Showing papers on "Heat sink published in 1976"

Counter-flow thermoelectric heat pump with discrete sections

Abstract: Thermoelectric heat pumps using parallel flow, crossflow, or counter-flow of the input and output fluid streams have been designed and built, but performance has been insensitive to flow arrangement due to the use of one-piece, essentially isothermal heat exchangers on the heated and cooled thermoelectric junctions. Thus, none of these designs have capitalized on the sensitivity of the thermoelectric coefficient of performance to the junctions temperature differences and the smaller temperature differences possible with the counter-flow arrangement. In the improved design, the thermoelectric heat pump is broken down into discrete sections which heat or cool the input fluid in stages. The system thus operates as several discrete heat pumps each doing only a small portion of the heat pumping without sacrificing the desired final outlet temperature. Thus, the junction temperature differentials for each thermoelectric unit in the system is less than that with conventional one-piece heat sink designs. Consequently, the coefficient of performance or "heat pump efficiency" of the sectioned system is significantly improved.

Method of making conduction-cooled circuit package

Abstract: A circuit package exhibiting an excellent heat transfer path from a semiconductor chip or other heat-generating device to the heat-sink can or cover of the package. A heat-conducting pad is metallurgically bonded to either said cover or a surface of said device; the pad is also separably attached, but metallurgically unbonded, to the other. In one preferred embodiment, a readily deformable metal or alloy, such as indium, is metallurgically bonded to a limited central region of the heat sink cover. The deformable metal is separably attached to a major surface of the chip so that there is no stress between the chip or its joints and the solder during the electrical operation of the chip when it generates heat. The preferred method of fabrication involves the mechanical deformation of a mass of solder against the back side of the chip, after the solder has been metallurgically bonded to heat sink. The process may be accomplished either at high or low temperatures, depending upon the solder composition and the relative strength of the leads which join the chip to conductive lands on its supportive substrate.

Heating and cooling system with heat pump and storage

Abstract: A heating and cooling system is provided which includes a reversible heat pump with three refrigerant coils, one of which is in an air duct for the space to be served, another of which is in heat exchange relation with outdoor air, and a third of which is adapted to exchange heat with a heat exchange fluid which is circulated from a heat storage location, the system including valve means in the refrigerant lines for connecting any of the three coils to operate as either an evaporator or a condenser and for connecting either one of the other two coils to operate as a condenser or evaporator, respectively, so that heat can be exchanged in any combination between air in the duct serving the space to be heated, outside air, and the storage fluid. The system also preferably includes a solar collector and a second fluid storage tank, and circulating means and fluid valve means as well as a fluid-to-air heat exchanger in the duct so that heat from solar insulation may be used to heat directly or placed in storage, or heat may be provided for the space directly from the storage. Heat from storage may also be used with the heat pump operating. Various other modes of heat pump operation are also available in a cooling operation. The system also includes the provision of a diverting valve arrangement for the three coil heat pump which precludes, through a physical blocking arrangement, the possibility of short circuiting the discharge from the refrigerant compressor to the suction side of the compressor.

Heat pumps with solar heat source

Abstract: A reversible compression type refrigeration system is commonly known as a heat pump for conditioning a space having a conditioning side and a service side. The conditioning side is that area or environment where it is intended to achieve the benefit of the alternate heating and cooling effects produced by the reversible system. The service side is that side from which heat is drawn or to which heat is rejected when the opposite effect is required on the conditioned side. The system includes a conditioning coil connected to the conditioning side for absorbing heat from the space when cooling is required (cooling cycle) and rejecting heat to the space when heating is required (heating cycle); a first "service" coil connected to the service side adapted to reject heat to the outdoor air during system cooling cycles and absorb heat from the outdoor air on heating cycles; a second "service" coil connected to the service side adapted to withdraw direct or stored heat from a liquid stream heated by a solar collector, and reversible means to allow the first service coil to withdraw heat from the outside air under conditions where the supply of direct or stored solar heat intended to be delivered to the second service coil has been exhausted.

Transistor cooling by heat pipes having a wick of dielectric powder

Abstract: A micro-electronic package which is capable of operating with power densities extending at least to 10 kilowatts per square centimeter comprises a sealed enclosure coupled to an external heat sink and electronic devices and circuitry within the enclosure. Electrical leads extend from the electronic devices and circuitry to the outside of the enclosure to couple the devices and circuitry into a larger electrical function. A dielectric powder is adhered as a complete and conformal coating substantially to all interior surfaces of the enclosure and to all exposed surfaces of the electronic devices and circuitry, and functions as a heat pipe wick. A dielectric working fluid within the enclosure, therefore, can intimately contact all the interior and exposed surfaces to minimize the occurrence of local hot spots on the electronic devices and circuitry and to maximize heat transfer therefrom to the external heat sink.

