The present disclosure addresses the problem of providing a refrigerant composition that has a low GWP and a refrigerating capacity equivalent to that of R404A, which is currently widely used. As a solution to the problem, the present disclosure provides a composition containing carbon dioxide and a mixture of fluorinated hydrocarbons, the mixture containing difluoromethane (R32), pentafluoroethane (R125), 2,3,3,3-tetrafluoropropene (R1234yf), 1,1,1,2-tetrafluoroethane (R134a), and carbon dioxide (CO.sub.2) in specific concentrations.

A compressor including a housing, a shaft configured to be rotated relative to the housing to compress a refrigerant, a motor configured to drive the shaft, a lubrication system configured to supply lubricant to the compressor, and a bearing configured to support the shaft. The shaft includes a wear-resistant sleeve-like treatment on at least a portion of an outer surface of the shaft adjacent the bearing. The lubricant is a lubricant blend composition that includes two or more lubricants, the two or more lubricants including a first lubricant and a second lubricant. The first lubricant is present at a higher volume percentage than the second lubricant, and the first lubricant includes a higher viscosity than the second lubricant.

A compressor including a housing, a shaft configured to be rotated relative to the housing to compress a refrigerant, a motor configured to drive the shaft, a lubrication system configured to supply lubricant to the compressor, and a bearing configured to support the shaft. The shaft includes a wear-resistant sleeve-like treatment on at least a portion of an outer surface of the shaft adjacent the bearing. The lubricant is a lubricant blend composition that includes two or more lubricants, the two or more lubricants including a first lubricant and a second lubricant. The first lubricant is present at a higher volume percentage than the second lubricant, and the first lubricant includes a higher viscosity than the second lubricant.

To provide a composition for a heat cycle system, which comprises a working fluid for heat cycle which has a low global warming potential and high stability, and which can replace R410A, and a heat cycle system employing the composition. A composition for a heat cycle system, which comprises a working fluid for heat cycle containing trifluoroethylene, and a stabilizer for preventing deterioration of the working fluid for heat cycle, such as an oxidation resistance-improving agent, a heat resistance-improving agent or a metal deactivator, and a heat cycle system employing the composition for a heat cycle system.

To provide a composition for a heat cycle system, which comprises a working fluid for heat cycle which has a low global warming potential and high stability, and which can replace R410A, and a heat cycle system employing the composition. A composition for a heat cycle system, which comprises a working fluid for heat cycle containing trifluoroethylene, and a stabilizer for preventing deterioration of the working fluid for heat cycle, such as an oxidation resistance-improving agent, a heat resistance-improving agent or a metal deactivator, and a heat cycle system employing the composition for a heat cycle system.

A lubricant composition comprises a lubricant and a stabilizer. The stabilizer comprises a first epoxide group and a second functional group selected from the group consisting of (i) a second epoxide group; (ii) an aliphatic carbon-carbon multiple bond conjugated with a second carbon-carbon multiple bond; (iii) an aliphatic carbon-carbon multiple bond conjugated with an electron withdrawing group; and (iv) an aliphatic carbon-carbon multiple bond conjugated with an aromatic group. A heat transfer composition comprises a lubricant composition as described above and a haloalkane, such as an iodoalkane (e.g., trifluoroiodomethane).

A lubricant composition comprises a lubricant and a stabilizer. The stabilizer comprises a first epoxide group and a second functional group selected from the group consisting of (i) a second epoxide group; (ii) an aliphatic carbon-carbon multiple bond conjugated with a second carbon-carbon multiple bond; (iii) an aliphatic carbon-carbon multiple bond conjugated with an electron withdrawing group; and (iv) an aliphatic carbon-carbon multiple bond conjugated with an aromatic group. A heat transfer composition comprises a lubricant composition as described above and a haloalkane, such as an iodoalkane (e.g., trifluoroiodomethane).

To provide a composition for a heat cycle system, which comprises a working fluid for heat cycle which has a low global warming potential and high stability, and which can replace R410A, and a heat cycle system employing the composition.

A composition for a heat cycle system, which comprises a working fluid for heat cycle containing trifluoroethylene, and a stabilizer for preventing deterioration of the working fluid for heat cycle, such as an oxidation resistance-improving agent, a heat resistance-improving agent or a metal deactivator, and a heat cycle system employing the composition for a heat cycle system.

To provide a composition for a heat cycle system, which comprises a working fluid for heat cycle which has a low global warming potential and high stability, and which can replace R410A, and a heat cycle system employing the composition.

A composition for a heat cycle system, which comprises a working fluid for heat cycle containing trifluoroethylene, and a stabilizer for preventing deterioration of the working fluid for heat cycle, such as an oxidation resistance-improving agent, a heat resistance-improving agent or a metal deactivator, and a heat cycle system employing the composition for a heat cycle system.

The present disclosure provides a composition comprising a refrigerant that has characteristics of having a coefficient of performance (COP) and a refrigerating capacity equivalent to or higher than those of R404A, and having a sufficiently low GWP. More specifically, the present disclosure provides a composition comprising a refrigerant, the refrigerant comprising trans-1,2-difluoroethylene (HFO-1132(E)), difluoromethane (HFC-32), and 2,3,3,3-tetrafluoropropene (HFO-1234yf), wherein the total concentration of the three components is 99.5% by mass or more, based on the entire refrigerant, and three components have a mass ratio that falls within a region surrounded by a figure passing through the following 4 points in a ternary composition diagram whose three vertices represent the three components: point A (HFO-1132(E)/HFC-32/HFO-1234yf=51.8/1.0/47.2 mass %), point B (HFO-1132(E)/HFC-32/HFO-1234yf=35.3/1.0/63.7 mass %), point C (HFO-1132(E)/HFC-32/HFO-1234yf=10.1/18.0/71.9 mass %), and point D (HFO-1132(E)/HFC-32/HFO-1234yf=27.8/18.0/54.2 mass %).