Abstract: A pressure wave generator (40) for driving one or more cryogenic refrigerator systems. The pressure wave generator (40) comprises a housing with one or more inlet/outlet ports (57,58) through which generated pressure waves of gas may pass through to drive a cryogenic refrigerator system or systems connected to the inlet/outlet ports (57,58). The pressure waves are generated by at least one pair of opposed diaphragms (41,42) located in the housing that are moveable in a reciprocating motion within the housing to create pressure waves in gas spaces (55,56) associated with each diaphragm (41,42). The gas spaces (55,56) each having associated inlet/outlet ports (57,58) through which the pressure waves may pass. An operable drive system is also provided to move the pair of diaphragms (41,42) in a reciprocating motion.

Abstract: A regenerative refrigerator includes a cylinder configured to cause a refrigerant gas to adiabatically expand; and a regenerator tube connected to the cylinder and including a partitioning member. The partitioning member partitions an internal space of the regenerator tube into a first space in which the refrigerant gas flows and a second space filled with a regenerator material formed of gas. The regenerator tube is configured to accumulate, in the regenerator material, cold generated in the cylinder with adiabatic expansion of the refrigerant gas. The area of exposure of the partitioning member to the second space is greater than the area of exposure of the partitioning member to the first space.

Abstract: Various embodiments are directed to a regenerator for use with a regenerative engine. The regenerator may comprise a plurality of regenerator disks. Each of the plurality of regenerator disks may comprises a plurality of concentric ribs defining a plurality of concentric gaps therebetween. Further, the plurality regenerator disks may be arranged within the regenerator longitudinally, such that the plurality of concentric gaps defined by adjacent regenerator disks are substantially aligned.

Abstract: A cooling system and method for cooling superconducting magnet coils are provided. One magnet system for a superconducting magnet device includes a cooling system having at least one coil support shell, a plurality of superconducting magnet coils supported by the at least one coil support shell and a plurality of cooling tubes thermally coupled to the at least one coil support shell. The magnet system also includes a cryorefrigerator system fluidly coupled with the plurality of cooling tubes forming a closed circulation cooling system.

Abstract: A substrate cooling device includes: a substrate holding stage including a recess defining a space between a substrate mounting unit and a substrate mounted on the substrate mounting unit; a holding member that exerts a pressing force against the substrate holding stage so as to fix the substrate to the substrate holding stage; a refrigerator connected to the substrate holding stage; a coolant gas inlet path including a coolant gas inlet opening that is provided at the substrate holding stage and opens to a recessed face of the recess, the coolant gas inlet path connecting a space in the recess via the coolant gas inlet opening to a coolant gas supply; and a coolant gas outlet path including a coolant gas outlet opening that is provided at the substrate holding stage independently of the coolant gas inlet opening and opens to the recessed face of the recess.

Abstract: A system for providing a thermal transformer to provide heating and cooling to enclosed structures, most generally a building using solar power combined with geothermal storage and a heat powered heat pump to raise or lower the temperature of the stored energy to a useful temperature as needed. The system also has an electrical generation embodiment to provide electricity in addition to the heating and cooling. The system will collect and store solar energy and supply heated or cooled water to the building's existing HVAC system while consuming no fossil fuels and emitting no greenhouse gases. The system may also be used in one embodiment to supply power for the pumps/fans used to circulate the heated or cooled air or water throughout the building.

Abstract: A thermo-electro-acoustic engine comprises a sealed body having a regenerator, hot and cold heat exchangers, an acoustic source, and an acoustic energy converter. An acoustic pressure wave is generated in a gas in the region of the regenerator. The converter converts a portion of the acoustic pressure into electrical energy. A portion of the electrical energy is used to drive the acoustic source. The acoustic source is controllably driven to produce acoustic energy which constructively adds to that of the acoustic pressure wave in the region of the regenerator. The remaining electrical energy produced by the converter is used external to the engine, such as to drive a load or for storage. The resonant frequency of the engine and the frequency of the energy output can be controlled electronically or electromechanically, and is not limited solely by the physical structure of the engine body and its elements.