Method and apparatus for thermally stabilizing workpieces

Abstract: A method and apparatus for providing temporary thermal contact between a part being processed and a heat sink is disclosed. A tacky, insert, polymer film is applied to establish intimate contact with the part and the heat sink. Since the polymer layer has greater cohesive strength than adhesive strength, the part may be separated cleanly from the polymer film with substantially no contamination. The part does adhere with sufficient force to permit improved processing such as ion etching, sputter deposition and etching, ion beam deposition, vacuum evaporation, plasma etching, reactive ion etching, chemical vapor deposition, and ion implantation without overheating. The heat sink is mounted in a supporting fixture having pressure means and vacuum means associated therewith. The vacuum means is used for pulling the device wafer onto the coated heat sink. The pressure means is used to dismount the wafer from the heat sink without physical damage or contamination.

Heat exchanger structure for electronic apparatus

Abstract: A chassis for an electronic apparatus having heat generating circuit components attached to heat exchangers along its top and bottom walls. Each heat exchanger includes a base from which parallel fingers project toward a plane passing horizontally through the center of the chassis, the various exchangers having fingers of differing lengths to define an air passage of varying effective cross-sectional area, thereby promoting air turbulence for increased cooling. The heat exchangers at the entrance to the air passage are aluminum, while those at the exit where the cooling air is warmest are copper.

Solar liquid heating apparatus

Abstract: A solar apparatus is provided for heating liquids such as water, to a high temperature by utilizing a movable parabolic heat collector to concentrate the sun's rays associated with a special piping arrangement to obtain progressive liquid pre-heating; a collector tracking device including photocells and a collimating system for controlling the movement of the collector to maintain alignment with the sun; a device for modulating the flow of the heat transfer liquid between the collector and the storage to maintain optimum heat replenishment therebetween; and also a vacuum insulated heat exchanger to isolate the heat transfer liquid from the water being heated.

Thermal Radiation from Finned Heat Sinks

Abstract: An accurate straightforward technique is presented to compute thermal radiation from finned heat sinks. A set of graphs is included to aid in the computational procedure. The analytical approach presented compares favorably with experimental data.

Postaccident Heat Removal—Part I: Heat Transfer Within an Internally Heated, Nonboiling Liquid Layer

Abstract: Correlations of experimental data on heat transfer from nonboiling, horizontal fluid layers with internal heat generation have been cast into a form suitable for analysis of postaccident heat remov...

Memory alloy heat engine and method of operation

Abstract: A heat engine and method of operation employing an alloy having a shape memory effect. A memory alloy element such as one or more wire loops are cyclically moved through a heat source, along a path toward a heat sink, through the heat sink and then along another path in counter-flow heat exchange relationship with the wire in the first path. The portion of the wire along the first path is caused to elongate to its trained length under minimum tension as it is cooled. The portion of the wire along the second path is caused to contract under maximum tension as it is heated. The resultant tension differential between the wires in the two paths is applied as a force through a distance to produce mechanical work. In one embodiment a first set of endless memory alloy wires are reeved in non-slip engagement between a pair of pulleys which are mounted for conjoint rotation within respective hot and cold reservoirs. Another set of endless memory alloy wires are reeved in non-slip engagement about another pair of pulleys which are mounted in the respective hot and cold reservoirs. The pulleys in the cold reservoir are of a larger diameter than those in the hot reservoir and the opposite reaches of the wires between the two sets of pulleys extend in closely spaced-apart relationship in counter-flow heat regenerator zones. The pulleys are turned to move the two sets of wires in opposite directions. The wires are stretched as they are cooled upon movement through the heat regenerator toward the cold reservoirs, and the wires contract as they are heated upon movement through the regenerator zones toward the hot reservoir. This contraction of wires exerts a larger torque on the greater diameter pulleys for turning the pulleys and supplying mechanical power. Means is provided for applying a variable tension to the wires. Phase change means is provided for controlling the angular phase of the pulleys of each set for purposes of start up procedure as well as for optimizing engine operation under varying conditions of load, speed and temperatures.

