An air-conditioning system includes: an air conditioner including a refrigerant circuit formed by connecting an outdoor unit and a plurality of indoor units together, the air conditioner being configured to condition air in a plurality of indoor spaces; at least one countermeasure device provided in correspondence with at least one of the plurality of indoor spaces and configured to operate during leakage of a refrigerant; a plurality of detectors configured to detect a concentration of the refrigerant, at least one of the detectors being provided in each of the plurality of indoor spaces; and a control unit configured to operate all of the at least one countermeasure device if at least one of the concentrations of the refrigerant respectively detected by the plurality of detectors exceeds a predetermined value.

An air-conditioning system includes: an air conditioner including a refrigerant circuit formed by connecting an outdoor unit and a plurality of indoor units together, the air conditioner being configured to condition air in a plurality of indoor spaces; at least one countermeasure device provided in correspondence with at least one of the plurality of indoor spaces and configured to operate during leakage of a refrigerant; a plurality of detectors configured to detect a concentration of the refrigerant, at least one of the detectors being provided in each of the plurality of indoor spaces; and a control unit configured to operate all of the at least one countermeasure device if at least one of the concentrations of the refrigerant respectively detected by the plurality of detectors exceeds a predetermined value.

A refrigeration cycle apparatus includes an outdoor unit including a compressor, a first heat exchanger, and a first expansion valve, an indoor unit including a second expansion valve and a second heat exchanger, and a first pipe and a second pipe connected between the outdoor unit and the indoor unit. In a cooling operation, refrigerant delivered from the compressor sequentially passes through the first heat exchanger, the first expansion valve, the first pipe, the second expansion valve, the second heat exchanger, and the second pipe and returns to the compressor, and in the cooling operation, the first expansion valve converts refrigerant from a liquid-phase state to a two-phase state and sends two-phase refrigerant to the first pipe.

An air-conditioning system includes: an air conditioner including an outdoor unit and a plurality of indoor units each provided in a corresponding one of a plurality of indoor spaces and each including a first control unit; and a second control unit capable of communicating with the first control units. Each first control unit is capable of communicating with a countermeasure device if the countermeasure device is installed in correspondence with one of the indoor spaces where the first control unit is located. The second control unit has a first function of prohibiting operation of the air conditioner if a first condition where communication between the first control unit and the countermeasure device is not established in any of the indoor units is satisfied.

An air conditioner may include: an outdoor unit including a compressor and an outdoor heat exchanger; a first indoor unit including a first indoor heat exchanger; and a second indoor unit including a second indoor heat exchanger and an indoor expansion valve, wherein the outdoor unit includes: a first outdoor pipe, an outdoor expansion valve provided in the first outdoor pipe, the first outdoor pipe allowing a refrigerant discharged from the outdoor heat exchanger to pass through the outdoor expansion valve and flow to the first indoor unit; and a second outdoor pipe allowing a refrigerant discharged from the outdoor heat exchanger to bypass the outdoor expansion valve and flow to the second indoor unit.

A method for controlling an air conditioning system, an outdoor apparatus of an air conditioning system and an air conditioning system are provided. The method includes: obtaining a working mode of the air conditioning system and starting a variable-frequency compressor in an outdoor apparatus of the air conditioning system according to the working mode; obtaining a target refrigerant saturation temperature; performing a variable-frequency control on the variable-frequency compressor according to the target refrigerant saturation temperature; during the variable-frequency control, obtaining a working time of the variable-frequency compressor and a stop-start number of time of the variable-frequency compressor in a first predetermined period; and adjusting the target refrigerant saturation temperature according to the working time of the variable-frequency compressor and the stop-start number of time of the variable-frequency compressor in the first predetermined time.

A refrigeration apparatus uses R32 as a refrigerant, and includes a compressor, a condenser, an expansion mechanism, an evaporator and an accumulator. The accumulator is disposed in the suction flow path supplying refrigerant to the compressor. The accumulator has a casing that forms an inside space to separate the refrigerant into gas refrigerant and liquid refrigerant and accumulating surplus refrigerant, an inlet pipe feeding the refrigerant that has evaporated in the evaporator into the inside space, and an outlet pipe channeling the separated gas refrigerant to the compressor. A distal end opening in the inlet pipe of the accumulator is located in a height position separated by a dimension from a bottom of the inside space. The dimension is 0 to 0.3 times a height dimension of the inside space.

An air conditioner including a hot gas line for receiving a portion of refrigerant compressed in a compressor, an indoor heat exchanger, an outdoor expansion device for expanding the refrigerant having exchanged heat in the indoor heat exchanger, an outdoor heat exchanger functioning as a condenser in a cooling mode while functioning as an evaporator in a heating mode, and a 4-way valve for receiving a remaining portion of the compressed refrigerant, to guide the refrigerant emerging from the compressor to the outdoor heat exchanger in the cooling mode and to the indoor heat exchanger in the heating mode. The outdoor heat exchanger includes a main heat exchanger section functioning as a condenser in the cooling mode while functioning as an evaporator in the heating mode, and an auxiliary heat exchanger for receiving the refrigerant from the hot gas line in a frosting prevention mode.

An air conditioner and a method for controlling an air conditioner are provided. The air conditioner may include at least one indoor device, an electric heat pump (EHP) outdoor device connected to the at least one indoor device and having an EHP compressor driven using an applied current, and a gas heat pump (GHP) outdoor device connected to the at least one indoor device having an engine driven using a combustion of gas and a GHP compressor driven by receiving a driving force from the engine. The EHP compressor may include an inverter that controls a frequency of the current applied to the EHP compressor. The GHP compressor may include a first compressor that receives a driving force from the engine to compress a refrigerant; and a second compressor that is connected to the first compressor in parallel and receives the driving force from the engine to compress the refrigerant.

A multi-connected heat recovery air conditioning system and a control method thereof. The multi-connected heat recovery air conditioning system includes an indoor unit, an outdoor unit and a hydraulic module, wherein the outdoor unit comprises a compressor, an outdoor heat exchanger, a first four-way valve and a second four-way valve. The multi-connected heat recovery air conditioning system further comprises an indoor unit temperature unit, a water temperature unit, a high-pressure sensor and a low-pressure sensor. The indoor unit temperature unit is arranged in the indoor unit for detecting and obtaining the outlet temperature value of the indoor unit, the water temperature unit is arranged at a heat exchange water tank for detecting and obtaining water temperature, and the high-pressure sensor and the low-pressure sensor are arranged at the output end and the air return end of the compressor respectively.