Abstract: A multi-well helium Dewar is provided for recirculating coolant about a cryostat probe; the Dewar includes a first well containing a first coolant reservoir, and a second well containing a second coolant reservoir. A fluid connection extends between the first and second coolant reservoirs. A low impedance conduit further connects a top end of the second well to the first well. In this regard, the Dewar at least partially contains a cryocooler within the first well and a cryostat probe within the second well. Vibrational noise is reduced by the incorporation of soft mounting components for connecting various features. A thermal shield of the Dewar can be thermally connected to isolated components for additional cooling power and increased efficiency during initialization. A second fluid connection may include a valve attached to a counter-flow heat exchanger for efficiently re-condensing excess gas within the Dewar.

Abstract: A thermo-electro-acoustic refrigerator comprises a sealed body having a regenerator, hot and cold heat exchangers, an acoustic source, and an acoustic energy converter. A first drive signal drives the acoustic source to produce an acoustic pressure wave in the region of the regenerator. The converter converts a portion of the acoustic pressure into a second drive signal which is fed back to and further drives the acoustic source. The pressure wave produces a thermal gradient between the cold and hot heat exchangers, permitting heat extraction (cooling) within at least one of the heat exchangers. The resonant frequency of the refrigerator can be controlled electronically, and is not limited by the physical structure of the refrigerator body and its elements.

Abstract: Pulse tube refrigeration or cooling systems are described which utilize a secondary regenerator or a secondary pulse tube. Use of such a secondary regenerator or pulse tube enables a commercially available pressure oscillator to be incorporated in the cooling system. The commercially available oscillator can be operated at room temperature or approximately so.

Abstract: A regenerator, for use in a heat engine, configured to receive and store heat from a high-temperature gas flowing from a high-temperature space into the regenerator, and to provide the heat to a low-temperature fluid flowing from a low-temperature space into the regenerator. The regenerator includes a large number of layered metal meshes. Each metal mesh includes a large number of mutually parallel longitudinal strands and a large number of mutually parallel lateral strands perpendicular to the longitudinal strands. The metal meshes are layered such that each metal mesh is sequentially rotated in a same direction by a fixed angle with respect to an immediately previously layered metal mesh.

Abstract: The present invention provides a power generator for generating electricity comprising a core having an interior chamber, the interior chamber having a top portion and a bottom portion. The core is filled with a volume of a gas. A frequency generator is provided for resonating the gas at a high frequency, and means for securing the frequency generator to the core are provided as well. In addition, a pair of electrical conductors is connected to the core to conduct the flow of electricity away from the core.

Abstract: A closed cycle Stirling cryogenic cooler, typically utilizing a noble gas (He or like) as a working fluid and containing a pneumatically driven expander interconnected with a low frequency pressure wave generator using a flexible transfer line or conduit, wherein the pressure wave generator includes a sealed gas discharge cavity containing the pressurized working fluid and a plurality of discharge electrodes which are electrically isolated, protrude through the walls of the cavity and are electrically connected to the high frequency pulse voltage supply, thus producing the glow discharge resulting in a cloud of cold plasma, making a so-called “plasmanized gas piston”.

Abstract: An apparatus for transferring cryogenic refrigeration includes a cryocooler interface, a housing, a working fluid, a heat exchanger, a flexible thermal link, and a remote cartridge cold head. The cryocooler interface is thermally connected to a cryocooler providing a source of refrigeration. The refrigeration is passed from the crycooler into the heat exchanger via the cryocooler interface. The remote cartridge cold head is attached to a remote location. Heat is drawn from the remote location through the remote cartridge cold head and into the heat exchanger via the working fluid within the flexible thermal link and housing. Within the heat exchanger, heat is transferred from the working fluid to the refrigeration source, such as a cryocooler; accordingly, the remote location is cooled.

