Showing papers on "Heat exchanger published in 1997"

Heater well method and apparatus

Abstract: A method and apparatus is disclosed for heating of formations using fired heaters. Each fired heater may consist of two concentric tubulars emplaced in the formation, connected via a wellhead to a burner at the surface. Combustion gases from the burner go down to the bottom of the inner tubular and return to the surface in the annular space between the two tubulars. The two tubulars may be insulated in an overburden zone where heating is not desired. A plurality of fired heaters can be connected together such that the combustion gases from a first fired heater well are piped through insulated interconnect piping to become the air inlet for a second fired heater well, which also has a burner at its wellhead. This can be repeated for other heater wells, until the oxygen content of the combustion gas is reduced near zero. The combustion gas from the last fired heater well may be routed through a heat exchanger in which the fresh inlet air for the first heater well is preheated. A substantially uniform temperature is maintained in each heater well by using a high mass flow into the heater well.

Multizone bake/chill thermal cycling module

Abstract: A thermal cycling module includes an array of thermoelectric devices 36! divided into multiple zones A, B, C, D! independently controlled by corresponding variable power supplies 56, 58, 60, 62!. The thermoelectric devices 36! provide localized, precise, and rapid control of both heating and cooling, while fluid from one of several fluid supplies 64, 66, 68! provides bulk heating or cooling via a fluid heat exchanger 38!. Sensors 46, 48, 50, 52! provide feedback of temperature or other process parameters to a controller 54! which generates control signals for controlling the power supplies 56, 58, 60, 62!, the fluid supplies 64, 66, 68!, and fluid valves 70, 72! which control fluid flow through the heat exchanger 38!.

Closed-loop dome thermal control apparatus for a semiconductor wafer processing system

Abstract: The disclosure relates to a closed-loop, dome thermal control apparatus (100) containing a high-volume fan (106), a heat exchange chamber (114), and an enclosure (130), that encloses the fan and the heat exchange chamber. The fan blows air over a dome (102), of a semi-conductor wafer processing system and through the heat exchange chamber (114), to uniformly control the temperature of a dome of a plasma chamber to prevent particle contamination of the wafer. The enclosure recirculates the temperature controlled air to the fan to form a closed-loop apparatus.

Closed loop liquid cooling for semiconductor RF amplifier modules

Abstract: A closed loop liquid cooling system for an RF transistor module including a plurality of elongated microchannels connected between a pair of coolant manifolds for conducting liquid coolant beneath one or more transistor dies to dissipate the heat generated thereby, a heat exchanger, a miniature circulating pump located on the module, and passive check valves having tapered passages for controlling the flow of coolant in the loop. The valves are truncated tapered passage microchannel valves having no moving parts and are fabricated so as to be a part of either the circulating pump, the coolant manifolds, or the microchannels.

Modeling of Vapor Compression Cycles for Multivariable Feedback Control of HVAC Systems

Abstract: This paper presents a new lumped-parameter model for describing the dynamics of vapor compression cycles. In particular, the dynamics associated with the two heat exchangers, i.e., the evaporator and the condenser, are modeled based on a moving-interface approach by which the position of the two-phase/single-phase interface inside the one-dimensional heat exchanger can be properly predicted. This interface information has never been included in previous lumped-parameter models developed for control design purpose, although it is essential in predicting the refrigerant superheat or subcool value. This model relates critical performance outputs, such as evaporating pressure, condensing pressure, and the refrigerant superheat, to actuating inputs including compressor speed, fan speed, and expansion valve opening. The dominating dynamic characteristics of the cycle around an operating point is studied based on the linearized model. From the resultant transfer function matrix, an interaction measure based on the Relative Gain Array reveals strong cross-couplings between various input-output pairs, and therefore indicates the inadequacy of independent SISO control techniques. In view of regulating multiple performance outputs in modern heat pumps and air-conditioning systems, this model is highly useful for design of multivariable feedback control.

