VAPOR COMPRESSION REFRIGERATION CYCLE

A vapor compression refrigeration cycle that prevents decrease in a discharge temperature at an outlet of a compressor and improves operating efficiency in a field of warming and water heating is obtained. A vapor compression refrigeration cycle of the present invention is a vapor compression refrigeration cycle using HFO as refrigerant including: a compressor provided with an injection port for injecting circulating refrigerant; a pressure sensor and a temperature sensor, provided adjacent to the injection port, that measure pressure and a temperature; an expansion device that compresses and expands the refrigerant; and a controller that controls an opening degree of the expansion device based on the pressure and the temperature obtained by the pressure sensor and the temperature sensor, in which the controller controls the expansion device for causing a portion, of a P-H diagram related to the vapor compression refrigeration cycle, corresponding to a compression process to be positioned outside a saturation curve composed of a saturated liquid line and a saturated vapor line, to be positioned below critical pressure, and to be positioned on a high enthalpy region side of the saturated vapor line.