Hydrofluoroolefin (HFO) and hydrocarbon (HC) refrigerants have been considered for use in air-conditioning systems and refrigerators as low global warming potential (GWP) refrigerants. These refrigerants are used to determine the lubrication performance of the sliding parts in compressor. To prevent wear and seizing at a contact of the sliding parts is important to ensure the reliability of equipments which are applied these refrigerants. To clarify lubrication performance of unsaturated and saturated refrigerants for these low GWP refrigerants, seizure and wear tests were conducted in the compound of liquid refrigerant and refrigeration oil. In comparison with unsaturated refrigerants such as HFO-1234yf and HFO-1234ze, the lubrication performance of saturated refrigerants such as HFC-134a and HFC-125 was studied. Unsaturated refrigerant such as R1270 (propylene) and saturated refrigerant such as R290 (propane) were similarly studied as HC refrigerants. Immiscible oils to refrigerants were used for lubrication. We confirmed that anti-wear and anti-seizure characteristics of unsaturated refrigerants are better than those of saturated refrigerants.

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