Showing papers on "Heat exchanger published in 1992"

Battery temperature control system in electric automobile

Abstract: A battery temperature control system in an electric automobile which is equipped with an air conditioner for supplying a cool or warm air into a passenger compartment and which travels by using batteries as a power source accommodated in a battery chamber. The system includes a battery temperature sensor for detecting a temperature of the battery, a control unit adapted to drive the air conditioner in an air-cooling mode when the battery temperature detected by the temperature sensor is higher than a predetermined upper limit, and in an air-heating mode when the battery temperature detected by the temperature sensor is lower than a predetermined lower limit. An air intake port is provided in the battery chamber for introducing an air supplied from the air conditioner into the battery chamber. Further, in order to obtain a sufficiently warm air even when the atmospheric temperature is low, an auxiliary heat exchanger 28 which is heated by the combustion heater 29 also is provided.

Air-conditioning apparatus

Abstract: An air-conditioning apparatus forms a refrigerating cycle with a coolant heater (43) and a compressor (17) having two cylinders. The apparatus simultaneously carries out a coolant heating operation and a heat pump operation when a required heating capacity is high, and when the required heating capacity is low, only the heat pump operation. This operation technique helps reduce the size of the apparatus and expand a variable width of heating capacity. The apparatus also has a defrosting unit for defrosting an outdoor heat exchanger (47) during the heat pump operation.

Methods and apparatus for operating a refrigeration system

Abstract: A refrigeration system of the type having an economizer cycle is provided with a null cycle, in addition to heating and cooling cycles, without shutting a compressor prime mover down, to preserve air flow in a conditioned space. First, second and third controllable valves respectively: (1) select main and auxiliary condensers, (2) open and close a liquid line, and (3) open and close a line which provides a warm liquid to an economizer heat exchanger. The valves are controlled in at least one predetermined open/close pattern during a null cycle, and preferably in a plurality of selectable predetermined open/close patterns, to provide a null cycle at any instant which substantially matches the net heat gain or loss taking place in the conditioned space. Thus, the temperature of the served space will be more apt to remain in a null temperature range close to set point, providing smoother and more accurate control over the temperature of the conditioned space for longer shelf life of perishables stored therein. The system achieves the latter by controlling a bypass value according to the load of the compressor.

Air conditioning system suitable for use in an electric vehicle

Abstract: An air conditioning system suitable for use in an electric vehicle. In the air conditioning system, a refrigerant gas circulatory system of the heat pump type for selectively effecting cooling and heating is disposed inside the electric vehicle and comprises lines which interconnect three heat exchangers, a directional control valve, a compressor and an expansion valve to one another. A control device is provided so as to activate and inactivate the heat exchanger, the directional control valve and the compressor. Before the expected running of the vehicle, at least a portion of the refrigerant gas circulatory system can be operated by the control device using a drive source different from the drive source used for running the vehicle. Accordingly, a comfortable room environment can be established for the expected time on riding by activating the air conditioning system in an unmanned state.

High throughput thermal cycler

Abstract: A batch thermal cycler for large numbers of biological or chemical samples uses n modules each in good thermal contact with the samples, but substantially isolated from one another, thermally and functionally. Each module carries samples on an upper sample plate. The module has a temperature sensor adjacent the samples, an electrical resistance heating element, and a circulating fluid heat exchanger for step cooling. Heating occurs at a point generally between the samples and the source of the cooling. The modules are individually replaceable. O-rings automatically seal fluid and electrical interfaces. An electrical controller has n simultaneous channels that provide closed loop control of the electrical power to each module. As a method, the invention includes at least one modular temperature zone where the temperature is sensed at a point adjacent the samples in that zone. The samples are heated adjacent the sample plate. Cooling is by a step change. The cooling overshoots a set lower temperature. A small, well-controlled heating corrects the overshoot.

Integral heat pipe, heat exchanger, and clamping plate

Abstract: An integral heat pipe, heat exchanger, and clamping plate. A base plate functioning as an evaporator has disposed in it a multiplicity of intersecting parallel and perpendicular internal channels extending laterally substantially across the base plate. A sintered copper thermal wick is applied to all channels. Thin-walled condenser tubes forming a condenser region are joined to the base plate at intersections of width wise and cross wise channels contained in the base plate. A multiplicity of fins extend to all condenser tubes. For heat pipe arrangements operating in horizontal configurations, all wick-lined channels within the base plate remain open. For heat pipe arrangements intended to operate in oblique or vertical configurations, horizontally extending channels vertically displaced relative to other horizontal channels are isolated from the latter by a multiplicity of plugs. The vertically isolated horizontally extending channels constrain the working fluid and its vapor to remain within a single horizontal channel and yet disperse laterally within the maximum internal dimensions of the evaporator. Condensed working fluid returning from the condenser region to the base plate and subsequently to the heated region via capillary action is cycled more rapidly through the evaporation and condensation phases, thereby increasing the efficiency of the integral heat pipe arrangement.

