Abstract: In heating and cooling apparatus, molecules of working gas are excited by light irradiation and thereby cooled as the gas flows through a mirrored cooling cell. In a closed loop embodiment, the gas then flows by means of a fan or compressor to a first heat exchanger where heat from the matter being cooled is transferred to the gas; and, then to a second heat exchanger where heat is transferred from the gas to a heat sink. The apparatus may be used either like a heat pump or air conditioner. In an open-end cooling apparatus embodiment, the gas flows from the cooling cell, through the first heat exchanger, and to atmosphere. The light source may be a 10.6 micron laser; or a 9-11 micron electric arc, a hot filament or the Sun. Working gases comprise N2 and C02; exhaust gases of engines or fuel cells; and gases which comprise different molecular composition gases or different isotopic species of the same molecular composition gas.

Abstract: A system for generating refrigeration wherein a hot process fluid is used to drive a thermoacoustic engine and residual heat from the process fluid is used to desorb refrigerant from a high pressure absorbent heat pump solution with the resulting refrigerant expanded to generate refrigeration prior to being reabsorbed by the absorbent.

Abstract: An air conditioning/cooling system employs an elastic medium such as, for example, a rubber band, instead of the working fluid gases typically used in conventional air conditioners. The system is thus benign and environmentally friendly.

Abstract: The invention relates to an air-conditioner for a motor vehicle having a refrigerant circuit through which a refrigerant flows. The circuit includes a heat exchanger (1) through which the refrigerant circulates. A second internal refrigerant circuit exists in the heat exchanger (1) and operates when the first refrigerant circuit is at a standstill.

Abstract: An electrochemical heat pump system comprising an electrochemical pump, refrigerant-based cooling system, and gas-driven compressor. The electrochemical pump is capable of reversibly producing and consuming hydrogen gas. The cooling system comprises a condenser, compressor, and evaporator in thermal communication with an object to be cooled. The compressor comprises a chamber having a fixed volume and a flexible separator that physically divides the chamber into a gas space and a refrigerant space containing vapor refrigerant. As hydrogen gas is produced in the gas space, the flexible separator extends into the refrigerant space thereby expanding the gas space and compressing the vapor refrigerant. As the vapor refrigerant is compressed, it is forced through the condenser where the refrigerant is liquefied. The liquid refrigerant then passes through the evaporator where the liquid refrigerant is evaporated by absorbing heat from the object to be cooled.

Abstract: Solid state thermioninc refrigerators with elements having at least one barrier segment connected to wire-equivalent segments. The barrier segment has solid state regions that establish a potential energy barrier to electric carriers. This barrier is such that the circulation of a negative electrical charge from one of such regions to another region experiences an increasing potential energy. Elements can be superconducting or nonsuperconducting. Elements can also include an inverse barrier.

Abstract: In heating and cooling apparatus, molecules of working gas are excited by light irradiation and thereby cooled as the gas flows through a mirrored cooling cell. In a closed loop embodiment, the gas then flows by means of a fan or compressor to a first heat exchanger where heat from the matter being cooled is transferred to the gas; and, then to a second heat exchanger where heat is transferred from the gas to a heat sink. The apparatus may be used either like a heat pump or air conditioner. In an open-end cooling apparatus embodiment, the gas flows from the cooling cell, through the first heat exchanger, and to atmosphere. The light source may be a 10.6 micron laser; or a 9-11 micron electric arc, a hot filament or the Sun. Working gases comprise N2 and C02; exhaust gases of engines or fuel cells; and gases which comprise different molecular composition gases or different isotopic species of the same molecular composition gas.

Abstract: Heat exchangers, hydrogen gas compressors, hydrogen gas storage devices, hydrogen gas purifiers and metal hydride air conditioners utilizing a flow of a hydrogen gas stream which is absorbed and desorbed by a metal hydride causes disproportionation and “poisoning” of the metal hydrides by introduction of impurities such as water vapor, oxygen and carbon monoxide. Use of a noble metal in powder form, when introduced in the metal hydride particles has been found to act as a catalyst and to delay absorption of the impurities in the metal hydride, and further permits the more efficient and longer use of such devices by inhibiting the undesirable disproportionation and poisoning. In another embodiment, a vent is provided in the initial stage of a hydrogen compressor to vent out the impurities before these result in decreasing efficiency of the devices due to disproportionation, poisoning and increased vapor pressure.

