Working fluid for heat cycle, composition for heat cycle system, and heat cycle system

17:

• The working fluid according to claim 16, comprising the hydrofluoroolefin other than trifluoroethylene and 2,3,3,3-tetrafluoropropene, which is a hydrofluorocarbon containing a carbon-carbon double bond.

18:

• The working fluid according to claim 17, wherein the hydrofluorocarbon containing a carbon-carbon double bond is at least one selected from the group consisting of 1,2-difluoroethylene, 2-fluoropropene, 1,1,2-trifluoropropene, trans-1,2,3,3,3-pentafluoropropene, cis-1,2,3,3,3-pentafluoropropene, trans-1,3,3,3-tetrafluoropropene, cis-1,3,3,3-tetrafluoropropene, and 3,3,3-trifluoropropene.

19:

• The working fluid according to claim 16, further comprising a saturated hydrofluorocarbon.

20:

• The working fluid according to claim 19, wherein the saturated hydrofluorocarbon is at least one selected from the group consisting of difluoromethane, 1,1-difluoroethane, 1,1,1-trifluoroethane, 1,1,2,2-tetrafluoroethane, 1,1,1,2-tetrafluoroethane, and pentafluoroethane.

21:

• A composition for a heat cycle system, comprising:
• the working fluid according to claim 16 and
• a lubricating oil.

22:

• A heat cycle system, comprising
• the composition according to claim 21.

23:

• The heat cycle system according to claim 22, which is a refrigerating apparatus, an air-conditioning apparatus, a power generation system, a heat transport apparatus or a secondary cooling machine.

24:

• The heat cycle system according to claim 22, which is a room air-conditioner, a store package air-conditioner, a building package air-conditioner, a plant package air-conditioner, a gas engine heat pump, a train air-conditioning system, an automobile air-conditioning system, a built-in showcase, a separate showcase, an industrial fridge freezer, an ice making machine or a vending machine.

25:

• The working fluid according to claim 16, wherein the working fluid has a temperature gradient of at most 8.4° C.

26:

• The working fluid according to claim 16, wherein the working fluid has a temperature gradient of at most 7.2° C.

27:

• The working fluid according to claim 16, wherein the working fluid has a temperature gradient of at most 3.9° C.

28:

• The working fluid according to claim 16, wherein a total proportion of trifluoroethylene and 2,3,3,3-tetrafluoropropene based on an entire amount of the working fluid is from 80 to 100 mass %.

29:

• The working fluid according to claim 16, wherein a total proportion of trifluoroethylene and 2,3,3,3-tetrafluoropropene based on an entire amount of the working fluid is from 90 to 100 mass %.

30:

• The working fluid according to claim 16, consisting essentially of trifluoroethylene and 2,3,3,3-tetrafluoropropene.

31:

• The working fluid according to claim 16, consisting essentially of hydrofluoroolefins.

32:

• The working fluid according to claim 16, having a temperature gradient of at most 5.6° C. and a refrigerating capacity of at least 0.875.

33:

• The working fluid according to claim 16, wherein the working fluid has an initiation temperature of evaporation and a completion temperature of evaporation that differ from each other.

34:

• The working fluid according to claim 16, wherein the working fluid has a temperature gradient of at most 9.5° C. and a refrigerating capacity relative to R410A of 0.66 or greater.