A heat exchanger includes heat exchange fins, refrigerant pipes are arranged across the heat exchange fins, and connecting pipes connected to the refrigerant pipes to thereby define refrigerant passages. The connecting pipes include a first pipe portion having a first end connected to one of the refrigerant pipes, a branch pipe portion that is branched from the first pipe portion, that extends parallel to the first pipe portion, and that is connected to another of the refrigerant passages, and a second pipe that is connected to the first pipe portion and that is configured to guide gas-phase refrigerant separated from the refrigerant in the first pipe portion. The second pipe includes an inner insert portion inserted into a second end of the first pipe portion and an outlet portion that extends from the inner insert portion in direction opposite to the second end of the first pipe portion.

Disclosed is an air conditioner and control method thereof. The air conditioner and control method thereof is to improve rapid heating performance without using a large-capacity compressor. The air conditioner includes an indoor unit having a first heat exchanger, an outdoor unit having a compressor and a second heat exchanger, a refrigerant cycle configured to form a refrigerant circulation path between the indoor unit and the outdoor unit, a flow path switch configured to switch a flow of a refrigerant in the refrigerant cycle, and a controller configured to control the flow path switch to allow one part of the refrigerant discharged from the compressor to flow into an inlet of the compressor and the other part of the refrigerant discharged from the compressor to flow into at least one of the first heat exchanger and the second heat exchanger.

An air conditioner may include a plurality of indoor units and a plurality of outdoor units connected to the plurality of indoor units. Each of the plurality of outdoor units may include a plurality of outdoor heat exchangers. Each of the outdoor heat exchangers may include a plurality of heat exchanger parts. When a defrosting operation condition is satisfied during a heating operation, indicating that a defrosting operation should be performed the plurality of heat exchanger parts of the plurality of outdoor heat exchangers may successively perform the defrosting operation.

A heating medium compression apparatus includes: first and second compressors compressing a heating medium; suction side and discharge side pipings connecting the first and second compressors to a heat exchanger; a connection piping connecting a discharge side of the first compressor and a suction side of the second compressor in series; and a control unit controlling a flow rate of the heating medium flowing in the suction side piping, the discharge side piping, and the connection piping. The control unit alternatively connects the first or second compressor to the suction side and discharge side pipings, or connects the first and second compressors in series between the suction side and discharge side pipings and performs control such that the flow rate of the heating medium suctioned into the second compressor connected in series becomes higher than that of the heating medium discharged from the first compressor.

Provided is an air conditioner capable of improving heating performance in a cold region by reducing a refrigerant pressure loss in an outdoor heat exchanger in a heating operation. The air conditioner includes a compressor, an outdoor heat exchanger, an expansion device, and an indoor heat exchanger. The outdoor heat exchanger may include a plurality of unit channels into which a refrigerant channel is partitioned, and a separating device installed in each of the plurality of unit channels and configured to separate a liquid refrigerant component and a vapor refrigerant component in each of the plurality of unit channels in a heating operation. The air conditioner may further include a compressor suction channel connecting a heating-operation outlet of the outdoor heat exchanger and an inlet of the compressor, and a bypass pipe connecting the separating device and the compressor suction channel.

A refrigeration cycle apparatus includes a main circuit through which refrigerant circulates and in which a compressor, a condenser, a first expansion device, a centrifugal gas-liquid separator that separates refrigerant into gas refrigerant and liquid refrigerant by using centrifugal force, and an evaporator are connected by refrigerant pipes; and a bypass that returns the gas refrigerant obtained through the separation by the gas-liquid separator to a suction side of the compressor. The gas-liquid separator includes a cylindrical container, an inflow pipe, a gas outflow pipe, and a liquid outflow pipe. The main circuit includes a second expansion device provided between the liquid outflow pipe of the gas-liquid separator and the evaporator. The gas refrigerant discharged from the gas outflow pipe of the gas-liquid separator flows into the bypass, and the bypass is provided with a third expansion device.

A heat exchanger includes heat exchange fins, refrigerant pipes are arranged across the heat exchange fins, and connecting pipes connected to the refrigerant pipes to thereby define refrigerant passages. The connecting pipes include a first pipe portion having a first end connected to one of the refrigerant pipes, a branch pipe portion that is branched from the first pipe portion, that extends parallel to the first pipe portion, and that is connected to another of the refrigerant passages, and a second pipe that is connected to the first pipe portion and that is configured to guide gas-phase refrigerant separated from the refrigerant in the first pipe portion. The second pipe includes an inner insert portion inserted into a second end of the first pipe portion and an outlet portion that extends from the inner insert portion in direction opposite to the second end of the first pipe portion.

A refrigeration cycle apparatus includes a main circuit through which refrigerant circulates and in which a compressor, a condenser, a first expansion device, a centrifugal gas-liquid separator that separates refrigerant into gas refrigerant and liquid refrigerant by using centrifugal force, and an evaporator are connected by refrigerant pipes; and a bypass that returns the gas refrigerant obtained through the separation by the gas-liquid separator to a suction side of the compressor. The gas-liquid separator includes a cylindrical container, an inflow pipe, a gas outflow pipe, and a liquid outflow pipe. The main circuit includes a second expansion device provided between the liquid outflow pipe of the gas-liquid separator and the evaporator. The gas refrigerant discharged from the gas outflow pipe of the gas-liquid separator flows into the bypass, and the bypass is provided with a third expansion device.

Provided is an air conditioner capable of improving heating performance in a cold region by reducing a refrigerant pressure loss in an outdoor heat exchanger in a heating operation. The air conditioner includes a compressor, an outdoor heat exchanger, an expansion device, and an indoor heat exchanger. The outdoor heat exchanger may include a plurality of unit channels into which a refrigerant channel is partitioned, and a separating device installed in each of the plurality of unit channels and configured to separate a liquid refrigerant component and a vapor refrigerant component in each of the plurality of unit channels in a heating operation. The air conditioner may further include a compressor suction channel connecting a heating-operation outlet of the outdoor heat exchanger and an inlet of the compressor, and a bypass pipe connecting the separating device and the compressor suction channel.

Disclosed is an air conditioner and control method thereof. The air conditioner and control method thereof is to improve rapid heating performance without using a large-capacity compressor. The air conditioner includes an indoor unit having a first heat exchanger, an outdoor unit having a compressor and a second heat exchanger, a refrigerant cycle configured to form a refrigerant circulation path between the indoor unit and the outdoor unit, a flow path switch configured to switch a flow of a refrigerant in the refrigerant cycle, and a controller configured to control the flow path switch to allow one part of the refrigerant discharged from the compressor to flow into an inlet of the compressor and the other part of the refrigerant discharged from the compressor to flow into at least one of the first heat exchanger and the second heat exchanger.