Abstract: A high-altitude long-endurance airship with a top surface that is highly emissive of infrared radiation and a bottom surface that is highly absorptive of infrared radiation. Movable displacer blankets inside the airship separate the upper and lower portions of the airship. Lifting gas in the airship is warmed by radiation from the earth when the displacer blankets are in their upper position. Lifting gas is cooled by radiation to space when the displacer blankets are in their lower position. The whole airship is a heat engine. By expanding the volume of lifting gas when it is relatively warm and compressing the lifting gas when it is relatively cold, net power output can be recovered in the form of electric power. The overall configuration of the preferred airship is a variable-thickness flying wing. If the whole airship is alternately expanded and compressed, imbalance between its weight and buoyancy allow gliding flight.

Abstract: A high-altitude long-endurance airship with a top surface that is highly emissive of infrared radiation and a bottom surface that is highly absorptive of infrared radiation. Movable displacer blankets inside the airship separate the upper and lower portions of the airship. Lifting gas in the airship is warmed by radiation from the earth when the displacer blankets are in their upper position. Lifting gas is cooled by radiation to space when the displacer blankets are in their lower position. The whole airship is a heat engine. By expanding the volume of lifting gas when it is relatively warm and compressing the lifting gas when it is relatively cold, net power output can be recovered in the form of electric power. The overall configuration of the preferred airship is a variable-thickness flying wing. If the whole airship is alternately expanded and compressed, imbalance between its weight and buoyancy allow gliding flight.

Abstract: A cooling load 90 is enclosed within the envelope of the pressure vessel that contains the working fluid in a pulse tube cooler in a load space 95 adjacent to a regenerator 58 of that pulse tube cooler. Flow-smoothing means 63, which include stacked screens and perforated plates, or diffuser nozzle 104 or diffuser cone 106, spreads the flow of fluid that enters the cold end of pulse tube 66.

Abstract: In a regenerator for a regenerative cycle machine, regenerator foil is grooved on both sides, with intersections of grooves on opposite side forming holes at which separate flows of fluid interact to induce flows ancillary to the overall direction of flow in the regenerator, thereby enhancing heat transfer to and from the material of the regenerator and improving thermodynamic performance of the gas cycle machine.

Abstract: In a regenerator for a regenerative cycle machine, regenerator foil is grooved on both sides, with intersections of grooves on opposite side forming holes at which separate flows of fluid interact to induce flows ancillary to the overall direction of flow in the regenerator, thereby enhancing heat transfer to and from the material of the regenerator and improving thermodynamic performance of the gas cycle machine.

Abstract: A regenerator 24 formed of concentric layers of regenerator foil 61 assembled with unbonded joints 68 and 70 inside a generally cylindrical space 74 and method of inserting and installing foil 60 using foil rolling apparatus 16 and foil installation apparatus 22 employing an inflatable bladder 94 to press foil 60 against the wall of generally cylindrical space 74.

Abstract: A joint connecting consecutive sheets of etched regenerator foil for a spiral-wrapped regenerator of a regenerative gas cycle machine such as a Stirling cycle engine or Stirling, pulse tube, or Gifford-McMahon cryocooler. The joint comprises a multiplicity of tabs on the end of one sheet of regenerator foil interlocked with a multiplicity of tabs on the end of another piece of regenerator foil. The joint is no thicker than the original thickness of the sheets of etched regenerator foil that it connects together, and the tabs substantially fill the holes into which they are locked, minimizing undesirable leakage through the joint after it has been incorporated in a regenerator.

Abstract: A joint connecting consecutive sheets of etched regenerator foil for a spiral-wrapped regenerator of a regenerative gas cycle machine such as a Stirling cycle engine or Stirling, pulse tube, or Gifford-McMahon cryocooler. The joint comprises a multiplicity of tabs on the end of one sheet of regenerator foil interlocked with a multiplicity of tabs on the end of another piece of regenerator foil. The joint is no thicker than the original thickness of the sheets of etched regenerator foil that it connects together, and the tabs substantially fill the holes into which they are locked, minimizing undesirable leakage through the joint after it has been incorporated in a regenerator.

Abstract: The pulse tube 59 of a pulse tube refrigerator is equipped with a thin liner 80 of low thermal mass and in poor thermal contact with pulse tube 59. One surface of liner 80 may be furnished with indented recesses 86, making the recessed portions of the liner thinner than the remainder of the material of liner.

