A heat pump system includes a heat source unit, a discharge refrigerant communication tube, a liquid refrigerant communication tube, a gas refrigerant communication tube, a first usage unit and a second usage unit. The first usage unit has a first usage-side heat exchanger capable of functioning as a radiator of the heat-source-side refrigerant introduced from the discharge refrigerant communication tube. The first usage unit is capable of performing operation in which an aqueous medium is heated by radiation of the heat-source-side refrigerant in the first usage-side heat exchanger. The second usage unit has a second usage-side heat exchanger capable of functioning as an evaporator of the heat-source-side refrigerant introduced from the liquid refrigerant communication tube. The second usage unit is capable of performing operation in which an air medium is cooled by evaporation of the heat-source-side refrigerant in the second usage-side heat exchanger.

An air-conditioning apparatus includes a heat medium system configured to control a flow rate of the heat medium supplied to the heat source unit side heat exchanger that exchanges heat between refrigerant and the heat medium, the heat medium system having at least one system of a heat medium conveyor, a heat medium flow rate adjuster, and a heat medium flow rate control device. In the air-conditioning apparatus, the operation of each of use-side heat exchangers is changed to a cooling operation or a heating operation in accordance with a control command, and a cooling and heating concurrent operation is performed. The refrigerant is caused to flow through the heat source unit side heat exchanger in accordance with the ratio of the total cooling capacity of the use-side heat exchangers to the total heating capacity of the use-side heat exchangers. The heat medium flow rate control device controls the flow rate of the heat medium supplied to the heat source unit side heat exchanger, using the temperature of the heat medium flowing into the heat source unit side heat exchanger and the temperature of the heat medium flowing from the heat source unit side heat exchanger.

A heat pump system includes a heat source unit, a discharge refrigerant communication tube, a liquid refrigerant communication tube, a gas refrigerant communication tube, a first usage unit and a second usage unit. The first usage unit has a first usage-side heat exchanger capable of functioning as a radiator of the heat-source-side refrigerant introduced from the discharge refrigerant communication tube. The first usage unit is capable of performing operation in which an aqueous medium is heated by radiation of the heat-source-side refrigerant in the first usage-side heat exchanger. The second usage unit has a second usage-side heat exchanger capable of functioning as an evaporator of the heat-source-side refrigerant introduced from the liquid refrigerant communication tube. The second usage unit is capable of performing operation in which an air medium is cooled by evaporation of the heat-source-side refrigerant in the second usage-side heat exchanger.

An air-conditioning apparatus includes two heat source units, each including a compressor, an outdoor heat exchanger functioning as an evaporator, an accumulator connected to a suction side of the compressor, and at least one of an outdoor air-sending device configured to supply air corresponding to a heat exchange target for refrigerant to the outdoor heat exchanger or a flow control device (bypass and expansion device for bypass) configured to regulate a flow rate of the refrigerant flowing through the outdoor heat exchanger. A controller is configured to control at least one of the outdoor air-sending device or the flow control device so that a suction quality of the compressor of an upper heat source unit installed on an upper side and a suction quality of the compressor of a lower heat source unit installed on a lower side become the same.

Described herein is a system and a method for controlling operation of a heat pump. The system comprises an electronic expansion valve (EXV) configured to fluidically connect an indoor unit of the heat pump with an outdoor unit of the heat pump, and a controller operatively connected to the EXV, where the controller is configured to issue a first control signal, during a first defrost mode, to at least partially close the EXV to increase discharge pressure in an outdoor coil of the outdoor unit to facilitate defrosting of the outdoor coil.

A method of operating a heat pump system includes performing two or more status checks of a reversing valve. Each status check includes comparing a respective set of measurements. The method further includes determining whether the reversing valve is in a fault condition based on at least one of the plurality of status checks.

An air conditioner and a control method of an air conditioner are provided. The air conditioner includes an outdoor unit, an indoor unit, a refrigerant circulation loop, and a controller. The controller is configured to determine whether the air conditioner is operating in a cooling mode; obtain a first target supercooling degree in a first standard condition if it determined that the air conditioner is operating stably in the cooling mode; convert a supercooling degree in a current condition into a supercooling degree in the first standard condition; obtain a first refrigerant amount difference according to the first target supercooling degree, the supercooling degree in the first standard condition, an outdoor unit internal volume in the first standard condition, and an outdoor unit internal volume in the current condition; and determine a refrigerant amount of the air conditioner according to the first refrigerant amount difference.