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: A plate stack includes a plurality of plates, each including corrugated portions formed on front and back surfaces thereof. First and second heat exchange flow passages are formed between plates, arranged alternately along stacking direction of the plates. Each plate has two through holes penetrating the front and back surfaces, through which the first heat exchange fluid is introduced and derived. The plate stack includes first partition weirs formed on at least one of two plate surfaces, the two plate surfaces forming a corresponding one of the first heat exchange flow passages therebetween. First partition weirs are symmetrically and obliquely arranged with respect to a center line connecting centers of two through holes as viewed from the stacking direction. A flow passage is formed along the center line on a side of at least one of the two through holes, from which first heat exchange fluid is introduced.

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 plate stack includes a plurality of plates, each including corrugated portions formed on front and back surfaces thereof. First and second heat exchange flow passages are formed between plates, arranged alternately along stacking direction of the plates. Each plate has two through holes penetrating the front and back surfaces, through which the first heat exchange fluid is introduced and derived. The plate stack includes first partition weirs formed on at least one of two plate surfaces, the two plate surfaces forming a corresponding one of the first heat exchange flow passages therebetween. First partition weirs are symmetrically and obliquely arranged with respect to a center line connecting centers of two through holes as viewed from the stacking direction. A flow passage is formed along the center line on a side of at least one of the two through holes, from which first heat exchange fluid is introduced.

Abstract: A CO2 cooling and heating apparatus and method permit simultaneous production of high-temperature heat source and low-temperature heat source having a temperature difference therebetween. The apparatus/method uses CO2 (carbon dioxide) as a refrigerant, and has a first refrigerating cycle circuit where the refrigerant is compressed to a supercritical zone and then decompressed via an expansion device to a pressure/temperature level of the CO2 triple point or below to thereby attain evaporation. The apparatus can include multistage compressors, intermediate cooler disposed in a first refrigerant flow path between a condenser and the expansion device.

Abstract: A CO2 cooling and heating apparatus and method permit simultaneous production of high-temperature heat source and low-temperature heat source having a temperature difference therebetween. The apparatus/method uses CO2 (carbon dioxide) as a refrigerant, and has a first refrigerating cycle circuit where the refrigerant is compressed to a supercritical zone and then decompressed via an expansion device to a pressure/temperature level of the CO2 triple point or below to thereby attain evaporation. The apparatus can include multistage compressors, intermediate cooler disposed in a first refrigerant flow path between a condenser and the expansion device.