An Automated and Interactive Approach for Heat Exchanger Network Retrofit

Abstract: This paper combines mathematical optimization techniques with a better understanding of the retrofit problem, based on thermodynamic analysis and practical engineering, to produce a systematic procedure capable of efficiently solving industrial size retrofit problems. The major characteristic of the approach presented is that it offers a systematic and automatic method for the retrofit design of heat exchanger networks (HENs), combined with a facility for meaningful user interaction. The new procedure employs a two-stage approach for retrofit HEN design: The first stage is the diagnosis stage, during which a minimum number of promising HEN topology modi-fications is obtained which enables a desired heat recovery target to be achieved. In the second stage, the optimization stage, the HEN obtained after implementation of the modi-fications is optimized using non-linear optimization techniques to minimize the cost of additional surface area employed. It has been observed that heat recovery in a HEN is thermodynamically limited by certain exchanger matches unavoidably tending to a zero degree temperature approach as the heat recovery increases. These exchanger matches, which are termed as pinching matches, act as a bottleneck to heat recovery in the HEN. To increase the potential for heat recovery beyond the limits caused by the pinching matches, the network topology must be altered by repiping of exchangers, addition of new exchanger matches or creation of stream splits. Based on the above observation, the diagnosis stage is made up of two steps. In the first step the HEN bottleneck is identified, and in the second step a mixed integer linear programming (MILP) formulation is used to select a single modification which will best overcome the identified bottleneck. These two steps are repeated in a loop to yield the required set of promising topology modifications.

Heat spreader system for cooling heat generating components

Abstract: An isothermal equilibrium system takes point sources of heat generated by the operation of heat generating components and spreads the heat throughout the system where the heat may be dissipated. An atomizer for atomizing a liquid coolant, is positioned inside a sealed housing. The atomized liquid coolant is distributed as a thin film over the surface of the heat generating components and the wall of the sealed housing. Heat is transferred from the surface of the heat generating components by vaporization of at least a portion of the thin film of liquid coolant. The coolant vapor condenses on the housing and other cool surfaces and returns to the liquid state. The system heat is then removed from the outer surfaces of the housing using conventional heat transfer mechanisms including free or forced air convection and/or circulation of liquid coolant over the exterior of the housing. If additional cooling is desired, heat exchanger tubes may be included inside the sealed housing. An input liquid or gaseous coolant is circulated through the exchanger tubes. Heat is transferred to the coolant and then conducted away from the heat generating component housing.

System for controlling recirculated exhaust gas temperature in an internal combustion engine

Abstract: A system for controlling the temperature of recirculated exhaust gas supplied to an internal combustion engine is provided In one embodiment, the system includes a heat exchanger having the recirculated exhaust gas flowing therethrough and further having coolant fluid flowing therethrough A control valve is disposed within the flow path of the coolant fluid, and the valve position is modulated to vary the rate of coolant fluid flow through the heat exchanger, thereby controlling the temperature of the recirculated exhaust gas supplied by the heat exchanger In another embodiment, the heat exchanger defines a number of exhaust gas flow passages therethrough and a number of gas flow control valves are disposed between the exhaust gas inlet of the heat exchanger and the number of exhaust gas flow passages The exhaust gas flow control valves are selectively actuated to disable exhaust gas flow through any number of subsets of the exhaust gas flow passages, thereby controlling the temperature of recirculated exhaust gas supplied by the heat exchanger

Device for producing cold therapy

Abstract: The present invention provides heat exchange devices for heating and/or cooling parts of the body for therapeutic treatment of injury. The heat exchange devices include a cooling module with a housing enclosing a cooling chamber. A thermoelectric Peltier unit has a cooled surface sealed against an opening in the housing and a pump is provided for pumping heat exchange fluid through the cooling chamber directly into contact with the cooled surface and through conduits to a patient blanket. A reservoir containing refrigerant is in flow communication with the chamber in the cooling module housing and refrigerant only flows into the housing when depleted from the recirculation flow path between the cooling module and the blanket. Another device uses a thermoelectric unit disposed between two water pumps each of which pumps water to different sections of a flexible water bag which is strapped to the affected area of the user. Water pumped over one side of the thermoelectric unit is heated and water pumped over the other side is cooled.

Exhaust gas recirculation in internal combustion engines

Abstract: An exhaust gas recirculation system (10) for an internal combustion engine (12) may comprise an EGR valve (14) having an inlet end (38) connected to the exhaust manifold (24) of the engine (12) and an outlet end (40) connected to the inlet end (52) of a heat exchanger (18) The outlet end of the heat exchanger (18) is in turn connected to the inlet end of a filter assembly (20), the outlet end (86) of which is connected to the intake manifold (26) of the engine (12) A valve control system (22) connected to the EGR valve (14) selectively opens and closes the valve (14) to direct cooled and filtered exhaust gases into the intake manifold (26) of the engine (12) An intermittent water injection system (30) may be connected to the inlet end (52) of the heat exchanger (18) and may be used to inject a predetermined quantity of water into the inlet (52) of the heat exchanger (18) at periodic intervals to remove accumulated soot deposits from the interior surfaces of the heat exchanger (18)

By-pass valves for heat exchangers

Abstract: A by-pass valve (14) and a heat exchanger (12) employing the same is disclosed where the by-pass valve (14) makes a short circuit from the heat exchanger inlet (26) to the heat exchanger outlet (30) to disable the heat exchanger (12) under certain temperature conditions. The by-pass valve (14) includes a housing (46) defining a chamber (48). Three main ports (50, 52, 54) communicate with the chamber (48), one (54) being a valve port. A temperature responsive actuator (64) located in the chamber (48) operates a spring loaded valve (62) to open and close the valve port (54). The valve port (54) can be connected to one of the heat exchanger inlet (26) or outlet (30), the other main ports are then connected in series with the other of the heat exchanger inlet (26) or outlet (28).

