Provided are a control method of a heat pump system and a heat pump system. The heat pump system includes a throttling element and a four-way valve. The four-way valve has a first state in a case that the heat pump system operates for refrigerating and a second state in a case that the heat pump system operates for heating. The control method includes that: before the four-way valve is switched from the first state to the second state, A is compared with B, and switching of the state of the four-way valve is controlled and the opening degree of the throttling element is adjusted according to the comparison result, or switching of the state of the four-way valve is controlled according to the comparison result, or the opening degree of the throttling element is adjusted according to the comparison result.

A heat exchanger includes a plurality of heat transfer tubes arranged at predetermined intervals in a vertical direction, a tubular header that has a plurality of connection portions where the heat transfer tubes are connected to a side portion of the header and that communicates with each of the heat transfer tubes, a refrigerant pipe that communicates with the header at a middle portion of the header in the vertical direction, and a first bypass pipe having ends one of which communicates with a lower portion of the header and the other of which communicates with a middle portion of the refrigerant pipe. A distance between a communication position at which the first bypass pipe and the refrigerant pipe communicate with each other and an inner wall of the header is not more than double an inside diameter of the refrigerant pipe.

An air-conditioning apparatus that includes a compressor, a flow switching device, an outdoor heat exchange unit, an expansion section and an indoor heat exchanger, which are connected by pipes, in which the outdoor heat exchange unit includes a first outdoor heat exchanger, a first flow rate control device, a second outdoor heat exchanger, a second flow rate control device, a bypass pipe, the second outdoor heat exchanger, the second flow rate control device, a third flow rate control device, and a flow control device.

An air-conditioning apparatus includes a compressor and an outdoor heat exchanger that operates as an evaporator. A first heat exchange unit of the outdoor heat exchanger includes: first heat transfer tubes extending in an upward/downward direction, and arranged apart from each other in a lateral direction; a first junction pipe extending in the lateral direction, and connected to the lower ends of the first heat transfer tubes; an outflow pipe connected to the first junction pipe at or below a center position of the first junction pipe in the upward/downward direction; second heat transfer tubes extending in the upward/downward direction, and arranged apart from each other in the lateral direction; a first distribution pipe extending in the lateral direction, and connected to the lower ends of the second heat transfer tubes, and a first connection part connecting upper ends of the first heat transfer tubes and upper ends of the second heat transfer tubes.

A heat pump system including a charge compensator having a liquid line port for an inflow of a refrigerant into the charge compensator and for an outflow of the refrigerant from the charge compensator. The heat pump system further includes an isolation valve configured to control flows of the refrigerant to and from the charge compensator through a liquid line piping of the heat pump system based on whether the heat pump system is operating in a cooling mode, a defrost mode, or a heating mode, where the liquid line port is fluidly coupled to the liquid line piping of the heat pump system.

A multi-way valve for controlling a refrigerant circuit of a refrigeration system with a heat pump function, having a housing which has two mutually opposite end faces which each comprise an insertion opening to which a regulating chamber is connected, having multi-way valve arrangements which can each be inserted in the regulating chamber, the multi-way valve arrangement comprising at least one base body and a rotary slide valve arrangement, with in each case one connection in the housing, which open into the respective regulating chamber, and with at least further connections in the housing, which open into at least one channel which extends between the regulating chambers.

A hybrid multi-air conditioning system with no receiver is provided for optimal valve control. The hybrid multi-air conditioning system includes: a hot-water unit for exchanging heat between refrigerant and water; at least one indoor unit installed indoors and comprising an indoor heat exchanger and an indoor unit expansion valve; and an outdoor unit connected to the indoor unit and the hot-water unit via a refrigerant pipeline and comprising an outdoor heat exchanger, a compressor, and an outdoor unit expansion valve, wherein, when an abnormal refrigerant enters either the at least one indoor unit or the outdoor unit according to an operation mode, the abnormal refrigerant is shut off from the hot-water unit and the at least one indoor unit or the outdoor unit which operates as a condenser. Accordingly, the hybrid multi-air conditioning system improves heat exchange efficiency via direct heat transfer between refrigerant and water by having a coil wound on the water tank to transfer heat between refrigerant and water.

A refrigeration cycle apparatus includes: a refrigerant circuit configured to circulate refrigerant; and a controller configured to control the refrigerant circuit. The refrigerant circuit includes a compressor, a first heat exchanger, a first expansion device, a second expansion device, a third expansion device, a second heat exchanger, and a cooler configured to cool a substrate of the controller. In a first path of the refrigerant circuit, the compressor, the first heat exchanger, the first expansion device, the second expansion device, and the second heat exchanger are connected in order of the compressor, the first heat exchanger, the first expansion device, the second expansion device, and the second heat exchanger. In a second path of the refrigerant circuit, the cooler and the third expansion device are connected in order of the cooler and the third expansion device from a first point between the first expansion device and the second expansion device to a second point between the compressor and the second heat exchanger.

An air conditioning apparatus is provided that may include an outdoor unit including a compressor and an outdoor heat exchanger and through which a refrigerant is circulated, an indoor unit through which a fluid, such as water is circulated, and at least one heat exchange device including a heat exchanger in which the refrigerant and the fluid are heat-exchanged with each other. The at least one heat exchange device may include a high-pressure guide tube that extends from a high-pressure gas tube of the outdoor unit so as to be connected to a first side of the heat exchanger, a low-pressure guide tube that extends from a low-pressure gas tube of the outdoor unit so as to be combined with the high-pressure guide tube, a liquid guide tube that extends from a liquid tube of the outdoor unit so as to be connected to a second side of the heat exchanger, and a solenoid valve installed in the high-pressure guide tube or the low-pressure guide tube to perform an opening and closing operation so as to allow the refrigerant to flow in a first direction. The high-pressure gas tube and the low-pressure gas tube may be connected to each other by a single gas tube, and when the indoor unit performs a cooling operation or a heating operation, flow of refrigerant in the first direction may be blocked in a state in which power is applied to the solenoid valve.

The invention provides a refrigeration apparatus configured to cool the interior of a casing of a heat source unit by a refrigerant. An air conditioner includes a heat source unit, a utilization unit having a utilization heat exchanger and constituting a refrigerant circuit along with the heat source unit, and a controller. The heat source unit causes heat exchange between a refrigerant and a heat source, and cools the interior of the casing, and causes a valve to switch to supply or not to supply the cooling heat exchanger with the refrigerant. The controller assesses, before the refrigerant is supplied to the cooling heat exchanger, whether or not the refrigerant flowing from the cooling heat exchanger toward the compressor comes into a wet state when the refrigerant is supplied, and determines whether or not to open the valve in accordance with an assessment result.