFHX). An earlier report presented the general performance and design characteristics of a steam recovery PFHX. This report reviews some additional material selection possibilities for the film surfaces and describes a prototype design of a plastic film heat exchange element. Also the facility for the elevated temperature testing of this element design is described and the test plan is presented.

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

1986-04-01

155

Plastic film heat exchanger development project  

SciTech Connect

This report presents the progress that has been achieved in the development of the plastic film heat exchanger system (PFHX). An earlier report presented the general performance and design characteristics of a steam recovery PFHX. This report reviews some additional material selection possibilities for the film surfaces and describes a prototype design of a plastic film heat exchange element. Also the facility for the elevated temperature testing of this element design is described and the test plan is presented.

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

1986-04-14

156

Small Scale Thermosyphon Heat Exchanger.  

National Technical Information Service (NTIS)

A small circular heat transfer cell was used to study the cooling of a disc heat source by a thin evaporating liquid film. This small scale thermosyphon is a thermal spreader and a passive heat sink in that the interfacially induced liquid flow rates are ...

M. Sujanani E. W. Kiewra P. C. Wayner

1986-01-01

157

High temperature active heat exchanger research for latent heat storage  

Microsoft Academic Search

An active heat exchange method in a latent heat (salt) thermal energy storage system that prevents a low conductivity solid salt layer from forming on heat transfer surfaces was developed. An evaluation of suitable media with melting points in the temperature range of interest (250 to 400 C) limited the candidates to molten salts from the chloride, hydroxide and nitrate

J. Alario; R. Haslett

1982-01-01

158

Simulation of induction heating process with radiative heat exchange  

Microsoft Academic Search

Purpose: Numerical modelling of induction heating process is a complex issue. It needs analysis of coupled electromagnetic and thermal fields. Calculation models for electromagnetic field analysis as well as thermal field analysis need simplifications. In case of thermal field calculations, correct modelling of radiative heat exchange between the heated charge and inductor's thermal insulation is essential. Most commercial calculation programs

A. Kachel; R. Przy?ucki

2007-01-01

159

Ceramic heat exchangers: manufacturing techniques and performance  

SciTech Connect

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

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

1981-01-01

160

Plume's buoyancy and heat fluxes from the deep mantle estimated by an instantaneous mantle flow simulation based on the S40RTS global seismic tomography model  

NASA Astrophysics Data System (ADS)

It is still an open question as to how much heat is transported from the deep mantle to the upper mantle by mantle upwelling plumes, which would impose a strong constraint on models of the thermal evolution of the earth. Here I perform numerical computations of instantaneous mantle flow based on a recent highly resolved global seismic tomography model (S40RTS), apply new simple fluid dynamics theories to the plume's radius and velocity, considering a Poiseuille flow assumption and a power-law relationship between the boundary layer thickness and Rayleigh number, and estimate the plume's buoyancy and heat fluxes from the deep lower mantle under varying plume viscosity. The results show that for some major mantle upwelling plumes with localized strong ascent velocity under the South Pacific and Africa, the buoyancy fluxes of each plume beneath the ringwoodite to perovskite + magnesiowüstite ("660-km") phase decomposition boundary are comparable to those inferred from observed hotspot swell volumes on the earth, i.e., on the order of 1 Mg s-1, when the plume viscosity is 1019-1020 Pa s. This result, together with previous numerical simulations of mantle convection and the gentle Clausius-Clapeyron slope for the 660-km phase decomposition derived from recent high-pressure measurements under dehydrated/hydrated conditions in the mantle transition zone, implies that mantle upwelling plumes in the lower mantle penetrate the 660-km phase decomposition boundary without significant loss in thermal buoyancy because of the weak thermal barrier at the 660-km boundary. The total plume heat flux under the South Pacific is estimated to be about 1 TW beneath the 660-km boundary, which is significantly smaller than the core-mantle boundary heat flux. Previously published scaling laws for the plume's radius and velocity based on a plume spacing theory, which explains well plume dynamics in three-dimensional time-dependent mantle convection, suggest that these plume fluxes depend critically on plume viscosity. This result implies that the predicted plume viscosity may not be as low as expected, i.e., on the order of 1020 Pa s, considering the weak thermal barrier for upwelling plumes at the 660-km boundary, and the plume heat fluxes in the deep lower mantle under the South Pacific may be comparable to the lower limit for estimated core-mantle boundary heat flux inferred from a number of independent geodynamic studies.

Yoshida, Masaki

2012-11-01

161

Transient geotherms in Archean continental lithosphere: New constraints on thickness and heat production of the subcontinental lithospheric mantle  

Microsoft Academic Search

Because of its large thickness and thermal relaxation time, Archean lithosphere cannot be in thermal equilibrium with the instantaneous rate of heat production in the lithospheric mantle and heat supplied to its base. Comparison of xenolith (P,T) data with time-dependent thermal models allows constraints on lithosphere thickness, in situ heat production in the lithospheric mantle and time changes of basal

C. Michaut; C. Jaupart; D. R. Bell

2007-01-01

162

Single Tube Hydride Heat Exchanger Test Facility.  

National Technical Information Service (NTIS)

The primary objective of heat exchanger testing is to develop heat transfer data which would be needed to design a reasonably optimal HYCSOS device. To meet this primary objective, it will be necessary to: (1) design and construct a test facility suitable...

H. P. Egbert J. S. Horowitz G. M. Warapius

1979-01-01

163

Heat exchanger with valved pipe connection  

Microsoft Academic Search

This patent describes a heating and ventilating unit for motor cars having air temperature regulation by a heat exchanger which may be variably slid into a fresh air stream and the operative surface of which is variably acted upon in a defined constant position. The surface is acted upon approximately at right angles to the fresh air stream from a

Knab

1986-01-01

164

The influence of tectonic plates on mantle convection patterns, temperature and heat flow  

NASA Astrophysics Data System (ADS)

The dynamic coupling between plate motion and mantle convection is investigated in a suite of Cartesian models by systematically varying aspect ratios and plate geometries. The aim of the study presented here is to determine to what extent plates affect mantle flow patterns, temperature and surface heat flux. To this end, we compare numerical convection models with free-slip boundary conditions to models that incorporate between one and six plates, where the geometries of the plates remain fixed while the plate velocities evolve dynamically with the flow. We also vary the widths of the plates and the computational domain in order to determine what constraint these parameters place on the mean temperature, heat flux and plate velocity of mantle convection models. We have investigated the influence of plates for three whole-mantle convection cases that differ in their heating modes (internally heated and basally heated) and rheologies (isoviscous and depth-dependent viscosity). We present a systematic investigation of over 30 models that exhibit increasingly complex behaviour in order to understand highly time-dependent systems using the insight gained from simpler models. In models with aspect ratios from 0.5 to 12 we find that for the same heating mode, variations in temperature can be as much as 40 per cent when comparing calculations with unit-width plates to models incorporating plates with widths equal to five times the model depth. Mean surface heat flux may decrease by 60 per cent over the same range of plate widths. We also find that internally heated mantle convection models incorporating plates exhibit novel behaviour that, we believe, has not been described previously in mantle convection studies. Specifically, in internally heated models, plate motion is characterized by episodic reversals in direction driven by changes in the mantle circulation from clockwise to counterclockwise and vice versa. These flow reversals occur in internally heated convection and are caused by a build-up of heat in the interiors of wide convection cells close to mantle downwellings. We find that flow reversals occur rapidly and are present in both single-plate and multiple-plate models that include internal heating. This behaviour offers a possible explanation for why the Pacific plate suddenly changed its direction some 43Ma.

Lowman, Julian P.; King, Scott D.; Gable, Carl W.

2001-09-01

165

Boiling heat transfer in compact heat exchangers  

SciTech Connect

Small circular and noncircular channels are representative of flow passages in compact evaporators and condensers. This paper describes results of an experimental study on heat transfer to the flow boiling of refrigerant- 12 in a small circular tube of diameter = 2.46 mm. The objective of the study was to assess the effect of channel size on the heat transfer coefficient and to obtain additional insights relative to the heat transfer mechanisms. The flow channel was made of brass and had an overall length of 0.9 m. The channel wall was electrically heated, and temperatures were measured on the channel wall and in the bulk fluid stream. Voltage taps were located at the same axial locations as the stream thermocouples to allow testing over an exit quality range of 0.21 to 0.94 and a large range of mass flux (63 to 832 kg/m{sup 2}s) and heat flux (2.5 to 59 kW/m{sup 2}). Saturation pressure was nearly constant, averaging 0.82 MPa for most of the testing; a few test data were also taken at a constant lower pressure of 0.52 MPa. Local heat transfer coefficients were determined experimentally. Analysis provided additional support for the conclusion, arrived at from previous studies, that a nucleation mechanism dominates for flow boiling in small channels; nevertheless, a convective-dominant region was identified at very low values of wall superheat (<{approx}3{degrees}C). Previous flow boiling studies in small channels, that did not include wall superheats this low, did not encounter the convective dominant mechanism. Conversely, cryogenic studies at very low wall superheats ({approx}l{degree}C) did not encounter the nucleation dominant regime. The apparent discrepancy is explained by the results of this study.

Tran, T.N.; Wambsganss, M.W. [Argonne National Lab., IL (United States); France, D.M. [Illinois Univ., Chicago, IL (United States). Dept. of Mechanical Engineering

1994-12-31

166

Observer-based monitoring of heat exchangers.  

PubMed

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

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

2007-08-15

167

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

168

The dry heat exchanger calorimeter system  

SciTech Connect

A radiometric isothermal heat flow calorimeter and preconditioner system that uses air instead of water as the heat exchange medium has been developed at Mound. The dry heat exchanger calorimeter is 42 inches high by 18 inches in diameter and the preconditioner is a 22 inch cube, making it extremely compact compared to existing units. The new system is ideally suited for transportable, stand-alone, or glovebox applications. Preliminary tests of the system have produced sample measurements with standard deviations less than 0.25% and sample errors less than 0.50%. These tests have shown that the dry heat exchanger system will yield acceptance data with an accuracy comparable to those of Mound water bath systems now in use. 4 figs., 1 tab.

Renz, D.P.; Wetzel, J.R.; James, S.J.; Kasperski, P.W.; Duff, M.F.

1991-01-01

169

Performance Evaluation of Heat Pipe Heat Exchanger  

Microsoft Academic Search

To the basis of first law of thermodynamics, mainly applicable to engineering calculations; to the basis of the second law of thermodynamics - entropy analysis method, can be used to apply to theoretical analysis and engineering calculations. In this paper, a single performance valuation and entropy analysis for heat recovery equipment have been used, which is to make performance evaluation

Zhang Jie; Ren Yan; Zhang Li Hong; Zhang Kang

2010-01-01

170

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

Microsoft Academic Search

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

Xinguo Li; Jun Zhao; Qian Zhou

2005-01-01

171

40 CFR 63.654 - Heat exchange systems.  

Code of Federal Regulations, 2010 CFR

...system in organic HAP service or from each heat exchanger exit line for each heat exchanger or group of heat exchangers in organic HAP...monitor monthly (in addition to monitoring each heat exchanger exit line) the fresh water feed line...

2010-07-01

172

Liquid–gas heat exchanger for household refrigerator  

Microsoft Academic Search

This paper considers the influence of heat exchangers to the efficiency of a household refrigerating system. A steady state mathematical model is used to compare three most commonly used heat exchanger designs. For each design, an optimal inner diameter of the heat exchanger, subject to the compressor's capacity and the heat exchanger's length is found. The influence of operating conditions,

V. Dagilis; L. Vaitkus; A. Bal?ius

2004-01-01

173

Microtube strip heat exchanger. Final technical report  

SciTech Connect

The purpose of this contract has been to explore the limits of miniaturization of heat exchangers with the goals of (1) improving the theoretical understanding of laminar heat exchangers, (2) evaluating various manufacturing difficulties, and (3) identifying major applications for the technology. A low-cost, ultra-compact heat exchanger could have an enormous impact on industry in the areas of cryocoolers and energy conversion. Compact cryocoolers based on the reverse Brayton cycle (RBC) would become practical with the availability of compact heat exchangers. Many experts believe that hardware advances in personal computer technology will rapidly slow down in four to six years unless lowcost, portable cryocoolers suitable for the desktop supercomputer can be developed. Compact refrigeration systems would permit dramatic advances in high-performance computer work stations with ``conventional`` microprocessors operating at 150 K, and especially with low-cost cryocoolers below 77 K. NASA has also expressed strong interest in our MTS exchanger for space-based RBC cryocoolers for sensor cooling. We have demonstrated feasibility of higher specific conductance by a factor of five than any other work in high-temperature gas-to-gas exchangers. These laminar-flow, microtube exchangers exhibit extremely low pressure drop compared to alternative compact designs under similar conditions because of their much shorter flow length and larger total flow area for lower flow velocities. The design appears to be amenable to mass production techniques, but considerable process development remains. The reduction in materials usage and the improved heat exchanger performance promise to be of enormous significance in advanced engine designs and in cryogenics.

Doty, F.D.

1992-07-09

174

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

175

Heat exchanger restart evaluation. Revision 1  

SciTech Connect

On December 24, 1991, the K-Reactor was in the shutdown mode with full AC process water flow and full cooling water flow. Safety rod testing was being performed as part of the power ascension testing program. The results of cooling water samples indicated tritium concentrations higher than allowable. Further sampling and testing confirmed a Process Water System to Cooling Water System leak in heat exchanger 4A (HX 4A). The heat exchanger was isolated and the plant shutdown. Heat exchanger 4A was removed from the plant and moved to C-Area prior to performing examinations and diagnostic testing. This included locating and identifying the leaking tube or tubes, eddy current examination of the leaking tube and a number of adjacent tubes, visually inspecting the leaking tube from both the inside as well as the area surrounding the identified tube. The leaking tube was removed and examined metallurgically to determine the failure mechanism. In addition ten other tubes that either exhibited eddy current indications or would represent a baseline condition were removed from heat exchanger 4A for metallurgical examination. Additional analysis and review of heat exchanger leakage history was performed to determine if there are any patterns which can be used for predictive purposes. Compensatory actions have been taken to improve the sensitivity and response time to any future events of this type. The results of these actions are summary herein.

Morrison, J.M.; Hirst, C.W.; Lentz, T.F.

1992-03-18

176

Dynamic significance of long-wave density gradients due to heat generation within the mantle  

NASA Astrophysics Data System (ADS)

We give a new solution of the Boussinesq equations of motion describing flow driven by internal heat generation within a plane horizontal layer of viscous but thermally non-conducting fluid. The solution models the central region of a long mantle convection cell, excluding the cold plate and slab, and gives the coupled velocity and temperature fields in terms of the heating rate and material properties. Interaction of the buoyantly-driven flow with internal heat generation creates a long-wave, horizontal density gradient. Scaled to the mantle, the predicted amplitude of that gradient appears too small to observe seismically with current methods, but the corresponding flow speeds are comparable with those observed. To assume that mantle flow is driven purely by currently observable density differences may therefore be to ignore a large part of the forcing.

Morris, S. J. S.

2007-08-01

177

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

178

Earth type heat exchanger for heat pump system  

Microsoft Academic Search

The heat exchanger unit is highly efficient in operation and is so constructed as to permit rapid installation in and removal from the earth at small size sites of desired use of the heat pump system. The unit includes a freon-conducting coil assembly preferably comprised of a plurality of concentric coils defining parallel flow paths for the fluid conducted to

Bingham

1985-01-01

179

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

180

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

181

Energy absorber for sodium-heated heat exchanger  

DOEpatents

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

Essebaggers, J.

1975-12-01

182

Stability of the rotation axis in high-resolution mantle circulation models: Weak polar wander despite strong core heating  

Microsoft Academic Search

Growing evidence points to a substantial heat flow across the core-mantle boundary (CMB), but the rotational stability of strongly bottom heated mantle flow with prominent upwelling plumes is poorly known. Here we calculate polar motion for the past 100 Myr induced in a new class of isochemical high-resolution mantle circulation models (MCMs) with Earth-like convective vigor and up to 12

K. Schaber; H.-P. Bunge; B. S. A. Schuberth; R. Malservisi; A. Horbach

2009-01-01

183

Heat Exchanger System and Method.  

National Technical Information Service (NTIS)

A device for causing a liquid to flow through a pipe without using pumps is described. Liquid is supplied to a conduit from a reservoir. Heat is supplied at a point on the conduit and causes local boiling. A check valve in the line prevents return motion ...

A. P. Sabol

1972-01-01

184

Modular tube bundle heat exchanger and geothermal heat pump system  

SciTech Connect

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 the refrigerant is circulated in the conduits through pressure changes and corresponding temperature changes in the refrigerant, the in-ground heat exchanger comprising at least one modular tube bundle comprising a plurality of substantially horizontally oriented subterranean tubes, buried in a substantially planar vertical array for installation along substantially vertical walls of at least one that is backfilled for setting the array in thermal engagement with the earth, said at least one bundle having a top and bottom displaced vertically from one another, and the refrigerant being subjected to phase change in the conduits.

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

1993-07-06

185

Analysis of compact heat exchanger performance  

SciTech Connect

Many cryogenic heat exchangers employ high-conductance metallic screens or perforated plates separated by insulating spacers normal to the fluid flow direction. The former insures a high rate of heat transfer between the fluid streams while the latter reduces longitudinal conduction. Packed-bed regenerators employing wire screens, perforated plates, or granular particles also have a similar structure. In these exchangers, any individual plate or particle has very high thermal conductivity and is essentially at a single temperature. As a result, the temperature profile along the length consists of many steps, rather than a single continuous curve. Conventional analysis based on a continuous temperature profile tends to overestimate the efficiency of these exchangers. Axial conduction down the bed, caused by finite contact or spacer resistance, further reduces the effectiveness. 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.

1984-01-01

186

Condensation Behavior in a Microchannel Heat Exchanger  

NASA Astrophysics Data System (ADS)

A small and high performance heat exchanger for small size energy equipments such as fuel cells and CO2 heat pumps is required in these days. In author's previous studies, the heat exchanger consisted of microchannels stacked in layers has been developed. It has resistance to pressure of larger than 15 MPa since it is manufactured by diffusion bond technique. Thus this device can be applied for high flow rate and pressure fluctuation conditions as boiling and condensation. The objectives of the present study are to clarify the heat transfer performance of the prototype heat exchanger and to investigate the thermal hydraulic behavior in the microchannel for design optimization of the device. As the results, it is clarified that the present device attained high heat transfer as 7 kW at the steam condensation, despite its weight of only 230 g. Furthermore, steam condensation behavior in a glass capillary tube, as a simulated microchannel, in a cooling water pool was observed with various inlet pressure and temperature of surrounding water. Relation between steam-water two-phase flow structure and the overall heat transfer coefficient is discussed.

Kaneko, Akiko; Takeuchi, Genki; Abe, Yutaka; Suzuki, Yutaka

187

Heat exchange system utilizing cavitating fluid  

SciTech Connect

A heat exchange structure is described comprising: a source of pressurized fluid, a valve communicating with the source of pressurized fluid, the valve being cyclically operable to open and close a line and allow the source of pressurized fluid to direct fluid through the valve; a vessel downstream of the valve such that the opening and closing of the valve allows pulses of the pressurized fluid to reach the vessel; a fluid line leading from the vessel to a downstream location; and a heat exchange structure at the downstream location communicating with the fluid line.

Sajewski, R.

1993-08-31

188

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

189

Effect of variable heat production on the thermal evolution of the mantle  

NASA Astrophysics Data System (ADS)

The Earth currently loses heat at about 44 TW; this reflects both cooling and radioactive decay. From cosmochemical models, the bulk silicate earth budgets of uranium, thorium, and potassium are thought to produce about 20 TW. Thermal history models, which balance the rate of heat loss against the resulting temperatures in the mantle, yield a slightly higher value of about 30 TW. This heat production is distributed among the continental and oceanic crust, mantle, and core. The total heat production in the depleted mantle (the MORB source), plus the crust, may total between 9.6 and 17 TW, leaving a substantial amount of heat unaccounted for (at least 3 to 10.4 TW, assuming that the cosmochemical models correctly estimate the bulk silicate earth.) The most likely reservoir for the excess is either in the deep mantle or in the core. We investigate the several models for the distribution of the excess heat within the mantle, using numerical models of convection. Our goal is to assess the effects on Earth's thermal history of a mantle reservoir of excess heat production. Such a reservoir could be formed, for example, by incomplete differentiation of the crust and mantle, or by separation and isolation of recycled oceanic crust. We concentrated on models with a moderate amount of excess heat production in a lower layer, while remaining within the constraints required above. The excess heat must be low enough to prevent an excessive temperature increase across any internal boundary layers. In models with two strictly isolated layers and equivalent total heat production, the temperature-dependent viscosity adjusts to maintain an equivalent temperature drop across the layers, regardless of the thickness of the layers. The regulation of viscosity by temperature is consistent with the results of earlier parameterized models of two-layered convection by a number of researchers. Using a double-diffusive model of two-component convection to relax the mass transfer constraint across the interface, we observe substantial topography on the boundary. We will discuss the effect of fully dynamical layering on the thermal evolution.

