| 摘要 |
PROBLEM TO BE SOLVED: To perform the defrosting of an in-warehouse heat exchanger surely within a certain time throughout the year, in a freezer which cools the interior of a warehouse. SOLUTION: A primary freezing circuit 20 is provided with two refrigerant heat exchangers 11, and the primary freezing circuit and two secondary freezing circuits are connected through this refrigerant heat exchanger 11. This freezer is provided with out-warehouse fans F1 and F2, and they blow air to the out- warehouse heat exchanger 22 of the primary freezing circuit 20. The secondary refrigerant circuit is provided with an in-warehouse heat exchanger, and this in-warehouse heat exchanger cools the air within the warerhouse. Moreover, this is provided with a controller 70 having a fan controller 71. This fan controller 71 regulates the out-warehouse fans F1 and F2, based on the pressure and temperature of the discharged refrigerant of the compressor 21, at defrost operation. Then, the evaporation pressure in the out-warehouse heat exchanger 22 at defrosting is kept within a specified range, regardless of the change of ambient temperature, and the condensation pressure of the primary freezing circuit 20 is maintained in a specified range.
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