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Showing papers on "Heat exchanger published in 1991"


Patent
15 Mar 1991
TL;DR: In this paper, an integrated fuel cell power generation system consisting of a fuel cell stack having a humidification section and an electrochemically active section is presented, which includes fuel cells for promoting the electrocatalytic conversion of the humidified fuel and oxidant streams to electric current and product water.
Abstract: An integrated fuel cell power generation system comprises a fuel cell stack having a humidification section and an electrochemically active section The humidification section imparts water vapor to an inlet hydrogen containing fuel stream and an inlet oxygen containing oxidant stream The electrochemically active section comprises fuel cells for promoting the electrocatalytic conversion of the humidified fuel and oxidant streams to electric current and product water The electrochemically active section also includes a coolant water stream for absorbing heat generated in the active section The system includes a heat exchanger for removing heat from the coolant water stream exiting the active section, a water separator for removing water from the oxidant stream exiting the fuel cell stack, and a coolant reservoir for receiving the removed water stream from the water separator and from the heat exchanger The coolant water stream is drawn from the coolant reservoir

154 citations


Journal ArticleDOI
TL;DR: In this paper, the power output of the closed Brayton cycle and the closed Carnot cycle was investigated for both finite and infinite thermal capacitance rates of the external fluid streams and the method of Lagrange multipliers was used to solve for working fluid temperatures that yield maximum power.
Abstract: In this paper optimization of the power output of Carnot and closed Brayton cycles is considered for both finite and infinite thermal capacitance rates of the external fluid streams. The method of Lagrange multipliers is used to solve for working fluid temperatures that yield maximum power. Analytical expressions for the maximum power and the cycle efficiency at maximum power are obtained. A comparison of the maximum power from the two cycles for the same boundary conditions, i.e., the same heat source/sink inlet temperatures, thermal capacitance rates, and heat exchanger conductances, shows that the Brayton cycle can produce more power than the Carnot cycle. This comparison illustrates that cycles exist that can produce more power than the Carnot cycle. The optimum heat power cycle, which will provide the upper limit of power obtained from any thermodynamic cycle for specified boundary conditions and heat exchanger conductances is considered. The optimum heat power cycle is identified by optimizing the sum of the power output from a sequence of Carnot cycles. The shape of the optimum heat power cycle, the power output, and corresponding efficiency are presented. The efficiency at maximum power of all cycles investigated in this study is found to be equalmore » to (or well approximated by) {eta} = 1 {minus} sq. root T{sub L.in}/{phi}T{sub H.in} where {phi} is a factor relating the entropy changes during heat rejection and heat addition.« less

139 citations


Patent
04 Jun 1991
TL;DR: In this article, a set of thermocouples (thermoelectric couples) arranged side-by-side to form a plate is described, where the heat flow is in a direction from one side of the plate to the other side, other than the direction of the device's working thermal gradient.
Abstract: Thermoelectric heat pumps using recuperative heat exchange are described. These devices use sets of thermocouples (thermoelectric couples) arranged side-by-side to form a plate. The plate is positioned in a fluid-containing vessel and heat exchanging fluid is flowed down one side of the plate and up the other side. In these devices the heat flow, and thus the driving thermal gradient on each thermoelectric couple in the device, is in a direction from one side of the plate to the other side, i.e., other than the direction of the device's working thermal gradient, which is the direction of the flow of fluid. Generally these two directions (driving gradient on the thermoelectric couples and fluid flow-working thermal gradient) are essentially orthogonal to each other.

135 citations


Patent
25 Jul 1991
TL;DR: In this article, a partition plate is provided between the electronic circuit unit and the cooling unit to partition the two so that in the event of occurrence of liquid leakage, the coolant may be prevented from migrating from the cooled unit to the electronic unit.
Abstract: An electronic apparatus comprises an electronic circuit unit having heat-generating electronic parts and cooling jackets fed with a coolant so as to cool the heat-generating electronic parts, and a coolant cooling unit having a heat exchanger for cooling the coolant from the cooling jackets and a pump for pressurizing and feeding the cooled coolant to the cooling jackets. The electronic circuit unit and the coolant cooling unit are housed in the same cabinet, and a partition plate is provided between the electronic circuit unit and coolant cooling unit to partition the two so that in the event of occurrence of liquid leakage, the coolant may be prevented from migrating from the coolant cooling unit to the electronic circuit unit. A coolant drainage drain may be provided at the bottom of a U-shaped portion of a path for circulating the coolant to facilitate drainage of the coolant.

