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 heat pump system for conditioning regeneration air from a space is provided. The heat pump system is operable in a winter mode and/or a summer mode, and may be selectively operated in a defrost mode or cycle. During a defrost mode, hot refrigerant may be used to directly and sequentially defrost the regeneration air heat exchanger. A compressor may be configured to be overdriven during a defrost cycle.

An approximately conical passage-forming member is disposed inside a body in which a swirling space for swirling a refrigerant is formed, and an ejector defines therein a nozzle passage that functions as a nozzle for depressurizing a refrigerant that has flowed out from the swirling space between an inner circumferential surface of the body and the passage-forming member, and a diffuser passage that pressurizes a mixed refrigerant obtained from a refrigerant sprayed from the nozzle passage and a refrigerant drawn from a suction-passage. A plurality of driving passages through which a refrigerant is introduced from a distribution space to the swirling space are formed in the body. In this case, the driving passages are formed in a manner such that a refrigerant flowing in from each driving passage into the swirling space flows along an outer circumference of the swirling space and flows in directions different from each other. Accordingly, nozzle efficiency is sufficiently improved.

An approximately conical passage-forming member is disposed inside a body in which a swirling space for swirling a refrigerant is formed, and an ejector defines therein a nozzle passage that functions as a nozzle for depressurizing a refrigerant that has flowed out from the swirling space between an inner circumferential surface of the body and the passage-forming member, and a diffuser passage that pressurizes a mixed refrigerant obtained from a refrigerant sprayed from the nozzle passage and a refrigerant drawn from a suction-passage. A plurality of driving passages through which a refrigerant is introduced from a distribution space to the swirling space are formed in the body. In this case, the driving passages are formed in a manner such that a refrigerant flowing in from each driving passage into the swirling space flows along an outer circumference of the swirling space and flows in directions different from each other. Accordingly, nozzle efficiency is sufficiently improved.

A chiller system is provided including a vapor compression circuit consisting of a fluidly coupled compressor, condenser, expansion valve, and evaporator. A refrigerant circulates through the vapor compression circuit. The evaporator is a direct exchange heat exchanger. Refrigerant provided at an outlet of the evaporator is a two-phase mixture including liquid refrigerant and vapor refrigerant. The vapor refrigerant comprises less than or equal to 85% of the two-phase mixture. A refrigerant to refrigerant heat exchanger is fluidly coupled to the circuit. The refrigerant to refrigerant heat exchanger is configured to convert the vapor refrigerant provided at the outlet of the evaporator into a superheated vapor.

A chiller system is provided including a vapor compression circuit consisting of a fluidly coupled compressor, condenser, expansion valve, and evaporator. A refrigerant circulates through the vapor compression circuit. The evaporator is a direct exchange heat exchanger. Refrigerant provided at an outlet of the evaporator is a two-phase mixture including liquid refrigerant and vapor refrigerant. The vapor refrigerant comprises less than or equal to 85% of the two-phase mixture. A refrigerant to refrigerant heat exchanger is fluidly coupled to the circuit. The refrigerant to refrigerant heat exchanger is configured to convert the vapor refrigerant provided at the outlet of the evaporator into a superheated vapor.

A multi-split system and a medium-pressure controlling method thereof are provided. The multi-split system includes an outdoor unit, a distribution device, and a plurality of indoor units. The distribution device includes a gas-liquid separator, a first heat exchange assembly, a first electronic expansion valve, a second heat exchange assembly and a second electronic expansion valve. The distribution device is configured to perform a routine correction on a medium-pressure control target value of the first electronic expansion valve according to the subcooling degree of the heating indoor unit, the outlet air temperature of the heating indoor unit and the opening of the throttling element in the heating indoor unit, and to correct a current medium-pressure control target value of the first electronic expansion valve according to a preset step when the opening of the throttling element reaches a maximum opening or a minimum opening and lasts for a first preset time.

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 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 heat exchanger includes a refrigerant flow path into which a gas refrigerant flows from two gas-side inlets in the second row, that are positioned off from each other. Refrigerant flow paths from the two gas-side inlets converge in the one end portion. The refrigerant flow path connects to a heat-transfer pipe in the first row from the second row. The refrigerant flow path includes a refrigerant flow path which is formed in a range from the same stage as one of the gas-side inlets of the second row to the same stage as the other of the gas-side inlets of the second row, while being arranged along both ways between the one end portion and the other end portion in the first row, and the refrigerant flow path extends to a liquid-side outlet.