A reduction in a permeability of refrigerant gas is suppressed while increasing a filling factor of regenerator material particles with respect to a stage of a cold head. A cold head includes a stage including regenerator material particle groups, and a metal mesh material partitioning the regenerator material particle groups. The metal mesh material has quadrangular mesh holes each having a length of a long side of 1/10 or more and ½ or less of each of average particle sizes of the regenerator material particle groups.

A thermoacoustic refrigeration assembly includes a resonating tube having a first end and a second end; a first mechanical oscillator at the first end; a second mechanical oscillator at the second end; and a thermoacoustic stack sandwich disposed along a length of the resonating tube through which gas travels. The stack sandwich includes a first outboard heat exchanger on a first side of the stack sandwich facing the first mechanical oscillator, a second outboard heat exchanger on a second side of the stack sandwich facing the second mechanical oscillator, and a center heat exchanger disposed between the first outboard heat exchanger and the second outboard heat exchanger.

A thermoacoustic stack includes an outer wall which is cylindrical and has a length extending between a first end and a second end. An internal wall structure is disposed inside the outer wall. The internal wall structure includes a plurality of spaced adjacent wall surfaces extending along the length of the outer wall to provide open flow passages between the spaced adjacent wall surfaces. A first cross member extends across the outer wall at the first end and is connected to the outer wall and the internal wall structure at the first end.

A thermoacoustic stack includes an outer wall which is cylindrical and has a length extending between a first end and a second end. An internal wall structure is disposed inside the outer wall. The internal wall structure includes a plurality of spaced adjacent wall surfaces extending along the length of the outer wall to provide open flow passages between the spaced adjacent wall surfaces. A first cross member extends across the outer wall at the first end and is connected to the outer wall and the internal wall structure at the first end.

A thermoacoustic refrigeration assembly includes a resonating tube having a first end and a second end; a first mechanical oscillator at the first end; a second mechanical oscillator at the second end; and a thermoacoustic stack sandwich disposed along a length of the resonating tube through which gas travels. The stack sandwich includes a first outboard heat exchanger on a first side of the stack sandwich facing the first mechanical oscillator, a second outboard heat exchanger on a second side of the stack sandwich facing the second mechanical oscillator, and a center heat exchanger disposed between the first outboard heat exchanger and the second outboard heat exchanger.

A cryocooler includes an expansion chamber, a cooling stage thermally coupled to the expansion chamber, the cooling stage including a first heat transfer block provided with a surface exposed to the expansion chamber and a first heat exchange surface disposed outside the expansion chamber and a second heat transfer block provided with a second heat exchange surface facing the first heat exchange surface, a refrigerant supply port installed in the cooling stage outside the expansion chamber, a refrigerant discharge port installed in the cooling stage outside the expansion chamber, and a refrigerant path fluidically separated from the expansion chamber, the refrigerant path being formed between the first heat transfer block and the second heat transfer block such that a refrigerant flows from the refrigerant supply port to the refrigerant discharge port along the first heat exchange surface and the second heat exchange surface.

A reduction in a permeability of refrigerant gas is suppressed while increasing a filling factor of regenerator material particles with respect to a stage of a cold head. A cold head includes a stage including regenerator material particle groups, and a metal mesh material partitioning the regenerator material particle groups. The metal mesh material has quadrangular mesh holes each having a length of a long side of 1/10 or more and or less of each of average particle sizes of the regenerator material particle groups.

A reduction in a permeability of refrigerant gas is suppressed while increasing a filling factor of regenerator material particles with respect to a stage of a cold head. A cold head includes a stage including regenerator material particle groups, and a metal mesh material partitioning the regenerator material particle groups. The metal mesh material has quadrangular mesh holes each having a length of a long side of 1/10 or more and or less of each of average particle sizes of the regenerator material particle groups.

A cryocooler includes an expansion chamber, a cooling stage thermally coupled to the expansion chamber, the cooling stage including a first heat transfer block provided with a surface exposed to the expansion chamber and a first heat exchange surface disposed outside the expansion chamber and a second heat transfer block provided with a second heat exchange surface facing the first heat exchange surface, a refrigerant supply port installed in the cooling stage outside the expansion chamber, a refrigerant discharge port installed in the cooling stage outside the expansion chamber, and a refrigerant path fluidically separated from the expansion chamber, the refrigerant path being formed between the first heat transfer block and the second heat transfer block such that a refrigerant flows from the refrigerant supply port to the refrigerant discharge port along the first heat exchange surface and the second heat exchange surface.

A thermoacoustic system for transfer of energy by an acoustic wave, includes a process volume. The process volume is filled with a fluid through which the acoustic wave propagates, and includes an acoustic network including a compliance volume, a thermoacoustic core and a fluidic inertia; the thermoacoustic core including a cold heat exchanger, a hot heat exchanger and a regenerator; the cold heat exchanger arranged on a first side of the hot heat exchanger with the regenerator between the hot and cold heat exchangers; a thermal buffer zone is positioned adjoining the hot heat exchanger on a second side thereof.

The thermoacoustic system includes a partitioning element that is arranged in the thermal buffer zone adjacent to the hot heat exchanger. The partitioning element is configured for blocking mass flow of the fluid through the thermal buffer zone in a direction of acoustic wave propagation in the thermal buffer zone, while allowing passage of the acoustic wave through the thermal buffer zone.