Abstract: To provide a defrost system capable of preferable defrosting and prevention of generation of icicles on a casing without installing a brine circuit. A defrost system includes a thermosiphon defrost circuit that is provided by being branched from a circulation line, in which, at the time of defrosting, a CO2 refrigerant staying inside a fin-tube heat exchanger repeats a two-phase change of a gaseous form and reliquefaction, and which forms a CO2 circulation path together with the fin-tube heat exchanger; electromagnetic opening/closing valves that are closed at the time of defrosting and set the CO2 circulation path to a closed circuit; and a first electric heater arranged above the thermosiphon defrost circuit so as to be adjacent to the thermosiphon defrost circuit, and naturally circulates the CO2 refrigerant in the closed circuit at the time of defrosting.

Abstract: This ice making machine includes an ice making unit that includes an ice making surface and a cryogen flow channel through which a cryogen for cooling the ice making surface flows; a pump that pressurizes and discharges the cryogen cooled by a heat exchanger; and a control unit that controls a discharge amount of the pump. The cryogen is carbon dioxide, and the control unit controls the pump such that the cryogen is in a gas-liquid mixed state at an outlet of the cryogen flow channel.

Abstract: To provide a defrost system capable of preferable defrosting and prevention of generation of icicles on a casing without installing a brine circuit. A defrost system includes a thermosiphon defrost circuit that is provided by being branched from a circulation line, in which, at the time of defrosting, a CO2 refrigerant staying inside a fin-tube heat exchanger repeats a two-phase change of a gaseous form and reliquefaction, and which forms a CO2 circulation path together with the fin-tube heat exchanger; electromagnetic opening/closing valves and that are closed at the time of defrosting and set the CO2 circulation path to a closed circuit; and a first electric heater arranged above the thermosiphon defrost circuit so as to be adjacent to the thermosiphon defrost circuit, and naturally circulates the CO2 refrigerant in the closed circuit at the time of defrosting.

Abstract: A defrost system includes: a cooling device in a freezer, and includes a casing, a heat exchanger pipe with a difference in elevation in the casing, and a drain receiver unit below the heat exchanger pipe; a refrigerating device to cool and liquefy CO2 refrigerant; and a refrigerant circuit for permitting the cooled and liquefied CO2 refrigerant to circulate to the heat exchanger pipe. The defrost system includes a bypass pipe of the heat exchanger pipe to form a CO2 circulation path; an on-off valve in the heat exchanger pipe to be closed during defrosting so that the CO2 circulation path is a closed circuit; a pressure adjusting unit for adjusting pressure of the CO2 refrigerant during defrosting; and a brine circuit as a first heating medium, in which the defrost system permits the CO2 refrigerant to naturally circulate in the closed circuit during defrosting by a thermosiphon effect.

Abstract: A defrost system includes: a cooling device in a freezer, and includes a casing, a heat exchanger pipe with a difference in elevation in the casing, and a drain receiver unit below the heat exchanger pipe; a refrigerating device to cool and liquefy CO2 refrigerant; and a refrigerant circuit for permitting the cooled and liquefied CO2 refrigerant to circulate to the heat exchanger pipe. The defrost system includes a bypass pipe of the heat exchanger pipe to form a CO2 circulation path; an on-off valve in the heat exchanger pipe to be closed during defrosting so that the CO2 circulation path is a closed circuit; a pressure adjusting unit for adjusting pressure of the CO2 refrigerant during defrosting; and a brine circuit as a first heating medium, in which the defrost system permits the CO2 refrigerant to naturally circulate in the closed circuit during defrosting by a thermosiphon effect.