| abstract |
To provide a heat cycle system in which the working fluid is incombustible and has less influence over the ozone layer and global warming even if it leaks out, which has excellent cycle performance and which is excellent in the safety. n A heat cycle system which employs a working fluid containing trifluoroethylene and either one or both of 1,1,1,2-tetrafluoroethane and pentafluoroethane, wherein the proportion of trifluoroethylene in a gaseous phase formed in the system is at most 50 mass %. For example, a refrigerating cycle system 10 comprising a compressor 11 , a condenser 12 , an expansion valve 13 and an evaporator 14 , wherein the working fluid is controlled as above. |