PURPOSE: To provide a refrigeration system utilizing a cooling zone being generated in a process where gas is absorbed to an adsorbent bed and then desorbed.

CONSTITUTION: The improvement comprises an adsorbent bed 3 and a cylinder 2 incorporating a gas, e.g. carbon dioxide gas. A piston compresses a gas which can be adsorbed to an adsorbent 3 and adsorption heat is dissipated to the atmosphere by means of a blade 4. When the piston is retracted, the gas which can be desorbed from the adsorbent 3 is decompressed (expanded). When compression and decompression (expansion) of the gas is repeated, a cooling zone is generated in the adsorbent 3 thermally coupled with a place being cooled.