Novel heat pipe combination

Abstract: The basic heat pipe principle is employed in a heat pipe combination wherein two heat pipes are combined in opposing relationship to form an integral unit; such that the temperature, heat flow, thermal characteristics, and temperature-related parameters of a monitored environment or object exposed to one end of the heat pipe combination can be measured and controlled by controlling the heat flow of the opposite end of the heat pipe combination.

Thermo-electric generators

Abstract: A thermo-electric generator of the kind making use of beta alumina ceramic through which sodium is circulated to produce an electric potential between the two surfaces of the ceramic has the ceramic in the form of a tube closed at its upper end and with its open end extending into liquid sodium. A heat pipe extends into the ceramic tube and there is an external tubular casing around the ceramic tube forming a closed structure for housing sodium in liquid and vapor form both inside and outside the ceramic tube. The heat pipe may be arranged either as a heat source or heat sink for the sodium inside the ceramic tube, the housing forming the heat sink in the former case of the heat source in the latter. The ceramic tube may, at its open end, be sealed to the housing and a pump used for pumping the sodium from the cold face to the hot face of the ceramic or capillary means may be used to circulate the sodium.

Heat sink welding and purging apparatus

Abstract: A heat sink welding and purging apparatus for use in the welding of pipe joints for piping to be used with nuclear power systems and the like wherein the weld area must be kept below a temperature at which the dangers of carbide precipitation occur. The various embodiments include expandable heat sink and sealing bladders which are expanded in use to respectively seal the adjacent interiors of the ends of the two pipes to be welded at the adjacent joints. After expanding and sealing the pipe openings, coolant is fed into the interior of the apparatus to cool the joint being welded. Also purging gases may be used to eliminate undesirable atmospheric gases adjacent the weld joint.

Process and apparatus for heat exchange

Abstract: A process and apparatus is provided for storing thermal energy and subsequently releasing and extracting the stored thermal energy upon demand. At least one sealed container of salt hydrate is agitated continually and is positioned in heat exchange relationship with a heat exchange liquid which is passed between a thermal energy source and a container enclosing or partially enclosing the sealed container(s) for the salt hydrate. Agitation of the container(s) of salt hydrate prevents or minimizes salt separation and supercooling so that the latent heat of fusion of the salt hydrate can be stored and extracted by the heat exchange liquid upon demand, in addition to the sensible heat of the salt hydrate composition.

Method for making loudspeaker with magnetic fluid enveloping the voice coil

Abstract: A method for the manufacture of loudspeakers having a ferromagnetic fluid contained in the voice coil magnetic air gap and being confined by the loudspeaker magnet field thereby enveloping the portions of the voice coil that are within the magnetic air gap. A critical viscosity range of the ferromagnetic fluid is required, the viscosity determined by the viscosity of the liquid phase and the concentration of the colloidal ferromagnetic particles which provide the viscous damping forces on the voice coil effective at low and high frequencies. The damping forces are due to shearing stress set up in the fluid by motion of the voice coil in response to electrical excitation and result in surprisingly improved acoustical performance, higher electrical output and freedom from hiss in the loudspeaker. The ferromagnetic fluid also provides an improved heat sink for the voice coil thus improving the electrical power dissipation capability of the voice coil. An opening in the cap over the voice coil permits entrapped air under the cap or dust cover to escape thereby eliminating a noticeable hiss.

The Thermal Design of an LSI Single-Chip Package

Abstract: Theoretical and experimental methods are used to predict the thermal properties of an air-cooled integrated-circuit package with a large LSl type of chip. A previously reported three-dimensional solution to the differential equation for steady-state heat transfer has been extended to include composite media with up to four layers of unequal thickness and thermal conductivity. The theoretical results are used to calculate the detailed thermal characteristics of a 1.3 X 0.6-in package with a 0.17-in square chip. Geometric and physical considerations include the effects of ceramic thickness and thermal conductivity, chip dimensions, lead conduction, and heat-sink variations. An empirical technique is used to determine the forced-convection heat-transfer coefficients for a variety of extruded aluminum heat sinks. The effects of fin length, air velocity, and number of fins per inch are measured.