Kellogg, L. H.; Ferrachat, S.; Natarajan, C. S.

2003-12-01

190

Optimizing Heat Exchangers for Air to Air Space Heating Heat Pumps in the United Kingdom.  

National Technical Information Service (NTIS)

The paper deals with some of the major aspects of heat exchanger design for electric heat pumps. After a discussion of heat transfer theory, it describes a method that can be used in design and sizing of air to refrigerant heat exchangers, and in calculat...

C. J. Blundell

1976-01-01

191

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

192

Carbon nanotube heat-exchange systems  

DOEpatents

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

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

2008-11-11

193

Fouling of heat exchanger surfaces: General principles  

NASA Astrophysics Data System (ADS)

This Data Item ESDU 86038 is an addition to the Heat Transfer Sub-series. The importance of various parameters that affect fouling are discussed. Appropriate methods for dealing with fouling in all stages from design through to operation of heat exchanger equipment are indicated. Methods of suppressing fouling by additives, or of cleaning equipment chemically or mechanically, are considered. A brief outline of the physical process of fouling including some mathematical models is given.

1986-12-01

194

Heat production and heat flow in the mantle lithosphere, Slave craton, Canada  

Microsoft Academic Search

Thermobarometric data for mantle xenoliths from a kimberlite pipe in the NWT, Canada are used to constrain the thermal properties of the lithospheric mantle underlying the Slave craton. We derive an analytical expression for a steady-state conductive mantle geotherm that is independent of the geometry and thermal properties of the crust. The model has an upper boundary coincident with the

James K. Russell; G. M. Dipple; M. G. Kopylova

2001-01-01

195

Heat transfer coefficients of shell and coiled tube heat exchangers  

SciTech Connect

In the present study, the heat transfer coefficients of shell and helically coiled tube heat exchangers were investigated experimentally. Three heat exchangers with different coil pitches were selected as test section for both parallel-flow and counter-flow configurations. All the required parameters like inlet and outlet temperatures of tube-side and shell-side fluids, flow rate of fluids, etc. were measured using appropriate instruments. Totally, 75 test runs were performed from which the tube-side and shell-side heat transfer coefficients were calculated. Empirical correlations were proposed for shell-side and tube-side. The calculated heat transfer coefficients of tube-side were also compared to the existing correlations for other boundary conditions and a reasonable agreement was observed. (author)

Salimpour, M.R. [Department of Mechanical Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran)

2009-01-15

196

Constraining the Present-day Mantle Heat Budget with Tomography-based Convection Models  

NASA Astrophysics Data System (ADS)

One of the outstanding problems in modern geodynamics, is the development of thermal convection models that satisfy a wide range of seismic, geodynamic, and mineral physical constraints on mantle structure and thermodynamic properties. An important application of such constrained convection models is to provide a time-dependent evolution of the mantle thermal structure that is as Earth-like as possible. These tomography-based convection models provide unique and robust information on the mean (global horizontal average) depth-dependent temperature that satisfies global energy-balance constraints on the mantle. We have developed a time-dependent, compressible convection model in 3-D spherical geometry that is consistent with tomography-based instantaneous flow dynamics. We considered two relevant surface boundary conditions (plate-like and rigid), along with geodynamically inferred radial viscosity profiles, and we obtained steady-state convective flows that are dominated by long wavelengths throughout the lower mantle. For both surface boundary conditions we obtained realistic values of surface heat flux, ranging from 37 TW to 44 TW. Our convection simulations deliver CMB heat flux that is on the high end of previously estimated values, ranging from 13 TW to 20 TW. These steady-state convection values are of the same magnitude as the CMB heat flux estimated with the present-day, tomography-based mantle flow models. We find that such substantial amounts of bottom-heating, across the CMB, of the mantle convective flow are necessary to sustain the active, large-scale hot upwellings that are so strongly expressed in the recent global tomography models.

Glisovic, P.; Forte, A. M.

2011-12-01

197

High Performance Woven Mesh Heat Exchange.  

National Technical Information Service (NTIS)

Woven mesh structures, consisting of bonded laminates of plain-weave conductive screens or three-dimensional orthogonal weaves are described. A mathematical model of the thermal performance of such a mesh, deployed as a heat exchange surface shows that th...

R. A. Wirtz

2003-01-01

198

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

199

Multiloop controller design for a heat exchanger  

Microsoft Academic Search

A new method to tune the parameters of two discrete controllers in a cascaded control structure is proposed and applied to the linear controller design of a heat exchanger system. Normally, this problem is solved either by decoupling the multiple loops and tuning the controllers independently or by keeping the structure but tuning the controllers consecutively from inwards to outwards.

Andrea Wellenreuther; Adrian Gambier; Essameddin Badreddin

2006-01-01

200

Heat Exchange After Atropine and Pralidoxime Administration.  

National Technical Information Service (NTIS)

This report summarizes a tightly controlled laboratory study in which the effects of intramuscular saline (control), atropine (2 mg), and/or pralidoxime (600 mg) on heat exchange were evaluated in four healthy males during seated, cycle exercise in a temp...

B. S. Cadarette L. A. Stephenson M. A. Kolka R. R. Gonzalez

1986-01-01

201

Improved ceramic heat exchanger materials. Final report  

Microsoft Academic Search

Numerous compositions were developed and evaluated for potential application as heat exchanger structures in automotive gas turbine engines. Test specimens were evaluated for thermal expansion and dimensional stability before and after exposure to sea salt and sulfuric acid, followed by thermal cycling up to 1200°C. Materials which survived the screening tests were considered for fabrication into honeycomb form. The material

H. W. Sr. Rauch; L. R. McCreight

1980-01-01

202

Failure analysis helps improve heat exchanger designs  

SciTech Connect

Industry's usual approach to evaluating the design of heat transfer equipment is to look for failures that have occurred in existing equipment of the same design, try to determine their causes, and then develop design modifications to prevent them from recurring. This is referred to as failure analysis. There is a tendency in industry to overlook successful designs of existing equipment that have operated for many years without major failures. A manufacturer of this type of equipment that also repairs and retubes heat exchangers is in a unique position to analyze and evaluate the deposition to analyze and evaluate the designs used. Data on the condition of individual components and materials used, and operating conditions, types of fluids and specific design features can all be compiled to develop a complete evaluation. In addition, calculations can be made to verify the validity of currently established design parameters from various sources. Utility heat exchangers cover a wide range of equipment, including feedwater heaters, evaporators, condensate coolers, lube oil coolers, turbine oil coolers, air preheaters, generator coolers, service water exchangers and air ejector condensers. The piece of equipment selected to be analyzed is a horizontal three-zone feedwater heater. Four major areas will be covered: tubeside, desuperheating, condensing, and subcooling zones of heat exchangers. The analysis will look at successful designs and the most common failures associated with each area.

Neel, L.

1993-08-01

203

Evaluation of heat exchangers for Cresap testing  

Microsoft Academic Search

Inherent with all coal liquefaction processes are streams containing coal-derived, heavy hydrocarbons and slurries of solid coal particles. The solid particles in the coal slurries (coal, silicate, and ash) cause erosion, corrosion, and fouling of heat exchangers. These high rates of erosion and corrosion cause rapid deterioration of the tubes. The flow media can polymerize and foul the tubes, ultimately

Ellefson

1976-01-01

204

Cleaning Agents for Reactor Heat Exchangers.  

National Technical Information Service (NTIS)

At SRP, oxalic acid is occasionally used to remove an oxide film from the shell side of reactor heat exchangers (HXs). The single-pass flow-through procedure utilizing 100 ppM oxalic acid removes the fouling layer at a rate proportional to the water tempe...

E. W. Wilde L. R. Berger J. A. Berger

1984-01-01

205

Effectiveness enchancement of heat exchanger by using nanofluids  

Microsoft Academic Search

Heat exchanger is the almost common equipment for the industrial process heating. Heat is transferred from one fluid to other fluids by convection and conduction through the wall of the heat exchanger. Effectiveness of heat exchanger depends on the convection heat transfer coefficient of the fluid. Convective heat transfer coefficient of water, Cu-water, AI-water, Al203-water and Ti02-water of 2% nanoparticle

M. Hasanuzzamana; R. Saidur; N. A. Rahim

2011-01-01

206

Non-linear effects from variable thermal conductivity and mantle internal heating: implications for massive melting and secular cooling of the mantle  

NASA Astrophysics Data System (ADS)

The temperature-dependence of the phonon portion of the thermal conductivity k( T, P) devised by Hofmeister [Science 283 1699-1706] decreases with temperature, the same as in the dependence of mantle viscosity. Such a functional relationship of ?k/ ?T<0, when coupled with internal heating would present a situation very conducive for positive feedback action. On the other hand, the photon dependence of the conductivity has a functional relationship of ?k/ ?T>0. Thus, there can be a tradeoff between the phonon and photon contributions in the conductivity in the presence of internal heating. We have conducted two-dimensional calculations of mantle convection up to a surface Rayleigh number of around five million and an internal heating of chondritic abundance, with the extended-Boussinesq approximation in which the dissipation number has been set to 0.47 and depth-dependent thermal expansivity, decreasing by a factor of 5 across the mantle. The value of the constant mantle viscosity and the amount of internal heating are varied. For an enhanced radiative contribution [J. Geophys. Res. 84 (B4) 1603-1610] the radiative component of the thermal conductivity can exceed the phonon contribution in the upper mantle. Our results show that in all cases with basal heating the average mantle temperature of the variable conductivity models are higher than those of the corresponding constant conductivity models. But the interior thermal difference between the two conductivity models decreases (1) with greater vigor of convection, (2) an increase of internal heating and (3) an increase in the radiative contribution to the conductivity. The interior mantle temperature is significantly hotter, more than 500 °C, than the constant conductivity model, for the k( T, P) model with the less enhanced radiative component [Science 283 1699-1706]. These results would suggest that some sort of massive melting in the young earth might have occurred with k( T, P) and that there should not be so much radioactivity in the lower mantle today without incurring the wrath of some melting. We have also studied the effects of k( T, P) on slowing down the mantle secular cooling process by monitoring the gradual decrease in mantle temperature following an imposition of an adiabatic boundary condition at the core-mantle boundary. A decay time of 3.6 Gy has been taken for the mantle radioactivity and we have varied the initial amount of radioactive heating from chondritic value to four times the chondritic value. A significant delay in the cooling process of at least 1-2 Gy is found for a surface Rayleigh number of between 5×10 6 to 5×10 7. The mantle temperature can be heated up by 300-400 °C for initial radiogenic heating value characteristic of the Archean. We find the strongest deviations from the constant conductivity case for a silicate model by Hofmeister [Science 283 1699-1706] and intermediate values for an enhanced radiative conductivity model comparable to the model of Shankland et al. [J. Geophys. Res. 84 (B4) 1603-1610]. Such high mantle temperatures maintained for a long time by variable thermal conductivity would have important consequences on the thermal and petrological evolution of the mantle.

van den Berg, A. P.; Yuen, D. A.; Allwardt, J. R.

2002-02-01

207

Liquid-Metal-Gas Heat Exchanger for HTGR Type Reactors.  

National Technical Information Service (NTIS)

The aim of this study is to investigate the heat transfer characteristics of a liquid metal heat exchanger (HE) for a helium-cooled high temperature reactor. A tube-type heat exchanger is considered as well as two direct exchangers: a bubble-type heat exc...

G. Werth

1980-01-01

208

Performance of a MEMS Heat Exchanger for a Cryosurgical Probe  

Microsoft Academic Search

This paper presents the experimental test results for two 2 nd generation Micro-Electro- Mechanical Systems (MEMS) heat exchangers that are a composite of silicon plates with micro- machined flow passages interleaved with glass spacers. The MEMS heat exchangers were designed for use as the recuperative heat exchanger within a Joule-Thomson (JT) cycle used to energize a cryosurgical probe. The heat

M. J. White; W. Zhu; G. F. Nellis; S. A. Klein; Y. B. Gianchandani

209

Thermal structure of continental upper mantle inferred from S-wave velocity and surface heat flow  

Microsoft Academic Search

Results from seismic tomography provide information on the thermal structure of the continental upper mantle. This is borne out by the good agreement between tectonic age, surface heat flow and a tomographic S-wave velocity model for depths less than 180 km. The velocity anomalies of tomographic layers deeper than 230 km have relatively small amplitudes and show little correlation with

Axel H. E Röhm; Roel Snieder; Saskia Goes; Jeannot Trampert

2000-01-01

210

Heat Exchanger Design in Combined Cycle Engines  

NASA Astrophysics Data System (ADS)

Combined cycle engines employing both pre-cooled air-breathing and rocket modes of operation are the most promising propulsion system for achieving single stage to orbit vehicles. The air-breathing phase is purely for augmentation of the mission velocity required in the rocket phase and as such must be mass effective, re-using the components of the rocket cycle, whilst achieving adequate specific impulse. This paper explains how the unique demands placed on the air-breathing cycle results in the need for sophisticated thermodynamics and the use of a series of different heat exchangers to enable precooling and high pressure ratio compression of the air for delivery to the rocket combustion chambers. These major heat exchanger roles are; extracting heat from incoming air in the precooler, topping up cycle flow temperatures to maintain constant turbine operating conditions and extracting rejected heat from the power cycle via regenerator loops for thermal capacity matching. The design solutions of these heat exchangers are discussed.

Webber, H.; Feast, S.; Bond, A.

211

Experimental Study of Heat Transfer and Pressure Drop Characteristics of Air\\/Water and Air-Steam\\/Water Heat Exchange in a Polymer Compact Heat Exchanger  

Microsoft Academic Search

Experiments of heat transfer and pressure drop in a polymer compact heat exchanger made of PolyVinyliDene-Fluoride were conducted under various conditions for air\\/water heat exchange and air-steam\\/water heat exchange, respectively. The overall heat transfer coefficients of air-steam\\/water heat exchange (150 to 600 W\\/mK) are much greater than that of air\\/water heat exchange (80 to 130 W\\/mK). The pressure drops of

Lixin Cheng; CEES W. M. VAN DER GELD

2005-01-01

212

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

213

Cost-effectiveness study of heat pipe heat exchangers  

Microsoft Academic Search

The initial costs of three types of heat pipe heat exchangers are presented: aluminum-Freon 11 for the temperature range from -23 C to 121 C, copper-water for 38 C to 232 C, and carbon steel-Dowtherm A for 120 C to 400 C. An optimization computer program for the cost-effectiveness analysis is developed, which takes into consideration the costs for equipment,

D. C. Lu; K. T. Feldman Jr.

1977-01-01

214

Controlling space humidity with heat-pipe heat exchangers  

Microsoft Academic Search

The performance of an existing 5 ton (17.6 kW) air conditioning system with an energy efficiency ratio, EER, of 8 has been simulated by retrofitting it with a heat-pipe heat-exchanger (HPHE) to improve cooling and dehumidification. Weather data for Dallas (ASHRAE, 1997) is used for this investigation. This investigation shows that by retrofitting an existing 5 ton (17.6 kW) air

G. D. Mathur

2000-01-01

215

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

Microsoft Academic Search

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

Mitsuo Kanzaka; Makio Iwabuchi

1992-01-01

216

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

217

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

NASA Astrophysics Data System (ADS)

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

Kanzaka, Mitsuo; Iwabuchi, Makio

1992-11-01

218

The analysis of heat transfer with and without condensation in a heat pipe heat exchanger  

Microsoft Academic Search

In most heat pipe heat exchangers, the fluid streams will be in counterflow, and the inlet temperatures and the volume or mass flow rates of each stream are known. The simplest analysis under these conditions is provided by the effectiveness method reported by Kreith (1967). An expression for the effectiveness of a counterflow heat exchanger is derived by Kays and

R. C. Prager; T. H. Sun

1978-01-01

219

Advanced Heat Exchangers Program Review Meeting  

NASA Astrophysics Data System (ADS)

On a semiannual basis a review meeting of the U.S. Department of Energy's Advanced Heat Exchangers Program is held with the objective of reviewing ongoing and recently completed project activities. During the meeting, personnel from industrial contractors and national laboratories who have been funded to develop advanced heat exchanger technology by the U.S. Department of Energy, Office of Industrial Programs present technical aspects of their projects. The projects generally deal with mid to high temperature waste heat recuperation and other subject areas of heat exchange. Each presentation is followed by a discussion period during which the presenters field questions from the meeting attendees. This report documents the most recent meeting, held October 11 to 12, 1989. It is composed primarily of a series of short sections addressing the individual projects. Each section includes presentation slides of the project and a summary of questions and answers that followed. An appendix of meeting attendees is also included. Individual projects have been processed separately for the data bases.

1990-07-01

220

Advanced Heat Exchangers Program review meeting  

SciTech Connect

On a semiannual basis a review meeting of the US Department of Energy's Advanced Heat Exchangers Program is held with the objective of reviewing ongoing and recently completed project activities. During the meeting, personnel from industrial contractors and national laboratories who have been funded to develop advanced heat exchanger technology by the US Department of Energy, Office of Industrial Programs present technical aspects of their projects. The projects generally deal with mid to high temperature waste heat recuperation and other subject areas of heat exchange. Each presentation is followed by a discussion period during which the presenters field questions from the meeting attendees. This report documents the most recent meeting, held October 11--12, 1989. It is composed primarily of a series of short sections addressing the individual projects. Each section includes presentation slides of the project and a summary of questions and answers that followed. An appendix of meeting attendees is also included. Individual projects have been processed separately for the data basis.

Not Available

1990-07-01

221

40 CFR 63.1435 - Heat exchanger provisions.  

Code of Federal Regulations, 2013 CFR

...HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED...Production § 63.1435 Heat exchanger provisions. ...operator of each affected source shall comply with the requirements of § 63.104 for heat exchange systems,...

2013-07-01

222

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

223

Modulation of mantle plumes and heat flow at the core mantle boundary by plate-scale flow: results from laboratory experiments  

NASA Astrophysics Data System (ADS)

We report results from analog laboratory experiments, in which a large-scale flow is imposed upon natural convection from a hot boundary layer at the base of a large tank of corn syrup. The experiments show that the subdivision of the convective flow into four regions provides a reasonable conceptual framework for interpreting the effects of large-scale flow on plumes. Region I includes the area of the hot thermal boundary layer (TBL) that is thinned by the large-scale flow, thereby suppressing plumes. Region II encompasses the critically unstable boundary layer where plumes form. Region III is the area above the boundary layer that is devoid of plumes. Region IV comprises the area of hot upwelling and plume conduits. Quantitative analysis of our experiments results in a scaling law for heat flux from the hot boundary and for the spatial extent of plume suppression. When applied to the Earth's core-mantle boundary (CMB), our results suggest that large-scale mantle flow, due to sinking lithospheric plates, can locally thin the TBL and suppress plume formation over large fractions of the CMB. Approximately 30% of heat flow from the core may be due to increased heat flux from plate-scale flow. Furthermore, CMB heat flux is non-uniformly distributed along the CMB, with large areas where heat flux is increased on average by a factor of 2. As a consequence, the convective flow pattern in the outer core may be affected by CMB heat-flux heterogeneity and sensitive to changes in plate-scale mantle flow. Because of plume suppression and 'focusing' of hot mantle from the CMB into zones of upwelling flow, plume conduits (hotspots) are expected to be spatially associated with lower-mantle regions of low seismic velocities, inferred as hot upwelling mantle flow.

