SHOWCASE COOLING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a showcase cooling device improved in refrigeration efficiency, by stably operating refrigerant circuits at a high stage side and a low stage side in a case of applying a binary refrigeration cycle.SOLUTION: An evaporator 11 of a high stage-side refrigerant circuit 12 and a radiator 14 of a low stage-side refrigerant circuit 18 are heat-exchangeably cascade-connected, and the inside is cooled by the evaporator of the low stage-side refrigerant circuit. A main control device determines a target evaporation temperature of a refrigerant of the high stage-side refrigerant circuit by PID calculation based on deviation between internal temperatures of showcases 3A-3E and a set temperature of the internal temperature, and a target operational frequency of a compressor 7 of the high stage-side refrigerant circuit is determined by PID calculation based on deviation between an evaporation temperature detected by a high stage-side evaporation temperature sensor 24 and the target evaporation temperature.