A heat pump device can discharge air in a heat medium circuit regardless of the height positions of two bodies of the heat pump device and prevents refrigerant outflow when the refrigerant enters the heat medium circuit in the liquid heat exchanger. A pump causes the liquid heat medium to flow in a predetermined circulatory direction in a heat medium pipe, and a liquid heat exchanger, a first air vent valve and a second air vent valve are arranged in this order along a circulatory direction.

A system (20; 300) comprises: a compressor (22) having a suction port (40) and a discharge port (42); an ejector (32) having a motive flow inlet (50), a suction flow inlet (52), and an outlet (54); a separator (34) having an inlet (72), a vapor outlet (74), and a liquid outlet (76); a first heat exchanger (24); an expansion device (28); and a second heat exchanger (26; 302). Conduits and valves are positioned to provide alternative operation in: a cooling mode; a first heating mode; and a second heating mode. In the cooling mode and second heating mode, a needle (60) of the ejector is closed.

A refrigeration cycle apparatus includes a heat exchanger, and a flow switching circuit configured to switch the heat exchanger to act as any one of an evaporator and a condenser, the flow switching circuit is configured to allow refrigerant to flow into the heat exchanger in the same direction both in a case where the heat exchanger acts as an evaporator and in a case where the heat exchanger acts as a condenser, the heat exchanger includes a path switching circuit including a plurality of paths, and the path switching circuit is configured to switch an order of the plurality of paths through which refrigerant flows between an order of the plurality of paths in the case where the heat exchanger acts as an evaporator and another order of the plurality of paths in the case where the heat exchanger acts as a condenser.

A heat exchanger includes: a heat exchanging part that includes flat tubes aligned vertically when the heat exchanger is installed; a first flow divider that includes a first pipe through which a refrigerant enters or exits from the first flow divider, second pipes that provide refrigerant flow paths between the heat exchanging part and the first pipe, and a main body that internally has a first space; and second flow dividers that each internally include one of second spaces that provide refrigerant flow paths between the heat exchanging part and the first flow divider. The first space communicates with a first end of the first pipe and a first end of each of the second pipes and causes the refrigerant to flow from the first pipe into the second pipes or from the second pipes into the first pipe.

Systems and methods are provided and include a variable-capacity compressor operable in a first capacity mode and in a second capacity mode that is higher than the first capacity mode. A control module is configured to switch the variable-capacity compressor between the first capacity mode and the second capacity mode based on a demand signal from a thermostat and an indoor relative humidity sensed by an indoor relative humidity sensor. The control module determines whether the indoor relative humidity is greater than a predetermined humidity and operates the variable-capacity compressor in the second capacity mode in response to receiving the demand signal from the thermostat and the indoor relative humidity exceeding the predetermined humidity.

An air conditioner performs a heating operation and a cooling operation with enhanced heat exchange performance and also performs a heating continuous operation, while preventing increases in manufacturing cost and packaging volume. An air conditioner comprises a refrigerant circuit through which refrigerant circulates. A second heat exchanger includes a first refrigerant flow path and a second refrigerant flow path. A first port of the flow path switching device is connected to a discharge portion of a compressor. A second port is connected to a first heat exchanger. A third port is connected to an intake portion of the compressor. A fourth port is connected to a pipe that connects a branch point to the first refrigerant flow path. A fifth port is connected to the second refrigerant flow path. A sixth port is connected to the first refrigerant flow path.

A heating and cooling system includes a reversing valve configured to adjust a flow of refrigerant through the heating and cooling system, where the reversing valve includes a first configuration to flow the refrigerant through a first circuit of the heating and cooling system and a second configuration to flow the refrigerant through a second circuit of the heating and cooling system. The heating and cooling system also includes a controller configured to determine an operating parameter of a compressor of the heating and cooling system, where the controller is configured to adjust operation of the compressor based on the operating parameter to adjust a position of the reversing valve.

A heat pump air conditioning system and a control method. The heat pump air conditioning system includes: a compressor; an indoor unit heat exchanger, an outdoor unit heat exchanger and a throttling device; a refrigerant circulation loop, connecting the compressor, the indoor unit heat exchanger, the outdoor unit heat exchanger and the throttling device in series; the heat storage module, disposed in the refrigerant circulation loop and configured to absorb heat from refrigerant in the refrigerant circulation loop and store heat when heat storage is required, and to heat the refrigerant in the refrigerant circulation loop when the outdoor unit heat exchanger defrosting is required. The heat pump air conditioning system can store excess heat of the system for defrosting when indoor heat load is low, and release heat for defrosting by means of the heat storage module during a defrosting process while continuing supplying heat to a room.

A method for controlling an operating discharge pressure in a multi-purpose HVAC system including an outdoor unit, and an indoor unit, the HVAC system including a plurality of flow control valves configured to isolate the indoor unit from the multi-purpose HVAC system, a compressor and a controller, operably coupled to a water heater module, the water heater module including at least one valve, the controller executing a method including operating the multi-purpose HVAC system in a water heating mode, monitoring the operating discharge pressure from the compressor; and generating a signal commanding at least one of the plurality of control valves to isolate the indoor unit from the outdoor unit and water heating module and direct high pressure refrigerant to the indoor unit when the operating discharge pressure is greater than or equal to a predetermined pressure value.

A refrigeration cycle apparatus according to the present invention, a controller is configured to cause a first operation mode and a second operation mode to be executed as operation modes of an air-sending fan. The first operation mode is an operation mode in which an operation of the air-sending fan is started based on a first manipulation performed on an operation unit and the air-sending fan is stopped based on a second manipulation performed on the operation unit. The second operation mode is an operation mode in which the operation of the air-sending fan is started when refrigerant is detected by a refrigerant detection unit, the air-sending fan is not stopped based on the second manipulation, the air-sending fan is stopped based on a third manipulation different from the second manipulation, and the operation of the air-sending fan is restarted based on a fourth manipulation different from the first manipulation.