Turbine engine with intercooler in bypass air passage

Abstract: A turbine engine (20) having bypass and core passages (30 and 40), a high pressure compressor (80) for compressing air in the core passage and an intercooler (120, 220) for cooling core air (42) in the core passage prior to discharge by the high pressure compressor. The intercooler includes a plurality of heat exchange elements (140) positioned in the bypass passage through which all or a portion of the core air is transported. Heat in the core air is transferred via the heat exchange elements to the relatively cool bypass air, thereby cooling the core air and heating the bypass air. The turbine engine may have a counterflow intercooler (120), a radial flow intercooler 220 or an intercooler of other configuration. The turbine engine may have a high pressure compressor with two sections (82 and 86), with core air transported to and from the intercooler between sections, or a single section high pressure compressor, with core air transported to and from the intercooler upstream of the high pressure compressor. The turbine engine may be of turbofan, turboshaft, turboprop or other design.

Vapor compression type refrigerating system

Abstract: A refrigerating system, using CO2 as a refrigerant, for an air conditioner for an automobile. A pressure at the outlet of the heat emitter 2 is controlled to a target value in accordance with the temperature of the refrigerant at the outlet of the heat emitter for obtaining an operation of the refrigerating system along the optimum control line ηmax. A pressure reducer 4 and a cooler 5 are provided on a branched passageway 28 branched from a refrigerant recirculating passageway 27 for injection. The cooler 5 is for obtaining a heat exchange between a flow of the refrigerant on the branched passageway 28 after being cooled by the pressure reducer and a flow of the refrigerant on the main passageway 27, thereby cooling the refrigerant directed to the evaporator. In a second aspect of the invention, a means is provided for increasing a target value of the pressure at the pressure reducer when a thermal load of the refrigerating system is high. In a third aspect, a series of pressure reducers are arranged on the main recirculating passageway. The second stage pressure reducer is controlled so as to obtain a desired value of degree of super heating at the inlet of the compressor.

Extruded manifold with multiple passages and cross-counterflow heat exchanger incorporating same

Abstract: A cross-counterflow heat exchanger comprising a pair of identical and identically-oriented, spaced manifolds and a plurality of parallel heat exchanger tubes extending between the manifolds. Each of the manifolds has an interior, longitudinally-extending dividing wall. In a 2n pass heat exchanger, each manifold is symmetric about a mirror plane, the dividing wall is configured to define n+1 upper channels and n lower channels, and the passages of the heat exchanger tubes are divided into 2n flow paths, n being a positive integer. In a 2n+1 pass heat exchanger, each manifold is symmetric about a rotation axis, the dividing wall is configured to define n+1 upper channels and n+1 lower channels, and the passages of th heat exchanger tubes are divided into 2n+1 flow paths, n again being a positive integer. Further, in a 2n pass heat exchanger, the dividing wall of each of the manifolds includes 2n-1 vertical webs, and each of the heat exchanger tubes includes 2n-1 partitions dividing the passages into 2n flow paths; while in a 2n+1 heat exchanger, the dividing wall of each of the manifolds includes including 2n vertical webs, and each of the heat exchanger tubes includes 2n partitions dividing the passages into 2n+1 flow paths. When the number of vertical webs is greater than 1 (that is, when n>1), the vertical webs alternately extend from opposite interior surfaces of the manifold. In both 2n and 2n+1 pass heat exchangers, the partitions of the heat exchanger tubes have notches at both ends for engaging the vertical sections of the manifolds. The dividing wall includes two transverse webs extending outwardly from each vertical web. These transverse webs can be configured as, for example, planar webs extending diagonally in opposite directions to form a zig-zag pattern (a series of interlocking, alternatingly-oriented Y-shapes), as coplanar webs, or as reverse curves forming a sinusoidal pattern. Different manifold geometries can be used, including, but not limited to circular, oval, flattened oval, and rectangular.

