A method for operating a heat pump (20; 300) includes operating in a cooling mode wherein heat is absorbed by refrigerant in the indoor heat exchanger (26) and rejected by refrigerant in the outdoor heat exchanger (24). The heat pump switches to operation in a heating mode wherein heat is rejected by refrigerant in the indoor heat exchanger, heat is absorbed by refrigerant in the outdoor heat exchanger, and there is an ejector (60) motive flow and ejector secondary flow. In the heating mode a refrigerant pressure (PH) or temperature (TL) is measured and, responsive to the measured refrigerant pressure or temperature, at least one of a fan speed is changed and a needle (132) of the ejector is actuated.

Refrigeration systems are described. The systems include a compression device, a heat rejecting heat exchanger, an ejector, and first and second expansion devices with respective heat absorbing heat exchangers. The ejector is arranged to receive refrigerant fluid from the heat rejecting heat exchanger at a high pressure inlet of the ejector. Fluid pathways extend from an outlet of the ejector into a branched flow path to provide flows of refrigerant from the ejector to the first and second expansion devices. The first heat absorbing heat exchanger provides cooling at a first temperature and refrigerant fluid from the outlet of the first heat absorbing heat exchanger is directed to a low pressure inlet of the ejector. The second heat absorbing heat exchanger provides cooling at a second temperature and refrigerant fluid from the outlet of the second heat absorbing heat exchanger is directed to the inlet of the compression device.

A method for controlling ejector capacity in a vapour compression system (1) is disclosed. A parameter value being representative for a flow rate of liquid refrigerant from the evaporator(s) (8, 10) and into a return pipe (12, 13) is obtained, and the capacity of the ejector(s) (6) is adjusted based on the obtained parameter value. Ejector capacity may be shifted between low pressure ejectors (liquid ejectors) (6a, 6b, 6c, 6d) and high pressure ejectors (gas ejectors) (6e, 6f).

A method for operating a heat pump (20; 300) includes operating in a cooling mode wherein heat is absorbed by refrigerant in the indoor heat exchanger (26) and rejected by refrigerant in the outdoor heat exchanger (24). The heat pump switches to operation in a heating mode wherein heat is rejected by refrigerant in the indoor heat exchanger, heat is absorbed by refrigerant in the outdoor heat exchanger, and there is an ejector (60) motive flow and ejector secondary flow. In the heating mode a refrigerant pressure (P.sub.H) or temperature (T.sub.L) is measured and, responsive to the measured refrigerant pressure or temperature, at least one of a fan speed is changed and a needle (132) of the ejector is actuated.

An ejector (200; 300; 400) has a primary inlet (40), a secondary inlet (42), and an outlet (44). A primary flowpath extends from the primary inlet to the outlet. A secondary flowpath extends from the secondary inlet to the outlet. A mixer convergent section (114) is downstream of the secondary inlet. A motive nozzle (100) surrounds the primary flowpath upstream of a junction with the secondary flowpath to pass a motive flow. The motive nozzle has an exit (110). The ejector has surfaces (258, 260) positioned to introduce swirl to the motive flow.

An ejector for a refrigerating machine having a main body crossed by a conduit for passage of refrigerant fluid and having a compartment which includes a seating, which is in communication with the conduit, and a mouth for inlet of refrigerant fluid; a nozzle which can be coupled with the seating and has an internal hole for passage of the refrigerant fluid, and a shutter having an end which can be coupled with the hole to close the hole.

A system (20; 300) comprises: a compressor (22) having a suction port (40) and a discharge port (42); an ejector (32) having a motive flow inlet (50), a suction flow inlet (52), and an outlet (54); a separator (34) having an inlet (72), a vapor outlet (74), and a liquid outlet (76); a first heat exchanger (24); an expansion device (28); and a second heat exchanger (26; 302). Conduits and valves are positioned to provide alternative operation in: a cooling mode; a first heating mode; and a second heating mode. In the cooling mode and second heating mode, a needle (60) of the ejector is closed.

A method for controlling a vapour compression system in an energy efficient and stable manner, the vapour compression system (1) including at least two evaporator groups (5a, 5b, 5c), each evaporator group (5a, 5b, 5c) including 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).

An apparatus includes an ejector, a first load, a second load, a third load, a first compressor, a second compressor, and an accumulator. The ejector directs a refrigerant to a flash tank that stores the refrigerant. The loads use the refrigerant from the flash tank to cool spaces. The first compressor compresses the refrigerant from the first load. During a defrost cycle, the first compressor directs the refrigerant to the third load to defrost the third load, the accumulator separates the refrigerant that defrosted the third load into a second liquid portion and a second vapor portion, the ejector directs the second liquid portion to the flash tank, and the second compressor compresses the second vapor portion.

An ejector and a refrigeration system. The ejector includes: a high-pressure fluid passage, a flow valve for controlling a flow rate in the high-pressure fluid passage; a suction fluid passage; a mixing chamber, which includes a mixed fluid outlet; a thermal bulb disposed upstream of the flow valve, in the high-pressure fluid passage or outside the high-pressure fluid passage; and an elastic diaphragm disposed in the high-pressure fluid passage, wherein a closed cavity is on a first side of the diaphragm, and the high-pressure fluid passage is on a second side of the diaphragm; the thermal bulb in communication with the closed cavity, and the thermal bulb and the closed cavity are filled with fluid; and the diaphragm is associated with the flow valve so that an opening degree of the flow valve varies in response to a change in a pressure difference across two sides of the diaphragm.