Abstract: A thermodynamic system includes a cyclical heat exchange system and a heat transfer system coupled to the cyclical heat exchange system to cool a portion of the cyclical heat exchange system. The heat transfer system includes an evaporator including a wall configured to be coupled to a portion of the cyclical heat exchange system and a primary wick coupled to the wall and a condenser coupled to the evaporator to form a closed loop that houses a working fluid.

Abstract: The present disclosure details a thermoacoustic driven compressor having a pressurized housing, which contains within a thermoacoustic engine and a working gas, coupled to a positive displacement reciprocating compressor. The thermoacoustic driven compressor generates scalable compressed air from a given heat source.

Abstract: A valve assembly is provided for dynamically controlling the inlet and exhaust of refrigeration gas between a cryocooler coldhead and a remote compressor. The valve assembly is optimized to minimize friction, power consumption, and wear while providing complete flexibility as to the timing, duration, and amplitude of its inlet and exhaust actions. The valve assembly comprises two separate open-close sections for the inlet and exhaust functions. These are mounted along a single rod, the position of which is controlled by a linear motor. The two sections are configured so that only one is open at each the rod's travel and neither is open at the midpoint of travel. A microprocessor and appropriate drive circuits precisely control the position of the rod as a function of time, and of displacer position when used with a Gifford-McMahon (G-M) cooler.

Abstract: A cryogenic magnet system, comprising a cryogenic vessel (1) housing a magnet winding, a vacuum jacket (3) enclosing the cryogenic vessel and a refrigerator (4) at least partially housed within the vacuum jacket and thermally linked (6) to the cryogenic vessel. In particular, the system further comprises an electromagnetic shield.

Abstract: A pressure wave generator (40) for driving one or more cryogenic refrigerator systems. The pressure wave generator (40) comprises a housing with one or more inlet/outlet ports (57,58) through which generated pressure waves of gas may pass through to drive a cryogenic refrigerator system or systems connected to the inlet/outlet ports (57,58). The pressure waves are generated by at least on pair of opposed diaphragms (41,42) located in the housing that are moveable in a reciprocating motion within the housing to create pressure waves in gas spaces (55,56) associated with each diaphragm (41,42). The gas spaces (55,56) each having associated inlet/outlet ports (57,58) through which the pressure waves may pass. An operable drive system is also provided to move the pair of diaphragms (41,42) in a reciprocating motion.

Abstract: Refrigerators, with particular, but not exclusive, application to the storage and transport of vaccines are disclosed. A refrigerator has a payload container (20) within which items can be placed for temperature-controlled storage. The payload container (20) is submerged in a reservoir (21) that contains water. The reservoir has a cooling region containing the payload container and a headspace containing water that is, in use, higher than the payload container. Cooling means, that might include a refrigeration unit (30) having cooling elements (32) or a cold thermal mass can cool waterwithin the headspace. Where there is a refrigeration unit, a power supply, typically solar powered, can act as a source of power for the refrigeration unit. Embodiments may include a freezer compartment close to the cooling elements (32). Alternatively, the cooling region may comprise a pipe manifold within the payload container.

Abstract: A cryogen free cooling apparatus comprises at least one heat radiation shield (54) surrounding a working region (20) and located in a vacuum chamber (4). A cryogen free cooling system has a cooling stage coupled to the heat radiation shield (54). Aligned apertures (56,58) are provided in the heat radiation shield and vacuum chamber walls. Sample loading apparatus has a sample holding device (2) attached to one or more elongate probes (3) for inserting the sample holding device through the aligned apertures (56,58) to the working region (20); and a thermal connector enables the sample holding device to be releasably coupled for heat conduction via said connector to a cold body or cold bodies within the vacuum chamber so as to pre-cool a sample on or in the sample holding device.

