| abstract |
To provide a composition for a heat cycle system having less influence over the ozone layer, having a low global warming potential and having excellent durability, and a heat cycle system. n A composition for a heat cycle system comprising a working fluid containing trifluoroethylene and difluoromethane, and a lubricating oil, wherein the interaction distance (Ra 1123 ) between trifluoroethylene and the lubricating oil as determined from the Hansen solubility parameters is shorter than the interaction distance (Ra 32 ) between difluoromethane and the lubricating oil. |