A system includes a high side heat exchanger, a flash tank, an air conditioner load, an air conditioner ejector, a refrigeration load, a first compressor, a second compressor, and a vapor ejector. The high side heat exchanger removes heat from a refrigerant. The flash tank stores the refrigerant from the high side heat exchanger. The air conditioner load uses the refrigerant from the flash tank to remove heat from a first space proximate the air conditioner load. The air conditioner ejector pumps the refrigerant from the air conditioner load to the flash tank. The refrigeration load uses the refrigerant from the flash tank to remove heat from a second space proximate the refrigeration load. The first compressor compresses the refrigerant from the refrigeration load. The second compressor compresses a flash gas from the flash tank. The vapor ejector pumps the refrigerant from the refrigeration load to the flash tank.

A vapour compression system (1) comprising at least two evaporator groups (5a, 5b, 5c), each evaporator group (5a, 5b, 5c) comprising an ejector unit (7a, 7b, 7c), at least one evaporator (9a, 9b, 9c) and a flow control device (8a, 8b, 8c) controlling a flow of refrigerant to the at least one evaporator (9a, 9b, 9c). For each evaporator group (5a, 5b, 5c) the outlet of the evaporator (9a, 9b, 9c) is connected to a secondary inlet (12a, 12b, 12c) of the corresponding ejector unit (7a, 7b, 7c). The vapour compression system (1) can be controlled in an energy efficient and stable manner. A method for controlling the vapour compression system (1) is also disclosed.

An ejector-type refrigeration cycle includes a radiator radiating heat of refrigerant discharged from a compressor, an ejector depressurizing the refrigerant cooled in the radiator, a gas-liquid separator separating gas and liquid of the refrigerant flowing out of a diffuser portion of the ejector, an evaporator disposed in a refrigerant passage connecting the gas-liquid separator and a refrigerant suction port of the ejector, and an opening-closing valve switching between a first refrigerant flow path, in which an ejection refrigerant ejected from a nozzle portion of the ejector flows out of the diffuser portion, and a second refrigerant flow path, in which the ejection refrigerant flows out of the refrigerant suction port. When a rotation rate of the compressor is lower than or equal to a standard rotation rate, the first refrigerant flow path is switched to the second refrigerant flow path.

A swirl space forming member that forms a swirl space in which a refrigerant flowing into a nozzle portion of an ejector swirls around an axis of the nozzle portion. In this way, even when the refrigerant flowing out of a first evaporator is a gas-phase refrigerant, pressure of the refrigerant on a swirling center axis side in the swirl space is reduced to be able to start condensation by swirling the refrigerant, and a gas-liquid two-phase refrigerant in which a condensation nucleus is generated can flow into the nozzle portion. Thus, occurrence of a condensation delay in the refrigerant in the nozzle portion can be restricted.

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.

In certain embodiments, a transcritical refrigeration system provides refrigeration by circulating carbon dioxide (CO.sub.2) refrigerant through the system. A flash tank of the transcritical refrigeration system is operable to supply the CO.sub.2 refrigerant, in liquid form, to a low temperature refrigeration case and a medium temperature refrigeration case. A low temperature compressor is operable to compress the CO.sub.2 refrigerant discharged from the low temperature refrigeration case. A medium temperature compressor, a parallel compressor, and an ejector are each operable to compress the CO.sub.2 refrigerant discharged from the medium temperature refrigeration case, the CO.sub.2 refrigerant discharged from the low temperature compressor, and/or CO.sub.2 flash gas discharged from the flash tank. A gas cooler is operable to cool the CO.sub.2 refrigerant discharged from the medium temperature compressor and the parallel compressor. A controller is operable to dynamically adjust a pressure set point for the flash tank.

A vapor compression system (200; 300; 400) comprising: a compressor (22); a first heat exchanger (30); a second heat exchanger (64); an ejector (38); separator (48); and an expansion device (70). A plurality of conduits are positioned to define a first flowpath sequentially through: the compressor; the first heat exchanger; the ejector from a motive flow inlet through (40) an outlet (44); and the separator, and then branching into: a first branch returning to the compressor; and a second branch passing through the expansion device and second heat exchanger to a secondary flow inlet (42). The plurality of conduits are positioned to define a bypass flowpath (202; 302; 402) bypassing the motive flow inlet and rejoining the first flowpath at essentially separator pressure but away from the separator.

A valve (9) for use in a vapour compression system (1) is disclosed. The valve (9) comprises a first inlet (13) arranged to be connected to a gaseous outlet (11) of a receiver (6), a second inlet (14) arranged to be connected to an outlet of an evaporator (8), a first outlet (15) arranged to be connected to an inlet of a compressor unit (2), a non-return valve arrangement (19) arranged to allow a fluid flow from the second inlet (14) towards the first outlet (15), but to prevent a fluid flow from the first outlet (15) towards the second inlet (14), and a control valve mechanism (20) arranged to control a fluid flow from the first inlet (13) towards the first outlet (15).

An ejector refrigeration circuit (1) comprises a high pressure ejector circuit (3) comprising in the direction of flow of a circulating refrigerant: a heat rejecting heat exchanger/gas cooler (4) having an inlet side (4a) and an outlet side (4b); at least two variable ejectors (6, 7) with different capacities connected in parallel, each of the variable ejectors (6, 7) comprising a primary high pressure input port (6a, 7a), a secondary low pressure input port (6b, 7b) and an output port (6c, 7c); wherein the primary high pressure input ports (6a, 7a) of the at least two variable ejectors (6, 7) are fluidly connected to the outlet side (4b) of the heat rejecting heat exchanger/gas cooler (4); a receiver (8), having an inlet (8a), a liquid outlet (8c), and a gas outlet (8b), wherein the inlet (8a) is fluidly connected to the output ports (6c, 7c) of the at least two variable ejectors (6, 7); at least one compressor (2a, 2b, 2c) having an inlet side (21a, 21 b, 21c) and an outlet side (22a, 22b, 22c), the inlet side (21a, 21 b, 21c) of the at least one compressor (2a, 2b, 2c) being fluidly connected to the gas outlet (8b) of the receiver (8), and the outlet side (22a, 22b, 22c) of the at least one compressor (2a, 2b, 2c) being fluidly connected to the inlet side (4a) of the heat rejecting heat exchanger/gas cooler (4). The ejector refrigeration circuit (1) further comprises a refrigerating evaporator flowpath (5) comprising in the direction of flow of the circulating refrigerant: at least one refrigeration expansion device (10) having an inlet side (10a), fluidly connected to the liquid outlet (8c) of the receiver (8), and an outlet side (7b); at least one refrigeration evaporator (12) fluidly connected between the outlet side (10b) of the at least one refrigeration expansion device (10) and the secondary low pressure input ports (6b, 7b) of the at least two variable ejectors (6, 7).

An oil separation device (14) for separating oil from a refrigerant-oil-mixture in a refrigeration cycle (1), the oil separation device (14) comprises a first refrigerant conduit having at least a first portion (16) with a first diameter (d1); a second refrigerant conduit arranged downstream of and connected to the first refrigerant conduit, the second refrigerant conduit having at least a second portion with a second diameter (d2) being smaller than the first diameter (d1); wherein the second portion (18) of the second refrigerant conduit having the second diameter (d2) extends into the first portion (16) of the first refrigerant conduit forming an oil separation pocket (32) between the outer diameter of the second portion (18) and the inner diameter of the first portion (16); and a suction line (20) having an inlet end (19), which opens into the oil separation pocket (32) and is configured to suck oil from the oil separation pocket (32).