PURPOSE: To heat and evaporate refrigerant when refrigeration load is reduced to prevent a return of liquid by providing a water.refrigerant heat exchanger between an evaporator and a compressor and providing in said heat exchanger a cooling line for causing cooling water to flow from the delivery side of a water-cooled condenser corresponding to the suction temperature of the refrigerant.

CONSTITUTION: In a refrigeration device, the high temperature, high pressure refrigerant leaving a compressor 1 is liquefied at a water-cooled condenser 2, throttled by a throttle valve 3, so as to be adiabatically expanded, and then absorbs heat at an evaporator 4 to cool the ambient air, where the refrigerant is evaporated and gassified, which is returned to the compressor 1. In such a device, a water.refrigerant heat exchanger 10 is provided on the suction side of the compressor l to introduce the cooling water from the outlet of the condenser 2 into the exchanger 10 through a cooling water line including a control valve 1!!J And when refrigeration load for the evaporator 4 has become reduced, suction temperature becomes lower than a set temperature of a regulator 12 and hence the valve 11 is opened. As a result, the refrigerant is heated and evaporated so as to increase the degree of suction overheating of the refrigerant, thereby preventing the return of liquid.