DEFROST SYSTEM FOR REFRIGERATION DEVICE AND COOLING UNIT

摘要

A defrost system for a refrigeration device, comprising: a cooler provided inside a freezer and having a heat exchange pipe and a drain receiving section that are provided inside a casing; a refrigerator that cools and liquefies a CO2 refrigerant; a refrigerant circuit for circulating through the heat exchange pipe the CO2 refrigerant cooled and liquefied by the refrigerator; a defrost circuit that branches from the inlet and outlet paths for the heat exchange pipe and which forms a CO2 circulation path with the heat exchange pipe; a switch valve that closes during defrost and makes the CO2 circulation path a closed circuit; a pressure adjustment unit for adjusting the pressure of the CO2 refrigerant that circulates through the closed circuit during defrost; and a first heat exchange unit provided lower than the cooler, having provided therein the defrost circuit and a first brine circuit that has circulating therein brine being a first heat medium, said first heat exchange unit being for heating the CO2 refrigerant that circulates the defrost circuit, by using the brine. The CO2 refrigerant is naturally circulated in the closed circuit during defrost, by a thermosiphon action.