To complete the defrosting at a high defrosting power of a coolant for a short time, without using electric heaters.
The refrigerator having a high- and low-temp. side refrigeration cycles A, B. The high-temp. side refrigeration unit A is constituted to be capable f a reverse cycle operation. A defrosting bypass circuit 18 is provided for bypassing a gas coolant x from a prim. refrigerator compressor 5 to the downstream of a prim. coolant pressure reducing mechanism 7 via a sec. refrigerant evaporator 12 in the reverse cycle operation. In the defrosting operation, the hot gas refrigerator x from the compressor 5 is fed to the evaporator 12 via are bypass circuit 18 to melt the frost on the evaporator 12, then evaporated by a sec. refrigerator condenser 6 acting as an evaporator and returned to the compressor 5.
MESAKI TAKEMUNE
FUJIMOTO YUUJI
