The present invention provides a composition, such as a refrigerant composition comprising 1, 1-difluoroethene (vinylidene fluoride, R-1132a); trifluoromethane (R-23); and one or more compound selected from hexafluoroethane (R-116), ethane (R-170) and carbon dioxide (R-744, CO.sub.2).

No studies have been made regarding what kinds of refrigerants should be used in a refrigeration cycle device for a vehicle. An air conditioner (1) for a vehicle includes a refrigerant circuit (10) and a refrigerant that is sealed in the refrigerant circuit (10). The refrigerant circuit (10) includes a compressor (80), a first heat exchanger (85), which serves as a heat dissipater in a dehumidifying heating mode, an outside-air heat exchanger (82), a cooling control valve (87), and a second heat exchanger (86), which serves as an evaporator in the dehumidifying heating mode. The refrigerant is a refrigerant having a low GWP.

The present invention provides a composition, such as a refrigerant composition comprising 1,1-difluoroethene (vinylidene fluoride, R-1132a); trifluoromethane (R-23); and one or more compound selected from hexafluoroethane (R-116), ethane (R-170) and carbon dioxide (R-744, CO.sub.2).

A refrigerant composition comprising carbon dioxide (CO.sub.2; R-744) and from 1 to 32 weight % difluoromethane (R-32) based on the total weight of the composition is described. Also described is the use of the refrigerant composition for providing heating and cooling and a refrigeration, air-conditioning or heat pump system comprising the refrigerant composition.

A refrigeration cycle apparatus (1) is capable of performing a refrigeration cycle using a small-GWP refrigerant. The refrigeration cycle apparatus (1) includes a refrigerant circuit (10) and a refrigerant enclosed in the refrigerant circuit (10). The refrigerant circuit includes a compressor (21), a condenser (23), a decompressing section (24), and an evaporator (31). The refrigerant contains at least 1,2-difluoroethylene.

A refrigeration cycle apparatus (1) is capable of performing a refrigeration cycle using a small-GWP refrigerant. The refrigeration cycle apparatus (1) includes a refrigerant circuit (10) and a refrigerant enclosed in the refrigerant circuit (10). The refrigerant circuit includes a compressor (21), a condenser (23), a decompressing section (24), and an evaporator (31). The refrigerant contains at least 1,2-difluoroethylene.

To provide a composition for a hat cycle system which comprises a working fluid containing 1,1,2-trifluoroethylene, having cycle performance sufficient as an alternative to R410A while suppressing influence over global warming, and a heat cycle system employing the composition. A composition for a heat cycle system, which comprises a working fluid for heat cycle containing 1,1,2-trifluoroethylene, CF.sub.3I and at least one compound selected from a hydrofluorocarbon, a hydrofluoroolefin other than 1,1,2-trifluoroethylene and a hydrocarbon, and having a temperature glide of at most 7° C., and a heat cycle system employing the composition for a heat cycle system.

The invention provides a composition comprising 1,1-difluoroethene (R-1132a); a second component selected from the group consisting of hexafluoroethane (R-116), ethane (R-170) and mixtures thereof; and, optionally carbon dioxide (CO.sub.2, R-744).

The propagation of a disproportionation reaction of a refrigerant is suppressed. Disclosed is a method that uses a composition in a device, in which the composition includes one or more compounds selected from the group of ethylene-based fluoroolefins, 2,3,3,3-tetrafluoropropene, and 1,3,3,3-tetrafluoropropene, and the heat capacity of a portion with a melting point greater than or equal to 1,000° C. in the device is greater than or equal to 6.5 J/K.

To provide a composition for a hat cycle system which comprises a working fluid containing 1,1,2-trifluoroethylene, having cycle performance sufficient as an alternative to R410A while suppressing influence over global warming, and a heat cycle system employing the composition.

A composition for a heat cycle system, which comprises a working fluid for heat cycle containing 1,1,2-trifluoroethylene, CF.sub.3I and at least one compound selected from a hydrofluorocarbon, a hydrofluoroolefin other than 1,1,2-trifluoroethylene and a hydrocarbon, and having a temperature glide of at most 7° C., and a heat cycle system employing the composition for a heat cycle system.