| abstract |
The present invention is directed to a working fluid composition for a refrigerating machine which contains difluoromethane and a refrigeration oil. An ester formed between (a) an aliphatic polyhydric alcohol having a carbon number of 2 to 12; and (b) a saturated aliphatic monocarboxylic acid having a carbon number of 4 to 9 or a derivative thereof, the ratio of the number of acyl groups having a branched chain or branched chains to the number of the entire acyl groups in the ester being not less than 95%, is used as a base oil of the refrigeration oil. The working fluid composition for refrigerating machine of the present invention is excellent not only in compatibility, lubricity, and electric insulating property but also in thermal stability as compared to the conventional products. |