Refrigerant leak detection methods and Refrigeration equipment

A refrigerant leakage detection method that can be implemented at low cost and can be introduced into an operating refrigeration cycle with less effort. In a refrigeration cycle having a compressor 17, a condenser 18, an expansion valve 15 and an evaporator 14, a room temperature C0 of a cooling device 9 cooled by evaporation of refrigerant in the evaporator 14 and an outlet of the evaporator 14 are provided. Based on the degree of superheat SH of the refrigerant and the valve opening OP of the expansion valve 15, the presence or absence of refrigerant leakage is determined. If refrigerant leakage is detected based on the indoor temperature C0, the degree of superheat SH, and the valve opening OP, there is no need to provide a dedicated sensor for detecting refrigerant leakage, and the cost can be reduced accordingly. Furthermore, it can be introduced into existing freezing and refrigeration equipment with less effort without requiring installation work of the sensor. [Selection] Figure 1