scispace - formally typeset
Search or ask a question

Showing papers on "Heat exchanger published in 2001"


Book
08 May 2001
TL;DR: The Heat Exchanger as Part of a System: Exergetic (Second Law) Analysis and Surface Comparisons, Size, Shape and Weight Relationships.
Abstract: Selected Contents. Chapter 1 Introduction. Chapter 2 Industrial Compact Exchangers. Chapter 3 The Heat Exchanger as Part of a System: Exergetic (Second Law) Analysis. Chapter 4 Surface Comparisons, Size, Shape and Weight Relationships. Chapter 5 Surface Types and Correlations. Chapter 6 Thermal Design. Chapter 7 Compact Heat Exchangers In Practice. Appendices.

349 citations


Journal ArticleDOI
TL;DR: In this article, the influence of the dimensions of the micro-channels on the heat transfer performance was analyzed numerically, based on these computations, deep micro-channel were used for the experimental studies reported here.

229 citations


Journal ArticleDOI
TL;DR: In this article, the authors consider the problem of accuracy in heat rate estimations from artificial neural network (ANN) models of heat exchangers used for refrigeration applications and present a methodology based on the cross-validation technique to find regions where not enough data are available to construct a reliable neural network.

220 citations


Journal ArticleDOI
TL;DR: In this article, crossflow and counterflow micro heat exchangers with microchannel or microcolumn structures have been developed for throughputs up to 7 t water/h with a heat transmission power up to 200 kW.
Abstract: Metallic microstructure devices have been manufactured and tested for applications in technical applications in thermal and chemical process engineering and in the laboratory. Manufacturing has been performed by micromachining of metal foils and diffusion bonding of a laminated foil stack, followed by welding of the microstructured core into a housing. Crossflow and counterflow micro heat exchangers with microchannel or microcolumn structures have been developed for throughputs up to 7 t water/h with a heat transmission power up to 200 kW. Overall heat transfer coefficients up to 54,000 W/m2 K have been determined with water as test fluid. Electrically driven microstructured heaters have been developed for fast and precise heating of sensitive liquids or gases. The heater has been used as an evaporator as well. Static micromixers have been developed for fast and complete mixing of reactands. They can be utilized with parallel reactions, for example, to decrease the yield of undesired by-products. For hete...

217 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the effect of cell shape and cell arrangement on the heat transfer performance of lightweight panels with two-dimensional metal cores, with emphasis on the effects of varying cell morphologies and cell arrangements.

206 citations


Journal ArticleDOI
TL;DR: In this article, a methodology has been developed for the design of cooling networks to satisfy any supply conditions for the cooling tower and a model of cooling tower performance has been explored systematically.

201 citations


Patent
09 Jan 2001
TL;DR: In this article, a data center having multiple rows of computer racks for holding heat-generating computer equipment is cooled by a liquid overfeed air conditioning unit that provides supply air at a temperature of about forty degrees Fahrenheit (40° F. or lower).
Abstract: A data center having multiple rows of computer racks for holding heat-generating computer equipment is cooled by a liquid overfeed air conditioning unit that provides supply air at a temperature of about forty degrees Fahrenheit (40° F. or lower). The air conditioning unit is positioned outside the data center. Ducting from the heat exchanger outlet of the unit is connected to supply registers mounted in aisles that are provided between the rows of computer racks so that very cold supply air enters the space between the racks. Each computer rack includes vertically spaced compartments that house computer components to be cooled. At least one circulation fan is associated with each compartment and causes supply air to flow through the compartment to cool the components. The supply air gradually warms as it flows through successive compartments and is approximately 72° Fahrenheit when it reaches a return register in the ceiling of the data center. The use of a high temperature differential conserves energy, reduces noise, increases usable data center floor space, and maintains proper data system component operating temperatures.

184 citations


Journal ArticleDOI
TL;DR: In this article, the thermal performance of a double U-pipe borehole heat exchanger can be assessed with a response test, which allows the in situ determination of the thermal conductivity of the ground in the vicinity of a BH, as well as the effective thermal resistance of this latter.

150 citations


Journal ArticleDOI
TL;DR: The artificial neural network (ANN) technique is extended to the simulation of the time-dependent behavior of a heat exchanger (HX) and used to control the temperature of air passing over it, which allows the system to reach steady-state operating conditions in regions where the PI and PID controllers are not able to perform as well.

