Refrigerating cycle device

Abstract

To prevent heat transfer inhibition and an increase in pressure loss due to refrigerating machine oil discharged into a cycle, and to provide a compact and highly efficient refrigerating cycle apparatus using carbon dioxide gas (CO). In a refrigerating cycle apparatus having at least a compressor, a radiator, a decompressor, a vaporizer and piping for successively connecting them, and provided with a refrigerant circuit in which refrigerant circulates in the compressor, the radiator, the decompressor, the vaporizer and the piping, carbon dioxide gas (CO) is enclosed as said refrigerant, and the drop in heat transfer rate and the increase in pressure loss in the heat exchanger can be restrained to very low levels by keeping oil enclosing volume in the refrigerant circuit to the quantity of carbon dioxide gas (CO) enclosed as refrigerant (weight %) to less than 40 weight % and more than 0, resulting in practical elimination of the increase in size and the impact on the drop in efficiency of the heat exchanger.