Thermal storage and heat transfer system and method

Abstract: A thermal storage and heat transfer system for use with a solar energy heat collector comprising a tank having a plurality of temperature zones therein each zone having, preferably, a plurality of layers of closely arranged cells of irregular shape occupying a minimum space to provide a maximum number of cells in said space in a manner to provide ample passages between the cells for a liquid heat transfer medium to contact and move past appreciable surface areas to effect heat transfer to and from said medium, said cells in said zones respectively having sealed therein different heat storage mediums of a nature to develope a substantially constant latent heat of fusion temperature when changing from liquid to solid state at a predetermined temperature, and a pump connected to said tank and operable to circulate said heat transfer medium through said passages from and to a solar heat collector. The prefered shape of said cells is a tetrahedron or a similar simple solid geometric configuration.

Furnace for practising temperature gradient zone melting

Abstract: A furnace for practising temperature gradient zone melting on one or more semiconductor bodies comprises a closable work chamber for receiving semiconductor bodies for processing, a radiant heat source which forms a first closure member and a heat sink which forms a second closure member, the closure members defining the work chamber and being mutually separable by, for example, a hydraulic actuator to allow access to the interior of the work chamber. A reflector is disposed between the heat source and heat sink in surrounding relationship to the semiconductor bodies being processed to ensure the maintenance of a uniform temperature gradient within the work chamber. The reflector and the heat sink are liquid cooled for the effective removal of heat therefrom. The heat sink is further provided with a plurality of radiation attenuating cavities to enhance the performance of the heat sink.

Heat exchanger utilizing heat pipes

Abstract: The heat exchanger utilizes variable conductance heat pipes to control the temperature of a cooled liquid or condensate, such as in dry cooling towers, chemical processes, air conditioning, and pollution control. Heat pipes, connected to common or separate gas reservoirs, extend between two separate ducts, one of which is for flow of air and the other is for cooling or condensation of a fluid. The fluid gives up heat to the heat pipes and cooled fluid is collected thereafter. In the air duct, heat is removed from the heat pipes, with the gas reservoir controlling the temperature of the heat pipes, as well as maintaining a constant temperature in the cooling side of the heat exchanger to control the cooling process, to maintain the gas front of the working fluid in the heat pipe solely within the air flow chamber, and to prevent solidification of fluids in the cooling side of the heat exchanger.

Heat collecting and transferring apparatus and systems adapted for use with solar energy

Abstract: Heat energy as from solar rays is collected by units including transparent plates covering a completely liquid filled chamber which has a heat absorbing layer as the internal surface of the chamber. The liquid is transparent and capable of absorbing, storing and/or transporting the heat energy. In one embodiment, the heat is removed to a storage tank from many such collector units by pumping. The system can allow draining of the collector when heat collection conditions do not prevail. In another embodiment of collector, the heat is transferred through the heat absorbing walls and the liquid medium acts mainly as a heat receiver and storing facility. A compartmentalized tank can be employed to enhance heat collection efficiency.

Method of making an annular tube-fin heat exchanger

Abstract: A method of making a heat exchanger in which extended heat transfer material, such as a fin annulus composed of thin corrugated deformable metal, is installed in annular fluid flow paths defined between concentric tubes Concepts of electromagnetic forming and metallurgical bonding are used in a unique combination of steps to arrive at a method well suited to economical production and which at the same time assures a high efficiency level of heat transfer and leak protection effects

Fluid sheet solar collector

Abstract: This fluid sheet solar collector is devised as an assembly to produce a sealed unit which contains an internal collector fluid circulating through a closed loop to pass in a thin sheet over a solar energy absorber surface and to pass in good thermal contact through a self contained heat exchanger to effect a net solar energy derived heat transfer to external devices. The internal collector fluid flows upward in a thin sheet contained between a semi-rigid transparent cover and a solar absorber surface wherein the fluid is heated; flows downward through a heat exchanger wherein the heat is transferred; the net effect is to maintain a thermo-kinetic circulation of the fluid with neither fluid conduits nor high thermal conductivity materials required in the heating portion of the assembly.

Temperature controlled airborne electronic assembly

Abstract: A streamlined electronic-component-containing pod is mounted on the exterior of a military aircraft in subjection to the airflow past the aircraft during flight An evaporator in the pod is close coupled thermally to the electronic components for cooling The outer skin of the pod acts as a condenser for return of liquid refrigerant to the evaporator during normal flight operations During short-term high-speed dash operation the outer skin of the pod becomes too hot for condensing refrigerant vapor, which then becomes condensed by a heat sink At this time the refrigerant at the outer skin remaining in the vapor phase acts as thermal insulation

High-power semiconductor assembly in disk-cell configuration

Abstract: A high-power semiconductor assembly of the disk-cell construction has an insulating housing and exhibits electrical and thermal pressure-contacting of the semiconductor chip. At least two zones of different conduction types are provided within the chip and the same is clamped, in an essentially doubly symmetrical arrangement with respect to the mid-plane of the chip and the central axis perpendicular thereto, with the interposition of pressure plates, heat-conducting paste, and electrodes, particularly cup-shaped electrodes with their open sides disposed away from the main surfaces of the semiconductor chip, and between two terminal electrodes serving as heat sinks.