132 citations


Patent
Imaiida Tsuyoshi1, Itoh Takeshi, Nozoe Hiroki, Katoh Iwanori, Sakai Hiroshi 
09 Jul 1991
TL;DR: In this article, an air conditioning apparatus comprises an air conditioner provided with an air inlet port opening to a room, a heat exchanger and a blower, a duct box connected to the air conditioning system directly or through a duct, a blow-off casing provided on the duct box to project into the room and having an air outlet opening to the room, and a fan disposed on a lower portion of the blowoff casing, wherein a conical partition wall is provided between the air outlet and the fan to diffuse conditioning air in the radial direction while turning into the
Abstract: An air conditioning apparatus comprises an air conditioner provided with an air inlet port opening to a room, a heat exchanger and a blower, a duct box connected to the air conditioner directly or through a duct, a blow-off casing provided on the duct box to project into the room and having an air outlet opening to the room, and a fan disposed on a lower portion of the blow-off casing, wherein a conical partition wall is provided between the air outlet and the fan to diffuse conditioning air in the radial direction while turning into the horizontal direction, a plurality of ring-like louvers are provided in the air outlet into the form of multiple stages, the fan is rotatable forward and backward and includes an outer rotor motor and a plurality of blades fixedly attached to an outer peripheral surface of an outer rotor of the motor, the air outlet and fan are disposed within a recess provided on the ceiling or wall surface, an oscillating mechanism is provided to oscillate the fan or both of the fan and air outlet integrally, and a start/stop switch is provided for starting and stopping the fan in synchronism with the start and stop of a conditioning air generator

129 citations


Patent
11 Oct 1991
TL;DR: In this paper, a liquid cooling system for a printed circuit board on which integrated circuit packages are mounted, heat sinks are secured respectively to the packages in heat transfer contact therewith, and nozzles are provided in positions corresponding to the heat sinks.
Abstract: In a liquid cooling system for a printed circuit board on which integrated circuit packages are mounted, heat sinks are secured respectively to the packages in heat transfer contact therewith. Nozzles are provided in positions corresponding to the heat sinks. A housing is tightly sealed to the printed circuit board to enclose the packages, heat sinks and nozzles in a cooling chamber. A feed pump pressurizes working liquid cooled by a heat exchanger and supplies the pressurized liquid to the nozzles for ejecting liquid droplets to the heat sinks. A liquid suction pump is connected to an outlet of the housing for draining liquid coolant to the heat exchanger and a vapor suction pump is connected to a second outlet of the housing for sucking vaporized coolant to the heat exchanger. The cooling chamber is maintained at a sub-atmospheric pressure to promote nucleate boiling of the working fluid.

118 citations


Patent
14 Mar 1991
TL;DR: A selectively cooled or heated seat has an outer layer (40) of corduroy appearance with perforations (46) between wales through which conditioned air can flow.
Abstract: A selectively cooled or heated seat has an outer layer (40) of corduroy appearance with perforations (46) between wales through which conditioned air can flow. Alternatively, layers (47,52) are constructed of molded plastic or rubber. The seat construction is made by molding a cushion (64) of foam over the seat outer layer. The conditioning apparatus has a unitary fin structure (74) or, alternatively, a heat pipe (82) for removing or adding heat to the thermoelectric auxiliary heat exchanger (20). In a further modification, heat exchanging coils (34) located within the seat (24) have a fluid circulating through them and the conditioning apparatus auxiliary heat exchanger with ambient air being blown across the coils.