Abstract: A pulse tube cryocooler modulating phase via an inertance tube and an acoustic amplifier (A1, A2) provided in the pulse tube cryocooler are disclosed. The acoustic power amplifier (A1, A2) is made of a metal pulse tube (PT1, PT2) filled with regenerative materials, which are located at a distance of X from the hot end of the pulse tube. The length of the regenerative materials is L which meets the requirement of X?L>0. The acoustic power amplifier (A1, A2) can be used not only in a single-stage pulse tube cryocooler, but also in a multi-stage pulse tube cryocooler thermally coupled or gas coupled. The regenerative materials may be any cold storage materials applicable at low temperatures, such as stainless steel wire mesh, lead pellet, lead thread et al. The acoustic power amplifier (A1, A2) can increase the acoustic power at the hot end of the pulse tube (PT1, PT2), which is advantageous to the phase modulation of the inertance tube, thereby the properties of the pulse tube cryocooler can be enhanced.

Abstract: A refrigeration system includes a plurality of heat exchangers (E1, E2, E3) in cascade, each of said heat exchangers including: a flow (150) of cold-producing liquefied methane; a high-pressure flow (122) of a two-phase mixture of refrigerant fluids giving up in heat and including refrigerant fluids having a low normal boiling temperature; and a low-pressure flow (100) of a cold-producing two-phase mixture of said refrigerant fluids.

Abstract: The present invention relates to a cryogenic cooler's expander supported by a support member, preferably a truncated conical tube. The support member provides additional stiffness to the expander to reduce movements at the distal end of the expander. The support member also increases the natural frequency of the expander. In one embodiment, the support member increases the natural frequency of the expander at least about two (2) times in the bending and/or twisting sense. In another embodiment, the bending natural frequency of the expander and support sub-assembly is at least about two times greater or lower than the natural frequency of the electrical wires that connect the infrared sensor to a control processing unit to reduce the maximum stress applied to the electrical wires during use. In another embodiment, additional or redundant electrical pathways are provided for the connection between the infrared sensor and the CPU.

Abstract: A novel thermal coupler apparatus and method to couple a cryocooler or another cooling device to a superconducting magnet or cooled object allows for replacement without a need to break the cryostat vacuum or to warm up the superconducting magnet or other cooled object. A method uses a pneumatic actuator for coupling, and a retractable mechanical actuator for uncoupling. Mechanical closing forces are balanced between the intermediate temperature and low temperature cooling surfaces and do not transfer to the cooled object. The pneumatic actuator provides permanent control under mechanical closing forces in the thermal coupling.

Abstract: A retainer and spring with threaded end are machined from a single piece of material for threading to a piston in a closed cycle cryogenic cooler. Since the machined retainer and spring are a unitary part, they cannot rub against each other during operation of the piston which reduces debris generation. The spring is preferably formed as a double start helix which further increases axial stability and reduces side loading. The spring extends into an integrally formed, threaded end at the end thereof opposite the retainer.

Abstract: A cryogenic refrigerator includes a pressure switching valve with a rotational element for switching between channels. The cryogenic refrigerator includes a first member located on one side in a direction of a rotational axis of the rotational element; a second member located on another side in the direction of the rotational axis of the rotational element; a bearing rotatably supporting the rotational element; and an elastic element. The first and second members sandwich the bearing via the elastic element.

Abstract: A heat pipe arranged between warm and cold connection elements is intended to be filled at least partially with a refrigerant, which can be circulated in the heat pipe by a thermosiphon effect. The parts of a device, particularly in superconducting technology, which are to be cooled are connected to the warm connection element and a heat sink is connected to the cold connection element. To thermally separate the warm and cold connection elements, the refrigerant can be pumped off through the pipeline connected to the interior of the heat pipe.

Abstract: A cooling arrangement for an electrical connector for a superconductor including at least one superconductor arranged in a container and the container is arranged in a vacuum chamber. A cryocooler is thermally connected to the container to cool the container and the contents of the container including the superconductor. The electrical connector extends through the vacuum chamber and the container to the at least one superconductor. The electrical connector has a thermally conducting and electrically insulating arrangement. The thermally conducting and electrically insulating arrangement comprises an electrically insulating member contacting the electrical connector. A thermally conducting member contacts the electrically insulating member and the thermally conducting member is thermally connected to the to cool the electrical connector.

