The present invention relates to a Stirling-cycle refrigerator, and more particularly to a Stirling-cycle refrigerator capable of lowering a refrigerating temperature.
Stirling-cycle refrigerators comprise an expansion chamber defined by a displacer and a compression chamber defined by a piston, the expansion and compression chambers being interconnected through a heater or a high-temperature heat exchanger, a regenerator, and a cooler or a low-temperature heat exchanger. The displacer and the piston are operated out of phase with each other by a crank mechanism or a swash plate cam mechanism to cause a working gas to go through a continuous cycle of isothermal compression, isometric change, isothermal expansion, and isometric change for refrigeration.
The regenerator in the Stirling-cycle refrigerator of the type described contains a material made of metal or the like for storing heat. In general, when the temperature of a metal drops, the specific heat of the metal declines as does the heat storing ability thereof. With conventional regenerators filled with a metallic material, the lowest temperature which the refrigerator can achieve is governed by the specific heat of the metallic material used, and has been in the range of from 8.degree. to 9.degree. K.