112 citations


Book
01 Jan 1991
TL;DR: In this article, Kakac et al. present the basic design methods of Heat Exchangers, including Forced Convection Correlations for Single Phase Side of Heat Echangers (S. Kakac & E. Paykoc).
Abstract: Basic Design Methods of Heat Exchangers (S. Kakac & E. Paykoc). Forced Convection Correlations for Single-Phase Side of Heat Exchangers (S. Kakac & R. Oskay). Heat Exchanger Fouling (A. Agrawal & S. Kakac). Industrial Heat Exchanger Design Practices (J. Taborek). Fossil-Fuel-Fired Boilers: Fundamentals and Elements (J. Kitto & M. Albrecht). Once-Through Boilers (R. Leithner). Thermohydraulic Design of Fossil-Fuel-Fired Boiler Components (Z. Lin). Nuclear Steam Generators and Waste Heat Boilers (J. Collier). Heat Transfer in Condensation (P. Marto). Steam Power Plant and Process Condensers (D. Butterworth). Evaporators and Condensers for Refrigeration and Air-Conditioning Systems (M. Pate). Evaporators and Reboilers in the Process and Chemical Industries (P. Whalley). Appendix. Tables. Index.

109 citations


Patent
25 Sep 1991
TL;DR: A convection braze furnace for brazing aluminum heat exchangers in an inert gas rich atmosphere includes entrance and exit vestibules forming atmosphere barriers of suspended stainless steel strips as discussed by the authors.
Abstract: A convection braze furnace for brazing aluminum heat exchangers in an inert gas rich atmosphere includes entrance and exit vestibules forming atmosphere barriers of suspended stainless steel strips. The interior of the braze furnace is divided into multiple zones for progressively heating the heat exchangers to a brazing temperature and then cooling the heat exchangers in the final zone. An impeller circulates the heated inert gas atmosphere within each zone to accelerate heat transfer. A chain type conveyor supports the heat exchangers as they are moved through the braze furnace. An isolated return tube surrounds the lower return side of the conveyor chain as it passes through the braze furnace. The braze furnace housing is comprised of inner and outer shells having an inert gas pressurized cavity interstitial therebetween. The inner shell includes a plurality of expansion strips having generally ellipsoidal corner expansion joints.

90 citations


Patent
18 Feb 1991
TL;DR: In this paper, a binary refrigerating system consisting of two sets of refrigerant circuits consisting of a middle-temperature middle pressure and high temperature high pressure while supplying hot-water is preheated by the second condensing liquefier 14 of the refrigerant circuit 1 of the side of a low stage.
Abstract: PURPOSE:To obtain the above heat pump type hot-water supplier, capable of supplying high-temperature hot-water efficiently and provided with air- conditioning function. CONSTITUTION:The subject hot-water supplier is a binary refrigerating system consisting of two sets of refrigerant circuits 1, 2 of a middle-temperature middle pressure and high-temperature high pressure while supplying hot-water is preheated by the second condensing liquefier 14 of the refrigerant circuit 1 of the side of a low stage. According to this method, the compression ratio of respective refrigerant circuits can be reduced whereby hot-water supplying performance is improved and high-temperature supplying hot-water can be obtained. On the other hand, the low stage side refrigerant circuit 1 is provided with a refrigerant distributing device 12, a four-way valve 17, an indoor heat exchanger 18 and a choke device 19 whereby not only the supplying of hot-water, but also the cooling and heating of a room can be effected by the subject hot-water supplier.

85 citations


Patent
14 Nov 1991
TL;DR: The potential for leakage of CFC, HCFC, HFC and HCs to the atmosphere as a result of leakage in vehicular refrigeration systems is reduced by employing conduits (42, 58 and 63) of relatively short length to interconnect closely grouped system components including a compressor, a condenser and an evaporator as mentioned in this paper.
Abstract: The potential for leakage of CFCs, HCFCs, HFCs and HCs to the atmosphere as a result of leakage in vehicular refrigeration systems is reduced by employing conduits (42, 58 and 63) of relatively short length to interconnect closely grouped system components including a compressor (38), a condenser (44) and an evaporator (62). The condenser (44) includes a liquid flow path (46) in heat exchange relation with a refrigerant flow path (48) and the same is connected by conduit (52) to heat exchanger (36). The evaporator (62) also includes a liquid flow path (65) in heat exchange relation with a refrigerant flow path (60) and the same is connected by conduits (66, 67) to at least one heat exchanger (68, 69) remote from an engine compartment (22) in which the compressor (38), condenser (44) and evaporator (62) are housed. The close proximity of the components minimizes the charge of refrigerant required and thus reduces the amount of refrigerant that may potentially leak from the system.

