The invention relates to a refrigerant circuit (10) of a vehicle air-conditioning system (12), in particular for electric vehicles, comprising a compressor unit (14) which includes a first compressor (16) and a second compressor (18) arranged downstream for compressing a refrigerant (20), a condenser (22) for heating air (24) which can be supplied to a vehicle interior, a first pressure reducing unit (26) arranged downstream of the condenser (22) for decompressing the refrigerant (20) from the condenser (22), a heat exchanger (28) through which refrigerant flows for heat exchange with vehicle ambient air (30), an evaporator (32) for cooling air (24) which can be supplied to a vehicle interior, and a second pressure reducing unit (34) arranged upstream of the evaporator (32) for decompressing the refrigerant (20) from the heat exchanger (28), the second compressor (18), the condenser (22) and the first pressure reducing unit (26) being bypassed in a cooling mode of the vehicle air-conditioning system (12), and the evaporator (32) and the second pressure reducing unit (34) being bypassed in a heating mode of the vehicle air-conditioning system (12). The invention furthermore relates to a method of air-conditioning a vehicle interior, in particular by means of the refrigerant circuit (10) described above.

A method of controlling injection into a compressor in a refrigeration cycle is described. A refrigeration cycle may comprise at least an economizer heat exchanger, a heat rejection heat exchanger, a first expansion device, and a compressor. A discharge port of the compressor is connected to the heat rejection heat exchanger via a discharge line and an injection port of the compressor is connected to the means for compressing. The economizer heat exchanger comprises a first path having an input connected to the heat rejection heat exchanger and an output connected to the first expansion device, and a second path having an input connected to the heat rejection heat exchanger via an economizer valve and an output connected to the injection port of the compressor via an injection line. The economizer valve is regulated based on a superheat level of the refrigerant in the economizer heat exchanger.

A system includes a flash tank and a thermal storage tank. The flash tank is configured to store refrigerant and discharge a flash gas. The thermal storage tank is fluidically coupled to the flash tank and configured, when a power outage is determined to be occurring, to receive at least a portion of the flash gas from the flash tank, and remove heat from the flash gas. When a power outage is determined not to be occurring, the thermal storage tank directs refrigerant to a compressor.

A control unit is configured to set a rotation speed of a compressor to be lower than that in a defrosting operation and set an opening degree of a pressure reducing device to be equal to or greater than that in the defrosting operation during a first control time after completion of the defrosting operation, stop the compressor and set the opening degree of the pressure reducing device to be less than that in the first control time during a second control time after lapse of the first control time, and control a refrigerant circuit switching device to resume a heating operation after lapse of the second control time.

A dehumidification system includes a compressor, a primary evaporator, a primary condenser, a secondary evaporator, a secondary condenser, a modulating valve, and an alternate condenser. The secondary evaporator receives an inlet airflow and outputs a first airflow to the primary evaporator. The primary evaporator receives the first airflow and outputs a second airflow to the secondary condenser. The secondary condenser receives the second airflow and outputs a third airflow to the primary condenser. The primary condenser receives the third airflow and outputs a dehumidified airflow. The compressor receives a flow of refrigerant from the primary evaporator and provides the flow of refrigerant to the modulating valve. The modulating valve directs the flow of refrigerant to the primary condenser and to the alternate condenser. The alternate condenser receives a portion of the flow of refrigerant for heat rejection, where the primary condenser receives the remaining portion of the flow of refrigerant.

A method for controlling a vapour compression system (1), the vapour compression system (1) comprising a compressor unit (2) comprising one or more compressors (10, 11, 13), is disclosed. At least one of the compressors (11, 13) of the compressor unit (2) is connectable to a gaseous outlet (9) of a receiver (5), and at least one of the compressors (10, 13) of the compressor unit (2) is connectable to an outlet of an evaporator (7). A parameter of the vapour compression system (1) is measured, an enthalpy of refrigerant leaving the heat rejecting heat exchanger (3) being derivable from the measured parameter. A setpoint value for a pressure inside the receiver (5) is calculated, based on the measured parameter, and the compressor unit (2) is operated in accordance with the calculated setpoint value, and in order to obtain a pressure inside the receiver (5) which is equal to the calculated setpoint value. The vapour compression system (1) is operated in an energy efficient manner over a wide range of ambient temperatures.

A method for monitoring a refrigerant charge in a vapour compression system (1) is disclosed, the vapour compression system (1) including a compressor unit (2), a heat rejecting heat exchanger (3), a high pressure expansion device (4), a receiver (5), at least one expansion device (9, 10), and at least one evaporator (11, 12) arranged in a refrigerant path. A change in net mass flow into or out of the receiver (5) and/or a change in net enthalpy flow into or out of the receiver (5) is detected, and a pressure inside the receiver (5) is monitored as a function of time, following the detected change in net mass flow and/or in net enthalpy flow. A time constant being representative for dynamics of the receiver (5) is derived, based on the monitored pressure as a function of time, and information regarding a refrigerant charge in the vapour compression system (1) is derived, based on the derived time constant.

There are provided a heat exchange apparatus and an air conditioner in which an occurrence of uneven refrigerant distribution of a heat exchanger is reduced such that heat exchange performance improves. The heat exchange apparatus includes: a heat-transfer pipe through which a refrigerant flows; a heat exchanger in which a plurality of the heat-transfer pipes are connected to one another; a distributor that distributes the refrigerant to the plurality of heat-transfer pipes; an inflow pipe that causes the refrigerant to flow into the distributor; and a confluent pipe which is connected to an intermediate position of the inflow pipe and in which the refrigerant flowing through an inside thereof is to merge with the refrigerant flowing through an inside of the inflow pipe. A merging part between the inflow pipe and the confluent pipe is positioned in the vicinity of the distributor.

To improve the heat exchange efficiency of a heat exchanger that includes an upstream heat exchange unit and a downstream heat exchange unit. When the heat exchanger functions as an evaporator, a gas outlet pipe is an upstream refrigerant outlet that is located adjacent to the other end of upstream flat pipes of the upstream heat exchange unit, and a gas outlet pipe is a downstream refrigerant outlet that is located adjacent to the other end of downstream flat pipes of the downstream heat exchange unit. First resistance to refrigerant flow in the upstream heat exchange unit and second resistance to refrigerant flow in the downstream heat exchange unit are adjusted in order that the degree of superheating of refrigerant at the downstream refrigerant outlet is smaller than the degree of superheating of refrigerant at the upstream refrigerant outlet.

To improve the heat exchange efficiency of a heat exchanger that includes an upstream heat exchange unit and a downstream heat exchange unit. When the heat exchanger functions as an evaporator, a gas outlet pipe is an upstream refrigerant outlet that is located adjacent to the other end of upstream flat pipes of the upstream heat exchange unit, and a gas outlet pipe is a downstream refrigerant outlet that is located adjacent to the other end of downstream flat pipes of the downstream heat exchange unit. First resistance to refrigerant flow in the upstream heat exchange unit and second resistance to refrigerant flow in the downstream heat exchange unit are adjusted in order that the degree of superheating of refrigerant at the downstream refrigerant outlet is smaller than the degree of superheating of refrigerant at the upstream refrigerant outlet.