Abstract: A method of preventing refrigerant condensation in a discharge volume or discharge line of a compressor is disclosed. The method involves the application of one or more heaters to a cooling circuit to prevent condensed refrigerant from migrating into the discharge line and/or discharge volume of the compressor. In one embodiment, a heater is in thermal communication with the dome of the compressor. The heater may be a band heater. In another embodiment, a flexible strip heater is used on the discharge line of the cooling circuit. In another embodiment, both a heater on the discharge volume of the compressor and a heater on the discharge line may be used to prevent migration and condensation of refrigerant.

Abstract: A displacement generator (10) has a housing (12) defining a chamber (14) containing an incompressible liquid (15). A port (22) of the housing (12) is closed by a movable member (24). Within the chamber (14), opposing, convex, flexible walls (16.1, 16.2) form an internal modulating chamber (18), which optionally contains a compressible gas. Opposed ends of the walls (16.1, 16.2) can be displaced toward and away from each other by a motion transducer, e.g. a stack of ceramic piezoelectric members (20), respectively to pressurize and depressurize the chamber (14) and thus to displace the member (24) to and fro to form an output of the displacement generator.

Abstract: A heating system for applying heat to a heat input air conditioning system generator. The system teaches a wave converting system for transforming radio waves into heat. The wave converting system is placed in association with a heat input air conditioning generator to transfer heat from the converting system to the air conditioning generator. The wave converting system is impacted by radio waves from a radio wave emitter such as a magnetron.

Abstract: An electrochemical heat pump system comprising an electrochemical pump, refrigerant-based cooling system, and gas-driven compressor. The electrochemical pump is capable of reversibly producing and consuming hydrogen gas. The cooling system comprises a condenser, compressor, and evaporator in thermal communication with an object to be cooled. The compressor comprises a chamber having a fixed volume and a flexible separator that physically divides the chamber into a gas space and a refrigerant space containing vapor refrigerant. As hydrogen gas is produced in the gas space, the flexible separator extends into the refrigerant space thereby expanding the gas space and compressing the vapor refrigerant. As the vapor refrigerant is compressed, it is forced through the condenser where the refrigerant is liquefied. The liquid refrigerant then passes through the evaporator where the liquid refrigerant is evaporated by absorbing heat from the object to be cooled.

Abstract: A refrigeration cycle is disclosed whereby: straining a material results in a solid phase change of the material. This phase change is accompanied by an adiabatic and nearly reversible temperature rise in the material. The material in its strained state rejects heat to its surroundings. When said material is relaxed from its strained state, a solid phase change occurs back to its initial phase. This phase change is accompanied by an adiabatic and nearly reversible temperature drop, in the material. In the relaxed state said material absorbs heat from a low temperature source.

Abstract: An air conditioning/cooling system employs an elastic medium such as, for example, a rubber band, instead of the working fluid gases typically used in conventional air conditioners. The system is thus benign and environmentally friendly.

Abstract: A thermodynamic power and cryogenic refrigeration system using a first and second (binary) working fluid has a low-temperature closed bottoming cycle and an open or closed topping cycle. In the bottoming cycle a mixture of a first gas such as helium or hydrogen and a low temperature liquid such as liquefied nitrogen is compressed in a polytropic process and then the liquid content is separated. The separated first gas is heated using rejected heat from a second gas expanded in the topping cycle or ambient air and then the heated first gas is adiabatically expanded and supercooled while performing useful work and thereafter is fed to the compressor and mixed with the separated liquid to serve as a coolant and facilitate rejection of polytropic heat and to supplement the cool gas/liquid mixture providing polytropic compression of the first gas and thus completes the bottoming cycle. The bottoming cycle functions to cool the second gas and liquefy it in the topping cycle.