149 citations


Patent
28 Mar 2001
TL;DR: In this paper, an improved cooling system provides cooling away from the surface of electrical and electronic components with very low parasitic power consumption and very high heat transfer rates, where the component to be cooled is in thermal contact with a cold plate evaporator device.
Abstract: An improved cooling system provides cooling away from the surface of electrical and electronic components with very low parasitic power consumption and very high heat transfer rates. The component to be cooled is in thermal contact with a cold plate evaporator device. Refrigerant is circulated by a liquid refrigerant pump to the cold plate evaporator device, and the liquid refrigerant is at least partially evaporated by the heat generated by the component. The vapor is condensed by a conventional condenser coil and the condensed liquid along with any unevaporated liquid is returned to the pump. The system operates nearly isothermally in both evaporation and condensation.

147 citations


Patent
08 Aug 2001
TL;DR: A rotating magnetic refrigeration apparatus has magnetic regenerator beds arranged in a ring (21) that is mounted for rotation about a central axis, such that each bed moves into and out of a magnetic field provided by a magnet.
Abstract: A rotating magnetic refrigeration apparatus has magnetic regenerator beds (22) arranged in a ring (21) that is mounted for rotation about a central axis, such that each bed moves into and out of a magnetic field provided by a magnet (29) as the ring (21) rotates. Heat transfer fluid is directed to and from the regenerator beds (22) by a distribution valve (24) which is connected by conduits to the hot and cold ends of the beds and which rotates with the ring (21) of beds (22). The distribution valve (24) has a stationary valve member which is connected by conduits to a hot heat exchanger (34) and to a cold heat exchanger (38). The beds include magnetocaloric material that is porous and that allows heat transfer fluid to flow therethrough. The distribution valve (24) directs heat transfer fluid to the hot end of a bed that is outside of the magnetic field which flows therethrough to the cold end where it is directed back to the distribution valve (24) and, when a bed is in the magnetic field, the distribution valve (24) directs fluid to the cold end of the bed for flow therethrough to the hot end, where the fluid is directed back to the distribution valve, completing an active magnetic regenerator cycle. The fluid flowing through each conduit flows only in a single direction or remains stationary, minimizing dead volume in the conduits.

Journal ArticleDOI
TL;DR: In this paper, the phase change stability of stearic acid as a phase change material (PCM) was investigated and the experimental results showed that the melting stability of the PCM is better in the radial direction than in the axial direction.

Journal ArticleDOI
TL;DR: In this article, a three-start spirally corrugated tubes combined with five twisted tape inserts with different relative pitches in the range of Reynolds number 3×103-6×104.

Journal ArticleDOI
TL;DR: In this article, an analysis of the influence of fluid flow rate, heat exchanger geometry, fluid properties and inlet temperatures on the power supplied by the thermoelectric generator has been done.

Journal ArticleDOI
TL;DR: In this paper, the phase change stability of myristic acid as a phase change material (PCM) has been studied experimentally and the experimental results showed that the melting stability of the PCM is better in the radial direction than the axial direction.

Journal ArticleDOI
TL;DR: Wang et al. as discussed by the authors developed and tested several prototype adsorption refrigeration systems, typical examples are continuous heat regenerative ad-sorption ice maker using spiral plate adsorbers, adsorsption heat pump using novel heat exchanger as adsorsbers, solar powered ad-a-sion ice maker, solar-powered hybrid system of water heater and ad-orption refrigerator, waste heat driven air conditioning system for automobiles.
Abstract: The research work on adsorption refrigeration in Shanghai Jiao Tong University (SJTU) started in 1993, various adsorption refrigeration cycles have been investigated, such as continuous heat recovery cycle, mass recovery cycle, thermal wave cycle, convective thermal wave cycle, cascade multi effect cycle, hybrid heating and cooling cycle etc. Several prototype adsorption refrigeration systems have been developed and tested, typical examples are continuous heat regenerative adsorption ice maker using spiral plate adsorbers, adsorption heat pump using novel heat exchanger as adsorbers, solar powered adsorption ice maker, solar powered hybrid system of water heater and adsorption refrigerator, waste heat driven air conditioning system for automobiles. Reasonable experimental results have been obtained, it was found that with a heat source temperature of 100°C, the refrigerator can obtain specific refrigeration power for 5.2 kg-ice/day per kg activated carbon in one adsorber, the heat pump can reach a specific cooling power for more than 150 W/kg-adsorbent with a COP close to 0.5, the adsorption solar ice maker yields 5–7 kg-ice per day per square meter solar collector, the hybrid solar water heater and ice maker is capable of heating 60 kg water up to about 90°C and meanwhile yields ice making about 5 kg per day with a 2 m 2 solar collector. The adsorption mechanisms of adsorption refrigeration pairs and also the thermo-physical properties have been also studied in SJTU, which are very helpful for adsorption refrigeration researches. This paper shows the various aspects researched in SJTU.

