The heat exchanger is equipped with a heat transfer member (10, 20) including a flow port (11, 12, 21, 22) for receiving or discharging a fluid (6, 7), a plurality of heat exchange passages (13, 23), and a connection passage part (14, 24) having both ends, one of the ends being connected to the flow port and the other thereof being connected to the plurality of heat exchange passages (13, 23). The connection passage part has a tournament shape branched into two by two as it advances toward the heat exchange passages.

A method for defrosting a heat exchanger of a refrigeration circuit is provided. The method includes monitoring a compressor suction parameter at a suction line to a compressor of the refrigeration circuit. The method also includes determining a compressor suction parameter threshold. Also, the method includes initiating a defrost mode of the refrigeration circuit when the compressor suction parameter is less than or equal to the compressor suction parameter threshold.

The absorbing device includes a hollow enclosed chamber including two pot parts. Open ends of the pot parts are connectable to each other by welding or soldering. Each of the pot parts is integrally formed in an opposing end of an air-conditioning conduit, wherein open ends of the pot parts are oriented toward each other. Each of the pot parts is provided with a reduced passage opening interconnected with an internal space of the air-conditioning conduit via a tapered section.

A vapor compression system (200; 400; 600; 700; 800; 900; 1000) comprises a plurality of valves (260, 262, 264; 260) controllable to define a first mode flowpath and a second mode flowpath. The first mode flowpath is sequentially through: a compressor (22); a first heat exchanger (30); a first nozzle (228; 624); and a separator (48), and then branching into: a first branch returning to the compressor; and a second branch passing through an expansion device (70) and a second heat exchanger (64) to the rejoin the flowpath between the first heat exchanger and the separator. The second mode flowpath is sequentially through: the compressor; the second heat exchanger; a second nozzle (248; 625); and the separator, and then branching into: a first branch returning to the compressor; and a second branch passing through the expansion device and first heat exchanger to the rejoin the flowpath between the first heat exchanger and the separator.

An ejector for a sealed system includes a motive liquid passage with a converging section, a throat and a diverging section. The throat of the motive liquid passage is disposed between the converging section of the motive liquid passage and the diverging section of the motive liquid passage. The ejector also includes a plurality of nucleation sites at the converging section of the motive liquid passage.

An economized refrigeration system includes a main refrigerant circuit having a condenser, an evaporator, an economizer, an expansion device intermediate the condenser and the economizer, and a main compressor fluidly connected by a main refrigerant line. The system also includes an economized refrigerant circuit including an auxiliary compressor system and an auxiliary refrigerant line fluidly connecting the economizer to the auxiliary compressor system and fluidly connecting the main refrigerant line to the auxiliary compressor at a location intermediate the main compressor system and the condenser. The auxiliary compressor system is independently controllable with respect to the main compressor system.

An economized refrigeration system includes a main refrigerant circuit having a condenser, an evaporator, an economizer, an expansion device intermediate the condenser and the economizer, and a main compressor fluidly connected by a main refrigerant line. The system also includes an economized refrigerant circuit including an auxiliary compressor system and an auxiliary refrigerant line fluidly connecting the economizer to the auxiliary compressor system and fluidly connecting the main refrigerant line to the auxiliary compressor at a location intermediate the main compressor system and the condenser. The auxiliary compressor system is independently controllable with respect to the main compressor system.

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 CO.sub.2 refrigerant; and a refrigerant circuit for permitting the cooled and liquefied CO.sub.2 refrigerant to circulate to the heat exchanger pipe. The defrost system includes a bypass pipe of the heat exchanger pipe to form a CO.sub.2 circulation path; an on-off valve in the heat exchanger pipe to be closed during defrosting so that the CO.sub.2 circulation path is a closed circuit; a pressure adjusting unit for adjusting pressure of the CO.sub.2 refrigerant during defrosting; and a brine circuit as a first heating medium, in which the defrost system permits the CO.sub.2 refrigerant to naturally circulate in the closed circuit during defrosting by a thermosiphon effect.

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 CO.sub.2 refrigerant; and a refrigerant circuit for permitting the cooled and liquefied CO.sub.2 refrigerant to circulate to the heat exchanger pipe. The defrost system includes a bypass pipe of the heat exchanger pipe to form a CO.sub.2 circulation path; an on-off valve in the heat exchanger pipe to be closed during defrosting so that the CO.sub.2 circulation path is a closed circuit; a pressure adjusting unit for adjusting pressure of the CO.sub.2 refrigerant during defrosting; and a brine circuit as a first heating medium, in which the defrost system permits the CO.sub.2 refrigerant to naturally circulate in the closed circuit during defrosting by a thermosiphon effect.

A packaged, pumped liquid, recirculating refrigeration system with charges of 10 lbs or less of refrigerant per ton of refrigeration capacity. The compressor and related components are situated in a pre-packaged modular machine room, and in which the condenser is mounted on the machine room and the evaporator is close coupled to the pre-packaged modular machine room. Prior art large receiver vessels may be replaced with a single or dual phase cyclonic separator also housed in the pre-packaged modular machine room.