Abstract: This application relates to a heat transfer apparatus and method employing an active regenerative cycle. The invention employs a working or “active” fluid and a heat transfer fluid which are physically separated. The working fluid is contained in an array of refrigeration elements that are distributed over the temperature gradient of a regenerative bed. The work for the refrigeration cycle is provided by alternative compression and expansion of the working fluid in each of the refrigeration elements at a temperature corresponding to the element's location in the temperature gradient. The compression and expansion strokes may be coupled together for optimum work recovery. The heat transfer fluid is circulated relative to the working fluid between a thermal load and a heat sink to enact a refrigeration cycle having improved energy efficiency.

Abstract: A regenerative thermo-acoustic energy converter includes a regenerator assembly located within an acoustic resonator room filled with gas, the regenerator assembly includes a regenerator located between a cold heat exchanger and a warm heat exchanger and a non-dissipative bypass circuit filled with gas connected across the regenerator assembly.

Abstract: A thermoacoustic driver incorporates a linear electrodynamic motor having electrical terminals and a moving part, a driver suspension housing, a piston, and a stiffness-enhancing device for raising the mechanical resonance frequency of the electrodynamic motor without reducing the piston stroke. The stiffness enhancement is accomplished by the use of specially optimized suspension spring structures and/or by attaching one or more electrical inductors to the electrical terminals of the driver. The stiffness enhancement using mechanical springs incorporates one or more starfish structures extending between the driver suspension housing and the piston and rigidly clamped to both. The starfish structures comprise radially extending legs, which are leaf springs or beams of varying width. The shape of the beams and the shape of the overall spring structure are optimized to enhance flexural or torsional stiffness and relieve arc tension within the constraints of cost-effectiveness.

Abstract: An air conditioning apparatus for a vehicle that includes a multi-stage compressor, an internal heat exchanger, an external heat exchanger, a heat exchanger switching circuit, a cooling expansion passage and a heating expansion passage. The compressor has at least two cylinder bores, one bore being smaller than the other. Refrigerant is compressed in two stages. Refrigerant is conducted from the large cylinder bore to the small cylinder bore via an intermediate chamber. The heat exchanger switching circuit connects the intake chamber of the compressor to one of the heat exchangers depending on whether heating or cooling is desired.

Abstract: A high efficiency compressor and heat exchange assembly adapted for utilization in air-conditioning/refrigeration systems. The assembly includes an electromechanical compressor instead of a traditional mechanical compressor, to effect compression and displacement of a working fluid in a thermodynamic cycle. The use of a electromechanical compressor permits employment of the Malone (liquid) thermodynamic cycle which has an intrinsically higher efficiency than the conventional Gifford-McMahon thermodynamic cycle. The assembly incorporates heat exchange disks which enclose a chamber for the working fluid. A densely perforated regenerator is centered in the chamber for absorbing and returning heat to the working fluid during the thermodynamic cycle. Ducts, in fluid communication with the heat exchange disks, define circuits for the flow of heat exchange fluid.

Abstract: A standing wave pump in which a standing compression wave is produced by a pair of diametrically opposing transducers. The vibrating surfaces of the transducers are oscillated at a frequency sufficient to generate a substantially cylindrical compression wave having substantially planar wave fronts between the transducer pair. The length of pump housing is made to be equal to an integer times half the wavelength of the compression wave and the pump housing acts as a resonant cavity having a standing wave pattern set up in it. Waves are simultaneously produced and reflected by the oscillating surface and are superimposed upon one another and travel to the opposing oscillating surface where this process is repeated, substantially multiplying the intensity of the standing compression wave, which provides a stored-energy effect.

Abstract: There is provided a cryogenic refrigerating apparatus capable of reducing a fluctuation range of refrigerating capacity as far as possible with respect to a wide range of change in outdoor temperature and performing stable refrigerating operation. This cryogenic refrigerating apparatus includes a compressor unit 101 which is installed outside a room and has a compressor 11 and a first air-cooling heat exchanger 12, an intermediate unit 103 which is installed inside a room and has a second air-cooling heat exchanger 31 for cooling gas from the compressor 11 through heat exchange with indoor air and a cryogenic expander 5.