Abstract: A nuclear magnetic resonance (NMR) apparatus (10) comprises a superconducting main field magnet coil system (14) which generates a homogeneous magnetic field of at least 3T, and a gradient coil system (15) which generates a gradient strength of at least 10 mTm?1, with a slew rate of at least 100 Tm?1s?1, wherein the main field magnet coil system (14) is arranged in a cryostat (12) with liquid helium and a refrigerator (16) in the form of a pulse tube cooler or a Gifford-McMahon cooler, and wherein an evaporation line (17a, 27a, 37a) is provided for helium that might evaporate from the cryostat. In all states of operation of the NMR apparatus (10) without gradient switching, the refrigerator provides a cooling capacity which is at least 0.

Abstract: The present disclosure relates to the separation of CO2 from a gas mixture. The CO2 may be removed by cooling the gas mixture such that the CO2 can be removed as a solid or liquid. In various embodiments the gas mixture from which the CO2 is removed may include exhaust gases generated as part of a combustion process, such as may be employed in a power generation process, though the gas mixture may be any gas mixture that includes CO2.

Abstract: Disclosed are a cooling device for high temperature fluid, a flight vehicle having the same and a cooling method for high temperature fluid, the cooling device including a heat exchanger configured such that fluid is introduced therein to be heat-exchanged with a refrigerant, and configured to vaporize the refrigerant by the heat exchange such that the fluid is discharged at temperature close to vaporization temperature of the refrigerant, a compressor connected to the heat exchanger and configured to compress the fluid discharged out of the heat exchanger, a turbine connected to the compressor and configured to expand the fluid compressed in the compressor to lower temperature of the compressed fluid, and a phase change heat exchanger connected to the turbine, storing a phase change material, and configured to cause heat exchange between the phase change material and the fluid discharged out of the turbine so as to control temperature of the discharged fluid, whereby a cooling device capable of minimizing in

Abstract: The invention is directed to an improved cryogenic cooler with an expander where the regenerator matrix is decoupled from the displacer or piston, thereby allowing the design of each to be optimized substantially independently. The regenerator matrix is preferably positioned spaced apart from the displacer and can be designed to enhance thermal exchanges and flow rates of the working gas. In one embodiment, the regenerator matrix has a serpentine shape or U-shape disposed around the displacer and the cold finger. Preferably, the regenerator matrix is static. The thermal lengths of the cold finger and/or the displacer can be extended by minimizing their geometrical lengths. Additionally, the structural integrity or stiffness of the cold finger and/or displacer can be strengthened.

Abstract: The present invention discloses a displacer valve for a cryogenic refrigerator, which is mounted on one circular surface of a displacer cover by a bolt to open and close a hole formed in the surface of the displacer cover. The displacer valve includes a rotation preventing guide fastened to an eccentric portion of the displacer cover by the bolt to prevent the displacer valve from rotating around the bolt. Therefore, the displacer valve does not rotate around the bolt but is fixed in a proper position, so that its operational reliability can be ensured.

Abstract: In one embodiment, a compressor includes a moving assembly configured to compress a gas within a compression volume; a guide rod connected to the moving assembly which reciprocates axially with the moving assembly; and a bellows seal positioned between the moving assembly and a stationary housing which at least partially defining the compression volume. In another embodiment, a compressor includes a motor assembly configured to compress a gas within a compression volume, the motor assembly including: a stationary coil assembly; a moving assembly having at least one magnet, and a gap located between the stationary coil assembly and the moving assembly; wherein the moving assembly is configured to reciprocate axially with respect to the stationary coil assembly when electrical current is applied to the stationary coil assembly, and to change the width of the gap between the stationary coil assembly and the moving assembly so as to provide magnetic axial stiffness against motion of the moving assembly.