Cooling system for a vehicle having an internal-combustion engine

Abstract: A cooling system for a vehicle having an internal-combustion engine has a plurality of cooling circuits with heat exchangers for each circuit. The temperatures of different cooling media are measured and processed in a switching device to form an output signal which serves to control a fan. In this way, the air flow through the heat exchangers can be varied depending on measured temperature conditions. Individual capacity control of each cooling circuit is possible, thereby preventing unfavorable operating conditions in the individual circuits. The cooling capacity demand of the individual cooling circuits is determined by a central control unit which receives signals from temperature sensors in each circuit. The central control unit includes a microprocessor. Each cooling circuit has an actuating means for individually controlling the capacity of the relevant heat exchanger.

Air conditioning apparatus for a vehicle

Abstract: An air conditioning apparatus for a vehicle for air conditioning only a zone adjacent a person sitting on a seat. A bottom duct 62 has inlets 60 which are located laterally of a sitting part 50 of the seat, and a top duct 70 has an outlet 72 located above a head rest portion 58 of the seat. Arranged in the bottom duct 62 is a blower fan 74, evaporator 78 and heater 80. The rotation of the fan 74 causes the air to be sucked into the duct 62 via the inlets 60, and is subjected to the heat exchange with the evaporator 78 and the heater 80 to obtain a desired temperature of the air. The air is discharged downwardly from the top outlet 72 to the bottom inlet 60, so that air flows for air conditioning are crated along an area only around the person sitting on the seat.

Design Considerations for Refrigeration Cycles

Abstract: The Carnot COP, which assumes a thermodynamically ideal cycle in which no irreversibilities exist, is often considered to be a design goal for actual cycles. However, the Carnot COP does not consider heat transfer mechanisms. Heat transfer at a finite rate is necessarily an irreversible process and unavoidable in a refrigeration cycle. The lack of consideration of rate processes reduces the usefulness of the Carnot COP as a realistic design goal. In this paper, the limitations of both thermodynamics and heat transfer are considered to identify a more realistic design goal for the COP of refrigeration cycles. The consideration of heat transfer limitations leads to a design rule for the optimum distribution of heat exchange area between the low- and high-temperature heat exchangers.

Inline heat exchanger and cardioplegia system

Abstract: A flexible-resilient heat exchanger that is designed to be disposed inline of a cardioplegia tubing set for heating or cooling blood and/or cardioplegia solution. The heat exchanger comprises a flexible-resilient inner tube defining an inner flow path for blood and/or cardioplegia solution, for example, and a flexible-resilient outer tube surrounding the inner tube. The outer tube has fluid inlet and outlet ports so as to define an outer flow path between the inner and outer tubes for heat exchanging fluid, for example. The outer tube is sealingly connected to the inner tube adjacent opposite ends of the outer flow path, and the inner tube defining a barrier between the first and second fluids while permitting heat transfer between the first and second fluids.

A Simplified Cycle Simulation Model for the Performance Rating of Refrigerants and Refrigerant Mixtures

Abstract: A simulation program, CYCLE11, which is useful for the preliminary evaluation of the performance of refrigerants and refrigerant mixtures in the vapour compression cycle is described. The program simulates a theoretical vapour-compression cycle and departures from the theoretical cycle that occur in a heat pump and in a refrigerator. The cycles are prescribed in terms of the temperatures of the external heat-transfer fluids with the heat exchangers generalized by an average effective temperature difference. The isethalpic expansion process is assumed. The program includes a rudimentary model of a compressor and a representation of the suction line and liquid line heat exchange. Refrigerant thermodynamic properties are calculated by using the Carnahan-Starling-DeSantis equation of state. Refrigerant transport properties are not included in the simulations. The program can generate merit ratings of refrigerants for which limited measured data are available. An example of simulation results stresses the need for careful application of simplified models and consideration for the assumptions involved.

Packaging structure of small-sized computer

Abstract: In a small-sized computer of a natural air-cooling type, a high-temperature radiator promotes natural convection so as to increase a quantity of heat radiation and to raise the allowable limit of heat generation of LSI chips, thereby improving the processing speed of the computer. For this purpose, a casing and fins are utilized as heat radiators at relatively low temperatures of about 40° C. which are safe even if they are touched by an operator's hands. On the other hand, the high-temperature radiator set at about 50° to 60° C. is provided inside of the casing, thus preventing the operator's hands from touching it directly. Heat generated by the LSI chips and so forth is transmitted to the high-temperature radiator through heat conduction or the like, and heat exchange is performed between the high-temperature radiator increased in temperature and the air introduced into the casing, in order to promote natural convection inside of the casing.