Patent
31 May 1991
TL;DR: In this paper, a high efficiency heat exchanger structure is created by micro-machining and plating methods by creating a form, making holes therein, plating all over including through the holes, machining the assembly to shape, and thereupon dissolving out the form to form the microchannel structure without burrs.
Abstract: Electroformed high efficiency heat exchanger structure (44) is created by micro-machining and plating methods by creating a form, making holes therein, plating all over including through the holes, machining the assembly to shape, and thereupon dissolving out the form to form the microchannel structure without burrs. Manifolds (40, 42) are attached. The heat exchanger structure is preferably used where compact and high heat rates or power density requirements are present.

Patent
James A. Matthews1
02 Apr 1991
TL;DR: In this paper, a microscopic laminar-flow heat exchanger, well suited for cooling a heat generating device such as a semiconductor integrated circuit, includes a plurality of thin plates, laminated together to form a block.
Abstract: A microscopic laminar-flow heat exchanger, well-suited for cooling a heat generating device such as a semiconductor integrated circuit, includes a plurality of thin plates, laminated together to form a block. Each plate has a microscopic recessed portion etched into one face of the plate and a pair of holes cut through the plate such that when the block is formed, the holes align to form a pair of coolant distribution manifolds. The manifolds are connected via the plurality of microscopic channels formed from the recessed portions during the lamination process. Coolant flow through these channels effectuates heat removal.

Patent
31 May 1991
TL;DR: In this paper, a temperature controller is used to accurately control the temperature of a device under test (DUT) a heat exchanger in heat exchange relationship with the DUT, where a temperature sensor is received within the heat exchange device and thermally isolated therefrom.
Abstract: A temperature controller to accurately control the temperature of a device under test (DUT) a heat exchanger in heat exchange relationship with the DUT. A temperature sensor is received within the heat exchange device and thermally isolated therefrom. This temperature sensor measures the temperature of the DUT. A second temperature sensor is received within the heat exchange device and measures the temperature of the heat exchange device. The temperature of the DUT is based on temperature readings from both the sensors.

Patent
10 Jul 1991
TL;DR: In this article, a method for treating water in a cooling system including a cooling tower and heat exchanger is described, which includes the steps of removing water from the main cooling water circuit, serially subjecting the water to magnetic treatment, treatment with ozone, filtering with a centrifugal separator, and then returning to the main water circuit.
Abstract: A method for treating water in a cooling system including a cooling tower and heat exchanger are disclosed herein. The method includes the steps of removing water from the main cooling water circuit, serially subjecting the water to magnetic treatment, treatment with ozone, filtering with a centrifugal separator, and then returning to the main cooling water circuit. Underflow from the centrifugal separator is filtered with a bag filter, and the filtered water returned to the magnetic treatment step. The pH of the water may be controlled by regulating the production of dry air supplied to the ozone generator.