Abstract: Optical refrigerator using reflectivity-tuned dielectric mirrors. Selected working materials can be optically pumped using monochromatic radiation such that the resulting fluorescence has an average photon energy higher than that of the pumping radiation; that is, net anti-Stokes fluorescence. If the quantum efficiency is sufficiently high, the working material will cool and optical refrigeration can be achieved. Parallel mirrored faces are employed to increase the optical path of the incident pumping radiation within the working material by multiple reflections. Reflectivity-tuned dielectric mirrors which allow higher-energy fluorescence photons to readily escape from the working material while inhibiting the escape of the lower-energy photons which are consequently partially trapped in the working material and ultimately reabsorbed and refluoresced at higher energies are employed. This increases the optical refrigerator efficiency.

Abstract: The electricity generating engine has modest efficiency, but may be attrave in remote applications where high-reliability or low cost or low environmental noise or solar powering is important. The generator is likely to be most attractive in capacities of a few kW to below 100 W where a tiny engine would be impractical using other technologies.

Abstract: A performance enhancing additive is introduced into a vapor compression system used in cooling and the like. The additive is selected from a class of compounds, e.g. tetraglyme, and added in a predetermined concentration measured relative to the mass of the system's lubricant. The additive can be soluble or non-soluble in the lubricant used in the system's single-phase compressor. It can be added anywhere in the system to provide lower thermodynamic load on the system compressor.

Abstract: This invention for the production of high amplitude acoustic standing wav which can be used for thermoacoustic heat transport purposes, describes the use of a rigid barrier in place of a piston, thereby allowing the suspension of the resonator to be external to the pressurized resonator and allowing an independent choice of motor mechanism, including the use of rotary motors instead of linear motors, while incidently providing a mechanism for circulating external heat transport fluids without requiring additional pumps or heat pipes.

Abstract: A microminiature Stirling cycle engine or cooler is formed utilizing semiconductor, planar processing techniques. Such a Stirling cycle thermomechanical transducer has silicon end plates and an intermediate regenerator. The end plates are formed with diaphragms and backspaces, one end plate forming the expansion end and the opposite end plate forming the compression end, with the regenerator bonded in between. A control circuit apparatus is linked to the diaphragms for controlling the amplitude, phase and frequency of their deflections. The control circuit apparatus is adapted to operate the transducer above 500 Hz and the passages and the workspace, including those within the regenerator, expansion space and compression space, are sufficiently narrow to provide a characteristic Wolmersley number, which is characteristic of the irreversibilities generated by the oscillating flow of the working fluid in the workspace, below substantially 5 at the operating frequency above 500 Hz.

Abstract: An active magnetic regenerator refrigeration apparatus includes one or more reciprocating regenerator beds and a heat transfer fluid distribution valve that is activated as the bed is moved between a position in which it is in the magnetic field of a magnet to a position in which it is outside the magnetic field of the magnet. The distribution valve has a first valve member and a moving second valve member slidingly engaged to each other, each of which has ports by which heat transfer fluid may be provided to and received from the valve member. The bed is mounted to the moving second valve member so that heat transfer fluid is conveyed to and through the valve in a single direction into the regenerator bed. The material of the bed exhibits the magnetocaloric effect and the temperature of the bed rises when it enters the magnetic field of the magnet and decreases when it exits the magnetic field, providing a refrigeration cycle.

Abstract: An external combustion thermodynamic system includes a compression stage for substantially adiabatically compressing a working medium to raise the temperature of the medium and an expansion stage for substantially adiabatically expanding the medium to decrease the temperature of the medium. A first heat exchanger is coupled to the compression stage and the expansion stage to allow the expanded medium to pass therebetween and is structured to transfer heat substantially isochoricly (i.e., at constant volume) between the cold reservoir and the expanded medium. A second heat exchanger is coupled to the compression stage and the expansion stage to allow the compressed medium to pass therebetween. The second heat exchanger is structured to transfer heat substantially isochoricly between the compressed medium and the hot reservoir.