Patent
06 Nov 2001
TL;DR: In this article, a single-use, disposable circulation set for a heat transfer catheter is presented, which is adapted to pump heat transfer fluid through the catheter from the fluid reservoir.
Abstract: The invention provides a single-use, disposable circulation set for a heat transfer catheter. The circulation set includes a single-use, disposable fluid reservoir adapted to supply a heat transfer fluid to the catheter, a single-use, disposable pump adapted to pump heat transfer fluid through the catheter from the fluid reservoir, a single-use, disposable filter assembly adapted to remove impurities from the heat transfer fluid, a single-use, disposable heat exchanger member adapted for use with a heat exchanger for transferring heat between the heat exchanger and the fluid, a single-use, disposable temperature and pressure sensor block member for use with a multi-use, non-disposable temperature and pressure sensor electronics member, a single-use, disposable supply line communicating the fluid reservoir, pump, filter assembly, heat exchanger, and temperature and pressure sensor block member, and adapted to be connected to the catheter for supplying heat transfer fluid to the catheter, and a single-use, disposable return line communicating the temperature and pressure sensor block member and fluid reservoir, and adapted to be connected to the catheter for returning heat transfer fluid to the fluid reservoir.

Journal ArticleDOI
TL;DR: In this paper, the authors presented measurements of ϵ for the case where the plate is perforated with circular holes on either a square or triangular layout, covering a range of wind speeds extending from zero to 5 m/s.

Patent
11 Jan 2001
TL;DR: In this article, an air conditioner outdoor unit (1) comprises a case having a rectangular shape and composed of side panels (4, 4,--) in which a machine chamber (3) and a heat exchanger chamber (2) are defined so as to be vertically aligned.
Abstract: An air conditioner outdoor unit (1) comprises a case having a rectangular shape and composed of side panels (4, 4,--) in which a machine chamber (3) and a heat exchanger chamber (2) are defined so as to be vertically aligned, with the heat exchanger chamber disposed above the machine chamber (3) and sectioned by a partition plate (12) which also acts as a drain pan, the side panels surrounding the heat exchanger chamber are formed with air suctions ports (4a, 4a --). The outdoor unit (1) further comprises a heat exchanger unit (17, 18) having four side wall sections of which at least two opposing two sections are inclined inwardly by a predetermined angle with respect to inner surfaces of the side panels to which the air suction ports are formed. The outdoor unit case also contains a duct unit (20) arranged in association with the drain pan (12) for discharging drain and cooling an electrical part such as a heat sink (22).

Patent
05 Jun 2001
TL;DR: In this paper, a solder composition has been introduced to interface between an IC chip and its associated heat exchanger cover, which has the desired property of absorbing and rejecting heat energy by changing state or phase with each temperature rise and decline resulting from temperature fluctuations associated with the thermal cycles of the integrated circuit chips.
Abstract: Solder compositions are introduced to interface between an IC chip and its associated heat exchanger cover. The solder compositions have a solidus-liquidus temperature range that encompasses the IC chip operational temperature range. The solder composition has the desired property of absorbing and rejecting heat energy by changing state or phase with each temperature rise and decline that result from temperature fluctuations associated with the thermal cycles of the integrated circuit chips. A path for high thermal conduction (low thermal resistance) from the IC chip to the heat exchanger to the ambient air is provided by an electronic module cover, configured as a cap with a heat exchanger formed or attached as a single construction, and made of the same material as the substrate, or made with materials of compatible thermal coefficients of expansion to mitigate the effects of vertical displacement during thermal cycling. The cap-heat exchanger cover is constructed to be compliant, and to contact both the IC chip and substrate.