Heat pump type air conditioning system for automotive vehicle

Abstract: A heat pump type air conditioning system (A) for an automotive vehicle. The heat type air conditioning system (A) comprises a first unit (10) including a heater core (11) through which an engine coolant of an engine flows, and a first heat exchanger (12) which forms part of a refrigeration cycle including a compressor (1) and a first condenser (3), in which a refrigerant circulates in the refrigeration cycle. A second unit (20) is provided including a second condenser (21) and a second heat exchanger (22) which are fluidly connected in parallel with the first heat exchanger (12). A valve (V2) is fluidly connected in series with the second condenser (21) and disposed such that a part of the refrigerant is introduced through the valve into the second condenser (21) and the second heat exchanger (22). A sub-heat exchanger (30) is disposed outside the first and second units and fluidly connected in series with the second heat exchanger (22), in which the refrigerant flowing from the second heat exchanger (22) is introduced into the sub-heat exchanger to be heated by a part of the engine coolant, the refrigerant discharged from the sub-heat exchanger being returned to the compressor. An electromagnetic clutch (40) is provided such that the compressor (1) is drivably connectable with the engine therethrough. The electromagnetic clutch is engaged to establish a driving connection between the compressor so as to operate the compressor and disengaged to cut the driving connection so as to make the compressor inoperative. A control device (C) is operatively connected to the electromagnetic clutch (40) for controlling the electromagnetic clutch to be disengageable in accordance with a temperature within the air conditioning system (A).

Fuel supply system for an internal combustion engine

Abstract: A fuel supply system for a marine propulsion system having an electronically controlled fuel injection system eliminates the need for a vapor separator. The system pumps an excessive amount of fuel through a plumbed fuel supply loop and cools recirculated fuel to cool all the components in the plumbed fuel supply loop, i.e. a continuous duty, constant displacement fuel pump; a pressure regulator; and a water separating fuel filter. Recirculated fuel flows from the pressure regulator to the water separating fuel filter as does make-up fuel from a fuel tank. The fuel stream from the water separating fuel filter flows to the low-pressure side of the fuel pump, which pumps the fuel through the plumb fuel supply loop. A fuel injection portion of the fuel flows to the engine for combustion, while the remaining portion of the fuel is recirculated. The recirculated portion of the fuel is cooled, preferably using a water-cooled heat exchanger. The cooled, recirculated fuel passes through the pressure regulator and repeats recirculation to the water separating fuel filter.

Heat flow meter instruments

Abstract: An apparatus, such as, a heat flow meter instrument, for measuring thermal properties of a specimen includes a first thermoelectric device and a second thermoelectric device, each device being thermally coupled to a hot plate and a cold plate, and a heat flow transducer, thermally connectable to a specimen and constructed to measure heat flowing through the specimen. The heat flow transducer and the specimen are positionable in thermal contact between the hot plate of the first thermoelectric device and the cold plate of the second thermoelectric device. The apparatus also includes an electric power supply connected to provide controlled amounts of electric power to the first and second thermoelectric devices to maintain the plates at selected temperatures, and a processor connected to receive from the heat flow transducer a signal corresponding to the measured heat. The processor is programmed to calculate a thermal property of the specimen based on the temperatures and the measured heat. The apparatus includes a closed loop heat exchange system, thermally connecting the cold plate of the first thermoelectric device and the hot plate of the second thermoelectric device, constructed and arranged to transfer heat between the plates. The closed loop heat exchange system may include a fluid pump and a first set of conduits thermally connected to the cold plate of the first thermoelectric device and a second set of conduits thermally connected to the hot plate of the second thermoelectric device. The conduits convey a heat exchange fluid in a closed loop arrangement.

Cooling apparatus for use in an electronic system

Abstract: A cooling apparatus for use with an electronic system provides an uninterrupted operation capability. A pump supplies a cooling liquid to a liquid-cooled electronic system. The pump is controlled by a controller that also controls a three way valve for controlling the operation of a three-way valve for regulating the flow quantity of the cooling liquid flowing into a heat exchanger for cooling the cooling liquid. The cooling apparatus has a plurality of cooling control units. While one cooling control unit is in operation, the other is in the standby state. If one cooling control unit fails, the standby cooling control unit is automatically put in the operating state, thereby allowing servicing of the failing unit without interrupting the operation of the liquid-cooled electronic system and the cooling apparatus.

Heat exchanger for a portable computing device and docking station

Abstract: A heat exchanger for a computing device and a docking station. The heat exchanger includes a first heat transfer element and a second heat transfer element. The first heat transfer element has a portion thermally coupled to an electronic component. The first and the second heat transfer element conformally engage each other yet are removable from each other.