Refrigerating machine oil, and working fluid composition for refrigerating machine which is produced using same
Provided is a refrigerating machine oil which comprises an ester between a polyol consisting of at least one of pentaerythritol and dipentaerythritol represented by formula (I) and 2-propylheptanoic acid, and is characterized in that the refrigerating machine oil can be used in combination with a refrigerant consisting of 1,3,3,3-tetrafluoropropene (HFO-1234ze). When the refrigerating machine oil is used in combination with a refrigerant consisting of HFO-1234ze, excellent miscibility with the refrigerant, lubricity, thermal and chemical stability and the like can be achieved.
1. A working fluid composition for a refrigerating machine, the working fluid composition comprising:
an ester between a polyol consisting of at least one of pentaerythritol and dipentaerythritol represented by formula (I):
and 2-propylheptanoic acid; and
a refrigerant consisting of HFO-1234ze;
wherein the working fluid composition is free from esters of a polyol and a fatty acid having 5 to 9 carbon atoms.
2. A method for refrigeration, the method comprising:
performing a refrigerant-circulation cycle in a refrigerating machine with a working fluid according to claim 1 .
3. The working fluid of claim 1 , wherein the working fluid composition is free from esters whose constituent carboxylic acid is other than 2-propylheptanoic acid.