A thermoacoustic device includes a stage coupled to a bar, wherein the stage includes a first heating component on a first terminus of the stage. The stage further includes a first cooling component on a second terminus of the stage. A thermal conductivity of the stage is higher than a thermal conductivity of the bar. A heat capacity of the stage is higher than a heat capacity of the bar.

The thermoacoustic energy converting element part is provided with a plurality of through holes extending along a direction to penetrate the thermoacoustic energy converting element part to form travelling routes of acoustic waves. The thermoacoustic energy converting element part includes a wall surrounding each of the through holes to extend in an extending direction of the through hole and configured to exchange heat with the fluid. The through hole includes a hole that has a hydraulic diameter of 0.4 mm or smaller, and an open area ratio of the through holes in the thermoacoustic energy converting element part is 60% or higher. Thermal conductivity of the thermoacoustic energy converting element part in fluid atmosphere is 0.4 W/m/K or lower, and heat capacity of the thermoacoustic energy converting element part at 400 C. in the fluid atmosphere is higher than 0.5 J/cc/K.

An energy conversion device includes a first acoustic wave generator, a second acoustic wave generator, and an output unit which are provided in a pipe member. The first acoustic wave generator has a thermal energy generator configured to generate thermal energy from electric energy, and converts the thermal energy generated by the thermal energy generator into acoustic energy to generate acoustic wave in working gas by a self-excited thermo acoustic vibration. The second acoustic wave generator converts thermal energy supplied from a heat supply source into acoustic energy and generates acoustic wave in working gas by a self-excited thermo acoustic vibration. The output unit converts the acoustic energy of the acoustic waves from the first acoustic wave generator and the second acoustic wave generator into cold energy to output.

A thermoacoustic device includes a process volume which is filled with a working fluid through which the acoustic wave propagates. The thermoacoustic device further includes an acoustic network comprising a tubular loop configured with a passage providing an opening in the loop and configured as acoustic circuit provided with a compliance volume, a thermo-acoustic core and an inertance volume. Within the loop, the thermoacoustic core is at a first side thereof adjacent to the passage at a first path length through the loop, and at its second side, opposite to the first side, the thermoacoustic core is at a second path length from the passage. The thermoacoustic device includes within the loop a spring-type partitioning element that is configured to close off the cross-section of the tube and to be impermeable for the working fluid while allowing transmission of pressure waves in the working fluid through the spring-type partitioning element.

A thermoacoustic heating device capable of effectively utilizing streaming, and including a prime mover in a first pipeline that forms a loop line, and a heating device in a second pipeline that forms another loop line. The first and second pipelines are connected to each other via a branch pipeline. A branch pipeline on the prime mover side and the second pipeline on the heating device side are positioned adjacent to each other, and a low-temperature side heat exchanger of the heating device is integrally formed with or held in contact with the branch pipeline on the prime mover side.

A thermoacoustic device includes a process volume which is filled with a working fluid through which the acoustic wave propagates. The thermoacoustic device further includes an acoustic network comprising a tubular loop configured with a passage providing an opening in the loop and configured as acoustic circuit provided with a compliance volume, a thermo-acoustic core and an inertance volume. Within the loop, the thermoacoustic core is at a first side thereof adjacent to the passage at a first path length through the loop, and at its second side, opposite to the first side, the thermoacoustic core is at a second path length from the passage. The thermoacoustic device includes within the loop a spring-type partitioning element that is configured to close off the cross-section of the tube and to be impermeable for the working fluid while allowing transmission of pressure waves in the working fluid through the spring-type partitioning element.

A heat/acoustic wave conversion component having a first end face and a second end face, includes a partition wall that defines a plurality of cells extending from the first end face to the second end face, inside of the cells being filled with working fluid that oscillates to transmit acoustic waves, the heat/acoustic wave conversion component mutually converting heat exchanged between the partition wall and the working fluid and energy of acoustic waves resulting from oscillations of the working fluid. Hydraulic diameter HD of the heat/acoustic wave conversion component is 0.4 mm or less, where the hydraulic diameter HD is defined as HD=4S/C, where S denotes a cross-sectional area of each cell perpendicular to the cell extending direction and C denotes a perimeter of the cross section, and the heat/acoustic wave conversion component has three-point bending strength of 5 MPa or more.

A thermoacoustic machine including a device for measuring at least one parameter representative of a temperature of a first external source and/or of a second external source, and a control device configured to modulate the acoustic power generated by one or more acoustic sources such that the temperature of one said external source connected to one or more thermoacoustic cells of the machine reaches or remains substantially identical to a setpoint temperature is disclosed.

A thermoacoustic device includes a process volume which is filled with a working fluid through which the acoustic wave propagates. The thermoacoustic device further includes an acoustic network comprising a tubular loop configured with a passage providing an opening in the loop and configured as acoustic circuit provided with a compliance volume, a thermo-acoustic core and an inertance volume. Within the loop, the thermoacoustic core is at a first side thereof adjacent to the passage at a first path length through the loop, and at its second side, opposite to the first side, the thermoacoustic core is at a second path length from the passage.

The thermoacoustic device includes within the loop a spring-type partitioning element that is configured to close off the cross-section of the tube and to be impermeable for the working fluid while allowing transmission of pressure waves in the working fluid through the spring-type partitioning element.

Disclosed is a resonant expander usable in a cryogenic cooling system. The resonant expander may comprise an expansion chamber with a reciprocating piston. The piston divides the expansion chamber into a warm and a cold displacement volume. Passive acoustic valves allow high-pressure fluid into the cold displacement volume and allow low-pressure fluid out of the cold displacement volume. The low-pressure fluid may cool at exiting the resonant expander. The piston free from solid contact with an external mechanism, thereby not requiring sliding seals. Piston and displacement volumes form a mechanically resonant system at the operating frequency of the resonant expander, ensuring correct acoustic valve actuation. Electromagnetic system having a permanent magnet assembly fixed to the piston and a coil at the expansion chamber with a control system, is disclosed. Disclosed is a cryogenic cooling system having the resonant expander, a compressor and recuperative heat exchanger providing low temperature fluid.