Ejector cycle, gas-liquid separator used therein, as well as water heaters and thermal management system using the ejector cycle

[Abstract] while reducing the CFC-free measures, to improve the coefficient of performance of the refrigeration cycle. In A ejector cycle, using carbon dioxide as the refrigerant, it is depressurized and expanded from the supercritical region at the ejector 400. Thus, carbon dioxide in addition to the ratio of the specific enthalpy variation Delta] h with respect to the change amount [Delta] P in pressure (= Δh / ΔP) is large compared to CFC, the pressure difference during decompression and expansion becomes larger, the nozzle 410 specific enthalpy difference at the refrigerant outlet of the refrigerant inlet and the nozzle 410 (adiabatic heat drop) can be increased. Also, at a supercritical range, the gas refrigerant also has a substantially equal density and liquid phase, decompressed and expanded refrigerant in the ejector 400 (the nozzle 410) is the liquid-phase refrigerant is also the gas-phase refrigerant It is accelerated to substantially the same speed. Therefore, the energy conversion efficiency of the ejector 400 (the nozzle 410) is increased, thereby improving the coefficient of performance.