Patent ID: 7299653

Claim:
A refrigerating system using a non-azeotropic refrigerant mixture, wherein the non-azeotropic refrigerant mixture comprises a refrigerant having a normal boiling point of approximately room temperature and a low-boiling-point refrigerant having a normal boiling point of −60° C. or less; the refrigerating system is a single-stage refrigerating system comprising a compressor, a condenser, an evaporator, and a heat exchanger for exchanging heat between a refrigerant in a path from the evaporator to the compressor and a refrigerant in another path from the condenser to the evaporator; a dew point of the refrigerant mixture at a pressure in the condensing process after the compression is above room temperature; and the refrigerating system is operated in the range in which the boiling point is higher than the dew point at a pressure in the lower-pressure region in the path from the evaporator to the compressor.