Gonnermann, Helge M.; Jellinek, A. Mark; Richards, Mark A.; Manga, Michael

2004-09-01

224

High temperature active heat exchanger research for latent heat storage  

NASA Astrophysics Data System (ADS)

An active heat exchange method in a latent heat (salt) thermal energy storage system that prevents a low conductivity solid salt layer from forming on heat transfer surfaces was developed. An evaluation of suitable media with melting points in the temperature range of interest (250 to 400 C) limited the candidates to molten salts from the chloride, hydroxide and nitrate families, based on high storage capacity, good corrosion characteristics and availability in large quantities at reasonable cost. The specific salt recommended for laboratory tests was a choride eutectic (20.5KCL o 24.5NaCL o 55.MgCl2% by wt.), with a nominal melting point of 385 C. Various active heat exchange concepts were given a technical and economic comparison to a passive tube shell design for a reference application (300 MW sub t for 6 hours). Test hardware was then built for the most promising concept: a direct contact heat exchanger in which molten salt droplets are injected into a cooler counter flowing stream of liquid metal carrier fluid (lead/Bismuth).

Alario, J.; Haslett, R.

1982-02-01

225

Cleaning agents for reactor heat exchangers  

SciTech Connect

At SRP, oxalic acid is occasionally used to remove an oxide film from the shell side of reactor heat exchangers (HXs). The single-pass flow-through procedure utilizing 100 ppM oxalic acid removes the fouling layer at a rate proportional to the water temperature. A comparison of the effectiveness of oxalic acid with other potential cleaning agents using test specimens from a fouled heat exchanger demonstrated that oxalic acid at comparable concentrations is superior to the alternatives. The effects of periodic treatment of the HXs with oxalic acid on carbon steel components in the system is small or negligible when the naturally formed protective corrosion layer is undisturbed. Although it does etch the bare metal, oxalic acid has little effect on the protective corrosion layer. Periodic use of oxalic acid on the HX system should not decrease the life of the carbon steel headers.

Wilde, E.W.; Berger, L.R.; Berger, J.A.

1984-03-01

226

Investigate Advanced Heat Exchanger Designs of Compact Heat Exchangers when Operative in a Marine Environment.  

National Technical Information Service (NTIS)

The overall objective of this contract is to obtain a fundamental understanding of the performance of perforated plates as a heat transfer surface for compact heat exchangers. In line with this, a low turbulence wind tunnel is to be used throughout the te...

1965-01-01

227

Conceptualizations for cleaning OTEC heat exchangers  

SciTech Connect

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

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

1978-09-01

228

Corrosion Problems for Heat Exchangers of Pressurized Water Reactors.  

National Technical Information Service (NTIS)

Heat exchangers are used between the primary and the secondary circuits of PWR-PHWR. The various corrosion types and the types of heat exchangers are described with the well-known corrosion regions in them. Corrosion defects in the heat exchangers are inv...

B. Tugrul H. Yavuz

1985-01-01

229

Heat exchanger support apparatus in a fluidized bed  

Microsoft Academic Search

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 there through to prevent deterioration

Lawton

1982-01-01

230

Heat exchanger support apparatus in a fluidized bed  

Microsoft Academic Search

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

Lawton; Carl W

1982-01-01

231

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

232

Development of high effectiveness droplet heat exchangers. Final report  

Microsoft Academic Search

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

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

1985-01-01

233

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

234

Investigation into fouling of a printed circuit heat exchanger.  

National Technical Information Service (NTIS)

A facility has been built to compare the fouling propensity of two heat exchangers operating with cooling water from an open cooling tower. Tests were carried out with a Printed Circuit Heat Exchanger and a heat exchanger having tube dimensions representa...

1991-01-01

235

Birch's Crustal Heat Production-Heat Flow Law: Key to Quantifying Mantle Heat Flow as a function of time  

NASA Astrophysics Data System (ADS)

Birch (1968) first showed the linear correlation of surface heat flow and radioactive heat production (Qs = Qo + bAs ) in granites in New England, USA and discussed implications to the vertical scale of radioactive heat generation in the crust. Subsequently similar relationships have been found worldwide and numerous papers written describing more details and expanding the implications of Birch's Law. The results are a powerful contribution from heat flow research to the understanding of the lithosphere and its evolution. Models are both well constrained experimentally and simple in implications. However, there still exist thermal models of the crust and lithosphere that do not have the same firm foundation and involve unnecessary ad hoc assumptions. A main point of confusion has been that the several of the original relationships were so low in error as to be considered by some to be "fortuitous". Interestingly a "similar" relationship has been proposed based on regional scale averaging of Qs -As data. A second point of confusion is that one admissible crustal radioactivity distribution model (the constant heat generation to depth b) has been criticized as unrealistic for a number of reasons, including the effect of erosion. However, it is appropriate to refer to the Qs -As relationship as a law because in fact the relationship holds as long as the vertical distribution is "geologically realistic." as will be demonstrated in this paper. All geologic and geophysical models of the continental crust imply decreasing heat production as a function of depth (i.e. the seismic layering for example) except in very special cases. This general decrease with depth is the only condition required for the existence of a "linear" Qs -As relationship. A comparison of all the Qs -As relationships proposed for terrains not affected by thermal events over the last 150 to 200 Ma shows a remarkably uniformity in slope (10 ± 3 km) and intercept value (30 ± 5 mWm-2 ). Therefore these parameters of Birch's Law equation represent the starting place for discussions of lithospheric thermal regime and evolution. The stability of the values of intercept Qo for areas with thermal ages of Paleozoic and older prove that the lithosphere heat flow does not vary significantly with age as is demonstrated in the companion paper. The minimum mantle heat flow for preMesozoic thermal terrains is 20 - 25 mWm-2. This value is consistent with the lack of indication from xenolith data that lithosphere thickness changes with age and with theoretical models of mantle convection.

Blackwell, D. D.; Thakur, M.

2007-12-01

236

Use of a fluidized bed heat exchanger to improve the performance of a heat pump  

Microsoft Academic Search

The outdoor evaporator heat exchanger of a 60,000 Btu heat pump in the heating mode was replaced with a fluidized bed heat exchanger. Air temperature control was achieved by recirculating the conditioned air from both the evaporator and condenser heat exchangers through a chambered plenum. Candidate particles and distributor plates for the design of the bed were tested separately. A

R. G. Sarubbi; J. C. Chen

1981-01-01

237

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

238

Analysis of Influencing Factors of Heat Transfer Performance of Heat Pipe Heat Exchanger  

Microsoft Academic Search

Heat transfer performance of heat pipe heat exchanger affected by many factors, such as the opening temperature of the heat pipe, the rate of fluid-filled, the physical nature of liquid refrigerant, the work temperature of tube, angle, tube spacing, tube length, hot and cold fluid flow and wind speed. The above-mentioned parameters can not be measured because of Test conditions,

Zhang Jie; Ren Yan; Zhang Lihong; Liang Huimin

2009-01-01

239

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...measurement, pump curves, heat balance calculations, or other...the density of water at the specific monitoring location temperature...hydrocarbon emissions for the leaking heat exchange system or heat...

2013-07-01

240

Advances in liquid fluidized-bed heat exchanger development  

Microsoft Academic Search

The paper reports the first heat transfer results from a horizontal liquid fluidized-bed heat exchanger. Geothermal water from Raft River Geothermal Wells provided the heat source. Treated water was the secondary fluid. Silica sand closely screened to 16 mesh was the bed material. The exchanger was 8 in. in diameter by 15 in. long. Heat transfer results are compared with

E. S. Grimmett; A. F. Fanous; C. A. Allen

1977-01-01

241

Time-dependent convection models of mantle thermal structure constrained by seismic tomography and geodynamics: implications for mantle plume dynamics and CMB heat flux  

NASA Astrophysics Data System (ADS)

One of the outstanding problems in modern geodynamics is the development of thermal convection models that are consistent with the present-day flow dynamics in the Earth's mantle, in accord with seismic tomographic images of 3-D Earth structure, and that are also capable of providing a time-dependent evolution of the mantle thermal structure that is as 'realistic' (Earth-like) as possible. A successful realization of this objective would provide a realistic model of 3-D mantle convection that has optimal consistency with a wide suite of seismic, geodynamic and mineral physical constraints on mantle structure and thermodynamic properties. To address this challenge, we have constructed a time-dependent, compressible convection model in 3-D spherical geometry that is consistent with tomography-based instantaneous flow dynamics, using an updated and revised pseudo-spectral numerical method. The novel feature of our numerical solutions is that the equations of conservation of mass and momentum are solved only once in terms of spectral Green's functions. We initially focus on the theory and numerical methods employed to solve the equation of thermal energy conservation using the Green's function solutions for the equation of motion, with special attention placed on the numerical accuracy and stability of the convection solutions. A particular concern is the verification of the global energy balance in the dissipative, compressible-mantle formulation we adopt. Such validation is essential because we then present geodynamically constrained convection solutions over billion-year timescales, starting from present-day seismically constrained thermal images of the mantle. The use of geodynamically constrained spectral Green's functions facilitates the modelling of the dynamic impact on the mantle evolution of: (1) depth-dependent thermal conductivity profiles, (2) extreme variations of viscosity over depth and (3) different surface boundary conditions, in this case mobile surface plates and a rigid surface. The thermal interpretation of seismic tomography models does not provide a radial profile of the horizontally averaged temperature (i.e. the geotherm) in the mantle. One important goal of this study is to obtain a steady-state geotherm with boundary layers which satisfies energy balance of the system and provides the starting point for more realistic numerical simulations of the Earth's evolution. We obtain surface heat flux in the range of Earth-like values : 37 TW for a rigid surface and 44 TW for a surface with tectonic plates coupled to the mantle flow. Also, our convection simulations deliver CMB heat flux that is on the high end of previously estimated values, namely 13 TW and 20 TW, for rigid and plate-like surface boundary conditions, respectively. We finally employ these two end-member surface boundary conditions to explore the very-long-time scale evolution of convection over billion-year time windows. These billion-year-scale simulations will allow us to determine the extent to which a 'memory' of the starting tomography-based thermal structure is preserved and hence to explore the longevity of the structures in the present-day mantle. The two surface boundary conditions, along with the geodynamically inferred radial viscosity profiles, yield steady-state convective flows that are dominated by long wavelengths throughout the lower mantle. The rigid-surface condition yields a spectrum of mantle heterogeneity dominated by spherical harmonic degree 3 and 4, and the plate-like surface condition yields a pattern dominated by degree 1. Our exploration of the time-dependence of the spatial heterogeneity shows that, for both types of surface boundary condition, deep-mantle hot upwellings resolved in the present-day tomography model are durable and stable features. These deeply rooted mantle plumes show remarkable longevity over very long geological time spans, mainly owing to the geodynamically inferred high viscosity in the lower mantle.

Glišovi?, P.; Forte, A. M.; Moucha, R.

2012-08-01

242

Fluidized bed reactor system and method having a heat exchanger  

SciTech Connect

A fluidized bed reactor system is described comprising a reactor, means for supporting a fluidized bed of combustible particulate material in said reactor, heat exchange means disposed adjacent said reactor, separating means for receiving a mixture of flue gases and entrained particulate material from said fluidized bed and separating said particulate material from said flue gases, means for passing said separated particulate material to said heat exchange means, means for passing air through said separated particulate material in said heat exchange means to fluidize said separated material, means disposed in said heat exchange means for passing a coolant in a heat exchange relation to said separated material to transfer heat from said separated material to said coolant, and means for supplying additional heat to said separated material in said heat exchange means to control the temperature of said coolant.

Garcia-Mallol, J.A.

1993-08-31

243

Liquid-fluidized-bed heat exchanger flow distribution models  

Microsoft Academic Search

Liquid-fluidized-bed shell-and-tube heat exchangers for geothermal applications are considered. Sand fluidized by geothermal water on the shell side prevents scaling and increases heat transfer coefficients over conventional heat exchangers. Tests conducted on two instrumented fluidized-bed heat exchanger models, constructed primarily of plexiglass, which differ in tube bundle orientation are described. Plexiglass construction allowed visual observation of flow patterns. The vertical

L. T. Cole; C. A. Allen

1979-01-01

244

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

245

Microbial fouling control in heat exchangers  

SciTech Connect

Biofilm formation in turbulent flow has been studied a great deal during the last 15 years. Such studies have provided the basis for further experiments designed to test the efficacy of industrial antimicrobials against biofilms in laboratory models and in actual real-world industrial water-treatment programs. Biofilm microbiology is relevant from the industrial perspective because adherent populations of microorganisms often cause an economic impact on industrial processes. For example, it is the adherent population of microorganisms in cooling-water systems that can eventually contribute to significant heat transfer and fluid frictional resistances. The microbiology of biofilms in heat exchangers can be related to the performance of industrial antimicrobials. The development of fouling biofilms and methods to quantitatively observe the effect of biofouling control agents are discussed in this paper.

McCoy, W.F.

1991-11-01

246

Baghouse heat exchanger saves fuel, protects equipment, warms workers  

SciTech Connect

A heat exchanger system designed to cool 900/sup 0/F exhaust air from a rotary kiln has also proven that it can provide large annual fuel savings, protect equipment from freezing and increase employee comfort. The system uses two plate-type heat exchangers and a fiber glass baghouse utilizing reverse air cleaning. The heat exchangers were designed to lower the kiln exhaust temperature from 900/sup 0/F to 500/sup 0/F prior to entering the baghouse. A bleed-in damper in the ductwork ensures that gases entering the heat exchanger do not exceed 900/sup 0/F. The units have a heat-transfer surface of 14,786 ft/sup 2/, design inlet volume of 120,000 ACFM and design outlet volume of 84,000 ACFM. The heat exchanger has a built-in cleaning mechanism which operates on a timer and limits the build-up of deposits on the heat exchanger surfaces.

Krout, B.; Kilheffer, J.

1984-03-01

247

Shell-and-double concentric-tube heat exchangers  

NASA Astrophysics Data System (ADS)

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

Bougriou, Chérif; Baadache, Khireddine

2010-03-01

248

MINLP heat exchanger network design incorporating pressure drop effects  

Microsoft Academic Search

Successful work has been done on heat exchanger network synthesis (HEN) using both Pinch Technology and MINLP techniques. However, most of the design procedures reported to date assume constant stream heat transfer coefficients. Motivated by the fact that detailed heat exchanger design is based on pressure drop of the streams, in this paper we extend the simutaneous MINLP model for

S. Frausto-Hernández; V. Rico-Ramírez; S. Hernández-Castro; A. Jiménez

2002-01-01

249

Heat exchanger development for Ocean Thermal Energy Conversion  

Microsoft Academic Search

Heat exchangers comprise one of the largest cost drivers for Ocean Thermal Energy Conversion (OTEC) systems. Reductions in fabrication costs and improvements in performance are critical to successfully commercialize sustainable energy power plants using this low (?20°C) ?T resource. Heat exchanger (HX) units should maximize heat transfer per unit area (U value) while minimizing pressure losses, corrosion and cost. Current

Michael P. Eldred; Joseph C. Van Ryzin; Steven Rizea; In Chieh Chen; Robert Loudon; N. John Nagurny; Scott Maurer; Eugene Jansen; Andrew Plumb; Michael R. Eller; Victor R. R. Brown

2011-01-01

250

Control of heat exchangers using Model Predictive Controller  

Microsoft Academic Search

The objective of this paper is to develop a Model Predictive Control (MPC) for a Shell and Tube Heat Exchanger. Since the heat exchanger is a highly non linear system, the operating zone of the system is divided into different zones. For each zone, a model is developed. Even though PID controllers are widely used for the control of heat

Krishna V Vinaya; K. Ramkumar; V Alagesan

2012-01-01

251

COMPACT HEAT EXCHANGERS FOR MOBILE CO2 SYSTEMS  

Microsoft Academic Search

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

A. Hafner

252

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

Microsoft Academic Search

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

G. K. Housley; J. E. OBrien; G. L. Hawkes

2008-01-01

253

14 CFR 29.1125 - Exhaust heat exchangers.  

Code of Federal Regulations, 2013 CFR

...powered rotorcraft the following apply: (a) Each exhaust heat exchanger must be constructed and installed to withstand the vibration, inertia, and other loads to which it would be subjected in operation. In additionâ (1) Each exchanger must be...

2013-01-01

254

Mantle Flow Uplift and Heating of the Anatolian Block: Interpretations from Geophysical Evidence and Geodynamic Modeling  

NASA Astrophysics Data System (ADS)

Western Anatolia and the eastern Aegean demonstrate an interesting geologic history of horizontal and vertical tectonics. Active normal faulting and exhumational zones indicate that western Anatolia has experienced significant extension since the Oligocene-Early Miocene ( ˜30 Ma). Geomorphological evidence indicates recent uplift: ˜700 m in the last 3 Myrs. We have conducted a series of geophysical analyses to demonstrate that the region is also uplifted relative to an elevation that would be expected given an isostatic response to the lithospheric structure. Namely, topography 'residuals' indicate a residual uplift of ˜1000 m over ˜500 km sections of western Anatolia and the eastern Aegean. We also calculate admittance functions between free-air gravity and topography to quantify the nature of the uplift. These data indicate that the regional topography is isostatically uncompensated and is likely owing to an underlying mantle flow component. Heat flow data indicate that the area is thermally elevated as well. Using forward geodynamic modeling we consider idealized sections of Anatolian lithosphere based on tomographic inversions and examine the magnitude and pattern of surface topography and heat flow to reconcile with the geophysical observables. The models test the response of the surface topography to various configurations of the Anatolian-Aegean surface plates, including variably strong lithosphere and the presence of a weak mantle wedge and weak zones in the crust. Together, the geophysical data and analyses and modeling provide independent quantitative evidence that the thin Anatolian/Aegean lithosphere is being buoyed upwards by underlying mantle flow. We propose that the mantle flow is associated with lithospheric delamination beneath the region; a process that would also explain the ongoing crustal extension.

Komut, T.; Gogus, O. H.; Gray, R.; Pysklywec, R. N.

2011-12-01

255

Heat Transfer with Phase Change in Plate-Fin Heat Exchangers.  

National Technical Information Service (NTIS)

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 m...

C. B. Panchal

1984-01-01

256

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

257

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

258

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

Microsoft Academic Search

The authors have measured heat transfer and pressure drop 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

D. A. Olson

1992-01-01

259

Heat exchanger development at Reaction Engines Ltd.  

NASA Astrophysics Data System (ADS)

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

Varvill, Richard

2010-05-01

260

Heat exchanger and water tank arrangement for passive cooling system  

DOEpatents

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

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

1993-01-01

261

Industrial applications for LIGA-fabricated micro heat exchangers  

NASA Astrophysics Data System (ADS)

One of the well-known benefits of micro scale is enhanced heat transfer. This fact provides the motivation for fabricating a variety of micro heat exchangers using derivatives of the LIGA micromachining process. These heat exchangers can be made of polymers, nickel (electroplated or electroless), or ceramics (Si3N4 and alumina are presently being investigated). These heat exchangers are envisioned for applications such as gas turbine blades, mechanical seals and/or bearings, boilers, condensers, radiators, evaporators, electronic component cooling, and catalytic converters. In this paper, methods to fabricate an array of heat exchangers for different applications are described. In addition, simple analytic models that illustrate the motivation for fabricating micro cross flow heat exchanges are shown to compare favorably with experimental heat transfer results.

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

2001-10-01

262

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

263

Performance degradation due to longitudinal heat conduction in very high NTU counterflow heat exchangers  

Microsoft Academic Search

High effectiveness heat exchangers are employed in most cryogenic systems. In some systems such as cryocoolers employed in space, the NTU of the heat exchangers employed is quite large. The effectiveness of all such exchangers is largely controlled by the longitudinal heat conduction through the walls. In this paper, we present a closed form expression for the effectiveness of very

S. Pradeep Narayanan; G. Venkatarathnam

1998-01-01

264

Design and evaluation of a heat pipe exchanger  

Microsoft Academic Search

A promising approach to energy conservation is the use of heat pipes to recover heat now lost in effluent processing wastewater streams. At Radford Army Ammunition Plant a prototype water-to-water heat pipe heat exchanger (HPHX) was evaluated. Heat was extracted from wastewater and recovered heat then used to preheat incoming fresh water. The heat pipe is schematicized. Design objectives--access to

C. H. Johnson; E. Zeigler

1982-01-01

265

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

Microsoft Academic Search

This paper presents the results of experimental and theoretical analysis on the heat extraction process from solar pond by using the heat pipe heat exchanger. In order to conduct research work, a small scale experimental solar pond with an area of 7.0m2 and a depth of 1.5m was built at Khon Kaen in North-Eastern Thailand (16°27?N102°E). Heat was successfully extracted

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

2010-01-01

266

Designing and troubleshooting plate heat exchangers  

SciTech Connect

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

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

1998-05-01

267

DEVELOPMENT OF ODS HEAT EXCHANGER TUBING  

SciTech Connect

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

Mark A. Harper, Ph.D.