Abstract: This invention describes a new geometry for a heat driven thermoacoustic me mover (i.e. acoustic motor) and its application to a thermoacoustic refrigerator and to an electricity generator. The heat driven acoustic refrigerator has no moving parts, and is thus extremely reliable, simple, and cheap to manufacture. Unlike previous heat driven acoustic cooling engines, it has good efficiency and compactness and is easy to start, avoiding destructively high temperatures upon start-up. The cooling engine is saleable over an extremely wide range of cooling capacities from integrated circuit and sensor cooling to building air-conditioning. The electricity generating engine has modest efficiency, but may be attractive in remote applications where high-reliability or low cost or low environmental noise or solar powering is important. The generator is likely to be most attractive in capacities of a few kW to below 100 W where a tiny engine would be impractical using other technologies.

Abstract: This invention concerns a method of operating a cryogenic cooling device (1) with a cylinder (4, 5) in which a piston (6, 7) reciprocates and with a gas drive (8, 9) which produces the motion of the piston. In order to reduce the vibrations which occur during operation, the invention proposes that the gas drive (8, 9) is controlled in such a way that the piston (6, 7) is only accelerated for part of the stroke.

Abstract: A Stirling-cycle refrigerator has a three-pump configuration and pumping sequence, in which one pump serves as a compressor, one pump serves as an expander, and one pump serves as a displacer. The pumps are ferroelectrically actuated diaphragm pumps which are coordinated by synchronizing the ferroelectric-actuator voltages in such a way that the net effect of the displacer is to reduce the deleterious effect of dead space; that is, to circulate a greater fraction of the working fluid through the heat exchangers than would be possible by use of the compressor and expander alone. In addition, the displacer can be controlled separately to make the flow of working fluid in the heat exchangers turbulent (to increase the rate of transfer of heat at the cost of greater resistance to flow) or laminar (to decrease the resistance to flow at the cost of a lower heat-transfer rate).

Abstract: The resonance frequency of a gas-filled acoustic resonator (12) is stabilized against changes in frequency due to changes in the temperature of the gas and resonator (12) by placing a gas mixture and an adsorbent (16) within the resonator (12). If the temperature dependence of the adsorbency is different for the different species comprising the gas mixture, then it is shown that the proper amount of adsorbent (16) can maintain the acoustic resonant frequency of the gas mixture within resonator (12) very nearly equal to a constant frequency.

Abstract: A electroacoustic cooling engine comprising a resonator pressure vessel for containing a compressible fluid, a double acting flexural disk centrally located in the resonant pressure vessel, an electromagnetic driver supported outside the vessel for driving the disk from outside the vessel, a thermodynamic element on each side of the disk and a pair of heat exchangers on opposite sides of the thermodynamic element. The electromagnetic driver linearly actuates the disk to cyclically drive a standing acoustic wave on both sides of the disk through each thermodynamic element and heat exchanger pair to generate a desired thermal response in a working fluid flowing through each heat exchanger.

Abstract: An electrical component cooling system is described which achieves low cooling temperatures for densely packaged electrical components using environmentally friendly working fluids. The cooling system uses a remotely located pressure wave generator to provide working fluid pulses to a plurality of regenerators. The mass flow and pressure relationships effecting cooling for the regenerator is controlled by tuning the pulse tube, orifice, and working fluid reservoir characteristics.

Abstract: A multistage type tube refrigerator comprising a regenerator-side pressure oscillation generator, first regenerator connected to the regenerator-side pressure oscillation generator, first cold head connected to the low temperature side of the first regenerator, a first pulse tube having one end connected to the first cold head and the other end connected by way of a first flow regulating mechanism to a first pulse tube-side phase shifter, second regenerator having one end connected to the first cold head and the other end connected to the second cold head, a second pulse having one end connected to the second cold head and the other end connected to second pulse tube-side phase shifter by way of second flow regulating mechanism, in which the first pulse tube-side phase shifter and the second pulse tube-side phase shifter are controlled independently of each other. Further, the pulse tube refrigerator operated while setting the phase angle of the pulse tube-side phase shifter to -50.degree. to -120.degree.