Abstract: A unitary pulse tube expander for removable attachment to a SADA II coldfinger and insertion within a Dewar assembly. The regenerator of the pulse tube expander is encased in a regenerator sleeve and a cold cap to create a unitary pulse tube expander that may function as a drop-in replacement for a Stirling type expander in a SADA II coldfinger cryocooler.

Abstract: A method of protecting a cylinder of a compressor comprising a piston, a linear permanent magnet (PM) having a coil and a magnet, and a sensor-less control of the PM for moving the piston in and out of the cylinder. The method including the steps of receiving a reference position of the piston from a temperature control loop; deriving a compensation voltage and a load spring effect information from a current through the coil; providing a model input voltage to a model of a mechanical structure of the compressor for predicting position of the piston, the model input voltage comprising a first voltage derived from the reference position; a compressor input voltage comprising the first voltage and the compensation voltage; and using a position control loop to recognize when the maximum compression ratio is desired and controlling the piston to achieve maximum compression ratio without causing damage to the discharge valve.

Abstract: A compact cryocooler includes a gas compression piston (304) supported for reciprocal linear translation along a first longitudinal axis (308) and a gas displacing piston (362) supported for reciprocal linear translation along a second longitudinal axis (366). The first longitudinal axis (308) and second longitudinal axis (366) are substantially orthogonal. A rotary motor (302) rotates a rotor (324) and associated motor shaft (320) about a motor rotation axis (328) disposed substantially parallel with the second longitudinal axis (366). Motor shaft (320) first and second mounting features (336, 340) traverse first and second eccentric paths around the motor rotation axis. A first drive coupling couples the first mounting feature (336) with the gas compression piston (304) and delivers a reciprocal linear translation along the first longitudinal axis (308) thereto.

Abstract: The present invention provides an apparatus for utilizing waste heat to power a reconfigurable thermodynamic cycle that can be used to selectively cool or heat an environmentally controlled space, such as a room, building, or vehicle. The present invention also integrates an electric machine, which may operate as a motor or generator, or both, and an additional prime mover, such as an internal combustion engine. Different combinations of these components are preferable for different applications. The system provides a design which reasonably balances the need to maximize efficiency, while also keeping the design cost-effective.

Abstract: A novel thermal coupler apparatus and method to couple a cryocooler or another cooling device to a superconducting magnet or cooled object allows for replacement without a need to break the cryostat vacuum or to warm up the superconducting magnet or other cooled object. A method uses a pneumatic actuator for coupling, and a retractable mechanical actuator for uncoupling. Mechanical closing forces are balanced between the intermediate temperature and low temperature cooling surfaces and do not transfer to the cooled object. The pneumatic actuator provides permanent control under mechanical closing forces in the thermal coupling.

Abstract: A fluid vapor distillation apparatus. The apparatus includes a source fluid input, and an evaporator condenser apparatus. The evaporator condenser apparatus includes a substantially cylindrical housing and a plurality of tubes in the housing. The source fluid input is fluidly connected to the evaporator condenser and the evaporator condenser transforms source fluid into steam and transforms compressed steam into product fluid. Also included in the fluid vapor distillation apparatus is a heat exchanger fluidly connected to the source fluid input and a product fluid output. The heat exchanger includes an outer tube and at least one inner tube. Also included in the fluid vapor distillation apparatus is a regenerative blower fluidly connected to the evaporator condenser. The regenerative blower compresses steam, and the compressed steam flows to the evaporative condenser where compressed steam is transformed into product fluid.

Abstract: Disclosed are the use of fluorine substituted olefins, including tetra- and penta-fluoropropenes, in a variety of applications, including connection with blowing agents, foams, foamable compositions, foaming methods, heat transfer compositions and methods, propellants, and solvating methods.