2001-01-01

268

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

NASA Astrophysics Data System (ADS)

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

Cheng, Xue-Tao; Liang, Xin-Gang

2013-08-01

269

Development of residential gas-fired furnaces using heat pipe heat exchangers. Final report, July 1988-February 1992  

SciTech Connect

The principal objective of the heat pipe heat exchanger development program was to design, fabricate, and demonstrate the performance of heat pipe heat exchangers for gas-fired residential furnaces that improved upon the previously marketed heat pipe furnace.

Dussinger, P.M.; Hartenstine, J.R.

1992-07-01

270

Development of Residential Gas-Fired Furnaces Using Heat Pipe Heat Exchangers. Final Report, July 1988-February 1992.  

National Technical Information Service (NTIS)

The principal objective of the heat pipe heat exchanger development program was to design, fabricate, and demonstrate the performance of heat pipe heat exchangers for gas-fired residential furnaces that improved upon the previously marketed heat pipe furn...

P. M. Dussinger J. R. Hartenstine

1992-01-01

271

Development of residential gas-fired furnaces using heat pipe heat exchangers. Final report, July 1988February 1992  

Microsoft Academic Search

The principal objective of the heat pipe heat exchanger development program was to design, fabricate, and demonstrate the performance of heat pipe heat exchangers for gas-fired residential furnaces that improved upon the previously marketed heat pipe furnace.

P. M. Dussinger; J. R. Hartenstine

1992-01-01

272

Surface heat flow and the mantle contribution on the margins of Australia  

NASA Astrophysics Data System (ADS)

We present thermal data from 473 oil exploration wells in Australia and New Zealand. Approximately 2300 bottom-hole temperatures are corrected to form a homogeneous set along with 86 temperatures from reservoir tests. Thermal conductivity profiles are estimated from a set of geophysical well logs using a recently developed neural network approach. Retaining wells in which temperature and thermal conductivity data overlap over an interval greater than 1000 m, we estimate 10 heat flow values in the Taranaki basin of New Zealand and 270 values in the northwestern, western, and southern margins and in the intracontinental Canning basin of Australia. The values are in the range 30-80 mW m-2. As a result of several differences in the data and methods, our heat flow values are 10-20 mW m-2 lower compared to previously published estimates for the same wells in New Zealand. For Australia, our values are consistent with previously measured values and trends in the continental and marine regions. On the northwestern and southeastern margins, we interpret the variations as reflecting changes in the nature of the underlying basement. Consistent with onshore data, it is inferred that the Archean crust is depleted in radiogenic elements compared to Proterozoic regions and that recent volcanism affects the eastern Paleozoic area. After removing from surface heat flow the sediment contributions, including a permanent radiogenic heat component and a transient sedimentation effect, a simple crustal model suggests that mantle heat flow on the continental margin bordering the Pilbara craton is higher than below the craton itself. Moreover, heat flow corrected for the sediment contributions is markedly lower in the Petrel intracontinental basin than in the adjacent margin, although the crust is thinner below this latter region. As both are underlaid by the same basement, this observation may indicate that the mantle contribution is also higher below that margin. Such a higher mantle heat flow on old continental margins is consistent with experiments of fluid convection below an insulating lid and suggests that the thermal regime of the continental lithosphere never returns to its prerift state, as usually assumed by several thermomechanical models of evolution of continental margins.

Goutorbe, Bruno; Lucazeau, Francis; Bonneville, Alain

2008-05-01

273

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

274

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

275

Use of Fluidized Bed Heat Exchangers in Heat Pump Systems for Improved Performance. Progress Report.  

National Technical Information Service (NTIS)

The performance of a residential-type heat pump nominally rated at 60,000 Btu/hr is being investigated, when its heat exchangers are replaced with fluidized bed heat exchangers. A York heat pump has been obtained and installed and a plenum and associated ...

J. C. Chen R. G. Sarubbi

1978-01-01

276

Cleaning and Heat Transfer in Heat Exchanger with Circulating Fluidized Beds  

Microsoft Academic Search

Fluidized bed type heat exchangers are known to increase the heat transfer and prevent the fouling. For proper design of circulating fluidized bed heat exchanger it is important to know the effect of design and operating parameters on the bed to the wall heat transfer coefficient. The present experimental and numerical study was conducted to investigate the effects of circulating

Ho Keun Kang; Soo Whan Ahn; Jong Woong Choi; Byung Chang Lee

2010-01-01

277

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

Microsoft Academic Search

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

Kraft

1975-01-01

278

Comparative Study of Rotating Regenerators and Heat-Pipe Heat Exchangers. Final Report.  

National Technical Information Service (NTIS)

The aim of this research was to make a comparison between two types of heat exchangers operating in a practical environment. The heat wheel (rotating regenerator) and the heat pipe heat exchanger were intended to have efficiencies of between 60 and 80% an...

D. B. A . Macmichael D. A. F. E. Reay

1980-01-01

279

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

Microsoft Academic Search

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

Jentung Ku; Seokgeun Yun; Edward J. Kroliczek

1992-01-01

280

Empirical Study of an Air-to-Air Heat Pipe Heat Exchanger in Tropical Climates  

Microsoft Academic Search

This article presents the empirical study of a heat pipe heat exchanger that was directly experiencing the ambient tropical air in its evaporator section. The performance of the heat pipe heat exchanger was monitored during two weeks of operation to determine the performance curves. The temperature of return air was controlled at about 22°C as the representative temperature of inside

Y. H. Yau; M. Ahmadzadehtalatapeh

2011-01-01

281

40 CFR 63.1328 - Heat exchange systems provisions.  

Code of Federal Regulations, 2010 CFR

...and Resins § 63.1328 Heat exchange systems provisions...specifies the monitoring plan retention requirements, and when § 63...1) refers to the record retention requirements in § 63.103...h) The compliance date for heat exchange systems subject...

2010-07-01

282

40 CFR 63.1328 - Heat exchange systems provisions.  

Code of Federal Regulations, 2010 CFR

...and Resins § 63.1328 Heat exchange systems provisions...specifies the monitoring plan retention requirements, and when § 63...1) refers to the record retention requirements in § 63.103...h) The compliance date for heat exchange systems subject...

2009-07-01

283

Integrated control, diagnosis and reconfiguration of a heat exchanger  

Microsoft Academic Search

Heat exchangers play an important role in chemical and process industries. In order to improve reliability and control performance, intelligent concepts for control, supervision and reconfiguration are necessary. In this paper, an approach is presented which integrates model-based adaptive control and reconfiguration based on fault detection\\/diagnosis applied to a heat exchanger plant. The adaptive controller and the fault detection scheme

P. Balle; Martin Fischer; Dominik Fussel; Rolf Isermann

1997-01-01

284

Internal dust recirculation system for a fluidized bed heat exchanger  

Microsoft Academic Search

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

Robert L. Gamble; Juan A. Garcia-Mallol

1981-01-01

285

Continuous Cleaning of Heat Exchanger with Recirculating Fluidized Bed  

Microsoft Academic Search

Fluidized bed heat exchangers for liquids have been studied in the United States, the Netherlands, and the Federal Republic of Germany. Between 1965 and 1970, fluidized bed heat exchangers were developed in the United States as brine heaters in seawater desalination. Furthermore, their potential in the utilization of geothermal energy was tested between 1975 and 1980. In the Netherlands, fluidized

Jochen St. Kollbach; W. Dahm; R. Rautenbach

1987-01-01

286

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...HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) ...Polymers and Resins § 63.1328 Heat exchange systems provisions...owner or operator of an affected source shall comply with §...

2013-07-01

287

All-metal, compact heat exchanger for space cryocoolers  

Microsoft Academic Search

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

Walter L. Swift; Javier Valenzuela; Herbert Sixsmith

1990-01-01

288

All-Metal, Compact Heat Exchanger for Space Cryocoolers.  

National Technical Information Service (NTIS)

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 stainl...

W. L. Swift J. Valenzuela H. Sixsmith

1990-01-01

289

40 CFR 63.1435 - Heat exchanger provisions.  

Code of Federal Regulations, 2010 CFR

...Environment 11 2009-07-01 2009-07-01 false Heat exchanger provisions. 63.1435 Section 63.1435 Protection...Emissions for Polyether Polyols Production § 63.1435 Heat exchanger provisions. (a) The owner or operator of...

2009-07-01

290

40 CFR 63.1435 - Heat exchanger provisions.  

Code of Federal Regulations, 2010 CFR

...Environment 11 2010-07-01 2010-07-01 true Heat exchanger provisions. 63.1435 Section 63.1435 Protection...Emissions for Polyether Polyols Production § 63.1435 Heat exchanger provisions. (a) The owner or operator of...

2010-07-01

291

Knowledge-based system for the design of heat exchangers  

Microsoft Academic Search

A knowledge based system has been developed to assist engineers in the design of compact heat exchangers. The main objectives of this project were to: (1) automate aspects of heat exchanger design; (2) produce multiple successful designs quickly; and (3) optimize these designs based on specific constraints or criteria. Productivity improvements from use of this system have been as much

W. J. Cochran; Don Hainley; Loay Khartabil

1993-01-01

292

Use of phosphoric acid to remove heat exchanger deposits  

Microsoft Academic Search

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

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

1979-01-01

293

Heat exchanger fouling and corrosion evaluation. Final technical report  

Microsoft Academic Search

The study is focused on the experimental determination of acid corrosion and fouling effects upon a series of tubular heat exchanger modules exposed to the exhaust gases from a large (8900-hp) diesel engine, with different fin geometries and materials. A study of the exhaust gas analysis was undertaken and acid dew point temperatures were determined. Heat exchanger test modules were

De Anda

1981-01-01

294

Corrosion and biofouling of OTEC heat exchangers: IFREMER researches  

Microsoft Academic Search

For the French OTEC program, an experimental study is carrying on to select heat exchangers materials and biofouling countermeasures. Aluminium alloys, stainless steels, titanium are tested comparatively in a marine test station. Test cells with several tubes have been developped to be representative of heat exchangers flow. Influence of mechanical cleaning and chlorination can be evaluated. Corrosion of materials is

L. Lemoine; J. Guezennec; D. Festy; P. Fera

1985-01-01

295

Integrated control, diagnosis and reconfiguration of a heat exchanger  

Microsoft Academic Search

Heat exchangers play an important role in chemical and process industries. In order to improve reliability and control performance, intelligent concepts for control, supervision and reconfiguration are necessary. In the paper, an approach is presented which integrates model-based adaptive control and reconfiguration based on fault detection\\/diagnosis applied to a heat exchanger plant. The adaptive controller and the fault detection scheme

P. Balle; M. Fischer; D. Fussel; O. Nelles; R. Isermann

1998-01-01

296

Building air cooled heat exchanger motors that last  

Microsoft Academic Search

Air cooled heat exchangers are commonly used in petrochemical facilities to cool process fluids. Motors in this application do not achieve their expected service life if special precautions aren't taken in their construction and application. Many forced and induced draft air cooled heat exchangers are built per API Standard 661. While this standard does give specifications defining electric motor drivers,

J. Hillhouse; K. Helton

2005-01-01

297

Active Heat Exchange System Development for Latent Heat Thermal Energy Storage.  

National Technical Information Service (NTIS)

The results of Contract DEN 3-38, Active Heat Exchanger System Development for Latent Heat Thermal Energy Storage Systems are documented. The overall project consisted of five tasks to select, design, fabricate, test and evaluate candidate active heat exc...

R. T. LeFrois A. K. Mathur

1980-01-01

298

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

Microsoft Academic Search

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 m² and a depth of 1.5 m was built at Khon Kaen in North-Eastern Thailand (16 27'N102 E).

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

2010-01-01

299

The cost of heat exchanger fouling in the US industries  

SciTech Connect

Fouling of heat exchangers costs the US industries hundreds of millions of dollars every year in increased equipment costs, maintenance costs, energy losses and losses in production. The designer of heat exchangers usually allows for fouling by using a fouling factor in the design which results in additional capital cost of the heat exchanger. As fouling deposits build up in a heat exchanger, its performance will start to deteriorate and less energy will be transferred through the unit. A plot is provided that gives the percent decrease in heat flux, for a constant driving temperature difference, as a function of the clean overall heat transfer coefficient and the fouling factor. Another plot gives the increase in surface area due to fouling for the same heat transfer rate and driving temperature difference, as a function of the clean overall heat transfer coefficient and the fouling factor. The overall heat transfer market was divided into four sectors: the chemical, petroleum, electric utility and other industries. The 1982 US sales of all industrial heat exchangers, excepting boilers and automotive radiators, was about 285,000 units amounting to about $1.6 billion. The total heat duty of all the heat exchangers in industrial operation, including electric utilities, was estimated at 11.7 Quads. If this represented the amount of heat transferred through clean heat exchangers, the decrease in energy transferred due to fouling or the cost of fouling in terms of energy lost was estimated at 2.9 Quads annually. The cost of fouling, in providing for additional surface area to compensate for a decrease in heat transfer, was conservatively estimated at $180 million in 1982. 12 refs., 2 figs., 5 tabs.

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

1988-01-01

300

Comparative study of rotating regenerators and heat-pipe heat exchangers  

Microsoft Academic Search

A heat wheel was purchased and installed for air to air heat recovery on a Terylene fiber drying and setting oven at ICI Wilton. At the same time a heat pipe heat exchanger was prepared at IRD and tested under controlled conditions. The heat wheel was then replaced by the heat pipe unit. During this procedure measurements were made regularly

D. B. A. MacMichael; D. A. Reay; E. L. Foster

1980-01-01

301

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

302

Ceramic heat-exchanger applications study  

NASA Astrophysics Data System (ADS)

To put the potential benefits of ceramic heat exchangers (CHX) applications into quantitative perspective, several industrial cogeneration and electric utility power generation systems were evaluated. Coal based fuel fired applications, for which system performance and economic assessments were made were studied. Seven CHX applications were selected for evaluation. These include: (1) gasified coal fired gas turbine; (2) pressurized fluidized bed combustor (PFBC) gas turbine; (3) atmospheric fluidized bed combustor (AFBC) gas turbine; (4) and (5) AFBC combined cycle with and without reheat; and (6) and (7) indirect coal fired gas turbine and combined cycle. The performance and economics of these cogeneration systems were evaluated and compared with other competing systems. For the electric utility power generation sector five applications utilizing a CHX were selected and evaluated; their performance and cost factors were compared to those of a reference pulverized coal fired steam plant with flue gas desulfurization. The five applications included: PFBC combined cycle, AFBC combined cycle, industrial coal gasifier combined cycle, indirect coal fired combined cycle, and indirect coal fired simple cycle. Of the five CHX applications evaluated in the power generation sector, only the AFBC system shows a clear gain over the reference pulverized coal system.

McFarlin, D. J.; Sgamboti, C. T.; Lessard, R. D.

1982-10-01

303

Ceramic heat-exchanger applications study  

SciTech Connect

To put the potential benefits of ceramic heat exchangers (CHX) applications into quantitative perspective, several industrial cogeneration and electric utiity power generation systems were surveyed and evaluated. This study was focused on coal-based fuel fired applications, for which system performance and economic assessments were made. Seven CHX applications in the industrial cogeneration sector were selected for evaluation. These include (1) Gasified Coal-Fired Gas Turbine, (2) Pressurized Fluidized Bed Combustor (PFBC)-Gas Turbine, (3) Atmospheric Fluidized Bed Combustor (AFBC)-Gas Turbine, (4 and 5) AFBC Combined Cycle with and without reheat and (6 and 7) Indirect Coal-Fired Gas Turbine and Combined Cycle. The performance and economics of these cogeneration systems were evaluated and compared with other competing systems (both advanced and State-of-the-Art). For the electric utility power generation sector five applications utilizing a CHX were selected and evaluated; their performance and cost factors were compared to those of a reference pulverized coal-fired steam plant with flue gas desulfurization. These five applications included (1) PFBC-Combined Cycle, (2) AFBC-Combined Cycle, (3) Industrial Coal Gasifier-Combined Cycle, (4) Indirect Coal-Fired Combined Cycle, and (5) Indirect Coal-Fired Simple Cycle. Of the five CHX applications evaluated in the power generation sector, only the AFBC system showed a clear gain over the reference pulverized coal system.

McFarlin, D.J.; Sgamboti, C.T.; Lessard, R.D.

1982-10-01

304

Mapping Heat Exchange in an Allosteric Protein  

PubMed Central

Nicotinic acetylcholine receptors (AChRs) are synaptic ion channels that spontaneously isomerize (i.e., gate) between resting and active conformations. We used single-molecule electrophysiology to measure the temperature dependencies of mouse neuromuscular AChR gating rate and equilibrium constants. From these we estimated free energy, enthalpy, and entropy changes caused by mutations of amino acids located between the transmitter binding sites and the middle of the membrane domain. The range of equilibrium enthalpy change (13.4 kcal/mol) was larger than for free energy change (5.5 kcal/mol at 25°C). For two residues, the slope of the rate-equilibrium free energy relationship (?) was approximately constant with temperature. Mutant cycle analysis showed that both free energies and enthalpies are additive for energetically independent mutations. We hypothesize that changes in energy associated with changes in structure mainly occur close to the site of the mutation, and, hence, that it is possible to make a residue-by-residue map of heat exchange in the AChR gating isomerization. The structural correlates of enthalpy changes are discussed for 12 different mutations in the protein.

Gupta, Shaweta; Auerbach, Anthony

2011-01-01

305

Heat transfer of dilute viscoelastic solutions in helical exchangers  

NASA Astrophysics Data System (ADS)

The study examined heat transfer of two dilute viscoelastic solutions in helical exchangers of circular cross-section. Ten helical coil heat exchangers with diameter ratios ranging from 4 to 50 were constructed. Results showed doubling the concentrations of polymer increased heat transfer performance by 12 %. The results were expressed in forms of some existing equations and were found to be in fair agreement to previous results.

Ismail, Z.; Karim, R.

2013-05-01

306

The gas turbine heat exchanger in the fluidized bed combustor  

Microsoft Academic Search

In a current research and development program a coal-fired atmospheric fluidized bed combustor is being designed to supply the heat to a closed cycle gas turbine cogeneration system. The major technical effort is directed towards the design of the in-bed heat exchanger, which is required to operate near bed temperature. This high temperature (850° C) exposes the heat exchanger tubes

C. F. Holt; A. A. Boiarski; H. E. Carlton

1983-01-01

307

A New Type Heat Exchanger for Coal Burning Boilers  

Microsoft Academic Search

To make the best of heat energy in the flue gas exhausted from a coal burning boiler, the design proposal for a new type of heat exchanger was put forward in the paper. Via the new type of heat exchanger, temperature of the flue gas can be decreased from 130~140°C to 70~80°C for the boilers in a coal burning power

Bingwen Zhang; Yingjin Zhang

2010-01-01

308

High-temperature ceramic heat exchanger. Final report  

Microsoft Academic Search

The results of an 18-month effort directed to developing the technology necessary to build a ceramic heat exchanger for operation with a small (200-hp) closed-Brayton-cycle engine are described. The ceramic heat exchanger operates with 3000°F combustion products on one side and heats high-pressure Argon gas, which subsequently is delivered to the turbine, to 1800°F. The design consisting of an array

M. Coombs; D. Kotchick; H. Warren

1979-01-01

309

Peltier cooling system utilizing liquid heat exchanger combined with pump  

Microsoft Academic Search

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

H. Nishihata; O. Kido; T. Ueno

2002-01-01

310

Evaluation of porous media heat exchangers for fusion applications  

SciTech Connect

Several types of porous media heat exchangers are being evaluated for use in fusion applications. Broadly, these devices can be classified as capillary-pumped (heat pipes) or mechanically-pumped heat exchangers. Monel/water thermosyphon heat pipes with a porous metal wick are being evaluated for use in Faraday shields. A subscale prototype has been fabricated, and initial tests at Oak Ridge National Laboratory have shown favorable results. Alkali metal heat pipes have demonstrated absorbed heat flux capability of over 1000 MW/m{sup 2}. An advanced gyrotron microwave cavity is being developed that uses water cooling in a mechanically-pumped copper porous metal heat exchanger. Tests on a prototype demonstrated absorbed heat flux capability in excess of 100 MW/m{sup 2}. Porous metal heat exchangers with helium, water, or liquid metal coolants are being evaluated for plasma-facing component cooling. Tests on a helium/copper porous metal heat exchanger demonstrated absorbed heat flux capability in excess of 15 MW/m{sup 2}. Applications, conceptual designs, fabricated hardware, and test results are summarized. 22 refs., 5 figs., 2 tabs.