Patent
28 Feb 1991
TL;DR: In this article, a control switch between a source of cryogenic cooling and an item which is to be cooled, using control valve means which are not itself subjected to the cryogenic temperatures involved, is presented.
Abstract: The invention provides a controlled connection, or heat switch, between a source of cryogenic cooling and an item which is to be cooled, using control valve means which is not itself subjected to the cryogenic temperatures involved. In one aspect, the invention provides cooling means, comprising a source of flow of a fluid, a supply line for supplying fluid from said source to a first heat exchanger, where it is cooled by a source of cryogenic cooling, and thereafter to a second heat exchanger where it is in heat-exchanging relationship with an item to be cooled by the cryogenic cooling source, and a return line for return flow of the fluid from the second heat exchanger to the fluid flow source, the return line and the supply line between the fluid flow source and the first heat exchanger being in heat exchange relationship with one another in a third heat exchanger, wherein between the fluid flow source and the third heat exchanger there is included in the supply line or the return line a control valve whereby the flow of fluid through the supply line and from the first to the second heat exchanger can be controlled. One embodiment is constituted by a multi-stage cryogenic cooling apparatus having a closed-loop Joule-Thomson expansion the compressor via a low-pressure return line), and a Joule-Thomson stage heat exchanger in which the high-pressure line and the low-pressure return line are in heat-exchanging relationship, and the pre-cooler stage being arranged to pre-cool gas in the high-pressure line before it enters the Joule-Thomson stage heat exchanger, wherein the high-pressure gas line of the Joule-Thomson stage is provided, upstream of its interaction with the pre-cooler stage, with a branch leading through a bypass valve.

Journal ArticleDOI
TL;DR: In this article, an experimental investigation was made into the effects of frost growth on the thermal performance of fin tube heat exchangers with wavy and corrugated fins, and it was found that higher air humidity and fin density lead to more frost growth and higher pressure drops.

Patent
27 Aug 1991
TL;DR: In this paper, a combined refrigerator-water heating system providing one or more insulated food storage compartments, including an insulated water storage compartment, a refrigeration system including a compressor, an evaporation heat exchanger configured to cool the food storage compartment(s), a condenser configured to heat the water storage, a flow restriction/expansion device, piping connecting the compressor, condenser, expansion device and evapores in a series flow loop, and a resistance electric heating element configured to Heat the Water storage compartment.
Abstract: A combined refrigerator-water heating system providing one or more insulated food storage compartments, includes an insulated water storage compartment, a refrigeration system including a compressor, an evaporation heat exchanger configured to cool the food storage compartment(s), a condenser configured to heat the water storage compartment, a flow restriction/expansion device, piping connecting the compressor, condenser, expansion device and evaporation in a series flow loop, a resistance electric heating element configured to heat the water storage compartment, and a control means to activate the compressor in response to cooling demand from the food storage compartment, and to activate the electric heating element in response to either heating demand from the water storage compartment or a time-of-day signal to bias resistance electric water heating operation toward times of off-peak electric use.

Patent
18 Oct 1991
TL;DR: In this paper, the authors present a controlled cooling system for a turbocharged internal combustion engine having a heat exchange radiator, liquid coolant to absorb heat from the engine, a pump to circulate coolant through the system, a fan to force air in heat exchange with the engine coolant radiator and a radiator for the charge-air after cooler coolant.
Abstract: A controlled cooling system for a turbocharged internal combustion engine having a heat exchange radiator, liquid coolant to absorb heat from the engine, a pump to circulate coolant through the system, a fan to force air in heat exchange with the engine coolant radiator and a radiator for the charge-air after cooler coolant. The cooling and turbocharge system includes a temperature control valve to direct a portion of the liquid coolant discharged from the engine to the radiator and to direct a portion of the liquid coolant to bypass the radiator in response to the temperature of the liquid coolant after discharge from the engine. A liquid subcooler heat exchanger lowers the temperature of the liquid coolant by passing the coolant in heat exchange with forced air from the fan. A flow control valve directs a portion of the liquid coolant discharged from the radiator to the subcooler heat exchanger and the remainder of the liquid coolant to the engine. An aftercooler heat exchanger lowers the temperature of the combustion air discharged from the turbocompressor by passing the combustion air charge in heat exchange with the liquid coolant from the subcooler heat exchanger.

