Air conditioner and control method thereof

An air conditioner, comprising:

• a compressor;
• a flow path switching valve;
• a first flow path connecting an outlet of the compressor to the flow path switching valve;
• a first heat exchanger;
• a second flow path connecting the first heat exchanger to the flow path switching valve;
• a first refrigerant port fluidly connected to an indoor unit;
• a third flow path extending from the first heat exchanger to the first refrigerant port;
• a sub-cooler provided on the third flow path;
• a first expansion valve provided between the first heat exchanger and the sub-cooler on the third flow path;
• a second expansion valve provided between the sub-cooler and the first refrigerant port on the third flow path;
• a fourth flow path branched from a branch point of the third flow path, passing through the sub-cooler, and extending to an inlet of the compressor;
• a third expansion valve provided between the sub-cooler and the branch point on the fourth flow path;
• a second refrigerant port fluidly connected to the indoor unit;
• a fifth flow path connecting the second refrigerant port to the flow path switching valve;
• a sixth flow path connecting the flow path switching valve to an intake port of the compressor;
• a first temperature sensor provided on the sixth flow path;
• a second temperature sensor provided between the first expansion valve and the first heat exchanger on the third flow path;
• and
• at least one processor, comprising processing circuitry, operatively connected to the compressor, the flow path switching valve, the first expansion valve, the second expansion valve, the third expansion valve, the first temperature sensor, and the second temperature sensor,
• wherein the at least one processor, individually and/or collectively, is configured to:
• control the flow path switching valve to connect the first flow path and the fifth flow path and connect the sixth flow path and the second flow path, based on an input for a heating operation, and
• control at least one expansion valve of the first expansion valve or the second expansion valve based on an output of the first temperature sensor and an output of the second temperature sensor.