DEFROST SYSTEM FOR REFRIGERATION APPARATUS, AND COOLING UNIT

摘要

A sublimation defrost system for a refrigeration apparatus including: a cooling device which is disposed in a freezer, and includes a casing and a heat exchanger pipe disposed in the casing; a refrigerating device for cooling and liquefying a CO 2 refrigerant; and a refrigerant circuit which is connected to the heat exchanger pipe and which is configured to permit the CO 2 refrigerant cooled and liquefied in the refrigerating device to circulate to the heat exchanger pipe, the defrost system including: a dehumidifier device for dehumidifying freezer inner air in the freezer; a CO 2 circulation path which is formed of a circulation path forming path connected to an inlet path and an outlet path of the heat exchanger pipe, and includes the heat exchanger pipe; an on-off valve disposed in each of the inlet path and the outlet path of the heat exchanger pipe and configured to be closed at a time of defrosting so that the CO 2 circulation path becomes a closed circuit; a circulating unit for CO 2 refrigerant, the circulating unit being disposed in the CO 2 circulation path; a first heat exchanger part configured to cause heat exchange between a brine as a first heating medium and the CO 2 refrigerant circulating in the CO 2 circulation path; and a pressure adjusting unit which adjusts a pressure of the CO 2 refrigerant circulating in the closed circuit at the time of defrosting so that a condensing temperature of the CO 2 refrigerant becomes equal to or lower than a freezing point of a water vapor in the freezer inner air in the freezer. The defrosting is able to be achieved without a drain receiving unit.