Refrigeration system with auxiliary defrost heat tank

Claim 1

A refrigeration system adapted to cycle alternately through a refrigeration cycle and a defrost cycle, comprising a compressor having discharge and suction ports, a condenser connected to the discharge port to receive refrigerant gas from the compressor during the refrigerant cycle and condense the same, an evaporator having an inlet connected to the condenser to receive condensed liquid refrigerant therefrom during the refrigeration cycle and having an outlet, hot gas conduit means for conveying gaseous refrigerant from the compressor to the evaporator during the defrost cycle, a suction accumulator tank connected by an outlet suction line to the suction port of the compressor and by an inlet suction line to the evaporator outlet for receiving any liquid refrigerant discharged from the evaporator outlet toward the compressor and having means for conveying warm liquid refrigerant coursing from the condenser to the evaporator therethrough in heat exchange relation with liquid refrigerant in the accumulator tank received from the evaporator outlet to vaporize the latter, an auxiliary defrost heat tank connected to said suction accumulator tank substantially filled with a heat storage liquid and having a conduit coil immersed therein connected by a feed line to said accumulator tank at a location slightly above a reference liquid level therein normally reached by the liquid refrigerant during the refrigeration cycle to convey liquid refrigerant during the defrost cycle to the heat tank only when the liquid refrigerant level in the accumulator tank exceeds said reference level, means for heating said heat storage liquid in said heat tank to a sufficient temperature for promptly vaporizing any liquid refrigerant conveyed into said conduit coil thereIn, and a heat tank outlet conduit for return of the vaporized refrigerant from the conduit coil in the heat tank to the suction port of said compressor.