An air conditioner includes: a heat-source-side unit including a compressor and a heat-source-side heat exchanger; use-side units each including a use-side heat exchanger; an intermediate unit that causes the use-side heat exchanger of each of the use-side units to individually function as an evaporator or a radiator of a refrigerant; and three or more connection pipes that connect the heat-source-side unit to the intermediate unit. The intermediate unit includes: an ejector that pressurizes the refrigerant; and a gas-liquid separator into which the refrigerant flowing out from the ejector flows. The refrigerant that has released heat in any of the use-side units that perform a heating operation is not pressurized by the ejector.

A thermal management system includes an integrated open-circuit refrigeration system and closed-circuit heat pump system. The thermal management system includes a receiver having a first receiver port and a second receiver port, the receiver configured to store a refrigerant fluid, an evaporator having a first evaporator port and a second evaporator port, the heat pump circuit having a closed-circuit fluid path with the receiver and the evaporator and an open-circuit refrigeration system configured to receive refrigerant from the receiver, with the open-circuit refrigeration system having an open-circuit fluid path that includes the receiver and the evaporator.

An air conditioning device includes a plurality of ejectors which have a refrigerant circuit including a compressor, a condenser and an evaporator, are connected in parallel to the refrigerant circuit, and are formed so as to each have a different maximum refrigerant flow, and a control unit which, according to a driving condition of the air conditioning device, controls so that the refrigerant flows to one ejector among the plurality of ejectors, and the refrigerant does not flow to the rest of the ejectors.

In order to provide climate control system for heating or cooling a space, in particular a vehicle interior, having a compressor for conveying a refrigerant, which can efficiently use the refrigerant CO.sub.2 for heat pump applications as well, it is proposed to arrange a high-pressure chiller for cooling the refrigerant downstream of the compressor and a low-pressure chiller for heating the refrigerant upstream of the compressor, wherein a refrigerant exiting from the high-pressure chiller can be supplied to a motive mass inlet of a first ejector and a refrigerant exiting from the low-pressure chiller can be supplied to a suction mass inlet of the first ejector, and wherein an outlet of the first ejector is connected directly or indirectly to a liquid separator.

A cooling system implements various processes to improve efficiency in high ambient temperatures. First, the system can flood one or more low side heat exchangers in the system. Second, the system can direct a portion of vapor refrigerant from a low side heat exchanger to a flash tank rather than to a compressor. Third, the system can transfer heat from refrigerant at a compressor suction to refrigerant at the discharge of a high side heat exchanger.

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.

A mixing portion that mixes an injection refrigerant and a suction refrigerant is formed in a range of an internal space of a heating-side body portion of a heating-side ejector from a refrigerant injection port of a heating-side nozzle portion to an inlet of a heating-side diffuser. Further, the mixing portion is formed in a shape that gradually decreases a refrigerant passage area toward a downstream side of a refrigerant flow, and a refrigerant passage area of the inlet of the heating-side diffuser is set smaller than that of the refrigerant injection port. Thus, the flow velocity of the mixed refrigerant is decelerated to a value lower than a two phase sound velocity within the mixing portion, thereby suppressing occurrence of shock wave in the heating-side diffuser and stabilizing the pressure increasing performance in the heating-side diffuser.

A method for controlling a vapour compression system (1) is disclosed, the vapour compression system (1) comprising an ejector (5). The method comprises controlling a compressor unit (2) in order to adjust a pressure inside a receiver (6), on the basis of a detected pressure of refrigerant leaving an evaporator (8). The portion of refrigerant leaving the evaporator (8) which is supplied to a secondary inlet (15) of the ejector is maximised and the portion of refrigerant supplied directly to the compressor unit (2) is minimised, while ensuring that the pressure of refrigerant leaving the evaporator (8) does not decrease below an acceptable level.

A method for controlling a variable capacity ejector unit (7) arranged in a refrigeration system (1) is disclosed. An ejector control signal for the ejector unit (7) is generated, based on an obtained temperature and an obtained pressure of refrigerant leaving a heat rejecting heat exchanger (3), or on the basis of a high pressure valve control signal for controlling an opening degree of a high pressure valve (6) arranged fluidly in parallel with the ejector unit (7). The ejector control signal indicates whether the capacity of the ejector unit (7) should be increased, decreased or maintained. The capacity of the ejector unit (7) is controlled in accordance with the generated ejector control signal. The power consumption of the refrigeration system (1) is reduced, while the pressure of the refrigerant leaving the heat rejecting heat exchanger (3) is maintained at an acceptable level.

A system has a compressor, a heat rejection heat exchanger, first and second ejectors, first and second heat absorption heat exchangers, and a separator. The ejectors each have a primary inlet coupled to the heat rejection exchanger to receive refrigerant. A second heat absorption heat exchanger is coupled to the outlet of the second ejector to receive refrigerant. The separator has an inlet coupled to the outlet of the first ejector to receive refrigerant from the first ejector. The separator has a gas outlet coupled to the secondary inlet of the second ejector to deliver refrigerant to the second ejector. The separator has a liquid outlet coupled to the secondary inlet of the first ejector via the first heat absorption heat exchanger to deliver refrigerant to the first ejector.