Rosenfeld, J.H.; Lindemuth, J.E.; North, M.T. [Thermacore Inc., Lancaster, PA (United States); Watson, R.D.; Youchison, D.L. [Sandia Natinal Lab., Albuquerque, NM (United States); Goulding, R.H. [Oak Ridge National Lab., TN (United States)

1996-07-01

311

Study on the Heat-flow Controlable Heat Exchanger (first report)  

NASA Astrophysics Data System (ADS)

Heat generating devices and heat recovery systems are desired to control the heat flow and the temperature, contrary to the prior thermo-siphon uncontrolable heat flow. Then, authors have developed a heat flow controlable heat exchanger having a bubble pump mechanism without movable par t. The heat exchanger is consisted of evaporator, condenser, vapor passage pipe, liquid return pipe with a reverse-U type pipe, and heater located on the reverse pipe. Further the system encloses evaporating liquid and is possible to control heat flow between the evaporator to the condenser by adjusting the heater power. This paper presents experimental results on the system. The following results are obtained. (1) The heat exchanger can control heat flow between the evaporator to the condenser by adjusting the heater input which is smaller about 1/20 the above heat flow. (2) The complex heat flow controlable heat exchanger system is possible to control the output temperature by changing its operating heat exchanger number. (3) This heat exchanger is useful to the heat recovery at the room, the temperature control at the space, and the system joining heat storage system.

Hamano, Masayoshi; Yanadori, Michio; Kawano, Tomohiro

312

Improvement of heat transfer by means of ultrasound: Application to a double-tube heat exchanger.  

PubMed

A new kind of ultrasonically-assisted heat exchanger has been designed, built and studied. It can be seen as a vibrating heat exchanger. A comprehensive description of the overall experimental set-up is provided, i.e. of the test rig and the acquisition system. Data acquisition and processing are explained step-by-step with a detailed example of graph obtained and how, from these experimental data, energy balance is calculated on the heat exchanger. It is demonstrated that ultrasound can be used efficiently as a heat transfer enhancement technique, even in such complex systems as heat exchangers. PMID:22546297

Legay, M; Simony, B; Boldo, P; Gondrexon, N; Le Person, S; Bontemps, A

2012-04-11

313

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

314

Some problems of heat exchange in fluidized beds  

Microsoft Academic Search

The use of calorimeters with different degrees of surface blackness to delineate the convective-conductive and radiative components of complex heat exchange is discussed. The effect of surface particle cooling on radiative heat transfer is investigated by reviewing results of various experiments performed in fluidized-bed installations. Heat transfer from the underdense to the dense phase of a fluidized bed by means

A. P. Baskakov; B. V. Berg; Iu. M. Goltsobin; A. M. Dubinin; A. A. Zharkov; G. Ia. Zakharchenko; S. V. Zviagin; O. M. Panov

1976-01-01

315

Parametric performance studies on fluidized-bed heat exchangers  

Microsoft Academic Search

The performance of single and multistage shallow fluidized beds is investigated for possible application to the recovery of heat from sources such as waste heat, and coal combustion or coal gasification. Tests are conducted to (1) investigate the effects of fouling due to liquid condensate in the gas stream on fluidized bed heat exchanger performance, (2) investigate the performance of

R. C. Stoeffler

1982-01-01

316

Heat exchanger fouling and corrosion evaluation. Final technical report  

SciTech Connect

The study is focused on the experimental determination of acid corrosion and fouling effects upon a series of tubular heat exchanger modules exposed to the exhaust gases from a large (8900-hp) diesel engine, with different fin geometries and materials. A study of the exhaust gas analysis was undertaken and acid dew point temperatures were determined. Heat exchanger test modules were then operated with metal surface temperatures below the acid dew point to allow for acid condensation and fouling. A continuous soot buildup was observed on the heat exchanger, as a function of the diesel engine operating time, heat transfer metal surface temperature, and fin geometry. The corrosion effects on the heat exchangers were minimal.

De Anda, E.

1981-10-25

317

Minimizing coke buildup in transfer line heat exchangers  

SciTech Connect

In a method of quenching high temperature gases while recovering useable heat therefrom by means of a shell-and-tube transfer line heat exchanger having heat exchange tubes contained within an outer shell and a primary tubesheet this patent describes the improvement comprising: (A) passing high temperature process gas into a heat exchanger to minimize inlet end fouling, which comprises: (1) a secondary porous tubesheet positioned on the process gas inlet end of the heat exchanger, through which a reactive gas can flow in amounts sufficient to react with coke deposits on the porous tubesheet's process gas inlet side, and (2) at least one gas inlet communicating with the enclosed space created by the porous tubesheet, the outer shell and the primary tubesheet; and (B) feeding a reactive gas through the gas inlet or inlets to flow through the porous tubesheet and react with coke deposits on the porous tubesheet's process gas inlet side.

Townsend, R.W.

1987-11-03

318

Chromate/silicate aluminum surface treatment for heat exchangers  

SciTech Connect

A process is described for surface treating an aluminum heat exchanger by successively immersing the heat exchanger within a series of chemical solutions to provided the heat exchanger with a corrosive-resistent hydrophilic coating; the process comprising the steps of: providing a cleaning mixture including 40 to 60 weight percent of nitric acid and 1 to 5 weight percent of sodium fluoride, adding water to the cleaning mixture to form an aqueous cleaning solution having a total concentration of cleaning mixture between 2.0 to 5.0 weight percent; providing a chromate mixture including 10 weight percent of chromium trioxide, 25 weight percent of nitric acid and between 10 to 11 weight percent of hydrofluoric acid, providing a chromate activator comprising less than 25 weight percent of molybdic acid and disodium salt, adding water and the chromate activator to the chromate mixture to form an aqueous chromate solution; providing a silicate mixture comprising 90 to 100 weight percent of silicate of soda and 0 to 10 weight percent of potassium hydroxide, adding water to the silicate mixture to form an aqueous silicate solution; immersing the heat exchanger within an aqueous cleaning solution, and removing the heat exchanger from the cleaning solution; immersing the cleansed heat exchanger in the aqueous chromate solution, and removing the heat exchanger from the chromate solution; immersing the chromed heat exchanger in the aqueous silicate solution, and subsequently removing the heat exchanger from the silicate solution; and characterized by maintaining the total concentration of chromate mixture within the aqueous chromate solution at 0.9 to 1.5 weight percent ([plus minus] 0.1%) and the total concentration of chromate activator within the aqueous chromate solution at 1.1 weight percent ([plus minus] 0.1 %) thereby providing the necessary chemical concentration for producing a corrosion-resistent hydrophilic coating which is substantially free from musty odor emission.

Patel, B.B.; Ramo, S.J. Jr.

1993-08-10

319

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

320

High performance microchannel heat exchanger for cooling high heat load x-ray optical elements  

SciTech Connect

Analysis has been carried out to demonstrate that a liquid nitrogen cooled microchannel heat exchanger can be designed to maximize the heat transfer from silicon to the working fluid. The results show that the performance of the liquid nitrogen cooled microchannel heat exchanger is significantly enhanced by approximately three times over flowing water through microchannels.

Choi, U.S.; Rogers, C.S.; Mills, D.M.

1992-12-01

321

High performance microchannel heat exchanger for cooling high heat load x-ray optical elements  

SciTech Connect

Analysis has been carried out to demonstrate that a liquid nitrogen cooled microchannel heat exchanger can be designed to maximize the heat transfer from silicon to the working fluid. The results show that the performance of the liquid nitrogen cooled microchannel heat exchanger is significantly enhanced by approximately three times over flowing water through microchannels.

Choi, U.S.; Rogers, C.S.; Mills, D.M.

1992-01-01

322

Preliminary Evaluation of a Heat Pipe Heat Exchanger on a Regenerative Turbofan.  

National Technical Information Service (NTIS)

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 ...

G. A. Kraft

1975-01-01

323

Modeling and optimization of isolated heat pipe heat exchange system based on Matlab  

Microsoft Academic Search

In order to reduce air-conditioning energy consumption of original computer room, an isolated heat exchange system is added to Beijing Unicom computer room. The steady-state model of the heat exchange system is built using mechanism modeling method according to actual operating data and the basic principles of heat transfer process. The optimal operating point of the system is obtained with

Yuanfang Zhu; Ruihua Wang; Yating Zhang

2010-01-01

324

Predicted energy savings for a residential heat pump utilizing a fluidized-bed heat exchanger  

Microsoft Academic Search

The objective of this study was to determine if the energy efficiency of an optimized, state-of-the-art, residential heat pump could be increased by utilizing a fluidized-bed heat exchanger in place of a conventional heat exchanger on the outdoor side of the heat pump system. Using the Oak Ridge National Laboratory (ORNL) Heat Pump Model, comparisons were made between the advanced

Vineyard

1984-01-01

325

Parametric performance studies on fluidized-bed heat exchangers  

NASA Astrophysics Data System (ADS)

The performance of single and multistage shallow fluidized beds is investigated for possible application to the recovery of heat from sources such as waste heat, and coal combustion or coal gasification. Tests are conducted to (1) investigate the effects of fouling due to liquid condensate in the gas stream on fluidized bed heat exchanger performance, (2) investigate the performance of fluidized beds which are staged using baffle plates, and (3) investigate the effects of different heat exchanger surface geometries. Work is progressing in selecting the conditions for that portion of the program involving fouling by a liquid condensate, and in modifying the fluidized bed heat exchanger facility for the fouling experiments. Preliminary tests were conducted with water vapor injection. Water vapor and glycerol vapor were chosen as the condensates. The results are summarized as follows: (1) heat exchanger performance is seriously degraded by condensation when the dew point temperature exceeds the heat exchanger wall temperature; and (2) the performance decrease occurs as a result of particle adherence to the heat exchanger surface and not as a result of particle agglomeration.

Stoeffler, R. C.

1982-01-01

326

40 CFR Table 8 to Subpart Vvvvvv... - Emission Limits and Compliance Requirements for Heat Exchange Systems  

Code of Federal Regulations, 2010 CFR

...comply with the requirements for heat exchange systems as shown in... Except * * * 1. Each heat exchange system with a cooling...104(f)(1) to record retention requirements in § 63.103...f). b. Comply with the heat exchange system...

2010-07-01

327

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

Code of Federal Regulations, 2013 CFR

... false Equipment leak and heat exchange system provisions...63.502 Equipment leak and heat exchange system provisions...506(e)(6). (h) If specific items of equipment, comprising...purposes of this subpart. (n) Heat exchange system...

2013-07-01

328

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

329

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

330

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...

2009-07-01

331

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...

2009-07-01

332

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

Code of Federal Regulations, 2013 CFR

...Does this subpart apply to my heat exchange system? 63.1083...HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) ...Manufacturing Process Units: Heat Exchange Systems and Waste Operations Applicability for Heat Exchange Systems §...

2013-07-01

333

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

Code of Federal Regulations, 2013 CFR

...What requirements apply to my heat exchange systems? 63.8030...HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) ...What requirements apply to my heat exchange systems? (a...this subpart that apply to your heat exchange systems, except...

2013-07-01

334

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

Code of Federal Regulations, 2013 CFR

...the general requirements for heat exchange systems? 63.1085...HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) ...Manufacturing Process Units: Heat Exchange Systems and Waste Operations Heat Exchange System...

2013-07-01

335

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

336

Heat exchanger and water tank arrangement for passive cooling system  

DOEpatents

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

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

1993-11-30

337

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

338

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

NASA Astrophysics Data System (ADS)

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

Taler, Dawid

2013-08-01

339

Experimental determination of correlations for mean heat transfer coefficients in plate fin and tube heat exchangers  

NASA Astrophysics Data System (ADS)

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

Taler, Dawid

2012-09-01

340

Development and demonstration of improved gas to gas heat pipe heat exchangers for the recovery of residual heat. Final report  

Microsoft Academic Search

A new form of heat exchanger has been developed with the following characteristics: (1) compact modular construction: the modules are built up to provide the final exchanger face area as required by the available exhaust gas stream; (2) the above construction allows in situ dismantling of the heat exchanger for cleaning in case of internal fouling; (3) in order that

M. J. Davies; G. H. Chaffey

2008-01-01

341

Imaging the thermal structure of the continental upper mantle: Joint inversion of heat flow and surface wave dispersion  

Microsoft Academic Search

The thermal lithosphere (TL) is the region of the crust and uppermost mantle where heat flow is dominated by conductive transport and which presumably does not participate actively in large-scale convection. An accurate estimate of the thickness of the TL, therefore, is necessary to understand the long-term stability of the continental lithosphere. We present and discuss a new thermal model

N. M. Shapiro; M. H. Ritzwoller

2001-01-01

342

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

343

The role of the heating mode of the mantle in intermittent reorganization of the plate velocity field  

NASA Astrophysics Data System (ADS)

The geological record indicates that stages of relatively steady plate motion have been punctuated by comparatively brief periods in which plate velocities have reorganized. The distribution of buoyancy sources in the mantle has generally been regarded as evolving too slowly to explain these rapid transitions in plate velocity. We investigate the feedback between mantle convection and plate velocity using 2-D and 3-D mantle convection models that incorporate mobile dynamic plates. We focus on the influence of internal heating in the mantle and consider the effect of mantle viscosity stratification and different plate geometries on the plate velocity time dependence. As either the Rayleigh number or the internal heating rate is increased to magnitudes approaching mantle values, the record of the plate motion from our calculations becomes characterized by intermittent changes in direction. This behaviour is a result of the influence of plates on heat loss from the inherently unsteady, internally heated convecting system. Plate motion instills a pattern of organization on the underlying convection that reflects the plate geometry and results in the formation of sheet-like downwelling structures at convergent plate boundaries in both 2-D and 3-D calculations (in contrast, upwellings in 3-D models are not sheet-like). The role of the sheet-like downwellings is critical in the observed episodic reorganization of the plate velocities. Warm material below the plates is entrained by plate motion into regions enveloping the downwelling sheets. During periods of fairly steady plate motion, buoyancy associated with the build-up of heat around the downwelling sheets leads to the creation of an unstable convection pattern. This build-up of heat is dramatic in calculations with mantle-like internal heating rates and resists continued long-term plate motion towards mature downwellings. When there are limitations on the degree of freedom of the direction of plate movement, such as in 2-D models, these effects become even more pronounced. Accordingly, the effect of plates on mean global thermal quantities is more dramatic in 2-D calculations than it is in 3-D calculations. Nevertheless, 3-D calculations incorporating plates of different sizes do exhibit rapid reorganizations in their convection patterns as the pull of young slab-like features supersedes the pull of mature downwelling sheets. We compare the timing and frequency of the reorganization events in our calculations with the general characteristics of plate motions determined from plate reconstruction studies.

Lowman, Julian P.; King, Scott D.; Gable, Carl W.

2003-02-01

344

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

National Technical Information Service (NTIS)

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 a...

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

1994-01-01

345

Liquid-Fluidized-Bed Heat Exchanger Flow Distribution Models.  

National Technical Information Service (NTIS)

Allied Chemical Corporation at the Idaho National Engineering Laboratory is developing liquid-fluidized-bed shell-and-tube heat exchangers for geothermal applications. Sand fluidized by geothermal water on the shell side prevents scaling and increases hea...

L. T. Cole C. A. Allen

1979-01-01

346

Heat Exchanger Technology Needs for Conservation Research and Technology, ERDA.  

National Technical Information Service (NTIS)

This report summarizes the results of a survey taken by the author, whose purpose was to identify current and future heat exchanger needs within the Division of Conservation Research and Technology (CONRT) of the Energy Research and Development Administra...

W. H. Thielbahr

1976-01-01

347

Simulation of the process of scaling of tube heat exchangers  

SciTech Connect

A semiempirical model of the process of deposit information on the inner surface of heat exchanger tubes is obtained. By experimental investigation, constants of the scaling process that close this model are obtained for carbonate-type deposits.

Baran, L.S.; Razladin, Y.S.

1994-09-01

348

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

349

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

350

Nosehouse: heat-conserving ventilators based on nasal counterflow exchangers.  

PubMed

Small birds and mammals commonly minimize respiratory heat loss with reciprocating counterflow exchangers in their nasal passageways. These animals extract heat from the air in an exhalation to warm those passageways and then use that heat to warm the subsequent inhalation. Although the near-constant volume of buildings precludes direct application of the device, a pair of such exchangers located remotely from each other circumvents that problem. A very simple and crudely constructed small-scale physical model of the device worked well enough as a heat conserver to suggest utility as a ventilator for buildings. PMID:19920310

Vogel, Steven

2009-11-17

351

Parametric performance studies on fluidized-bed heat exchangers  

NASA Astrophysics Data System (ADS)

The performance of single and multistage shallow fluidized beds for possible application to the recovery of heat from sources as waste heat, and coal combustion or coal gasification were investigated. The following tests are investigated: (1) the effects of fouling due to liquid condensate in the gas stream of fluidized beds which are staged using baffle plates; and (3) the effects of different heat exchanger surface geometries. The conditions fouling by a liquid condensate are selected. Modifications are made to the fluidized bed heat exchanger facility for the fouling experiments.

Stoffler, R. C.

1981-10-01

352

Progress in heat pipe and porous heat exchanger technology  

Microsoft Academic Search

This is a review of the papers presented at the 1st International Heat Pipe Conference held in Stuttgart, 15-17 October 1973. The review deals with heat pipe application in different branches of technology, heat- and mass-transfer processes in heat pipes, design of variable-conductance heat pipes, optimization of their parameters, operation of heat pipes under weightlessness and in the field of

A. V. Luikov; L. L. Vasiliev

1975-01-01

353

Effectiveness of crossflow plate heat exchanger for indirect evaporative cooling  

Microsoft Academic Search

A short-cut method for calculating the effectiveness of wet surface crossflow plate heat exchangers is developed. It introduces a correction for the effectiveness estimated according to the method of Maclaine-cross and Banks. For this purpose a new model with a water film that flows down, corresponding to the real conditions in these heat exchangers, is developed. The method of Maclaine-cross

N. J. Stoitchkov; G. I. Dimitrov

1998-01-01

354

Fluidized bed reactor having an integrated recycle heat exchanger  

SciTech Connect

This patent describes a fluidized bed combustion system. It includes a furnace, a fluidized bed of combustible particulate material disposed in the furnace, a recycle heat exchanger disposed adjacent the furnace and sharing a common wall with the furnace separating means for receiving a mixture of flue gases and entrained particulate material from a fluidized bed in the furnace and separating the particulate material from the flue gases, means for passing the separated partition disposed in the heat exchanger.

Campbell, W.R.; Alliston, M.G.; Sisson, B.H.

