Patent ID: 6962059

Claim:
A refrigerating cycle apparatus comprising at least a compressor for raising the pressure of refrigerant; a radiator for cooling the refrigerant raised in pressure by said compressor; a decompressor, arranged further downstream of the refrigerant flow than said radiator, for decompressing and expanding said cooled refrigerant; a vaporizer for heating the refrigerant decompressed by said decompressor; and piping for consecutively connecting said compressor, said radiator, said decompressor and said vaporizer, and provided with a refrigerant circuit in which said refrigerant circulates within said compressor, said radiator, said decompressor, said vaporizer and said piping, wherein carbon dioxide gas (CO 2 ) is enclosed as said refrigerant, and a quantity of oil in said refrigerant circuit is not more than 40 weight % of the enclosed quantity of said CO 2 and more than 0; and said refrigerating cycle apparatus is further provided with an auxiliary heat exchanger for exchanging heat between the radiating side refrigerant channel formed between the refrigerant outlet side of said radiator and the inlet side of said decompressor and the vaporizing side refrigerant channel formed between the refrigerant outlet side of said vaporizer and the intake part of said compressor, wherein: the vaporization side refrigerant channel within said auxiliary heat exchanger has a plurality of through-holes formed in a flat tube; and a hydraulic power-equivalent diameter of said through-holes of the vaporization side refrigerant channel within said auxiliary heat exchanger is not smaller than the hydraulic power-equivalent diameter of the through-holes of the outlet of said vaporizer.