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

Abstract

To provide a working fluid for heat cycle having a low global warming potential and having high durability, which can replace R410A, a composition for a heat cycle system comprising it, and a heat cycle system employing the composition.A working fluid for heat cycle, which contains trifluoroethylene, 2,3,3,3-tetrafluoropropene and difluoromethane, wherein the proportion of the total amount of trifluoroethylene, 2,3,3,3-tetrafluoropropene and difluoromethane based on the entire amount of the working fluid is higher than 90 mass % and at most 100 mass %, and based on the total amount of trifluoroethylene, 2,3,3,3-tetrafluoropropene and difluoromethane, the proportion of trifluoroethylene is at least 10 mass % and less than 70 mass %, the proportion of 2,3,3,3-tetrafluoropropene is at most 50 mass %, and the proportion of difluoromethane is higher than 30 mass % and at most 75 mass %.

1 - 8 . (canceled) 
     
     
         9 . A working fluid for a heat cycle, comprising:
 trifluoroethylene; and   difluoromethane;   wherein:   the working fluid exhibits a pressure change of 0.00 and a temperature change of 0.5° C. or less in an evaluation of self-decomposition; and   the evaluation of self-decomposition is conducted by:
 enclosing a sample of the working fluid and a platinum wire in a spherical pressure resistant reactor having an internal capacity of 650 cm 3  at a temperature is 250° C. and a pressure of 0.98 MPaG; 
 fusing the platinum wire to apply an energy of about 30 J to the working fluid; and 
 measuring the temperature change and pressure change in the pressure resistant reactor after applying energy to the working fluid. 
   
     
     
         10 . The working fluid according to  claim 9 , wherein:
 trifluoroethylene is present in an amount of 80 mass % or less based on a total mass of trifluoroethylene and difluoromethane; and   difluoromethane is present in an amount of 20 mass % of more based on the total mass of trifluoroethylene and difluoromethane.   
     
     
         11 . The working fluid according to  claim 9 , wherein:
 trifluoroethylene is present in an amount of 70 mass % or less based on a total mass of trifluoroethylene and difluoromethane; and   difluoromethane is present in an amount of 30 mass % of more based on the total mass of trifluoroethylene and difluoromethane.   
     
     
         12 . The working fluid according to  claim 9 , wherein a Global Warming Potential (GWP) of the working fluid is 300 or less. 
     
     
         13 . A composition for a heat cycle system, comprising the working fluid according to  claim 9  and a lubricating oil. 
     
     
         14 . A heat cycle system, comprising the composition according to  claim 13 . 
     
     
         15 . The heat cycle system according to  claim 14 , wherein the heat cycle system is at least one selected from the group consisting of a refrigerating apparatus, an air-conditioning apparatus, a power generation system, a heat transport apparatus, and a secondary cooling machine. 
     
     
         16 . The heat cycle system according to  claim 14 , wherein the heat cycle system is at least one selected from the group consisting of 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, and a vending machine.