Patent
25 Apr 2001
TL;DR: In this paper, a condenser of a refrigerant cycle system includes a first heat exchange unit into which refrigerant discharged from a compressor flows, a second heat exchange Unit disposed at a downstream of the first unit, and a gas-liquid separator disposed between the first and second units in the refrigerant flow direction.
Abstract: A condenser of a refrigerant cycle system includes a first heat exchange unit into which refrigerant discharged from a compressor flows, a second heat exchange unit disposed at a downstream of the first heat exchange unit in a refrigerant flow direction, and a gas-liquid separator disposed between the first and second heat exchange units in the refrigerant flow direction. In the refrigerant cycle system, at least gas refrigerant separated in the gas-liquid separator flows into the second heat exchange unit so that an amount of liquid refrigerant stored in the gas-liquid separator is changed in accordance with a super-heating degree of refrigerant discharged from the compressor.

Patent
06 Mar 2001
TL;DR: In this paper, a cooling system using low profile extrusions is described for wireless base station for removing heat from power amplifiers and other electronic components, which is carried out by drawing heat away from the electronic components and into at least one low profile extrusion attached directly to the heat generating components or a heat sink, and transferring the removed heat to a cooling fluid circulating through a plurality of micro tubes or channels within each low-profile extrusion.
Abstract: A cooling apparatus using 'low profile extrusions' is disclosed. The cooling apparatus of the present invention may be incorporated into a closed loop liquid cooling system which is particularly well suited to heat removal from electronic components in applications where space is limited. A cooling system in accordance with the present invention is illustrated for use in a typical wireless telecommunication bases station for removing heat from power amplifiers and other electronic components. Cooling is carried out by drawing heat away from the electronic components and into at least one low profile extrusion attached directly to the heat generating components or a heat sink, and transferring the removed heat to a cooling fluid circulating through a plurality of micro tubes or channels within each low profile extrusion. The cooling fluid is subsequently pumped through a liquid-to-air heat exchanger, to reject the removed heat into the atmosphere, prior to being recirculated through each of the low profile extrusions.

Journal ArticleDOI
TL;DR: In this paper, an integral type solar-assisted heat pump water heater (ISAHP) was designed to operate at an evaporating temperature lower than the ambient temperature and a matched condition (near saturated vapor compression cycle and compressor exhaust temperature).

Patent
26 Nov 2001
TL;DR: In this article, the authors present a boiler with heat exchanger coils containing water and receives hot exhaust gases for vaporizing water in the coils and producing steam which is supplied to a steam turbine coupled to a generator for expanding steam produced by the boiler, and driving the generator and producing power and expanded steam.
Abstract: Retrofit equipment includes an auxiliary gas turbine unit including an auxiliary compressor for compressing ambient air to produce compressed air, a solar collector that receives the compressed air for heating the same to produce heated compressed air, and an auxiliary turbine coupled to the auxiliary compressor and to an auxiliary generator for expanding the heated compressed air and driving the auxiliary compressor and auxiliary generator thereby producing power and hot exhaust gases. When solar insolation is available, a flow control selectively supplies the hot exhaust gases from the retrofit equipment to a boiler which is part of a conventional fossil fueled power plant. The boiler has heat exchanger coils containing water and receives hot exhaust gases for vaporizing water in the coils and producing steam which is supplied to a steam turbine coupled to a generator for expanding steam produced by the boiler, and driving the generator and producing power and expanded steam. A condenser condenses the expanded steam to condensate, and a pump returns the condensate to the boiler. When solar insolation is not available. e.g., during the night, the flow control supplies the boiler with hot gases from a primary gas turbine unit which includes a primary compressor that compresses ambient air to produce compressed air, and a combustor that receives the compressed air for burning fossil fuel and heating the compressed air to produce heated compressed air that is supplied to the primary turbine.

