Vapor compression cooling cycle

Vapor-compression refrigerant cycle for transferring heat from a low-temperature refrigerant to a high-temperature refrigerant, with a compressor (1) for compressing refrigerant; a high pressure heat exchanger (2) for cooling the compressed in the compressor high-pressure refrigerant; and a low-pressure heat exchanger (4) for evaporating the low-pressure refrigerant after its decompression, wherein the refrigerant has a critical temperature of 60 ° C or lower, wherein a pressure of the refrigerant in the low-pressure heat exchanger (4) to a predetermined pressure or lower is controlled, wherein the pressure of the refrigerant in the low-pressure heat exchanger (4) to or lower than a critical pressure of the refrigerant is controlled, the pressure of the refrigerant in the low-pressure heat exchanger (4) is controlled equal to or lower than a pressure at which a product of the is latent heat of evaporation of the refrigerant and the density of the refrigerant gas at a maximum level, and the pressure of the refrigerant in the low-pressure heat exchanger (4) by controlling a flow rate passing through the low-pressure heat exchanger (4) flowing air is controlled, and wherein the flow rate of air is controlled equal to or lower than a predetermined flow rate, when the pressure of the refrigerant in the low-pressure heat exchanger (4) is higher than the predetermined pressure.