Abstract: A superconducting magnet apparatus comprises a superconducting coil unit, and a refrigerant-filled chamber type refrigerator having a plurality of cooling stages. At least a final cooling stage of the cooling stages includes a static-type refrigerant-filled chamber and is associated with the superconducting coil unit, and at least a first cooling stage of the cooling stages includes a movable-type refrigerant-filled chamber.

Abstract: A thermoacoustic device having a thermal stack made from a piece of porous material which provides a desirable ratio of thermoacoustic area to viscous area, which has a low resistance to flow, which minimizes acoustic streaming and which has a high specific heat and low thermal conductivity is disclosed. The thermal stack is easy and cheap to form and it can be formed in small sizes. Specifically, in one embodiment, a thermal stack which is formed by the natural structure of a porous material such as reticulated vitreous carbon is disclosed. The thermal stack is formed by machining a block of reticulated vitreous carbon into the required shape of the thermal stack. In a second embodiment, a micro-thermoacoustic device is disclosed which includes a thermal stack made of a piece of porous material such as reticulated vitreous carbon. In another embodiment, a heat exchanger is disclosed which is formed of a block of heat conductive open cell foam material.

Abstract: A high-power thermoacoustic refrigerator including a half-wave length resonator, first and second drivers located in housings at first and second ends of said resonator, two pusher cones, a plurality of heat exchangers, a first and second stack, utilizing a compressible gas mixture capable of being tuned to the driver resonance frequency, a half-wave length tube, fluids disposed within said heat exchangers for transferring heat, and voice coils wired 180 degrees out of phase for compressing said compressible fluid into a standing wave oscillating within said resonator.

Abstract: A multi-staged gas cycle refrigerator having a first stage regeneration part including a compression piston, a second stage regeneration part including a double inlet pulse tube and a buffer is described. Temperatures below 10K are achieved without leakage of refrigerant gas, this configuration resulting in the improvement of efficiency and reduction of cost.

Abstract: A device and method for laser cooling of a solid to extremely low temperature is disclosed, the device including an active cooling structure having a high purity surface passivated direct band gap semiconductor crystal of less than about 3 microns thick and a transparent hemispherical body in optical contact with the crystal. The crystal is itself cooled when illuminated with a laser beam tuned to a frequency no greater than the band gap edge frequency of the crystal. Cooling is caused by emission of photons of higher energy than photons entering the crystal, the additional energy being accounted for by process of absorption of thermal phonons from the crystal lattice.

Abstract: A passive temperature regulating system for cooling a structure exposed to extreme heat and a method for manufacturing the temperature regulator system. The system comprises at least one temperature regulator integrally formed to the roof of the structure. The temperature regulator is manufactured from a mold having a lower mold portion removably attached to an upper wall. The upper wall has an uneven lower surface and is adapted to be part of the roof. A resinous material is molded within the mold to form a container. After cooling, the lower portion is removed and the container remains an integral part of the upper wall because the melted plastic has conformed to the uneven lower surface of the upper wall. Thus, the container will remain in intimate contact with the roof, thereby supporting it own weight and eliminating the need for an expensive support system.

Abstract: A low-temperature end of a pulse tube (1) and a low-temperature end of a cold accumulator (2) are communicated with each other through an endothermic connection passage (3), so that refrigerant gas to be supplied from a compressor (7) to a high-temperature end of the cold accumulator (2) through a refrigerant gas passage (28) is introduced from the low-temperature end of the pulse tube (1) to the high-temperature end thereof through the cold accumulator (2) and the endothermic connection passage (3). A buffer tank (30) is connected to the high-temperature end of the pulse tube (1) through a first orifice (31). A sub gas passage (32) branched off from the refrigerant gas passage (28) is connected to the the buffer tank (30) through a second orifice (33).

Abstract: A cryogenic heat exchanger, such as a pulse tube cryogenic heat exchanger, is provided wherein the chilled heat transfer connection point can be conveniently disposed at an "apex." The heat exchanger has a bridging chamber with a first opening and a second opening. Disposed within the bridging chamber is a plurality of fins disposed longitudinally between the first opening and the second opening so as to partition the bridging chamber into a plurality of parallel longitudinal channels of equal cross-section. The first opening and the second opening are disposed at an angle to one another, so that a heat transfer gas flowing through the heat exchanger, changes direction within the bridging chamber.

