Abstract: A warm liquid defrost refrigeration system (10) comprising a primary refrigeration loop (12) including a compressor (16), a condenser (18), an expansion device (22), and a first side of a chiller (24), and a secondary refrigeration loop (14) including a pump (26), a refrigerated space heat exchanger (28), and a second side of the chiller. The refrigeration system further includes a defrost heat exchanger (40) having a hot side and a cold side. The hot side of the defrost heat exchanger is connected to the primary refrigeration loop between the condenser and the expansion device such that liquid refrigerant can flow from the condenser through the hot side of the defrost heat exchanger. The cold side of the defrost heat exchanger is connected to the secondary refrigeration loop at a point downstream of the pump such that coolant can be selectively transported from the pump through the cold side of the defrost heat exchanger.

Abstract: A crossover warm liquid defrost refrigeration system (10) having a medium temperature side (12) for cooling refrigerated goods and a low temperature side (14) for cooling frozen goods. The medium temperature side has a primary refrigeration loop (16) and a secondary refrigeration loop (18). The low temperature side also has a primary refrigeration loop (46) and a secondary refrigeration loop (48). Further included in the refrigeration system is a low temperature defrost heat exchanger (28) that is connected to the primary refrigeration loop of the medium temperature side and the secondary refrigeration loop of the low temperature side such that coolant from the low temperature side secondary refrigeration loop can be heated by the refrigerant of the medium temperature side, and then transported to the low temperature side refrigerated space heat exchanger (64) to melt any frost formed thereon.