Lubrication and cooling system for a powertrain including an electric motor

Abstract: A hydraulic pump forces fluid from a sump supplied from a lubrication circuit and a cooling circuit that takes heat from an electric motor. The lubrication circuit is supplied with fluid directly from the discharge side of the pump and is returned directly to the sump. The cooling circuit, disposed in parallel arrangement with the lubrication circuit, has its volumetric flow rate from the discharge side of the pump controlled by a bimetallic valve, which opens and closes in accordance with the temperature of the fluid. When fluid temperature is low, the pump discharge is fully opened both to the lubrication circuit and the cooling circuit. When fluid temperature is relatively high, the pump discharge is directly entirely through a heat exchanger which transfers heat to a cooling air stream, and the fluid exiting the heat exchanger is delivered to the cooling circuit. The speed of the pump is controlled in accordance with a signal produced by a temperature sensor mounted on a traction motor.

Process for cooling drive components and heating the passenger compartment of a motor vehicle, especially an electrically driven vehicle, and arrangement for implementing the process

Abstract: In vehicles having drive systems with a highly variable degree of heat generation but in which the total quantity of heat generated is small, the heat given off is inadequate to warm the vehicle properly. The cooling system must nevertheless be designed for the worst-possible operating point, i.e. the greatest amount of heat generated, even if it is generated only briefly. It is the purpose of the present development to make the best possibly exergetic use of the available energy sources while ensuring that the drive components are cooled. The air extracted from the passenger compartment (1) comprises a proportion of exhaust air and one of recirculated air, where the recirculated air is heated in the heat exchanger (9) for the cooling circuit (16) of the drive system and taken to the passenger compartment. The system is particularly suitable for electric vehicles, vehicles with hydrogen and hybrid drives and vehicles developing little heat.

Method of fabricating a heat exchanger for solid-state electronic devices

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.

Integrated multi-chip module having a conformal chip/heat exchanger interface

Abstract: A multi-chip module having a conformal heat transfer interface to adapt to variations in the height and angle of integrated circuit chips and to achieve a thermal energy path between each chip and a heat sink. The conformal heat transfer interface includes a deformable metallic membrane and a liquid under pressure. The liquid has a high thermal conductivity and provides a pressure for deforming the metallic membrane to compensate for non-coplanarity of the chips. The module integrates the structural support, RF shielding, contamination-protection elements, and the heat-dissipating mechanism that are desired in the design of multi-chip modules. Double-sided cooling of the module significantly improves the thermal characteristics of a module, even in the absence of the conformal heat transfer interface.

Phase change heat exchanger

Abstract: A heat exchanger for a phase change material is provided which comprises a container holding the phase change material, a tube surrounding the container to define an annular space therebetween, and at least two divider walls extending across the annular space to divide the annular space into at least upper and lower flow passageways. The heat exchanger can preferably be operated in either a melt cycle or a freeze cycle. In the melt cycle, the lower flow passageway is configured to receive heat exchange fluid to initiate melting of the phase change material from the bottom so that newly-formed liquid phase change material is displaced toward the top of the container. In the freeze cycle, the upper flow passageway receives heat exchange fluid to initiate freezing of the phase change material at the top. The newly-formed solid phase change material falls to the bottom of the container, displacing liquid phase change material toward the top.

Thermal storage system for a vehicle

Abstract: A thermal storage system for cooling and/or heating the passenger compartment of a vehicle has a heat exchanger arranged for fluid communication with a vehicle engine. The thermal storage system also has thermal energy storage means for storing thermal cooling and/or heating and being in fluid communication with the first heat exchanger on the vehicle. The thermal storage system further has fluid control means for controlling the flow of fluid from the heat exchanger selectively between the thermal storage means and the vehicle engine.

Method for forming an in-line water heater having a spirally configured heat exchanger

Abstract: A method for forming an in-line heater for heating water supplied to a hot water carpet cleaning extractor includes the formation of a spiral flange upon the exterior surface of an elongated cylindrical body having a bore therein to define a heat exchanger. The flanged heat exchanger is inserted into a cylindrical housing having an inner diameter smaller than the outer diameter of the spirally flanged heat exchanger by heating the housing to increase the inner diameter thereof sufficiently to allow the spirally flanged heat exchanger to be be received therein. Upon cooling, the housing shrinks into watertight engagement with the spiral flange to define a spiral water floe conduit between the ends of the in-line heater. The first and second ends of the heat exchanger are then welded to the housing. Quick disconnect fittings are threaded into the in-line heater to establish communication with the end of the spiral water conduit. The in-line heater is heated by a removable electric resistance heating element inserted into the bore of the heat exchanger body and controlled by a control thermostat and a overheat cutoff switch.