Patent
15 Feb 1991
TL;DR: In this paper, a high intensity heat exchanger that uses a solid copper heat sink having alurality of integral pins formed on one side thereof, and an electrical insulator comprised of thin film of aluminum nitride (AlN) or diamond-like carbon (C) deposited on the other side is described.
Abstract: A high intensity heat exchanger that uses a solid copper heat sink having alurality of integral pins formed on one side thereof, and an electrical insulator comprised of thin film of aluminum nitride (AlN) or diamond-like carbon (C) deposited on the other side A device to be cooled, such as a computer chip, or an infrared detector cell is secured to the insulating layer by means of a very thin film of solder A cooling liquid is circulated to the pins through conduits which also support the heat sink The pins have a rectangular cross section and the spacing of the pins, and the fluid velocity are optimized to provide turbulent flow around the pins The apparatus is provided with a space under the pins for a removable orifice plate, thereby enabling the optimization of the size, shape and number of orifices for a particular application

Journal Article
TL;DR: In this paper, the authors show how allowable pressure drop can be used as a basis of network design and consistency between expectation and realisation achieved in heat exchanger network synthesis targeting and design procedures.
Abstract: Current heat exchanger network synthesis targeting and design procedures involve the use of assumed stream heat transfer coefficients. However, during detailed heat exchanger design, allowable pressure drops are often the most critical factors. The result can be big differences between the exchanger sizes and costs anticipated by the network designer and those realised by the exchanger designer. This in turn prejudices any optimisation attempted at the network design stage. In the paper it is shown how allowable pressure drop can be used as a basis of network design and consistency between expectation and realisation achieved


Journal ArticleDOI
TL;DR: In this article, an experiment of direct contact condensation of saturated steam on subcooled water sprays characterized by droplets of uniform size has been carried out with the aim of testing the influence of droplet diameter and velocity on the heat transfer rate, up to a pressure of 0.6 MPa.

Journal ArticleDOI
TL;DR: In this article, a semi-empirical correlation is presented for the purpose of designing heat pipe heat exchangers for waste heat recovery in vertical and inclined thermosyphons.
Abstract: In recent years, heat-pipe heat exchangers have played a significant role in waste heat recovery. In some cases, the heat-pipe heat exchangers are required to be inclined to gravity as several experimental investigations have reported. Similarly Chato studied laminar condensation inside inclined tubes. However, no uniform conclusion on optimum inclination angle can be made due to the differences among the operating conditions. In this paper, both theoretical and experimental studies on vertical and inclined thermosyphons have been carried out. A semi-empirical correlation is presented for the purpose of designing heat pipe heat exchangers.

Patent
17 Jun 1991
TL;DR: In this paper, a thermal energy storage apparatus for use in refrigeration and air conditioning holdover systems is described, which comprises a refrigeration circuit, energy storage medium disposed in expandable, preferably cylindrical capsules, and a convective heat transfer fluid which remains liquid over the temperature range of operation.
Abstract: A thermal energy storage apparatus for use in refrigeration and air conditioning holdover systems is disclosed. The apparatus comprises thermal energy storage media encapsulated in a way that enables use of corrosive and/or aqueous thermal energy storage media in high efficiency refrigeration and air conditioning thermal storage systems; natural convection of a non-freezing, non-corrosive heat exchange fluid provides heat transfer between the encapsulated thermal energy storage media and the refrigeration/air conditioning circuit. Several possible embodiments of the encapsulated media and thermal coupling system that provide efficient heat transfer between the refrigeration circuit and the thermal energy storage media are described. In one preferred embodiment the apparatus comprises a refrigeration circuit, energy storage medium disposed in expandable, preferably cylindrical capsules, and a convective heat transfer fluid which remains liquid over the temperature range of operation, the fluid thermally coupling the refrigeration circuit and the energy storage medium. The preferred embodiments of the invention entail use of a multiplicity of small cylindrical capsules mounted in supporting fixtures (racks, grids, or frames, which are optionally integral to the capsules) or attached to a sheet or grid that supports many capsules. Capsules are by this method closely packed in the space surrounding the refrigeration heat exchanger circuit.

