| abstract |
To provide a working medium for heat cycle, of which combustibility is suppressed, which has less influence over the ozone layer, which has less influence over global warming and which provides a heat cycle system excellent in the cycle performance (efficiency and capacity), and a heat cycle system, of which the safety is secured, and which is excellent in the cycle performance (efficiency and capacity). n A working medium for heat cycle comprising 1-chloro-2,3,3,3-tetrafluoropropene and a polyol ester oil is employed for a heat cycle system (such as a Rankine cycle system, a heat pump cycle system, a refrigerating cycle system 10 or a heat transport system). |