Patent ID: 8889031

Claim:
A working fluid composition for a refrigerator machine, comprising: a refrigerating machine oil comprising a base oil containing an ether-based compound selected from the group consisting of a polyalkylene glycol represented by the following formula (2), (3), (5), (6), (7) or (8), a polyvinyl ether, a polyphenyl ether and a perfluoroether, CH 3 O—(C 3 H 6 O) h —CH 3 (2) wherein h represents an integer of 6-80, CH 3 O—(C 2 H 4 O) i —(C 3 H 6 O) j —CH 3 (3) wherein i and j are each 1 or greater, and are numbers such that the total of i and j is 6-80, CH 3 O—(C 3 H 6 O) 1 —H (5) wherein 1 represents an integer of 6-80, CH 3 O—(C 2 H 4 O) m —(C 3 H 6 O) n —H (6) wherein m and n are each 1 or greater, and are numbers such that the total of m and n is 6-80, C 4 H 9 O—(C 2 H 4 O) m —(C 3 H 6 O) n —H (7) wherein m and n are each 1 or greater, and are numbers such that the total of m and n is 6-80, CH 3 COO —(C 3 H 6 O) 1 —COCH 3 (8) wherein, 1 represents an integer of 6-80, wherein the content of the ether-based compound is at least 70% by mass based on the total amount of the refrigerating machine oil, a carbodiimide compound, and an unsaturated fluorinated hydrocarbon refrigerant.