1990-01-30

355

Fabrication of metallic heat exchangers using sacrificial polymer mandrils  

Microsoft Academic Search

This paper demonstrates the use of poly(dimethylsiloxane) (PDMS), polyurethane (PU), epoxy, and poly(methyl methacrylate) (PMMA) as mandrils to fabricate metallic heat exchangers having 300-700 ?m internal channels. The mandrils were prepared using two soft lithographic techniques-replica molding and microembossing. To fabricate the heat exchangers, the polymeric mandrils were coated with a thin layer of metal by thermal evaporation or sputtering;

Francisco Arias; Scott R. J. Oliver; Bing Xu; R. Erik Holmlin; George M. Whitesides

2001-01-01

356

Control of a liquid–liquid heat exchanger  

Microsoft Academic Search

The analytical solutions of equations describing the dynamics of distributed parameter systems are usually complicated in\\u000a form and derivations and inconvenient to use for simulation and control system design. The liquid–liquid counter flow heat\\u000a exchanger is an example of these disturbed parameter systems. An analytical solution of the dynamics of a symmetrically operated\\u000a counter flow heat exchanger in the form

N. H. Abu-Hamdeh

2002-01-01

357

Process water heat exchanger failures, December 1953November 1966  

Microsoft Academic Search

In the Savannah River Plant reactor buildings, the process water heat exchangers, are of shel1 and tube design, fabricated from AISI types 304 and 304L stainless steels. They are 33 ft 6-1\\/2 inches long by 87-1\\/2 inches in diameter. The heat exchangers operate with countercurrent flows of moderator (heavy water) on the tube side and cooling water (river water) on

R. F. Mittelberg; D. T. Walker

1967-01-01

358

Tube vibration in industrial size test heat exchanger  

Microsoft Academic Search

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

H. Halle; M. W. Wambsganss

1980-01-01

359

Plastic film heat exchanger development project: Topical report  

SciTech Connect

This report presents the progress that has been achieved in the development of the plastic film heat exchanger system (PFHX). An earlier report presented the general performance and design characteristics of a steam recovery PFHX. This report reviews some additional material selection possibilities for the film surfaces and describes a prototype design of a plastic film heat exchange element. Also the facility for the elevated temperature testing of this element design is described and the test plan is presented.

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

1986-04-11

360

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

361

Heated ion exchange process for the recovery of uranium  

SciTech Connect

The present invention relates to an improved method for the recovery of uranium values from a uranium-containing lixiviant by passing the lixiviant through a heated ion exchange resin to cause the resin to retain uranium values. The uranium values are subsequently recovered from the ion-exchange resin.

Fletcher, A.

1984-02-07

362

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

363

Heat-producing elements in the lunar mantle: Insights from ion microprobe analyses of lunar pyroclastic glasses  

NASA Astrophysics Data System (ADS)

We provide new estimates for the abundance of heat-producing elements in the lunar mantle by using SIMS techniques to measure the concentrations of thorium and samarium in lunar pyroclastic glasses. Lunar pyroclastic glasses are utilized in this study because they represent quenched products of near-primary melts from the lunar mantle and as such, they provide compositional information about the mantle itself. Thorium and samarium were measured because: (1) Th is not significantly fractionated from Sm during partial melting of the pyroclastic glass source regions, which are dominated by olivine and pyroxene. Therefore, the Th/Sm ratios that we measure in the pyroclastic glasses reflect the Th/Sm ratio of the pyroclastic glass source regions. (2) Strong correlations between Th, U, and K on the Moon allow us to use measured Th concentrations to estimate the concentrations of U and K in the pyroclastic glasses. (3) Th, Sm, U, and K are radioactive elements and as such, their concentrations can be used to investigate heat production in the lunar mantle. The results from this study show that the lunar mantle is heterogeneous with respect to heat-producing elements and that there is evidence for mixing of a KREEP component into the source regions of some of the pyroclastic glasses. Because the source regions for many of the glasses are deep (?400 km), we propose that a KREEP component was transported to the deep lunar mantle. KREEP enriched sources produce 138% more heat than sources that do not contain KREEP and therefore, could have provided a source of heat for extended periods of nearside basaltic magmatism. Data from this study, in conjunction with models for the fractional crystallization of a lunar magma ocean, are used to show that the average lunar mantle contains 0.15 ppm Th, 0.54 ppm Sm, 0.039 ppm U, and 212 ppm K. This is a greater enrichment in radiogenic elements than some earlier estimates, suggesting a more prolonged impact of radiogenic heat on nearside basaltic volcanism.

Hagerty, Justin J.; Shearer, Charles K.; Vaniman, David T.

2006-07-01

364

Use of fluidized bed heat exchangers in heat pump systems for improved performance. Progress report  

Microsoft Academic Search

The performance of a residential-type heat pump nominally rated at 60,000 Btu\\/hr is being investigated, when its heat exchangers are replaced with fluidized bed heat exchangers. A York heat pump has been obtained and installed and a plenum and associated ductwork have been constructed. The plenum recirculates exhaust and inlet air from and to the evaporator and condenser to maintain

J. C. Chen; R. G. Sarubbi

1978-01-01

365

Air-side flow and heat transfer in compact heat exchangers: A discussion of enhancement mechanisms  

SciTech Connect

The behavior of air flows in complex heat exchanger passages is reviewed with a focus on the heat transfer effects of boundary-layer development, turbulence, spanwise and streamwise vortices, and wake management. Each of these flow features is discussed for the plain, wavy, and interrupted passages found in contemporary compact heat exchanger designs. Results from the literature are used to help explain the role of these mechanisms in heat transfer enhancement strategies.

Jacobi, A.M. [Univ. of Illinois, Urbana, IL (United States). Dept. of Mechanical and Industrial Engineering; Shah, R.K. [Delphi Harrison Thermal Systems, Lockport, NY (United States)

1998-10-01

366

Time variability in Cenozoic reconstructions of mantle heat flow: plate tectonic cycles and implications for Earth's thermal evolution.  

PubMed

The thermal evolution of Earth is governed by the rate of secular cooling and the amount of radiogenic heating. If mantle heat sources are known, surface heat flow at different times may be used to deduce the efficiency of convective cooling and ultimately the temporal character of plate tectonics. We estimate global heat flow from 65 Ma to the present using seafloor age reconstructions and a modified half-space cooling model, and we find that heat flow has decreased by approximately 0.15% every million years during the Cenozoic. By examining geometric trends in plate reconstructions since 120 Ma, we show that the reduction in heat flow is due to a decrease in the area of ridge-proximal oceanic crust. Even accounting for uncertainties in plate reconstructions, the rate of heat flow decrease is an order of magnitude faster than estimates based on smooth, parameterized cooling models. This implies that heat flow experiences short-term fluctuations associated with plate tectonic cyclicity. Continental separation does not appear to directly control convective wavelengths, but rather indirectly affects how oceanic plate systems adjust to accommodate global heat transport. Given that today's heat flow may be unusually low, secular cooling rates estimated from present-day values will tend to underestimate the average cooling rate. Thus, a mechanism that causes less efficient tectonic heat transport at higher temperatures may be required to prevent an unreasonably hot mantle in the recent past. PMID:17720806

Loyd, S J; Becker, T W; Conrad, C P; Lithgow-Bertelloni, C; Corsetti, F A

2007-08-24

367

Costs of heat exchanger fouling in the US industrial sector  

SciTech Connect

Heat exchangers are used in many heat source, heat sink and process applications throughout the US industrial sector. In 1984 heat exchanger sales totaled $1.3 billion (in 1984 dollars), and sales are expected to grow at 6% per year through 1985. The presence of fouling in heat exchangers represents an additional cost to the industrial sector in terms of additional capital, energy, and labor. Several estimates are available on the costs of fouling to specific industries; however, no real attempt has been made to estimate these costs for the entire industrial sector. The objective of this paper is to provide on order-of-magnitude estimate of the costs of fouling to the entire US industrial sector.

Smith, S.A.; Dirks, J.A.

1985-06-01

368

Proceedings of the 1987 International Symposium on Condensing Heat Exchangers  

NASA Astrophysics Data System (ADS)

Technology for advanced, high-efficiency heating equipment was discussed. Twenty-six papers from nine countries were presented, covering various aspects of such equipment designed to operate with condensing heat exchangers - including furnaces, boilers, water heaters, and fuel-fired heat pumps. The emphasis was on residential and commercial equipment, and both gas- and oil-firing were considered. Specific topics included: (1) condensate characterization; (2) metallic materials for condensing heat exchangers - aluminum and stainless steel; (3) non-metallic materials for heat exchangers and vents - ceramics and polymers; (4) example condensing units and systems; (5) experience with oil-fired condensing units; (6) field experience; (7) design techniques and efficiency test procedures. Papers are indexed separately.

1987-04-01

369

Chemical Exchange Between the Core and the Convecting Mantle of the Earth: Evidence from Highly Siderophile Elements (HSE)  

NASA Astrophysics Data System (ADS)

Core formation is a major physical and chemical event in the evolution of a differentiated planet. The core is the dominant repository of HSE in the Earth. Element ratios of HSE in peridotites provide insights into the accretion processes of the Earth and the effect of core formation. Depletion of HSE in the Earth's mantle results from core formation. Refractory siderophile elements are about a factor of > 100 depleted in the Earth's mantle compared to CI carbonaceous chondrites. Nevertheless, the concentrations of PGE, Re and Au (7.1 +/- 0.8 x 10^-3 CI chondrite abundances) are higher than would be expected from metal-silicate partitioning during core formation [1]. Several different explanations have been suggested to explain the low absolute abundances of these elements. (1) Os, Re, Ir, Ru, Rh, Pd, Pt, and Au were added with a late chondritic veneer containing less than 1% of a CI component [2-9]. (2) Insufficient core formation, i.e. some metallic Fe-Ni was retained in the upper mantle during core formation [10]. (3) Disequilibrium during core formation; Segregation of metal from the upper mantle in later stages of accretion was so rapid that equilibrium was not attained [4,11,12]. (4) There was continuous formation of the core during accretion; Equilibrium between sinking metal grains and a molten magma ocean at high temperatures (3000-3500 K) [13]. (5) Increase in silicate/metal partition coefficients by pressure, temperature, or high f(O2) [5,14]; Solution of FeO in the core raises the f(O2) conditions at the core-mantle interface sufficiently to increase the equilibrium concentrations of the siderophile elements in the mantle [15]. Studies of mantle-derived samples such as massif peridotites and peridotite xenoliths provide direct information on the nature and composition of the upper mantle. Massive peridotitic rocks from Zabargad island (Red Sea), Lanzo (Italy), Ronda (Spain) and peridotitic xenoliths from Mongolia were analysed for Os, Re, Ir, Ru, Rh, Pd, and Au with a slightly modified neutron activation analysis in combination with a NiS extraction method [16]. All samples (except peridotitic xenoliths) have essentially unfractionated patterns (except Pd/Ir) despite significant variations in absolute abundances [17]. Os/Re ratios from massive peridotitic rocks from Zabargad are chondritic. Peridotitic xenoliths generally have Os/Re-ratios much higher than the chondritic ratio [2]. The Pd/Ir ratios from all studied peridotites are approximately two times and the Rh/Ir ratios are approximately 1.5 times higher than the chondritic ratio of 1.21 and 0.29, respectively. This is in qualitative agreement with estimates of Pd and Ir in primitive undepleted mantle [1]. The non-chondritic Pd/Ir and Rh/Ir ratios is either the result of Pd and Rh addition or these elements are not quantitatively removed from the mantle in the process of core formation [10]. Extrapolation of experimentally determined palladium and iridium metal/silicate partition coefficients to 3500 K are 3.8x10^3 and 2x10^8, respectively [18,19]. The observed non-chondritic ratio of Ir to Pd in the upper mantle is in qualitative agreement with experimentally determined metal/silicate partition coefficients for Ir and Pd. This could support recent speculation on the possibility of chemical exchange between the outer liquid shell of the core and the convecting mantle of the Earth. Acknowledgements. This work was supported by DFG. References: [1] Morgan J. W. (1986) JGR, 91, 12375-12387. [2] Morgan J. W. et al. (1981) Tectonophys., 75, 47-67. [3] Anders E. (1968) Acc. Chem. Res., 1, 289-298. [4] Turekian K. K. and Clark S. P. (1969) EPSL, 6, 346-348. [5] Kimura K. et al. (1974) GCA, 38, 683-701. [6] Ganapathy R. and Anders E. (1974) Proc. LPSC. [7] Chou C.-L. (1978) Proc. LPSC 9th, 219-230. [8] Jagoutz E. et al. (1979) Proc. LPSC 10th, 2031-2050. [9] Wanke H. (1981) Philos. Trans. R. Soc. London, A303, 287-302. [10] Jones J. H. and Drake M. J. (1986) Nature, 322, 221-228. [11] Ringwood A. E. (1966) GCA, 30, 41-104. [12] Morgan J. W. and Lovering J. F.

Schmidt, G.; Palme, H.; Kratz, K. L.

1995-09-01

370

Continuous cleaning of heat exchanger with recirculating fluidized bed  

SciTech Connect

Fluidized bed heat exchangers for liquids have been studied in the United States, the Netherlands, and the Federal Republic of Germany. Between 1965 and 1970, fluidized bed heat exchangers were developed in the United States as brine heaters in seawater desalination. Furthermore, their potential in the utilization of geothermal energy was tested between 1975 and 1980. In the Netherlands, fluidized bed heat exchangers have been developed since 1973 for brine heating and heat recovery in multistage flash evaporators for seawater desalination and, since about 1980, for applications in the process industry. The authors became interested in fluidized bed heat exchangers first in 1978 in connection with wastewater evaporation. The authors emphasize that the results of all these groups were in basic agreement. They can be summarized as follows: 1. The fluidized bed will in many cases maintain totally clean surfaces and neither scaling nor fouling will occur. In cases where even a fluidized bed cannot completely prevent scaling or fouling, the thickness of the layer is controlled. In these cases stable operation maintaining acceptable overall heat transfer coefficients is possible without cleaning. 2. There are always excellent heat transfer coefficients as low superficial velocities of less than ..nu.. < 0.5 m/s. 3. The pressure losses are comparable with those in normal heat exchangers since fluidized bed heat exchangers are mostly operated at low superficial velocities. 4. Feed flow may be varied between 50 and 150% or more of the design feed flow. 5. Erosion is negligible. 6. Fluidized bed particles can be manufactured from all sorts of chemically and mechanically resistant materials, such as sand, glass, ceramics, and metals.

St. Kollbach, J.; Dahm, W.; Rautenbach, R.

1987-01-01

371

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.

372

Use of a fluidized bed heat exchanger to improve the performance of a heat pump. Final report  

Microsoft Academic Search

The outdoor evaporator heat exchanger of a York 60,000 Btu heat pump in the heating mode was replaced with a fluidized bed heat exchanger. Air temperature control was achieved by recirculating the conditioned air from both the evaporator and condenser heat exchangers through a chambered plenum. Candidate particles and distributor plates for the design of the bed were tested separately.

R. G. Sarubbi; J. C. Chen

1981-01-01

373

The heat pipe heat exchanger: a review of its status and its potential for coolness recovery in tropical buildings  

Microsoft Academic Search

The heat pipe heat exchanger (HPHX) is a proven device for heat recovery in HVAC systems, and competes effectively with other available systems such as heat recovery wheels and run-around coils. This paper reviews major research work done on heat pipe heat exchangers (HPHXs) installed in HVAC systems since 1970. It reveals that research work on HPHXs for HVAC heat

YH Yau

2008-01-01

374

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

375

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

Microsoft Academic Search

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

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

376

Assessment of ASME code examinations on regenerative, letdown and residual heat removal heat exchangers  

SciTech Connect

Inservice inspection requirements for pressure retaining welds in the regenerative, letdown, and residual heat removal heat exchangers are prescribed in Section XI Articles IWB and IWC of the ASME Boiler and Pressure Vessel Code. Accordingly, volumetric and/or surface examinations are performed on heat exchanger shell, head, nozzle-to-head, and nozzle-to-shell welds. Inspection difficulties associated with the implementation of these Code-required examinations have forced operating nuclear power plants to seek relief from the U.S. Nuclear Regulatory Commission. The nature of these relief requests are generally concerned with metallurgical, geometry, accessibility, and radiation burden. Over 60% of licensee requests to the NRC identify significant radiation exposure burden as the principle reason for relief from the ASME Code examinations on regenerative heat exchangers. For the residual heat removal heat exchangers, 90% of the relief requests are associated with geometry and accessibility concerns. Pacific Northwest National Laboratory was funded by the NRC Office of Nuclear Regulatory Research to review current practice with regard to volumetric and/or surface examinations of shell welds of letdown heat exchangers regenerative heat exchangers and residual (decay) heat removal heat exchangers Design, operating, common preventative maintenance practices, and potential degradation mechanisms are reviewed. A detailed survey of domestic and international PWR-specific operating experience was performed to identify pressure boundary failures (or lack of failures) in each heat exchanger type and NSSS design. The service data survey was based on the PIPExp® database and covers PWR plants worldwide for the period 1970-2004. Finally a risk assessment of the current ASME Code inspection requirements for residual heat removal, letdown, and regenerative heat exchangers is performed. The results are then reviewed to discuss the examinations relative to plant safety and occupational radiation exposures.

Gosselin, Stephen R.; Cumblidge, Stephen E.; Anderson, Michael T.; Simonen, Fredric A.; Tinsley, G. A.; Lydell, B.; Doctor, Steven R.

2005-07-01

377

Heat transfer effectiveness of three-fluid separated heat pipe exchanger  

NASA Astrophysics Data System (ADS)

A heat transfer model for three-fluid separated heat pipe exchanger was analyzed, and the temperature transfer matrix for general three-fluid separated heat exchanger working in parallel-flow or counter-flow mode was obtained. It was found that the forms of temperature transfer matrix are similar for heat pipe rows with equal or different heat transfer surface area. Furthermore, by using the temperature transfer matrix of the heat pipe exchanger, the relationship between heat transfer effectiveness ? 1, ? 2 and M, NTU, U, ?t i were derived for the exchanger operating in parallel-flow or counter-flow mode, and a simple special example was adopted to demonstrate the correctness of these relationships.

Shi, Chengming; Wang, Yang; Yang, Ying; Liao, Quan

2011-03-01

378

Studies of inertial deposition of particles onto heat exchanger elements  

SciTech Connect

This thesis examines gas-side fouling mechanisms in heat exchangers that involve the inertial impaction of small particles onto tubular exchanger surfaces. An aerosol processes wind tunnel was constructed that facilitates quantitative studies of particle interactions with heat-exchanger surfaces. Three sets of experiments were performed. First, single heat-exchanger tubes were exposed to a cross flow of particle-laden air. Stainless steel tubes coated with a thin layer of grease to ensure that particle collisions resulted in capture were used to verify a numerical model for the inertial transport of ammonium fluorescein particles to the tube surface. Particle bound was quantified for the case of clean tubes and solid particles. Second, the transient deposition of particles onto single heat-exchanger tubes in cross flow was studied. It was found that a steady-state condition could be reached for cases in which particle bounce occurred. Finally, the deposition patterns for the aerosol particles as they passed through a tube bank were studied. The quantities of aerosol deposited on various tubes depended on tube surface condition, tube position within the tube bank, and the overall geometry of the bank. Using these findings, heat exchangers can be designed that will resist gas-side fouling.

Fuhs, S.E.

