Provided is an air conditioner including a connection pipe connected to a refrigerant pipe disposed inside an outdoor heat exchanger that operates as a condenser during a cooling operation and as an evaporator during a heating operation, a header connected to the connection pipe, wherein a refrigerant separated from a two-phase refrigerant flowing through the refrigerant pipe flows through the header, a bypass pipe connected to the header to guide a flow of the refrigerant to a compressor, a flow rate control valve installed at the bypass pipe to control a flow velocity of the refrigerant, a subcooler configured to superheat the refrigerant flowing through the bypass pipe, and a controller configured to control an opening degree of the flow rate control valve.

A refrigeration cycle apparatus includes a refrigeration cycle circuit that has a compressor, a condenser, an expansion device, and an evaporator that are connected through a pipe, the refrigeration cycle circuit being configured to allow refrigerant to circulate in the refrigeration cycle circuit, and a controller configured to determine whether the refrigerant leaks or whether the expansion device malfunctions on the basis of a degree of subcooling at an outlet of the condenser and a degree of superheat at an outlet of the evaporator or a degree of superheat at a suction port of the compressor.

A refrigeration cycle apparatus includes a refrigeration cycle circuit that has a compressor, a condenser, an expansion device, and an evaporator that are connected through a pipe, the refrigeration cycle circuit being configured to allow refrigerant to circulate in the refrigeration cycle circuit, and a controller configured to determine whether the refrigerant leaks or whether the expansion device malfunctions on the basis of a degree of subcooling at an outlet of the condenser and a degree of superheat at an outlet of the evaporator or a degree of superheat at a suction port of the compressor.

A refrigeration cycle apparatus includes a first refrigerant circuit including a first compressor, a first heat exchanger, a first refrigerant flow path of a second heat exchanger, a first expansion device, a third heat exchanger, and a second refrigerant flow path of a fourth heat exchanger, and a second refrigerant circuit including a second compressor, a fifth heat exchanger, a second expansion device, a third refrigerant flow path of the second heat exchanger, and a fourth refrigerant flow path of the fourth heat exchanger, a first refrigerant flows through, in order, the first compressor, the first heat exchanger, the first refrigerant flow path, the first expansion device, the third heat exchanger, and the second refrigerant flow path, the second refrigerant flows through, in order, the second compressor, the fifth heat exchanger, the second expansion device, the third refrigerant flow path, and the fourth refrigerant flow path.

A refrigeration cycle apparatus includes a first refrigerant circuit including a first compressor, a first heat exchanger, a first refrigerant flow path of a second heat exchanger, a first expansion device, a third heat exchanger, and a second refrigerant flow path of a fourth heat exchanger, and a second refrigerant circuit including a second compressor, a fifth heat exchanger, a second expansion device, a third refrigerant flow path of the second heat exchanger, and a fourth refrigerant flow path of the fourth heat exchanger, a first refrigerant flows through, in order, the first compressor, the first heat exchanger, the first refrigerant flow path, the first expansion device, the third heat exchanger, and the second refrigerant flow path, the second refrigerant flows through, in order, the second compressor, the fifth heat exchanger, the second expansion device, the third refrigerant flow path, and the fourth refrigerant flow path.

A refrigeration system includes a compressor, a heat rejecting heat exchanger, an expansion device, and a heat absorbing heat exchanger fluidly connected to form a closed loop through which a refrigerant is configured to circulate. An economizer heat exchanger is located downstream from an outlet of the heat rejecting heat exchanger and upstream from the expansion device relative to a flow of the refrigerant. The economizer heat exchanger has a main flow path and an economizer flow path formed therein. All liquid refrigerant provided at an outlet of the heat rejecting heat exchanger is provided to the main flow path.

A refrigeration system includes a compressor, a heat rejecting heat exchanger, an expansion device, and a heat absorbing heat exchanger fluidly connected to form a closed loop through which a refrigerant is configured to circulate. An economizer heat exchanger is located downstream from an outlet of the heat rejecting heat exchanger and upstream from the expansion device relative to a flow of the refrigerant. The economizer heat exchanger has a main flow path and an economizer flow path formed therein. All liquid refrigerant provided at an outlet of the heat rejecting heat exchanger is provided to the main flow path.

A vapor compression system including: a condenser; an evaporator; and an expansion control system on the main flowpath between the condenser and the evaporator, wherein the expansion control system further includes: one or more electronic expansion valves; and a modulated ball valve.

A vapor compression system including: a condenser; an evaporator; and an expansion control system on the main flowpath between the condenser and the evaporator, wherein the expansion control system further includes: one or more electronic expansion valves; and a modulated ball valve.

The invention relates to a refrigerant for use in a single-stage or auto cascade refrigeration system. The refrigerant comprises a mixture of gasses of at least three different hydrocarbons. The at least three different hydrocarbons include butane (C4H10), ethene (C2H4) and methane (CH4). The mixture of gasses comprises at the most 10% by weight of methane (CH4). The invention also relates to a refrigeration system with methane-containing refrigerant, to a refrigeration cabinet with methane-containing refrigerant and to use of a refrigeration cabinet with such refrigerant.