Refrigerator oil and working fluid composition for refrigerating machine

摘要

The refrigerator oil of the invention comprises an ester of a polyhydric alcohol and a fatty acid with a content of a C5-C9 fatty acid of 50-100 % by mole, a content of a C5-C9 branched fatty acid of at least 30 % by mole and a content of a C5 or lower straight-chain fatty acid of not greater than 40 % by mole, and it is used with a fluoropropene refrigerant and/or trifluoroiodomethane refrigerant. The working fluid composition for a refrigerating machine according to the invention comprises the ester and a fluoropropene refrigerant and/or trifluoroiodomethane refrigerant.