A cooling system is provided and includes a compressor, an expansion valve, a gas cooler through which a refrigerant received from the compressor passes toward the expansion valve in a supercritical state, an evaporator interposed between the expansion valve and the compressor and a vapor sorption subcooling system. The vapor sorption subcooling system includes a desorber disposed to remove heat from refrigerant flowing from the gas cooler toward the expansion valve.