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

摘要

An object of the present invention is to provide, as a working fluid to be used for a heat cycle system, a working fluid for heat cycle that has cycle performance replaceable with that of R410A, and at the same time, has a small burden on an apparatus, low flammability, suppressed self-decomposition, and less effect on global warming, and therefore, is usable stably even if leaked, a composition for heat cycle system containing the same, and a heat cycle system using the composition. The working fluid for heat cycle contains trifluoroethylene, difluoromethane, and at least one selected from 1,1-difluoroethane, fluoroethane, propane, propylene, carbon dioxide, 2,3,3,3-tetrafluoropropene, and (E)-1,3,3,3-tetrafluoropropene at mass ratios satisfying predetermined expressions and at a ratio of the total content to be 90 to 100 mass % relative to the total amount of the working fluid and has a temperature glide of 10° C. or less.