A method for operating a heat pump (20; 300) includes operating in a cooling mode wherein heat is absorbed by refrigerant in the indoor heat exchanger (26) and rejected by refrigerant in the outdoor heat exchanger (24). The heat pump switches to operation in a heating mode wherein heat is rejected by refrigerant in the indoor heat exchanger, heat is absorbed by refrigerant in the outdoor heat exchanger, and there is an ejector (60) motive flow and ejector secondary flow. In the heating mode a refrigerant pressure (PH) or temperature (TL) is measured and, responsive to the measured refrigerant pressure or temperature, at least one of a fan speed is changed and a needle (132) of the ejector is actuated.

To highly accurately determine whether a refrigerant amount in a refrigerant circuit is appropriate. An air conditioning apparatus comprises a refrigerant circuit in which a plurality of indoor units respectively including an indoor heat exchanger and an indoor expansion valve are connected to an outdoor unit including an outdoor expansion valve via a liquid-refrigerant connection pipe. Moreover, the air conditioning apparatus individually controls each of the indoor units to operate or stop. The air conditioning apparatus includes a controller. When at least one of the indoor heat exchangers functions as a radiator, the controller controls an opening degree of the indoor expansion valve and an opening degree of the outdoor expansion valve. The apparatus determines whether a refrigerant amount in the refrigerant circuit is appropriate on the basis of an amount of change corresponding to a change in state of a refrigerant between the indoor expansion valve and the outdoor expansion valve.

An air conditioning system is provided. The system has a high-pressure pipe, a low-pressure pipe, an indoor heat exchanger, an outdoor heat exchanger, a leak-free thermal expansion valve and a variable capacity compressor. The variable capacity compressor has a shell, a first cylinder and a second cylinder. The shell has a suction port and an exhaust port. The first cylinder has a first suction hole connected to the suction port and a first exhaust hole connected to the exhaust port. The second cylinder has a second suction hole connected to the suction port, a second exhaust hole connected to the exhaust port, and a pressure relief hole connected to the high-pressure pipe and the low-pressure pipe in an on-off manner. Before the variable capacity compressor is started, the high-pressure pipe and the low-pressure pipe are connected and also disconnected after the first preset duration.

An air conditioner includes: an indoor heat exchanger, an outdoor heat exchanger, an expansion valve, an indoor fan, a compressor, a four-way valve, a temperature control assembly, an outdoor assembly, a signal control assembly, and an indoor assembly. The indoor heat exchanger is configured to exchange heat between indoor air and a refrigerant flowing in the indoor heat exchanger. The outdoor heat exchanger is configured to exchange heat between outdoor air and a refrigerant flowing in the outdoor heat exchanger. The expansion valve is connected between the outdoor heat exchanger and the indoor heat exchanger, and the expansion valve is configured to adjust a pressure of a refrigerant flowing through the outdoor heat exchanger and the indoor heat exchanger, so that a flow rate of the refrigerant flowing through the outdoor heat exchanger and the indoor heat exchanger is adjusted.

A refrigerant circuit (11), in which carbon dioxide circulates as a refrigerant, includes a plurality of heat exchangers (12), a receiver (60), a degassing passage (61), and a degassing valve (62). The refrigeration system implements a first operation during which one of the plurality of heat exchangers (12) functions as a radiator while two of the plurality of heat exchangers (12) function as evaporators, and the refrigerant flows from the heat exchanger (12) functioning as a radiator into the receiver (60) and then flows from the receiver (60) into each of the two heat exchangers (12) functioning as evaporators. The control unit (15) changes the degassing valve (62) from a closed state to an open state when a pressure (RP) in the receiver (60) exceeds a first pressure (Pth1) set in advance, in the first operation.

A refrigerant control system includes: a charge module configured to determine an amount of refrigerant that is present within a first portion of a refrigeration system within a building; and an isolation module configured to selectively open and close an isolation valve of the refrigeration system and to, via the isolation valve, maintain the amount of refrigerant within the first portion within the building below a predetermined amount of the refrigerant.

An air conditioner unit includes a compressor for circulating refrigerant through refrigeration loop, an indoor fan, and an outdoor fan. A controller is configured to operate the air conditioner unit in a standard mode of operation to heat a room, determine that an occupant is present in the room, and operate the air conditioner unit in an occupant mode of operation in response to determining that the occupant is present in the room. The occupant mode of operation includes adjusting at least one operating parameter of the air conditioner unit to increase a discharge temperature of a flow of indoor air relative to the standard mode of operation.

Air conditioner units and methods of operating the same are provided. A method of operating an air conditioner unit includes determining a fan speed as a function of a compressor speed of a variable speed compressor of the air conditioner unit. The method also includes activating a variable speed fan of the air conditioner unit at the fan speed. An air conditioner unit may include a controller, and the controller may be configured for performing the method.

A refrigerant control system includes: a charge module configured to determine an amount of refrigerant that is present within a refrigeration system of a building; a leak module configured to diagnose that a leak is present in the refrigeration system based on the amount of refrigerant; and at least one module configured to take at least one remedial action in response to the diagnosis that the leak is present in the refrigeration system.

A refrigeration cycle apparatus that can improve operation efficiency when a refrigerant that contains at least 1,2-difluoroethylene is used is provided. An air conditioning apparatus 1 includes a compressor (21), an outdoor heat exchanger (23), an outdoor expansion valve (24), an indoor heat exchanger (31), and a suction injection pipe (40), and uses a refrigerant that contains at least 1,2-difluoroethylene. The suction injection pipe (40) allows a part of a refrigerant that flows toward the indoor heat exchanger (31) from the outdoor heat exchanger (23) to merge with a low-pressure refrigerant that is sucked into the compressor (21).