Solar energy conversion system

Abstract: A solar energy conversion system that provides for complete utilization of the solar energy impinging on solar collectors by having cylindrical lens type collection panels. This system can be used with separate heat sinks with fluid retained at different temperature levels activated to provide domestic water heating, hydronic building heating, and power generation by utilization of temperature differentials in the heat sumps and the generation of hot air pressure and flow within the panels, accomplished by special application of intermittent flow of both fluid and gas through the panel system.

Transient Response of Solid Sensible Heat Thermal Storage Units—Single Fluid

Abstract: The transient response of a solid sensible heat storage unit which receives or supplies heat to a single flowing fluid is presented. The storage unit is composed of a number of rectangular cross-sectional channels for the flowing fluid, connected in parallel and separated by the heat storage material. The energy equation for the fluid and the transient conduction equation for the storage material are solved using finite difference techniques. The parameters which characterize the transient behavior of these units are identified. Results suitable for the prediction of the rate of heat storage and the outlet temperature of the fluid leaving the storage unit are presented as functions of the identified nondimensional parameters.

Air type solar heating system

Abstract: An air type heating system includes a heat collector connected to heat air streams running through the collector by solar heat and a heat storage member containing heat-storage material for absorbing heat of the air heated by the heat collector and progressively accumulating heat, starting with one air port. A room is heated by the heated air supplied from the heat collector and/or the heat storage member through the one air part thereof.

Power conversion and systems for recovering geothermal heat

Abstract: A process for the conversion of geothermal heat energy into electrical power by advantageously combining direct and indirect heat exchange systems and other systems to maximize the power production is presented herein. More specifically, a process and system is presented for the utilization of geothermal heat from flashed geothermal hot fluids composed of hot liquid and vapor. The heat from the hot liquid is advantageously exchanged with a working fluid in a direct contact heat exchanger, while the hot geothermal vapor is used in a boiler for heating, boiling and vaporizing the working fluid. The vaporized working fluid thus formed is fed into a power extraction device which may advantageously form a liquid mist upon expansion. The working fluid vapor is then condensed at the exhaust side of the power extraction device, and returned to the direct contact heat exchanger, thus closing the power cycle. The internal pressure inside the direct contact heat exchanger is carefully controlled to suppress boiling in the direct contact heat exchanger. The operating pressure of the boiler is also carefully controlled to fully evaporate the working fluid by condensing a portion or all the hot geothermal vapors. The direct contactor has a plurality of processing zones including a heat transfer zone, one or more separation zones for separating both liquids and solids, a precipitation zone, and a wash zone. In the heat exchanger zone and the precipitation zone, there is advantageously included precipitation trays vertically spaced for allowing salt precipitation without interfering with a secondary or the working fluid flow. The wash zone is advantageously equipped with a wash tray where the liquid secondary fluid can be scrubbed with water. The process also provides for removal of non-condensable gases normally present in the geothermal fluid by converting some salt solution or brine electrochemically into an absorbing solution that can be used to absorb the non-condensables from the geothermal vapors.

Injection laser array

Abstract: An array of closely spaced injection lasers is mounted upon a common substrate of grooved semiconductor or insulating material, with the active (hot) layers of the lasers as close as possible to the substrate. Individual grooves of relatively large cross-sectional area are formed in the portions of the substrate upon which the respective lasers are seated, each of these grooves underlying a respective one of the lasers, and each groove is filled with a material that has high thermal and electrical conductivity, thereby providing a massive beam lead which also serves to dissipate heat generated by the respective laser. The walls of the grooves are treated to provide electrical isolation between the beam leads, so that these leads can be used to establish individual switching connections to the active elements of the respective lasers. With this arrangement, individual lasers in the array can be independently switched on and off as needed during a multiple beam scan, and each laser has an individual heat sink for efficiently dissipating the heat that it generates.