Wind-powered energy production and storing system

Abstract: A wind-powered energy production and storing system comprises a wind rotor (1) in driving engagement with a power generator via transmission means, to which is also connected a heat pump for operation of at least one heat exchanger unit. The wind rotor (1) is designed as a wind wheel having a rim in direct driving engagement with a main shaft positioned in a subjacent engine housing (3) to which main shaft, in addition to the power generator and the heat pump, a dual circulation pump is coupled for conveying heated and cooled liquid, from a heating container and a cooling container, respectively, positioned in the engine housing (3) to separate heat and cold storing stations (16, 18). Via a steam separator (21) and a pumping device (22), a steam generator (17) may be connected to the heat storing station (16), which via a steam turbine (19) drives an additional power generator (20) for power production during periods of slack winds.

Optimal heating and cooling strategies for heat exchanger design

Abstract: The optimal heating or cooling strategy that minimizes entropy production is derived for a simple class of common heat transfer processes that are constrained to proceed in a fixed, finite time. The empirical wisdom embodied in conventional single‐pass counterflow heat exchanger design is examined in light of this solution. For judiciously selected system parameters, the counterflow heat exchanger can yield the optimal solution.

Method of producing a gaseous hydrogen peroxide-containing sterilization fluid

Abstract: A method of producing a gaseous, hydrogen peroxide-containing sterilization fluid displaying good, uniform sterilization properties is disclosed. The method includes vaporizing liquefied hydrogen peroxide by injecting the liquefied hydrogen peroxide intermittently in finely-divided form into an air current which serves as a vaporization agent, wherein the air current is kept at a constant or insignificantly varying elevated vaporization temperature. An even vaporization temperature of the air current is ensured because the air, prior to vaporization, is heated by heat exchange with a heating element having a large mass or thermal capacity and a large heat exchange surface area which is kept at the desired elevated temperature by regulated energy supplied to the heating element. During breaks in vaporization between the intermittent injection of the liquefied hydrogen peroxide, the heat exchange surface area is heated with the aid of heat stored in the heating element.

Thermoelectric heat pump w/hot & cold liquid heat exchange circutis

Abstract: A thermoelectric system (10) includes a thermoelectric module (12) and volume defining manifolds (14) attached to opposed faces of the module (12). Fluid pumps (44) circulate fluid from remote heat exchangers (46) and through the manifolds (14). The module (12) provides opposing hot and cold faces with respective manifolds (14) attached thereto. The cold faces and manifolds (14) are connected to a first fluid pump (44) and heat exchanger (46), and the hot faces and manifolds (14) are connected to a second fluid pump (44) and heat exchanger (46). The manifolds (14) include an outer wall spaced from the module (12) and side walls abutting the respective faces thereby defining an open face wherein the side walls and outer wall and outer face define a volume for receiving fluid.

Air conditioning apparatus for distributing primarily-conditioned air to rooms

Abstract: Primarily-conditioned air is discharged from a heat source, and distributed into a plurality of rooms through a duct. The duct has a plurality of air passages connected to the rooms, and a damper is provided in each air passage for adjusting the flow of the primarily-conditioned air. Further, a heat exchanger is provided in each air passage, and connected to a refrigerating cycle for the heat source. The thermal load in each room is detected, and the required air flow in the room is determined based on the thermal load. The opening degree of a damper corresponding to the room is controlled on the basis of the required air flow. Each damper has an allowable minimum opening degree. When the opening degree of any damper becomes equal to the allowable minimum value, refrigerant flows into a heat exchanger corresponding to the damper, thereby correcting the temperature of the primarily-conditioned air.

Fuel cell power plant fuel processing apparatus

Abstract: The integrated apparatus includes within a single vessel a plurality of components for processing fuel in a fuel cell plant. Along with the gas reformer is an air preheater for the burner and a plenum for supplying the shift converter. The shift converter is also in the vessel with upstream steam and fuel heat exchangers. The shift converter heat exchanger is also included.

Heat transfer enhancement using tangential injection

Abstract: A process for improving the efficiency of heat transfer to a flowing fluid in a tubular heat exchanger by placing an injector on the inlet of each heat exchanger tube, the injector designed to create tangential flow in the tube. The injector used to generate tangential flow comprises a tubular cap with multiple passageways therethrough so that fluid entering the passageways enters the heat exchanger tube along a line tangent to the circumference of the hole extending along the length of the heat exchanger tube. A significant increase in heat transfer at the same pumping power is obtained as a result of the cross sectional shape of the passageway and the dimensions thereof in relationship to the inner diameter of the heat exchanger tube.