Refrigeration system comprising a refrigerant release-to-atmosphere device

An expansion device 4 has an expansion valve 8 that supplies throttled and expanded refrigerant to an evaporator 5, an electromagnetic valve 7 connected in series to the expansion valve 8, a check valve 9 that prevents backflow of refrigerant from the evaporator 5. A release-to-atmosphere device 6 is provided in low-pressure piping connected to the compressor 1, for allowing the refrigerant therein to be selectively released into the atmosphere. When refrigerant tends to leak out, or when there is a possibility of refrigerant leakage, the electromagnetic valve 7 is closed to isolate the evaporator 5 from high-pressure piping of the refrigeration cycle, and at the same time the release-to-atmosphere device 6 is opened to thereby dispose of the refrigerant in the low-pressure piping to the outside the vehicle compartment.