The compositions and heat cycle system heat cycle system

HFC-134a and HFC-245fa is a possible alternative, the thermodynamic cycle system for a composition comprising a working medium for high small stable global warming potential thermal cycling, and provide the thermodynamic cycle system using the composition. A working medium for heat cycle including a 1-chloro-2,3,3,3-tetrafluoropropene, oxidation resistance enhancing agents, heat resistance improving agent, a deterioration of the thermal cycle for the working medium, such as a metal deactivator thermodynamic cycle system employing a composition for the thermodynamic cycle system, and the heat cycle system for a composition comprising inhibiting and stabilizing agent.