An air conditioner includes: a heat-source-side unit including a compressor and a heat-source-side heat exchanger; use-side units each including a use-side heat exchanger; an intermediate unit that causes the use-side heat exchanger of each of the use-side units to individually function as an evaporator or a radiator of a refrigerant; and two connection pipes that each connect the heat-source-side unit and the intermediate unit. The intermediate unit includes: an ejector that is configured to pressurize the refrigerant evaporated in the use-side heat exchanger that functions as the evaporator by using a driving flow; and a gas-liquid separator into which the refrigerant flowing out from the ejector flows.

An HVAC system with a refrigerant gas sensor is provided. In one embodiment, an HVAC system includes a heat exchanger coil installed within a housing. The heat exchanger coil is operable to exchange heat with air in the housing via a refrigerant passing through the heat exchanger coil. The system also includes an HVAC sensor assembly installed within the housing. The HVAC sensor assembly includes a refrigerant gas sensor and an orientation sensor positioned to detect an orientation of the refrigerant gas sensor. The HVAC system may also or instead include a position sensor to detect the position of the refrigerant gas sensor within the system. Additional systems, devices, and methods are also disclosed.

According to one embodiment, a motor drive unit includes a motor including a plurality of phase windings in a mutually unconnected state, a first inverter which controls application of electric power to one ends of the phase windings, a second inverter which controls application of electric power to the other ends of the phase windings, relays each of which includes a make break contact connected between the other ends of the phase windings, and a controller which switches, according to a value of a current flowing through the motor, between an open-windings mode and a star-connection mode.

This air conditioning system includes a refrigerant circuit including an indoor heat exchanger of an indoor unit and an outdoor heat exchanger of an outdoor unit, and a detection unit capable of detecting a refrigerant leaking from the indoor unit. The detection unit is capable of switching between an energized state and a non-energized state on the basis of information on a refrigerant filling amount by which the refrigerant circuit is filled with the refrigerant.

A heat pump system is provided. The heat pump system comprises a compressor, a first heat exchanger, a second heat exchanger, a third heat exchanger and a six-way valve. The compressor comprises an air suction port and an air discharge port. The first heat exchanger is arranged in a first circulation path, the second heat exchanger is arranged in a second circulation path, and the third heat exchanger is arranged in a third circulation path, wherein the first circulation path, the second circulation path and the third circulation path are parallel paths. A first end of the first circulation path, a first end of the second circulation path and a first end of the third circulation path are connected to the six-way valve and are in controllable communication with the air suction port and the air discharge port of the compressor by means of the six-way valve. A second end of the first circulation path, a second end of the second circulation path and a second end of the third circulation path are connected to a common path converging point. The components of the heat pump system in the present application have simple pipelines, have a high degree of integration, are not difficult to mount, and have a small pressure drop during air suction and discharge, and the control logic therefor is simple.

According to one embodiment, in a low speed drive of outdoor fans, a first flow rate adjusting valve in a main outdoor heat exchanger side is narrowed to a closing degree or a close range thereof, and an opening degree of a second flow rate adjusting valve is controlled such that a supercooling degree of refrigerant in auxiliary outdoor heat exchangers becomes constantly a target value.

A refrigeration cycle apparatus (1) is capable of performing a refrigeration cycle using a small-GWP refrigerant. The refrigeration cycle apparatus (1) includes a refrigerant circuit (10) and a refrigerant enclosed in the refrigerant circuit (10). The refrigerant circuit includes a compressor (21), a condenser (23), a decompressing section (24), and an evaporator (31). The refrigerant contains at least 1,2-difluoroethylene.

A refrigerant cycle apparatus includes a first heat source unit, a utilization unit, and a connection pipe. An installation method includes a refrigerant recovery step of recovering a first refrigerant having a first GWP and one or both of flammability and toxicity from the first heat source unit, and a refrigerant accommodation step of accommodating, in the first heat source unit, a second refrigerant recovered and regenerated from an existing facility and having a second GWP and one or both of non-flammability and non-toxicity.

A flow path switch is provided with a first opening to a fourth opening. A discharge side of a compressor is connected to the first opening. A first end of a first heat exchange unit is connected to the fourth opening. A first end of the second inner flow path is connected to the second opening. A first branching portion is connected to a first end of the second valve and the third opening. When an operation mode of an air conditioning apparatus is a first mode, the second valve is open, the first opening is connected to the fourth opening, and the second opening is connected to the third opening. When the operation mode of the air conditioning apparatus is a second mode, the second valve is closed, the first opening is connected to the third opening, and the second opening is connected to the fourth opening.

An air-conditioning management system includes: an air conditioning apparatus configured to carry out a refrigerant recovery operation of recovering a refrigerant from a refrigerant circuit that connects an outdoor unit and an indoor unit and sending the recovered refrigerant to each recovery unit of the outdoor unit; and a control unit configured to make a determination whether all the recovered refrigerant is sendable to each recovery unit before a start of the refrigerant recovery operation by the air conditioning apparatus, and to output, when determining that all the recovered refrigerant is not sendable to each recovery unit, a command for notifying the determination.