Journal ArticleDOI
TL;DR: In this paper, the effect of short-tube orifice diameter on the response of a heat pump during the reverse-cycle defrost was investigated. But the authors did not consider the effects of different sizes of orifices on defrost performance.
Abstract: Many air source heat pumps use the reverse-cycle defrost to eliminate frost that forms on the outdoor heat exchanger during normal winter operation. During the defrost, the heat pump is switched from the heating to the cooling mode to provide heat to the outdoor heat exchanger to melt the frost. Once the frost is melted and drained from the heat exchanger, the unit is switched back to the heating mode. The objective of this research was to characterize the effect of short-tube orifice diameter on the response of a heat pump during the reverse-cycle defrost. An experimental apparatus was constructed containing a nominal 3 ton (cooling capacity) residential air source heat pump. A manifold was constructed which allowed for the switching of different sized orifices by turning a shut-off valve. Refrigerant temperature and pressure measurements were made throughout the system as well as refrigerant flow-rates, air-side capacity, compressor/outdoor fan power and refrigerant level in the accumulator. A detailed comparison of the effect on defrost performance is provided.

Patent
19 Jul 1991
TL;DR: In this article, a miniature heat exchanger is used to provide temperature control to localized areas or large surfaces, where cooling fluid enters through a base plate and is sprayed through holes in the shower head on to the underside of the cooling surface.
Abstract: A miniature heat exchanger. A small housing provides a heat exchanger surface, contains a spray shower head. A cooling fluid enters through a base plate and is sprayed through holes in the shower head on to the underside of the cooling surface. The heated coolant exists through exit holes in the nozzle and out a coolant outlet in the base plate. The device may also be used as a heater to provide temperature control to localized areas or large surfaces.

Journal ArticleDOI
TL;DR: In this paper, the dimensionless exergy loss of an aqua-ammonia absorption refrigeratio system (ARS) has been determined by second law analysis, assuming that the ammonia concentration at the generator exit is, independent of other parameters, equal to 0.999 and at the evaporator exit the gas is saturated vapour.
Abstract: Irreversibilities in components of an aqua-ammonia absorption refrigeratio system (ARS) have been determined by second law analysis. The components of the ARS are as follows: condenser, evaporator, absorber, generator, pump, expansion valves, mixture heat exchanger and refrigerant heat exchanger. It is assumed that the ammonia concentration at the generator exit is, independent of the other parameters, equal to 0.999 and at the evaporator exit the gas is saturated vapour. Pressrre losses between the generator and condenser, and the evaporator and absorber are taken into consideration. In the results the dimensionless exergy loss of each component, the exergetic coefficient of performance, the coefficient of performance and the circulation ratio are given graphically for each different generator, evaporator, condenser and absorber temperature.

Patent
05 Nov 1991
TL;DR: In this paper, a control system for regulating the temperature of a heat detector disposed on a heat exchanger is presented, which includes a temperature detector (42), non-liquid cooling means (50,52) for cooling the detector when its temperature is above the desired temperature range, and nonliquid heating means (48,53) for heating the detector if its temperature below the temperatures range.
Abstract: A control system for regulating the temperature of a heat detector disposed on a heat exchanger. The control system includes a temperature detector (42) for determining the temperature of the hot spot sensor (32), non-liquid cooling means (50,52) for cooling the detector when its temperature is above the desired temperature range, and non-liquid heating means (48,53) for heating the detector when its temperature is below the temperatures range. The control system includes control means (82) coupling the temperature sensing means to the non-liquid heating and cooling means. By keeping the heat detector at a generally constant temperature, the accuracy of the hot spot sensor on the heat exchanger is improved.

Patent
11 Oct 1991
TL;DR: In this article, an apparatus for cooling a vehicle air conditioning system electrical controller (20) includes a chill block (10) in juxtaposition to the controller, which forms a cooling groove in heat exchange relation with the controller.
Abstract: An apparatus (10) for cooling a vehicle air conditioning system electrical controller (20) includes a chill block (10) in juxtaposition to the controller (20). The chill block (10) includes a channel (22) that forms a cooling groove in heat exchange relation with the controller (20). The chill block (10) receives a portion of the refrigerant being circulated in the system (12). The portion of the refrigerant received expands in the chill block (10) to a saturated vapor and extracts heat from the controller (20) as the heat of vaporization from such expansion.