1988-01-01

379

Fluid dynamics of a fluidized bed packed with heat exchangers  

Microsoft Academic Search

Tests of two fluidized bed facilities are described. Bed dynamics of a one foot gas fired fluidized bed (GFFB) and its interrelation with the heat transfer characteristics of immersed heat exchangers of different configurations were studied. The GFFB, capable of achieving different gas velocity distributions in the bed with the help of a specially designed gas distributor, was operated to

V. Zakkay; G. Miller; A. Kolar; J. Franceschi; S. Panunzio; W. Skelley; C. C. Ho; A. Brentan; G. Kiviat; S. Rosen

1981-01-01

380

MINLP synthesis of heat exchanger networks considering pressure drop effects  

Microsoft Academic Search

Considerable research effort has been reported in both Pinch Technology and MINLP techniques for the synthesis of heat exchanger networks. However, most of the design procedures assume constant stream heat transfer coefficients. A problem arises because there is no guarantee that the values of the coefficients assumed during network synthesis are the same as those actually achieved in detailed equipment

Sergio Frausto-hernández; Vicente Rico-ramírez; Arturo Jiménez-gutiérrez; Salvador Hernández-castro

2003-01-01

381

Fouling of Heat Exchanger Surface: Measurement and Diagnosis  

Microsoft Academic Search

Fouling in heat exchange equipment results in a significant energy toss by increasing heat transfer resistance and fluid frictional resistance. This paper deals with an effective way to monitor fouling and describes a potentially useful diagnostic approach for discriminating different types of deposit in situ. Information regarding deposit type would be useful in selecting an appropriate treatment procedure. Some cautions

M. Turakhia; W. G. Characklis; N. Zelver

1984-01-01

382

Nuclear reactor having double tube helical coil heat exchanger  

Microsoft Academic Search

A method for removing decay heat in a nuclear power plant is described comprising a nuclear reactor having a circulating liquid metal cooling system, which cooling system includes at least one heat exchanger comprising a vessel having a closed lower end. The cylindrical vessel is closed at its upper end by a closure plate having feedwater inlet nozzles and steam

G. Garabedian; R. A. De Luca

1988-01-01

383

Flexibility test for heat exchanger networks with uncertain flowrates  

Microsoft Academic Search

According to Cerdá et al (Computers ehem. Engng14, 197, 1990), a heat exchanger network is structurally flexible for a given variation range of parameters if it guarantees operability (feasibility) and maximum energy recover in the whole set of operation points. In this paper we present a flexibility test (in the previous sense) at the level of heat matches when only

N. Aguilera; G. Nasini

1995-01-01

384

POTENTIAL IMPROVEMENT IN THE DESIGN OF IMMERSED COIL HEAT EXCHANGERS  

Microsoft Academic Search

Although there is a notable move towards fresh water stations in the European markets, using the cheaper internal solutions of smooth or finned coil heat exchangers for smaller solar thermal system storage devices still dominates. Varying significantly in type and geometry, the functions used to account for heat transfer are possibly outdated and in light of the still relatively high

W. Logie; E. Frank

385

Normal fluid heat-exchange drag in liquid helium II  

Microsoft Academic Search

An examination is made of the modification to Stokes' law for a heated sphere in liquid helium II, as calculated by Springett. His calculation yields an extra term in the drag, over and above the ordinary viscous drag and the Penney-Hunt heat-exchange drag. It is shown that this term is an artifact of the handling of the inertial term in

Robert Lynch

1980-01-01

386

FFTF and CRBRP intermediate heat exchanger design, testing, and fabrication  

Microsoft Academic Search

The Heat Transport Systems of the Fast Flux Test Facility (FFTF) and the Clinch River Breeder Reactor Plant (CRBRP) include Intermediate Heat Exchangers (IHXs) to form barriers between the primary radioactive and secondary non-radioactive sodium coolant loops. The design, development and fabrication of the IHX for the FFTF has been completed and the units installed in the facility. The design

R. W. Devlin; J. D. Bresnahan

1977-01-01

387

Two-phase flow distribution in compact heat exchanger manifolds  

Microsoft Academic Search

In this paper an experimental study to investigate two-phase flow distribution in compact heat exchanger manifolds is presented. An experimental test rig to measure the flow distribution in realistic manifold geometries and under relevant operating conditions was built. To elucidate the effect on the flow distribution, the following factors are investigated: vapour fraction at the manifold inlet, heating load on

Sivert Vist; Jostein Pettersen

2004-01-01

388

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

389

Experimental Performance of R-134a-Filled and Water-Filled Loop Heat Pipe Heat Exchangers  

Microsoft Academic Search

Experimental investigations were conducted to determine the thermal performances of an R-134a-filled thermosyphon heat pipe heat exchanger (THPHE) and a water-filled loop heat pipe heat exchanger (LHPHE) for hot and cold energy recovery for air conditioning purposes. For such applications, the heat pipe heat exchangers are operated at low temperatures. Both exchangers were operated in the countercurrent flow mode. This

K. S. Ong

2010-01-01

390

Hydraulic and thermal design of a gas microchannel heat exchanger  

NASA Astrophysics Data System (ADS)

In this paper investigations on the design of a gas flow microchannel heat exchanger are described in terms of hydrodynamic and thermal aspects. The optimal choice for thermal conductivity of the solid material is discussed by analysis of its influences on the thermal performance of a micro heat exchanger. Two numerical models are built by means of a commercial CFD code (Fluent). The simulation results provide the distribution of mass flow rate, inlet pressure and pressure loss, outlet pressure and pressure loss, subjected to various feeding pressure values. Based on the thermal and hydrodynamic analysis, a micro heat exchanger made of polymer (PEEK) is designed and manufactured for flow and heat transfer measurements in air flows. Sensors are integrated into the micro heat exchanger in order to measure the local pressure and temperature in an accurate way. Finally, combined with numerical simulation, an operating range is suggested for the present micro heat exchanger in order to guarantee uniform flow distribution and best thermal and hydraulic performances.

Yang, Yahui; Brandner, Juergen J.; Morini, Gian Luca

2012-05-01

391

Sprinkled Heat Exchangers in Evaporation Mode  

NASA Astrophysics Data System (ADS)

The paper presents research on the heat transfer at sprinkled tube bundles situated in a test chamber at atmospheric pressure and low-pressure. Dynamic effects of physical quantities influencing the heat transfer coefficient during boiling are examined experimentally. Experimental results were achieved by means of balance measuring using thermocouple probes and by analysis of thermal diagrams created during operation periods.

Kracik, P.; Snajdarek, L.; Pospisil, J.

2013-04-01

392

Electrically enhanced fluidized bed heat exchanger  

Microsoft Academic Search

The experiments have shown that a high level of electrical charging can be achieved in a fluidized bed of two resistive particle types; that bed stabilization rather than increased sensible heat transport dominates low frequency electric field effects on heat transfer with most bed loadings; and, hence, that applying an oscillatory potential difference between tubes or rods in a fluidized

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

1994-01-01

393

Balance-of-plant heat exchanger condition assessment guidelines  

SciTech Connect

In nuclear power plants, service water system heat exchanger integrity and thermal performance are receiving close scrutiny to ensure that they perform their functions in an emergency condition. Many safety-related service water systems are called upon to function only in emergency conditions and are therefore difficult to monitor on a regular basis to ensure functionality. For some heat exchangers it is difficult to measure and extrapolate their thermal performance data since performance testing is often conducted at flows, temperatures, and heat loads which are different from design conditions. Tube fouling and plugged tubes may also contribute to this difficulty. Performance testing and analysis of heat exchanger alone does not provide information relative to structural integrity of remaining tubes. This document is provided to complement the existing performance testing with a periodic inservice inspection program.

Krzywosz, K. (Electric Power Research Inst., Charlotte, NC (United States). Nondestructive Evaluation Center); Tombaugh, R. (Pennsylvania Power and Light Co., Allentown, PA (United States)); Syverson, L. (Washington Public Power Supply System, Richland, WA (United States)); Lozier, G. (Power Authority of the State of New York, NY (United States))

1992-07-01

394

Effects of latent heat release at phase boundaries on flow in the Earth’s mantle, phase boundary topography and dynamic topography at the Earth’s surface  

Microsoft Academic Search

Mantle flow models that do not consider the effects of latent heat on phase boundaries typically predict dynamic surface topography too large to be compatible with observations. Here these effects were implemented in a mantle flow model and resulting changes in dynamic topography and topography of phase boundaries were computed. Inclusion of these effects was found to reduce the rms

Bernhard Steinberger

2007-01-01

395

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

1985-01-01

396

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

397

Development of a High Temperature Heat Pipe Heat Exchanger.  

National Technical Information Service (NTIS)

Research has been carried out on sulphur/iodine mixtures for potential use as a new heat pipe fluid for the economically attractive temperature range between about 300 deg C and 500 deg C. Heat transfer tests were conducted on silica and metal heat pipes,...

G. Chaffey J. C. Ralph C. D. Wade

1985-01-01

398

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

399

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

400

Theory of One and Two-Pass Cross-Flow Heat Exchanger.  

National Technical Information Service (NTIS)

There are numerous ways to connect heat exchangers. The fluids may be mixed or unmixed between the heat exchangers and inside the heat exchangers. The heat exchangers may be connected in counterflow or in cocurrent flow. The efficiency of the cross-flow s...

J. Saastamoinen

1987-01-01

401

Comparison of the thermal performance of double U-pipe borehole heat exchangers measured in situ  

Microsoft Academic Search

A borehole heat exchanger is a ground heat exchanger devised for the extraction or injection of thermal energy from\\/into the ground. The thermal performance of a borehole heat exchanger can be assessed with a response test. The response test method allows the in situ determination of the thermal conductivity of the ground in the vicinity of a borehole heat exchanger,

D. Pahud; B. Matthey

2001-01-01

402

Method and apparatus for in situ testing of heat exchangers  

SciTech Connect

A method of determining the extent of fouling in a heat exchanger including a plurality of tubes, the tubes of said heat exchanger being fouled to some degree is described, said method comprising the steps of: connecting a test reservoir to an inlet port and an outlet port of one of said tubes, said one of said tubes remaining in place in said heat exchanger; circulating a service fluid from said test reservoir through said one of said tubes; altering the heat content of said service fluid in said test reservoir; and detecting (a) the temperature of said service fluid at the respective ends of said tube, (b) the flow rate of said service fluid, and (c) the temperature of a process fluid on the outside of said tube; using the values of said items (a), (b) and (c) to compute a heat transfer efficiency for said one of said tubes; using the heat transfer efficiency of said one of said tubes to determine the extent of fouling of the tubes in said heat exchanger.

Hirota, N.S.

1993-06-01

403

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

404

Supercooling of Water in ACES Heat Exchangers.  

National Technical Information Service (NTIS)

Supercooled operation of the Annual Cycle Energy System (ACES) ice-maker heat-pump system was examined. From a theoretical analysis of heterogeneous nucleation, four parameters were determined: extent of supercooling, ice-water interfacial tension, contac...

G. M. Rinaldi L. W. Bonnell C. T. Geary

1977-01-01

405

Pd and Ag metal-silicate partitioning applied to Earth differentiation and core-mantle exchange  

NASA Astrophysics Data System (ADS)

Abstract- Pd and Ag partitioning between liquid Fe metallic sulfide and liquid silicate under plausible magma ocean conditions constrains potential core 107Ag content and the origin of observed Pd and Ag mantle abundances. DPdmetallic sulfide/silicate (element concentration in metallic liquid/concentration in silicate liquid) in our experiments is insensitive to S content and temperature, but increases with total Pd content. DPdmetallic sulfide/silicate at low Pd concentration ranges from approximately 150-650. Metallic sulfide Pd content and silicate Pd content anticorrelate in our study. A curved silicate saturation surface in the Fe sulfide-silicate Pd ternary can explain both the metallic sulfide-silicate Pd anticorrelation and interstudy differences in DPdmetallic sulfide/silicate behavior. The size and shape of the curved silicate phase volume may respond to physical and chemical conditions, reducing the general applicability of D calculations. Ag becomes decreasingly siderophile as S increases: DAgmetallic sulfide/silicate decreases from 144 at 0 wt% S to 2.5 at 28 wt% S added to the starting metal sulfide liquid. Model calculations indicate that 1% core material incorporated into the Hawai’ian plume would yield a 107Ag signature on the surface smaller than detectable by current analytical techniques. Observed Pd and Ag mantle depletions relative to bulk Earth are consistent with depletions calculated with the data from this study for a magma ocean scenario without additional accretionary input after core formation.

Wheeler, Kevin T.; Walker, David; McDonough, William F.

2011-02-01

406

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

Microsoft Academic Search

The development of a novel condensing heat exchanger, a modulating gas burner, and a zone-controlled residential warm-air heating system is described. The condensing heat exchanger uses ten thermosyphons which are manifolded at both the condenser and evaporator ends to achieve a compact low-cost design. Initial tests have demonstrated a + 92 percent steady-state efficiency for a conventional clamshell furnace operating

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

1986-01-01

407

Mantle-Crust Interaction Disclosed by He Isotopes, Seismic Profiles and Surface Heat Flow in the Larderello Geothermal Field (Italy).  

NASA Astrophysics Data System (ADS)

Heat flow, seismic and He isotopic data of the Tuscan geothermal province were integrated into the geological model of Larderello to: - understand the role of the mass and heat flow, entering the base of the crust and crossing the entire crust, on the evolution of this complex geothermal system; - validate the thermal model describing the present variability of the deep temperatures, including the heat transfer mechanisms and their space and time variability; - understand the nature of the "K horizons" seismic reflectors and their role on the deep fluid transfer toward the surface; - Speculate on the primary mantle source signature. The different components of the heat flow derived from 2D thermal modelling are related to the different fractions of He: 3He-enriched fluids are related to long-wave heat anomaly while short-wave thermal anomaly is related with 4He enriched fluids derived from crustal rocks. The Larderello geothermal field is fed by conduits deeply rooted which allow the rising to surface of mantle fluids with the lowest crustal contamination compared to other areas in Central Italy like Mt.Amiata or Mts.Volsini. This implies the He isotopic composition in the Tuscan area to be strongly dependent on the crustal fluid dilution due to the complex geological setting, and to be highly influenced by the depth of the feeding channels where fluid uprise. The R/Ra distribution at surface comes out as the result of a dynamic balance between crustal derived and mantle derived fluids rising trough the vertical conduits and partially homogenizing at the K-horizons. The presence of such "buffering" reservoirs could introduce an important constraint for the extrapolation of the primitive signature of the mantle beneath central Italy.

Bellani, S.; Magro, G.; Della Vedova, B.

2006-12-01

408

Applicability of uniform heat flux Nusselt number correlations to thermosyphon heat exchangers for solar water heaters  

SciTech Connect

Nusselt numbers are measured in three counterflow tube-in-shell heat exchangers with flow rates and temperatures representative of thermosyphon operation in solar water heating systems. Mixed convection heat transfer correlations for these tube-in-shell heat exchangers were previously developed in Dahl and Davidson (1998) from data obtained in carefully controlled experiments with uniform heat flux at the tube walls. The data presented in this paper confirm that the uniform heat flux correlations apply under more realistic conditions. Water flows in the shell and 50 percent ethylene glycol circulates in the tubes. Actual Nusselt numbers are within 15 percent of the values predicted for a constant heat flux boundary condition. The data reconfirm the importance of mixed convection in determining heat transfer rates. Under most operating conditions, natural convection heat transfer accounts for more than half of the total heat transfer rate.

Dahl, S.; Davidson, J. [Univ. of Minnesota, Minneapolis, MN (United States). Mechanical Engineering Dept.

1999-05-01

409

Supercritical heat exchanger field test (SHEFT), I. Field performance data on shell-and-tube heat exchangers in geothermal service  

SciTech Connect

Field performance data on shell-and-tube heat exchangers in geothermal service are presented. The test data were taken for geothermal brine on the tube side and hydrocarbon on the shell side in counterflow for six primary heat exchangers, and for hydrocarbon on the shell side and cooling water on the tube side for the condenser. Test data were for heating isobutane, 1 90/10 isobutane/isopentane mixture, and a 80/20 isobutane/isopentane mixture at supercritical conditions in the vicinity of their critical pressure and temperature, and for condensing the same fluids. The test data were used in a preliminary data analysis to determine the reported heat exchanger performance parameters.

Silvester, L.F.; Beaulaurier, L.O.; Mirk, K.F.; Fulton, R.L.

1981-06-01

410

Electrically enhanced fluidized bed heat exchanger  

SciTech Connect

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

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

1994-05-01

411

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

SciTech Connect

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

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

2011-01-01

412

Calculational methods for performance of heat exchangers enhanced with fluidized bed  

Microsoft Academic Search

The characteristics of fluidized beds are such that the analytical procedures for calculating the performance of conventional heat exchangers are not applicable to heat exchangers using fluidized bed heat transfer enhancement. Analytical procedures applicable to two different design approaches to heat exchangers utilizing fluidized bed heat transfer enhancement are developed, and the results are presented in graphical form.

M Suo

1976-01-01

413

Oil-fluorocarbon direct contact heat exchanger for low temperature power generation  

Microsoft Academic Search

In order to demonstrate the feasibility of power generation from medium and low temperature waste heat, geothermal heat, etc, a direct contact heat exchanger was developed. This new heat exchanger is especially excellent in its economies and heat exchange characteristics. To obtain design data for actual applications, a full-scale test was conducted to clarify problems encountered in the basic experiments.

S. Sakaguchi; U. Kuroda

1983-01-01

414

On the performance of copper foaming metal in the heat exchangers of pulse tube refrigerator  

Microsoft Academic Search

As key components in pulse tube refrigerators (PTRs), heat exchangers have great influence on the performance of the PTRs, especially the cold end heat exchangers which dominate the cooling effect between the cold gas and heat load. Filling copper screens are widely used to improve the performance of heat exchange and laminar flow. Whereas, the heat transfer rate of copper

K. Wang; Y. L. Ju; X. S. Lu; A. Z. Gu

2007-01-01

415

The performance of a new gas to gas heat exchanger with strip fin  

Microsoft Academic Search

A compact gas to gas heat exchanger needs large heat transfer areas on both fluid sides. This can be realised by adding secondary surfaces. The secondary surfaces are plate fin, strip fin, and louvered fin, etc. The fins extend the heat transfer surfaces and promote turbulence.This paper presents a gas to gas heat exchanger with strip fins. The heat exchanger

J. Wang; G. G. Hirs; P. Rollmann

1999-01-01

416

Dynamic tube/support interaction in heat exchanger tubes  

SciTech Connect

The supports for heat exchanger tubes are usually plates with drilled holes; other types of supports also have been used. To facilitate manufacture and to allow for thermal expansion of the tubes, small clearances are used between tubes and tube supports. The dynamics of tube/support interaction in heat exchangers is fairly complicated. Understanding tube dynamics and its effects is important for heat exchangers. This paper summarizes the current state of the art on this subject and to identify future research needs. Specifically, the following topics are discussed: dynamics of loosely supported tubes, tube/support gap dynamics, tube response in flow, tube damage and wear, design considerations, and future research needs. 55 refs., 1 fig.

Chen, S.S.

1991-01-01

417

Fundamental Experiment of Potassium Heat Exchanger Using Principle of Heat Pipe  

Microsoft Academic Search

In order to provide compact and reliable sodium equipments including a steam generator, performance tests are conducted with a potassium heat exchanger, which is featured by the separate construction of primary and secondary coolant systems. A small amount of potassium plays a role as an intermediate media of heat transportation between these two coolant systems. Heat is transfered by evaporation

Isao SUMIDA; Koichi KOTANI

1976-01-01

418

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

Microsoft Academic Search

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

Xiao Ping Wu; Peter Johnson; Aliakbar Akbarzadeh

1997-01-01

419

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

Microsoft Academic Search

In an earlier paper (Mathur, 1996), the author had investigated the impact that a heat pipe heat exchanger (HPHE) has on the energy consumption and the peak demand on an existing air conditioning system. A detailed performance investigation was carried out for a number of cities for year round operation of the HVAC system with HPHE. Heating degree days and

G. D. Mathur

1997-01-01

420

Heat exchange tube for fluidized bed reactor  

Microsoft Academic Search

Liquid containing heat transfer tube for use in a fluidized bed reactor is disclosed which is protected against erosive effects of the fluidized medium by having radially outwardly extending fins on its outer surface and by having the entire outer surface area between the fins covered by a layer of an abrasion resistant refractory which is supported by a metallic

Thompson

1978-01-01

421

Heat exchanger module for stirling engines  

SciTech Connect

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

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

1985-02-12

422

Corrosion of ceramics in heat exchanger applications  

Microsoft Academic Search

The gasification of domestic coals in the US has become increasingly attractive as a source of clean energy, as a result of the decreasing availability of natural gas and petroleum. The efficiency of conversion of the total coal energy is an important consideration in this process. Approximately 25% of the coal energy is released as waste or by-product heat during

T. E. Easler; R. B. Poeppel

2008-01-01

423

Research on heat-exchanger corrosion  

Microsoft Academic Search

Research conducted to develop technology for selecting corrosion resistant materials in high efficiency, gas fired, residential space heating equipment is reported. The methodology and results of sampling in over 500 homes to statistically characterize the corrosivity of flue gas condensate are described. The corrosion resistance of over 40 metal alloys was evaluated in accelerated laboratory tests with specimens exposed to

R. Razgaitis; J. H. Payer; G. H. Stickford; E. L. White; S. G. Talbert; R. A. Cudnick; D. W. Locklin; C. A. Farnsworth

1984-01-01

424

Sludge, fuel degradation and reducing fouling on heat exchangers  

SciTech Connect

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

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

1992-02-01

425

Diffusion Welding of Compact Heat Exchangers for Nuclear Applications  

SciTech Connect

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

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

2012-06-01

426

Increasing the efficiency of heat exchange devices in chemical shops  

SciTech Connect

Whenever a heat transfer agent and a medium being heated contain suspended (solid) substances or such substances are produced during the heat exchange process, ensuring the purity of the heat-transfer surface presents certain difficulties and involves considerable costs. From the point of view of lessening the quantity of particles in the heatexchanged mediums it is the processes for cooling water - its careful preparation which are considered, however, practically speaking, it is not possible to solve this problem fully; thus, preventing deposits is the main condition for reliable functioning of the device and a lowering of the expenditures for cleaning their surfaces.