Abstract: A refrigeration system includes a cryogenic freezer and a mechanical refrigerator, wherein the mechanical refrigerator includes an enclosure containing an atmosphere, the cryogenic freezer includes a cryogen exhaust conduit, and a heat pipe heat exchanger including a warm end and a cold end, wherein the heat pipe heat exchanger is in heat transfer relationship with the mechanical refrigerator and the cryogenic freezer such that the warm end of the heat pipe heat exchanger contacts the atmosphere within the mechanical refrigerator enclosure, and the cold end of the heat pipe heat exchanger is disposed within the cryogen exhaust conduit of the cryogenic freezer. A refrigeration process includes cooling an atmosphere within a mechanical refrigerator by exposing the atmosphere to a warm end of a heat pipe heat exchanger, wherein a cold end of the heat pipe heat exchanger is disposed within an exhaust duct of a cryogenic freezer.

Abstract: A non-polluting, closed-cycle condensing heat engine and operating method is provided for propelling road vehicles at high efficiencies and high power densities by using a phase-changing working fluid having a critical temperature close to the natural ambient temperature of the surrounding atmosphere and shifting the high temperature heat reservoir downward by several hundred degrees by creating an artificial low temperature heat reservoir below ambient temperature by evaporating water.

Abstract: A thermoacoustic apparatus includes multiple thermoacoustic device stages, such as individual thermoacoustic refrigerators, connected in a looped series such that excess acoustic energy from a first stage forms a part of the input energy to the next successive stage. Each stage includes an acoustic source, a regenerator, and a plurality of heat exchangers. The stages are interconnected by transmission lines. The dimensions of the transmission lines, materials used, and the operating parameters are selected so that that excess acoustic power is communicated to a succeeding stage with a pressure phase at the back of an acoustic source of the succeeding stage such that the electric power required by the acoustic source of the succeeding stage is minimized for a given acoustic power produced by the second stage. Improved operating efficiency of the thermoacoustic apparatus is thereby provided.

Abstract: In a thermoacoustic refrigerator, operating temperatures, ambient temperature, and selected user input are utilized to control frequency and/or input power in order to optimize the efficiency of the thermoacoustic refrigerator operation. In a thermoacoustic heat engine, operating temperatures, ambient temperature, and selected user input are utilized to control impedance of a load to optimize the efficiency of the thermoacoustic heat engine operation.

Abstract: A standing wave thermoacoustic piezoelectric refrigerator is provided. The standing wave thermoacoustic piezoelectric refrigerator includes a housing, a porous stack, and a piezoelectric bimorph. The housing comprises a compressible fluid and has a first portion and a second portion. The porous stack is positioned between a hot heat exchanger and a cold heat exchanger within the housing, at an end of the first portion of the housing opposite to an end of the first portion having the porous stack and is capable of oscillating to generate acoustic energy upon receiving energy from an external energy source. The oscillation of the piezoelectric bimorph compresses and expands the compressible fluid within the housing. Whereby, the compressible fluid traverses between the first portion and the second portion through the porous stack to generate standing acoustic waves enabling the compressible fluid to transfer heat from the cold heat exchanger to the hot heat exchanger.

Abstract: A fault current limiter comprising: an input node; an output node; a variable impedance element coupled between the input node and the output node; a closed loop cryocooler circuit, comprising a first cryocooler for cooling the variable impedance element and a second cryocooler, thermally coupled to the first cryocooler, for cooling the first coolant, wherein the variable impedance element comprises Magnesium Diboride.

Abstract: A method for cooling an object includes coupling a cooling device to the object, wherein the cooling device includes at least one thermoacoustic engine and a plurality of gas diodes, generating acoustic power with the thermoacoustic engine, channeling acoustic oscillations of a fluid through the gas diodes, and transferring the heat produced by the object to the fluid to facilitate moving the heat away from the object.

Abstract: The use of pentafluoropropene (HFO-1225) and tetrafluoropropene (HFO-1234) in refrigeration equipment is disclosed. These materials are generally useful as refrigerants for heating and cooling, as blowing agents, as aerosol propellants, as solvent composition, and as fire extinguishing and suppressing agents.