Abstract: In a regenerator for a regenerative cycle machine, regenerator foil is grooved on both sides, with intersections of grooves on opposite side forming holes at which separate flows of fluid interact to induce flows ancillary to the overall direction of flow in the regenerator, thereby enhancing heat transfer to and from the material of the regenerator and improving thermodynamic performance of the gas cycle machine.

Abstract: A double inlet passage 70 connects a compressor 40 to remote end 53 of a vortex tube 51 that serves as the heat-rejecting heat exchanger of an orifice pulse tube refrigerator. Double inlet passage 70 includes means 3 for controlling DC flow in that passage. Fluid flows between compressor and reservoir enhance heat-rejecting effectiveness of vortex tube 51.

Abstract: A method of assembling a regenerator comprising multiple concentric layers of foil, each with an unbonded joint inside a generally cylindrical space, by inserting each successive layer of foil into the remaining space inside said generally cylindrical space and pressing it outward against the wall of the generally cylindrical space until its edges do not overlap.

Abstract: Fluidic devices, including blind vortex tubes, constant-rotation double diodes and constant-rotation double vortex tubes, are disclosed with which to construct pulse tube refrigerators, including ones having diode loops, constant-rotation double diodes, constant-rotation double vortex tubes, and asymmetrical diode stacks. Present orifice pulse tube refrigerators use an orifice connected at the warm end of the pulse tube to a reservoir. The orifice and reservoir serve to control flows at the warm end of the pulse tube so that they are not in phase with flows at the cold end. Present heat exchangers at the warm end suffer inefficiencies due to heat-regenerative effects caused by return flows through the orifice. The fluidic devices disclosed herein create dynamic replacement orifices for pulse tube refrigerators that also serve as efficient heat exchangers and supercoolers with minimal regenerative characteristics.

Abstract: Fluidic devices, including constant-rotation double diodes and constant-rotation double vortex tubes, are disclosed with which to construct pulse tube refrigerators having diode loops, constant-rotation double diodes, constant-rotation double vortex tubes, and asymmetrical diode stacks. Present orifice pulse tube refrigerators use an orifice connected at the warm end of the pulse tube to a reservoir. The orifice and reservoir serve to control flows at the warm end of the pulse tube so that they are not in phase with flows at the cold end. Present heat exchangers at the warm end suffer inefficiencies due to heat-regenerative effects caused by return flows through the orifice. The fluidic devices disclosed herein create dynamic replacement orifices for pulse tube refrigerators that also serve as efficient heat exchangers and supercoolers with minimal regenerative characteristics.

Abstract: A pulse tube refrigerator is equipped with a constant-diameter inertance tube (41) or a stepped or tapered intertance tube (48) which is coiled in a reservoir (20) to protect it from damage from external impacts and from structural failure due to differences between external and internal pressures. A tapered inertance tube (48) improves thermodynamic performance of the pulse tube refrigerator by improving heat transfer at the warm end of pulse tube (10).

Abstract: This invention relates to compact, high efficiency foil regenerators for use in regenerative gas cycle (e.g. Stirling cycle, Ericsson cycle, Vuilleumier cycle, Gifford-McMahon cycle, Sibling Cycle and similar) cryocoolers, heat engines, refrigerators and heat pumps. Very thin foil us formed in patterns of slits and slots that produce highly efficient regenerators when the foil is stacked in layers as by rolling it upon itself.

Abstract: A double-acting, rotating piston reciprocating in a cylinder with the motion of the piston providing the valving action of the Sibling Cycle through the medium of passages between the piston and cylinder wall. The rotating piston contains regenerators ported to the walls of the piston. The piston fits closely in the cylinder at each end of the cylinder except in areas where the wall of the cylinder is relieved to provide passages between the cylinder wall and the piston leading to the expansion and compression spaces, respectively. The piston reciprocates as it rotates. The cylinder and piston together comprise an integral valve that seqentially opens and closes the ports at the ends of the regenerators alternately allowing them to communicate with the expansion space and compression space and blocking that communication.

Abstract: Novel hot gas engines and heat pumps are provided which operate on an improved cycle related to the Stirling cycle. These hot gas engines and heat pumps use at least two separate heat exchanger assemblies and a plurality of valves to control fluid flow through the heat exchanger assemblies.