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

A working fluid for heat cycle, comprising:

• trifluoroethylene;
• difluoromethane;
• and
• at least one compound selected from the group consisting of 1,1-difluoroethane, fluoroethane, propane, propylene, and carbon dioxide, wherein
• the total content ratio of trifluoroethylene, difluoromethane, 1,1-difluoroethane, fluoroethane, propane, propylene, and carbon dioxide relative to the total amount of the working fluid for heat cycle is 90 to 100 mass %,
• content ratios by mass of the respective compounds satisfy all Expressions A, B, C, D and E or all Expressions A2, B, C, D and E below when the total content of trifluoroethylene, difluoromethane, 1,1-difluoroethane, fluoroethane, propane, propylene, carbon dioxide, 2,3,3,3-tetrafluoropropene, and (E)-1,3,3,3-tetrafluoropropene contained in the working fluid for heat cycle is set to 1,
• 0<−1.000×[HFO-1123]+1.179×[R32]+1.316×[1234yf]+1.316×[1234ze(E)]+3.831×[CO2]+2.632×[R152a]+2.390×[R161]+6.262×[propane]+2.237×[propylene], Expression A;
• 0<−1.000×[HFO-1123]+1.033×[R32]+0.896×[1234yf]+0.896×[1234ze(E)]+2.891×[CO2]+1.955×[R152a]+1.410×[R161]+3.737×[propane]+1.520×[propylene], Expression A2;
• 10>3.426×[HFO-1123]+5.673×[R32]+2.193×[1234yf]−0.596×[1234ze(E)]−0.768×[CO2]+29.897×[R152a]+64.400×[R161]+118.965×[propane]+94.943×[propylene], Expression B;
• 1.78>1.293×[HFO-1123]+1.029×[R32]+0.369×[1234yf]+0.354×[1234ze(E)]+3.807×[CO2]+0.229×[R152a]+0.406×[R161]+0.568×[propane]+0.719×[propylene], Expression C;
• 0.91<1.214×[HFO-1123]+1.133×[R32]+0.402×[1234yf]+0.346×[1234ze(E)]+3.359×[CO2]+0.323×[R152a]+0.548×[R161]+0.588×[propane]+0.725×[propylene], and Expression D;
• 160>0.3×[HFO-1123]+675×[R32]+4×[1234yf]+6×[1234ze(E)]+1×[CO2]+124×[R152a]+12×[R161]+3.3×[propane]+1.8×[propylene], Expression E;
• where in Expression A to Expression E, [HFO-1123] represents the content ratio by mass of trifluoroethylene, [R32] represents the content ratio by mass of difluoromethane, [R152a] represents the content ratio by mass of 1,1-difluoroethane, [R161] represents the content ratio by mass of fluoroethane, [propane] represents the content ratio by mass of propane, [propylene] represents the content ratio by mass of propylene, [CO2] represents the content ratio by mass of carbon dioxide, [1234yf] represents the content ratio by mass of 2,3,3,3-tetrafluoropropene, and [1234ze(E)] represents the content ratio by mass of (E)-1,3,3,3-tetrafluoropropene respectively when the total content of trifluoroethylene, difluoromethane, 1,1-difluoroethane, fluoroethane, propane, propylene, carbon dioxide, 2,3,3,3-tetrafluoropropene, and (E)-1,3,3,3-tetrafluoropropene is set to 1, and
• a temperature glide is 10° C. or less when operating a standard refrigeration cycle system under a temperature condition (T) that in the case of the working fluid for heat cycle being a zeotropic mixture, an average temperature of an evaporation start temperature and an evaporation completion temperature is 0° C., in the case of the working fluid for heat cycle being an azeotropic mixture, an evaporation temperature is 0° C., in the case of the working fluid for heat cycle being a zeotropic mixture, an average temperature of a condensation start temperature and a condensation completion temperature is 40° C., in the case of the working fluid for heat cycle being an azeotropic mixture, a condensation temperature is 40° C., a degree of supercooling (SC) is 5° C., and a degree of superheating (SH) is 5° C.