Abstract: A cryogenic cooler of the pulse tube type is provided wherein the reservoir is disposed within the compressor housing. The invention provides the high efficiencies associated with orifice pulse tube cryogenic coolers, but is more compact and is generally lighter in weight than conventional pulse tube cryogenic coolers.

Abstract: A simple heat cascading regenerative sorption heat pump process with rejected or waste heat from a higher temperature chemisorption circuit ("HTCC") powering a lower temperature physisorption circuit ("LTPC") which provides a 30% total improvement over simple regenerative physisorption compression heat pumps when ammonia is both the chemisorbate and physisorbate, and a total improvement of 50% or more for LTPC having two pressure stages. The HTCC contains ammonia and a chemisorbent therefor contained in a plurality of canisters, a condenser-evaporator-radiator system, and a heater, operatively connected together. The LTPC contains ammonia and a physisorbent therefor contained in a plurality of compressors, a condenser-evaporator-radiator system, operatively connected together. A closed heat transfer circuit ("CHTC") is provided which contains a flowing heat transfer liquid ("FHTL") in thermal communication with each canister and each compressor for cascading heat from the HTCC to the LTPC.

Abstract: A thermoacoustic stack for connecting two heat exchangers in a thermoacoustic energy converter provides a convex fluid-solid interface in a plane perpendicular to an axis for acoustic oscillation of fluid between the two heat exchangers. The convex surfaces increase the ratio of the fluid volume in the effective thermoacoustic volume that is displaced from the convex surface to the fluid volume that is adjacent the surface within which viscous energy losses occur. Increasing the volume ratio results in an increase in the ratio of transferred thermal energy to viscous energy losses, with a concomitant increase in operating efficiency of the thermoacoustic converter. The convex surfaces may be easily provided by a pin array having elements arranged parallel to the direction of acoustic oscillations and with effective radial dimensions much smaller than the thicknesses of the viscous energy loss and thermoacoustic energy transfer volumes.

Abstract: Fluorescent refrigeration is based on selective radiative pumping, using substantially monochromatic radiation, of quantum excitations which are then endothermically redistributed to higher energies. Ultimately, the populated energy levels radiatively deexcite emitting, on the average, more radiant energy than was initially absorbed. The material utilized to accomplish the cooling must have dimensions such that the exciting radiation is strongly absorbed, but the fluorescence may exit the material through a significantly smaller optical pathlength. Optical fibers and mirrored glasses and crystals provide this requirement.

Abstract: An air treating device having a bellows box in which is mounted a bellows compressor formed of two spaced apart diaphragms having memory-shaped metal alloy elements embedded therein. The diaphragms are caused to contract and expand by selective heating of the memory-shaped metal alloy elements. The bellows compressor is supported spaced in the bellows box whereby air can flow through the box and as the bellows expand the air in the box is cooled and expelled. As the diaphragms of the bellows compressor contract, more air is sucked into the bellows box and at the same time the refrigerant fluid inside the bellows is expelled into a condenser where it is condensed to liquid. When the refrigerant liquid enters into the bellows it is vaporized and cools the bellows walls in their expanded state and the diaphragms act as a heat exchanger to cool air in said bellows box and expel it therefrom.

Abstract: A pulse tube refrigerator includes a compression space defined by a compression piston inside a cylinder, an expansion space defined by an expansion piston inside a cylinder, the expansion piston being reciprocated at an advance angle of a constant phase difference within a range of 10.degree.-45.degree. relative to the compression piston, and first and second thermal systems communicating the compression and expansion spaces. Each thermal system has a radiator, a regenerator, a cold head and a pulse tube, with the regenerator of the second thermal system being composed of two regenerator sections. The cold head of the first thermal system is made to perform a heat exchange with the second thermal system between the two regenerator sections thereof, whereby a very low temperature is obtained from the cold head of the second thermal system.