Patent
05 Jun 2001
TL;DR: In this article, an air conditioner for a vehicle which maintains comfortableness in a vehicle room irrespective of season by controlling blowing air amount into the vehicle room to the optimum amount even when cooling and heating capacity for the vehicle is reduced.
Abstract: PROBLEM TO BE SOLVED: To provide an air conditioner for a vehicle which maintains comfortableness in a vehicle room irrespective of season by controlling blowing air amount into the vehicle room to the optimum amount even when cooling and heating capacity of the air conditioner for the vehicle is reduced. SOLUTION: This air conditioner for the vehicle is provided with: an air amount setting means for setting amount of blowing air into the vehicle room in accordance with a vehicle room condition; and a fan motor for feeding air blown into the vehicle room into a heat exchanger in accordance with air amount set by the air amount setting means. It is also provided with: a heat exchange capacity detection means for detecting the reduction of heat exchange capacity of the heat exchanger based on a running condition of the vehicle; and an air amount reducing means for reducing air amount of the fan motor set by the air amount setting means by predetermined amount when the heat exchange capacity detection means detects the reduction of heat exchange capacity of the heat exchanger. COPYRIGHT: (C)2004,JPO

Journal ArticleDOI
TL;DR: In this article, the importance of heat exchanger operating conditions on carbon deposition was investigated to evaluate their effectiveness and provide a basis for combining them into a single design philosophy, including selection of favorable operating conditions (viz., pressure, temperature, heat flux, residence time, and passage size).
Abstract: The development of a viable strategy for limiting coke deposition involves combining synergistic approaches for suppressing deposit buildup and reducing its impact on performance. Candidate approaches, including selection of favorable operating conditions (viz., pressure, temperature, heat flux, residence time, and passage size) and coke-tolerant heat exchanger designs, were investigated to evaluate their effectiveness and provide a basis for combining them into a single design philosophy. These approaches were evaluated through testing of current jet fuels in single-tubes and segments of heat exchanger configurations at temperatures up to 1000°F, pressures up to 1200 psi and liquid hourly space velocities up to 40,000/h. A key result of this work is the ranking of the importance of heat exchanger operating conditions on carbon deposition, with fuel temperature and those parameters that control species diffusion having the most pronounced impact. Residence time and pressure are of lesser importance. Alternative coke-tolerant heat exchanger designs featuring interchannel communication were evaluated and ranked, with several of these concepts demonstrating improvement over continuous passages.

Journal ArticleDOI
TL;DR: In this paper, the main geometric features of a flow component can be deduced from the thermodynamic optimization of the global performance of the largest flow system that incorporates the component, and the method illustrated in this paper is applicable to any system that runs on the basis of a limited amount of fuel (exergy) installed onboard.

Patent
27 Nov 2001
TL;DR: In this paper, a closed-loop fluidic circuit is coupled to the surface for removing heat from the integrated circuit, where the blower moves air through the heat exchanger.
Abstract: A water-cooled system and method for cooling electronic components. The system includes a surface. At least one electronic component is coupled to the surface, the at least one electronic component including an integrated circuit. A closed-loop fluidic circuit is coupled to the surface for removing heat from the integrated circuit. The closed-loop fluidic circuit includes a heat exchanger. A blower is coupled to the surface, the blower having a first port, a second port, and an impeller that rotates around an axis. The blower is oriented such that the axis is perpendicular to the surface and non-intersecting with the heat exchanger, wherein the blower moves air through the heat exchanger.

Patent
12 Oct 2001
TL;DR: In this article, a second heat exchanger disposed adjacent to and in front of the first one is used for cooling a cooling liquid of a battery, and a fan is rotated to cool external air with the second one.
Abstract: The passenger compartment air-conditioning apparatus has a second heat exchanger disposed adjacent to and in front of a first heat exchanger for cooling a cooling liquid of a battery. When the temperature of the battery is increased at the time the battery is charged in a quick charge mode, a compressor of the passenger compartment air-conditioning apparatus is actuated by a coaction of a battery ECU and an air-conditioning ECU to supply a refrigerant to the second heat exchanger. A fan is rotated to cool external air with the second heat exchanger. The cooled external air is introduced into the first heat exchanger, which cools the cooling liquid of the battery.

Journal ArticleDOI
TL;DR: In this article, the activity and the heat transfer characteristics of several microstructured reactors have been compared in the ammonia oxidation on Pt catalyst, where the main parameters which influence reactor performance are catalyst loading, temperature, and the intrinsic conductivity of the reactor material.