An air conditioner may include a controller; a compressor; an outdoor heat exchanger; a plurality of indoor heat exchangers; a switching valve that selectively guides a refrigerant discharged from the compressor to the outdoor heat exchanger or the plurality of indoor heat exchangers; high pressure pipes that connect the switching valve and the plurality of indoor heat exchangers; high pressure valves installed in the high pressure pipes; low pressure pipes that connect an inlet of the compressor and the high pressure pipes. low pressure valves installed in the low pressure pipes; indoor pipes, which are opposite to the high pressure pipes with respect to the plurality of indoor heat exchangers and connected to the plurality of indoor heat exchangers; indoor expansion valves installed in the indoor pipes; a liquid pipe that connects the outdoor heat exchanger and the indoor pipes; and an outdoor expansion valve installed in the liquid pipe.

A controller, at least during the heating operation, controls the opening degree of a second expansion device and/or a third expansion device based on a discharge refrigerant temperature detected by a discharge refrigerant temperature detector, or a value computed using the discharge refrigerant temperature, and causes refrigerant having a quality equal to or greater than 0.9 and less than or equal to 0.99 to be suctioned into a compressor.

An air conditioner may include a controller; a compressor; an outdoor heat exchanger; a plurality of indoor heat exchangers; a switching valve that selectively guides a refrigerant discharged from the compressor to the outdoor heat exchanger or the plurality of indoor heat exchangers; high pressure pipes that connect the switching valve and the plurality of indoor heat exchangers; high pressure valves installed in the high pressure pipes; low pressure pipes that connect an inlet of the compressor and the high pressure pipes. low pressure valves installed in the low pressure pipes; indoor pipes, which are opposite to the high pressure pipes with respect to the plurality of indoor heat exchangers and connected to the plurality of indoor heat exchangers; indoor expansion valves installed in the indoor pipes; a liquid pipe that connects the outdoor heat exchanger and the indoor pipes; and an outdoor expansion valve installed in the liquid pipe.

An air-conditioning apparatus includes at least one system including a heat-medium conveying device, a heat-medium flow regulator, and a heat-medium flow control device, as a heat medium system capable of regulating a flow rate of a heat medium supplied to a heat source device-side heat exchanger exchanging heat between refrigerant and the heat medium. The air-conditioning apparatus switches each of a plurality of use-side heat exchangers to a cooling operation or a heating operation in accordance with a control command to perform a cooling and heating simultaneous operation. The refrigerant is caused to flow through the heat source device-side heat exchanger depending on a ratio of a total cooling capacity and a total heating capacity of the plurality of use-side heat exchangers. The heat-medium flow control device controls the flow rate of the heat medium supplied to the heat source device-side heat exchanger based on a difference between the total cooling capacity and the total heating capacity of the plurality of use-side heat exchangers and a total operation capacity of the heat source device-side heat exchanger.

A controller performs medium pressure control that controls the opening degree of a second expansion device based on a deviation between a target value of medium pressure, and a detection result of a medium pressure detector or a predicted value. The controller controls the opening degree of a third expansion device based on a target value of a discharge refrigerant temperature of a compressor or a target value related to the discharge refrigerant temperature, and a detection result of a discharge refrigerant temperature detector or a value related to the discharge refrigerant temperature computed using a detected detection result, and regulates a flow rate of refrigerant to supply to a suction side of the compressor via an injection pipe.

Systems and methods are presented for improving stabilization of a heating, ventilating, and air conditioning (HVAC) system. More specifically, the systems and methods include a heat-flow modulator for regulating an exchange of thermal energy between a flow of refrigerant and a sensory bulb. The exchange of thermal energy allows an expansion valve to respond to a refrigerant temperature using an actuator, which is coupled to the sensory bulb. The heat-flow modulator is formed of a body that includes a first contact surface and a second contact surface. The first contact surface is thermally-coupled to a suction line of the HVAC system, which conveys the flow of refrigerant. The second contact surface is thermally-coupled to the sensory bulb. In one instance the heat-flow modulator has variable volume depending on how installed. Other systems and methods are presented. Variable heat-flow modulators are also presented.

The refrigerant discharged from a compressor is distributed based on the priorities set by the user in advance and the remaining refrigerant is further distributed based on the priorities. Thus, setting the priorities for indoor units according, for example, to the usage of work spaces and the like in an office building, the user can operate a heat pump system efficiently in accordance with the intended use. Furthermore, the remaining capacity of the outdoor unit is distribute to the remaining indoor units according to their priorities so that the indoor units are operated efficiently within the range of the cooling capacity of the outdoor unit.

An air-conditioning apparatus includes at least one system including a heat-medium conveying device, a heat-medium flow regulator, and a heat-medium flow control device, as a heat medium system capable of regulating a flow rate of a heat medium supplied to a heat source device-side heat exchanger exchanging heat between refrigerant and the heat medium. The air-conditioning apparatus switches each of a plurality of use-side heat exchangers to a cooling operation or a heating operation in accordance with a control command to perform a cooling and heating simultaneous operation. The refrigerant is caused to flow through the heat source device-side heat exchanger depending on a ratio of a total cooling capacity and a total heating capacity of the plurality of use-side heat exchangers. The heat-medium flow control device controls the flow rate of the heat medium supplied to the heat source device-side heat exchanger based on a difference between the total cooling capacity and the total heating capacity of the plurality of use-side heat exchangers and a total operation capacity of the heat source device-side heat exchanger.

When a fully-closable expansion valve is used, there is a possibility that the expansion valve is fully closed thereby to block a refrigerant circuit. In an air conditioner 1 of the present invention, an indoor heat exchanger 14 includes an auxiliary heat exchanger 20 and a main heat exchanger 21 disposed leeward from the auxiliary heat exchanger 20. In an operation in a predetermined dehumidification operation mode, a liquid refrigerant supplied to the auxiliary heat exchanger 20 all evaporates midway in the auxiliary heat exchanger 20, i.e., before reaching the outlet. Therefore, only an upstream partial area in the auxiliary heat exchanger 20 is an evaporation region, while an area downstream of the evaporation region in the auxiliary heat exchanger 20 is a superheat region. Further, an evaporation temperature sensor 30 which detects an evaporation temperature is disposed downstream of an expansion valve 13 in an outdoor unit 3.

A switching mechanism (TV1, TV2, TV3, TV4, FV) includes an electric motor (74), a flow path switching portion (71) to be driven by the electric motor (74), a first port (P1) connected to a high-pressure flow path (7, 24, 28b, 31, 32) of a refrigerant circuit (6), a second port (P2) connected to a low-pressure flow path (8, 25, 28a, 33, 34) of the refrigerant circuit (6), and a third port (P3) connected to a predetermined flow path of the refrigerant circuit (6). The switching mechanism (TV1, TV2, TV3, TV4, FV) is switched between a first state in which the first port (P1) communicates with the third port (P3) and a second state in which the second port (P2) communicates with the third port (P3) in such a manner that the electric motor (74) drives the flow path switching portion (71).