BACKUP OPERATION UNIT FOR REFRIGERATOR

PROBLEM TO BE SOLVED: To protect a matter to be reserved even when various units are abnormal. SOLUTION: A refrigerator including a coolant circuit comprising a compressor 1, a condenser 2, an electronic expansion valve 3, an evaporator 4 and a suction proportional valve 5 connected sequentially is further provided with a sensor 7 for detecting the suction air temperature of the evaporator 4, and a backup control means executing start/stop control of the compressor 1 upon occurrence of abnormality in the suction temperature sensor 7 based on an operating rate being set depending on the actual operating rate of the compressor 1 during cooling operation between the defrosting operation immediately before occurrence of abnormality and the following defrosting operation. Upon occurrence of abnormality in the suction temperature sensor 7 during operation of the refrigerator, start/stop control of the compressor 1 is executed based on an operating rate being set depending on the actual operating rate immediately before occurrence of abnormality which will be substantially equal to the operating rate at the time of occurring abnormality.