Stetsenko, E.Ya.

1984-01-01

427

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

NASA Astrophysics Data System (ADS)

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.

1992-07-01

428

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

SciTech Connect

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. 12 refs.

Ku, Jentung; Yun, Seokgeun; Kroliczek, E.J. (NASA, Goddard Space Flight Center, Greenbelt, MD (United States) OAO Corp., Greenbelt, MD (United States))

1992-07-01

429

Exergy optimization in a steady moving bed heat exchanger.  

PubMed

This work provides an energy and exergy optimization analysis of a moving bed heat exchanger (MBHE). The exchanger is studied as a cross-flow heat exchanger where one of the phases is a moving granular medium. The optimal MBHE dimensions and the optimal particle diameter are obtained for a range of incoming fluid flow rates. The analyses are carried out over operation data of the exchanger obtained in two ways: a numerical simulation of the steady-state problem and an analytical solution of the simplified equations, neglecting the conduction terms. The numerical simulation considers, for the solid, the convection heat transfer to the fluid and the diffusion term in both directions, and for the fluid only the convection heat transfer to the solid. The results are compared with a well-known analytical solution (neglecting conduction effects) for the temperature distribution in the exchanger. Next, the analytical solution is used to derive an expression for the exergy destruction. The optimal length of the MBHE depends mainly on the flow rate and does not depend on particle diameter unless they become very small (thus increasing sharply the pressure drop). The exergy optimal length is always smaller than the thermal one, although the difference is itself small. PMID:19426351

Soria-Verdugo, A; Almendros-Ibáñez, J A; Ruiz-Rivas, U; Santana, D

2009-04-01

430

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

431

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

432

Subsurface environment database for application of ground heat exchanger system  

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

433

EHD (Electrohydrodynamics) enhancement of heat transfer in heat exchangers  

NASA Astrophysics Data System (ADS)

The potential of using an electric field with negligible power consumption (the corona discharge) to enhance corrective heat transfer coefficients for air flow in straight tubes was investigated experimentally. Pressure drop and heat transfer measurements were performed for Reynolds numbers and for electrode potentials. The effects were studied in the presence of both negative and positive corona fields. Based on the results obtained, a maximum of 215 percent enhancement in heat transfer coefficients at Reynolds number of Re sub D = 2000 and at field potential of 0 = 7.75 kV was obtained.

Nelson, D. A.; Ohadi, M. M.

1988-08-01

434

Desktop Learning Module Heat Exchanger Performance  

Microsoft Academic Search

Researchers at Washington State University have developed miniaturized hands-on learning stations or Desktop Learning Modules (DLM) to help demonstrate most basic fluid and heat transfer concepts in the classroom. Low-cost, 1 ft3 modules have been developed with interchangeable cartridges for dye injection into a flow stream; flow measurement with venturi, orifice and pitot tube meters; shell-and-tube, extended area and double

Colin D. Paul; Melinda B. O'Neil; W. Roy Penney; Bernard J. Van Wie; Paul B. Golter; Robert R. Beitle; Edgar C. Clausen

435

Understanding and mitigating heat exchanger fouling in bauxite refineries  

NASA Astrophysics Data System (ADS)

Laboratory and plant measurements have been performed to evaluate possibilities of reducing the formation of desilication product (DSP) scale in the heat exchangers of the low-temperature Bayer process. It was found that the rate of scale formation is independent of the flow velocity, proportional to the square of the silica super saturation, and it increases exponentially with heat-transfer surface temperature. Because of the restricted operation conditions, variation of operating conditions may not reduce DSP formation sufficiently. Installation of turbulence promoters in the heat exchanger pipes had no beneficial aspects. Laboratory and plant measurements with a fluidized bed test heater indicated a strong potential of this technology to increase the operation times between chemical washes. Deposition of DSP could almost be eliminated if the process was modified such that developed subcooled boiling occurred at the heat-transfer surface.

Müller-Steinhagen, H.; Jamialahmadi, M.; Robson, B.

1994-11-01

436

Effect of particle ingestion on the fouling reduction and heat transfer enhancement of a No-Distributor-Fluidized heat exchanger  

Microsoft Academic Search

To overcome the fouling problem that is common in heat exchangers for waste heat recovery, a new type of fluidized heat exchanger\\u000a was devised and tested. Fluidized bed heat exchangers are considered to be a good candidate for waste heat recovery flue gases\\u000a due to their demonstrated ability to avoid fouling or to clean out deposition on heat transfer surfaces,

Yongdu Jun; Kumbae Lee; Seokbo Ko

2008-01-01

437

Predicted energy savings for a residential heat pump utilizing a fluidized-bed heat exchanger  

SciTech Connect

The objective of this study was to determine if the energy efficiency of an optimized, state-of-the-art, residential heat pump could be increased by utilizing a fluidized-bed heat exchanger in place of a conventional heat exchanger on the outdoor side of the heat pump system. Using the Oak Ridge National Laboratory (ORNL) Heat Pump Model, comparisons were made between the advanced system (utilizing a fluidized-bed heat exchanger) and the base system (optimized, state-of-the-art) in eleven cities. The calculated annual energy savings for the advanced system ranged from 29 to 777 kWh/y, with the largest savings occurring in areas where the frosting and defrosting losses of the base unit are greatest, such as in the northeast.

Vineyard, E.A.

1984-01-01

438

Design Development Analyses in Support of a Heat pipe-Brayton Cycle Heat Exchanger  

SciTech Connect

One of the power systems under consideration for future space exploration applications, including nuclear electric propulsion or as a planetary surface power source, is a heat pipe-cooled reactor coupled to a Brayton cycle. In this system, power is transferred from the heat pipes to the Brayton gas via a heat exchanger attached to the heat pipes. This paper discusses the fluid, thermal and structural analyses that were performed in support of the design of the heat exchanger to be tested in the SAFE-100 experimental program at the Marshall Space Flight Center. An important consideration throughout the design development of the heat exchanger was its capability to be utilized for higher power and temperature applications. This paper also discusses this aspect of the design and presents designs for specific applications that are under consideration. (authors)

Steeve, Brian E. [NASA Marshall Space Flight Center, Huntsville, AL 35812 (United States); Kapernick, Richard J. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2004-07-01

439

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

440

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

441

Fouling of heat exchanger surface: measurement and diagnosis  

SciTech Connect

Fouling in heat exchange equipment results in a significant energy loss by increasing heat transfer resistance and fluid frictional resistance. This paper deals with an effective way to monitor fouling and describes a potentially useful diagnostic approach for discriminating different types of deposit in situ. Information regarding deposit type would be useful in selecting an appropriate treatment procedure. Some cautions regarding the indiscriminate use of fouling factor or fouling resistance are also discussed.

Turakhia, M.; Characklis, W.G.; Zelver, N.

1984-01-01

442

Three-dimensional numerical modeling of heat exchangers  

Microsoft Academic Search

A comprehensive, multi-dimensional, thermal-hydraulic model is developed for the analysis of shell and tube heat exchangers for liquid metal services. For the shell-side 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

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

1982-01-01

443

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

444

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

Microsoft Academic Search

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

Patrick Avran; Pierre Bernard

1993-01-01

445

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

Microsoft Academic Search

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

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

1963-01-01

446

Fluid dynamics of a fluidized bed packed with heat exchangers  

NASA Astrophysics Data System (ADS)

Tests of two fluidized bed facilities are described. Bed dynamics of a one foot gas fired fluidized bed (GFFB) and its interrelation with the heat transfer characteristics of immersed heat exchangers of different configurations were studied. The GFFB, capable of achieving different gas velocity distributions in the bed with the help of a specially designed gas distributor, was operated to gain useful information on the influence of various operating parameters, such as the superficial gas velocity and its profile, the bed temperature and pressure, and settled bed height, on the bed expansion and heat transfer characteristics of vertica and horizontal tube bundles, and an inverted U-tube. Tests were also performed on an inverted U-tube with longitudinal fins, and two unfinned inverted U-tubes to study the effect of heat exchanger solidity. Particle attrition studies were also performed at atmospheric pressure. A one-foot, coal-fired fluidized bed was also built and initial tests were performed. Typical heat transfer and particle attrition data were collected with a single vertical tube heat exchanger axially located in the bed. The behavior of deep and shallow beds, as observed in the GFFB, was confirmed.

Zakkay, V.; Miller, G.; Kolar, A.; Franceschi, J.; Panunzio, S.; Skelley, W.; Ho, C. C.; Brentan, A.; Kiviat, G.; Rosen, S.

1981-04-01

447

Contribution to chlorine cycle: a Cl stable isotope approach on Mantle-Ocean exchanges  

Microsoft Academic Search

The stable isotope composition of chlorine (37Cl\\/35Cl) can be used to trace its geochemical cycle and is a powerfull tool to constrain the origin of high chlorine contents found for some fresh MORB glasses. Despite the fact that chlorine is a volatile element of primary importance, its cycle and isotopic fractionation factors during exchange processes between Earth's reservoirs or phases

M. Bonifacie; N. Jendrzejewski; F. Pineau; P. Agrinier

2003-01-01

448

Fouling characteristics of compact heat exchangers and enhanced tubes.  

SciTech Connect

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

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

1999-07-15

449

Design of Cryogenic Heat Exchangers for a Superconducting Magnet.  

National Technical Information Service (NTIS)

Computer programs were written to design and simulate the behavior of three heat exchangers for cooling supercritical helium to approximately 4.3 exp 0 K at 4 atm. Helium, at 1, 3, or 5 gm/sec, is cooled by passing it through 0.635-cm-diam copper tubing i...

W. A. Chrusciel B. Y. Tao S. A. Ventura

1976-01-01

450

Gas turbine power plant having a heat exchanger  

Microsoft Academic Search

A gas turbine power plant, such as a gas turbine engine for a motor vehicle, having a gas turbine, a combustor for producing hot gas to drive the turbine, and an air compressor for furnishing compressed air to the combustor are described. A heat exchanger, such as a rotary regenerator or a cross-flow recuperator, is located between the air compressor

J. Huller; W. Krockow

1981-01-01

451

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

452

REDUCED TOTAL LIFE CYCLE COSTS USING HELIXCHANGER™ HEAT EXCHANGERS  

Microsoft Academic Search

Initial Capital Cost is usually the primary concern to project managers of new plants or major plant upgrades. On Lump Sum TurnKey (LSTK) projects, major effort is made to control the capital costs of new equipment. The purpose of this article is to present two arguments. The first is that the full economic benefit of heat exchanger technology can only

Bashir I. Master; Krishnan S. Chunangad; Bert Boxma; Graham T. Polley; Mohamed B. Tolba

453

Permeation Barrier Coatings for the Helical Heat Exchanger  

Microsoft Academic Search

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

Korinko

1999-01-01

454

Fluidized bed reactor system and method having a heat exchanger  

Microsoft Academic Search

A fluidized bed reactor system is described comprising a reactor, means for supporting a fluidized bed of combustible particulate material in said reactor, heat exchange means disposed adjacent said reactor, separating means for receiving a mixture of flue gases and entrained particulate material from said fluidized bed and separating said particulate material from said flue gases, means for passing said

Garcia-Mallol

1993-01-01

455

Gas turbine heat exchanger in the fluidized bed combustor  

Microsoft Academic Search

Design guidelines for an in-bed heat exchanger that is exposed to high temperatures (850C) and sulfidation are given based on research results. The combustor was designed to use a high sulfur coal of approximately 4 percent sulfur. Limestone or dolomite additions neutralize the sulfur action to a certain extent. Results of series of measurements of oxygen partial pressure at various

C. F. Holt; A. A. Boiarski; H. E. Carlton

1982-01-01

456

Fluidized bed reactor having an integrated recycle heat exchanger  

Microsoft Academic Search

This patent describes a fluidized bed combustion system. It includes a furnace, a fluidized bed of combustible particulate material disposed in the furnace, a recycle heat exchanger disposed adjacent the furnace and sharing a common wall with the furnace separating means for receiving a mixture of flue gases and entrained particulate material from a fluidized bed in the furnace and

W. R. Campbell; M. G. Alliston; B. H. Sisson

1990-01-01

457

Better system design reduces heat-exchanger fouling costs  

SciTech Connect

Fouling in heat exchangers is usually compensated for by overdesign. The authors say the opposite approach is better. Oversize to compensate for fouling, but oversize the nonfouling equipment. The article describes the current design practice and its drawbacks and then gives an alternate solution. The proposed approach allows the designer to make maximum benefit of the knowledge available by being specific in design.

Kotjabasakis, E.; Linnhoff

1987-09-28

458

Detection of cracked heat exchangers on warm air furnaces  

Microsoft Academic Search

Tests conducted by Wisconsin Gas Co. have shown that a sodium carbonate test for detecting holes or cracks in the heat exchangers of warm-air furnaces is more reliable than conventional methods and avoids the usual side effects caused by corrosive test solutions, smoke, or odors. In a test furnace simulating residential conditions, only the sodium carbonate test detected holes as

Wunderlin

1979-01-01

459

Ocean thermal energy conversion heat exchanger biofouling - Strategies of control  

Microsoft Academic Search

The potential effect of biofouling on OTEC heat exchanger performance is considered. A brief review is presented of some of the candidate biofouling control systems, including chlorination, Amertap (a continuous tube-cleaning system that circulates sponge rubber balls), a shuttle brush system, biocidal soak, toxic impregnation, slurries, screening, and a number of experimental countermeasures. Factors considered in evaluating the suitability of

P. C. Springer

1977-01-01

460

Retaining wall with heat exchange characteristics for thermal regeneration  

Microsoft Academic Search

In a heat exchange apparatus, this patent describes the combination comprising: (a) a central high temperature combustion zone, (b) a vertical wall having a closed curve configuration surrounding the zone and made principally of refractory, corrosion-resistant blocks. The wall has portions which comprise curved element-holding wall portions in which the blocks are of unitary construction and are disposed in contiguous

Benedick

1987-01-01

461

Investigation of Shear Lag in Heat Exchanger Module.  

National Technical Information Service (NTIS)

Results of a photoelastic model test which simulates the junction of the closure bar with sheet of a heat exchanger are presented. Values of shear stress 30 per cent above predicted values were found to exist. A linear technique for determination of maxim...

R. F. Machado

1967-01-01

462

Evaluation of flow maldistribution in air-cooled heat exchangers  

Microsoft Academic Search

Investigation of the evaluation of flow maldistribution in air-cooled heat exchangers is presented. The flow field in the inlet and return headers was obtained through the numerical solution of the governing partial differential equations including the conservation equations of mass and momentum in addition to the equations of the turbulence model. The effects of the number of nozzles, nozzle location,

M. A. Habib; R. Ben-Mansour; S. A. M. Said; M. S. Al-Qahtani; J. J. Al-Bagawi; K. M. Al-Mansour

2009-01-01

463

Research needs in low Reynolds number flow heat exchangers  

Microsoft Academic Search

A summary of research needs for the theoretical development and\\/or improvement of the thermal design of heat exchangers operating at low Reynolds number is presented. The summary is based on a listing developed at the request of the NATO Advanced Study Institute to affiliated researchers. Attention is given to topics in laminar forced convection internal flow, low Reynolds number turbulent

R. K. Shah

1981-01-01

464

Steam generators and other heat exchangers for RAPP and MAPP  

Microsoft Academic Search

A description of the steam generating equipment at Rajasthan Power ; Plant, India, consisting of eight steam generators is given. The design data of ; some of the heat exchangers used in the reactor building are presented. Monel is ; the material used for the tubes and the channel covers are of carbon steel and ; welded to the heavy

S. K. Chatterjee; M. L. Mitra

1973-01-01

465

Dynamic modeling of active solar thermal systems with heat exchangers  

SciTech Connect

The successful design of cost-effective controllers for active solar energy systems requires the use of simulation models to predict the distributed dynamic thermal response of each system component. Such models have been developed for the collector and transport. However, the effects of distributed heat exchanger dynamics in the modeling of solar energy system dynamic performance have often been neglected due to model complexity. A dynamic distributed parameter heat exchanger model suitable for solar energy applications is presented. An exact transcendental transform solution is derived for this model. Analytical methods are used to obtain a rational approximate transform solution for counter flow operation which is capable of accepting arbitrary inputs. An error analysis of this approximate transform solution is presented. The exact and approximate transform solutions are in close agreement for a range of heat exchanger characteristics common in solar energy applications. The approximate heat exchanger model solution is incorporated into a simulation capable of estimating the distributed short-term dynamics and long-term thermal performance of an active solar energy system. A graphical presentation of simulation results is given.

Konyk, S. Jr.

1985-01-01

466

Spiral-Passage-Honeycomb Chemical Converter-Heat Exchanger.  

National Technical Information Service (NTIS)

A spiral passage chemical converter-heat exchanger formed by a cross-sectionally rectangular housing containing a pair of rows each having a plurality of side-by-side passages. The rectangular housing is wound into a spiral with the inner-most row forming...

T. A. Chubb

1978-01-01

467

High-Temperature Ceramic-Heat-Exchanger Development. Final Report.  

National Technical Information Service (NTIS)

This report describes the results of a 27-month follow-on effort directed toward developing the technology necessary to build a high-temperature, high-pressure ceramic heat exchanger for operation with a small (200-hp) closed Brayton cycle engine. The cer...

M. Coombs D. Kotchick M. Weidhaas

1983-01-01

468

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

469

MATERIAL REQUIREMENTS FOR HEAT EXCHANGERS IN GAS CONDENSING BOILERS  

Microsoft Academic Search

A corroded heat exchanger failing after only a few years of service has been investigated. Critical species causing corrosion were identified. These are sulfuric acid generated by oxidation of SO2 to SO3 and dissolution in water and nitric acid by dissolution of NO2 in water. Corrosion products hydrolyse during service to a significant extent. By a calculation of burning of

G. Mori; H. Zitter

470

Geothermal heat exchanger test at Heber, California. Final report  

Microsoft Academic Search

A tube-in-shell counterflow heat exchanger, having four sections in series, was tested for approximately 2000 hours under field conditions. The objective of the test was to measure long term corrosion and fouling rates for use in commercial plant design. The geothermal brine used in the test was produced from the Nowlin No. 1 well at the Heber geothermal field in

E. L. Ghormley; J. L. Stern

1978-01-01

471

METALLOGRAPHIC EXAMINATION OF HIGH VELOCITY HEAT EXCHANGER (SHE NO.1)  

Microsoft Academic Search

Judging from the condition of the tube walls, this heat exchanger was ; close to failure. The depth of intergranular attack on the inner NaK surface ; (0.003 in.) and the depth of subsurface voids on the fuel side (0.007 in.) were ; more than half the wall thickness and these measurements were only from a few ; scattered specimens

Gray

1956-01-01

472

Qualification of Stainless Steel for OTEC Heat Exchanger Tubes.  

National Technical Information Service (NTIS)

The history of the AL-6X alloy is reviewed and its credentials as a candidate for use as tubing in Ocean Thermal Energy Conversion Heat Exchangers are examined. Qualification is based on results of accelerated tests using ferric chloride for resistance to...

F. L. LaQue

1979-01-01

473

Qualification of stainless steel for OTEC heat exchanger tubes  

Microsoft Academic Search

The history of the AL-6X alloy was reviewed and its credentials as a candidate for use as tubing in ocean thermal energy conversion (OTEC) heat exchangers were examined. Qualification was based on results of accelerated tests using ferric chloride for resistance to crevice corrosion and pitting, long time crevice and pitting tests in natural sea water and anticipated resistance to

F. L. Laque

1979-01-01

474

Development of a lightweight long life heat exchanger  

Microsoft Academic Search

A lightweight long life heat exchanger has been developed utilizing as its basis a composite aluminum-titanium sheet material capable of withstanding pitting corrosion which may occur when aluminum is exposed to wet air. Extensive testing demonstrated that the aluminum construction is compatible with a stainless steel water loop and that interface problems should not exist. A full scale Shuttle condensing

E. H. Tepper; E. K. Moore

1977-01-01

475

Tempering of Chocolate in a Scraped Surface Heat Exchanger  

Microsoft Academic Search

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