Air conditioning apparatus

An air conditioning apparatus comprising:

• an outdoor unit that has a compressor and an outdoor heat exchanger;
• an indoor unit that has an indoor heat exchanger;
• and
• a liquid refrigerant connection pipe and a gas refrigerant connection pipe that interconnect the outdoor unit and the indoor unit,
• the outdoor unit further having, in an outdoor liquid refrigerant pipe that interconnects a liquid-side end of the outdoor heat exchanger and the liquid refrigerant connection pipe, a liquid pressure adjusting expansion valve which, when a refrigerant circulates in the order of the compressor, the outdoor heat exchanger, the liquid refrigerant connection pipe, the indoor heat exchanger, the gas refrigerant connection pipe, and the compressor, reduces a pressure of the refrigerant flowing through the liquid refrigerant connection pipe in such a way that the refrigerant is in a gas-liquid two-phase state,
• wherein an external expansion valve unit having an external expansion valve that further reduces the pressure of the refrigerant whose pressure has been reduced in the liquid pressure adjusting expansion valve is provided in the liquid refrigerant connection pipe,
• the indoor unit further has an indoor expansion valve in an indoor liquid refrigerant pipes that interconnect the liquid refrigerant connection pipe and a liquid-side end of the indoor heat exchanger, and
• a controller, that controls constituent devices of the outdoor unit, the indoor unit, and the external expansion valve unit, completely opens the indoor expansion valve and controls an opening degree of the external expansion valve when the refrigerant circulates in the order of the compressor, the outdoor heat exchanger, the liquid refrigerant connection pipe, the indoor heat exchanger, the gas refrigerant connection pipe, and the compressor and completely opens the external expansion valve and controls an opening degree of the indoor expansion valve when the refrigerant circulates in the order of the compressor, the gas refrigerant connection pipe, the indoor heat exchanger, the liquid refrigerant connection pipe, the outdoor heat exchanger, and the compressor.

An air conditioning apparatus comprising:

• an outdoor unit that has a compressor and an outdoor heat exchanger;
• an indoor unit that has an indoor heat exchanger;
• and
• a liquid refrigerant connection pipe and a gas refrigerant connection pipe that interconnect the outdoor unit and the indoor unit,
• the outdoor unit further having, in an outdoor liquid refrigerant pipe that interconnects a liquid-side end of the outdoor heat exchanger and the liquid refrigerant connection pipe, a liquid pressure adjusting expansion valve which, when a refrigerant circulates in the order of the compressor, the outdoor heat exchanger, the liquid refrigerant connection pipe, the indoor heat exchanger, the gas refrigerant connection pipe, and the compressor, reduces a pressure of the refrigerant flowing through the liquid refrigerant connection pipe in such a way that the refrigerant is in a gas-liquid two-phase state,
• wherein an external expansion valve unit having an external expansion valve that further reduces the pressure of the refrigerant whose pressure has been reduced in the liquid pressure adjusting expansion valve is provided in the liquid refrigerant connection pipe,
• the indoor unit further has an indoor expansion valve in an indoor liquid refrigerant pipes that interconnect the liquid refrigerant connection pipe and a liquid-side end of the indoor heat exchanger, and
• a controller, that controls constituent devices of the outdoor unit, the indoor unit, and the external expansion valve unit, controls an opening degree of the external expansion valve both when the refrigerant circulates in the order of the compressor, the outdoor heat exchanger, the liquid refrigerant connection pipe, the indoor heat exchanger, the gas refrigerant connection pipe, and the compressor and when the refrigerant circulates in the order of the compressor, the gas refrigerant connection pipe, the indoor heat exchanger, the liquid refrigerant connection pipe, the outdoor heat exchanger, and the compressor.

An air conditioning apparatus comprising:

• an outdoor unit that has a compressor and an outdoor heat exchanger;
• an indoor unit that has an indoor heat exchanger;
• and
• a liquid refrigerant connection pipe and a gas refrigerant connection pipe that interconnect the outdoor unit and the indoor unit,
• the outdoor unit further having, in an outdoor liquid refrigerant pipe that interconnects a liquid-side end of the outdoor heat exchanger and the liquid refrigerant connection pipe, a liquid pressure adjusting expansion valve which, when a refrigerant circulates in the order of the compressor, the outdoor heat exchanger, the liquid refrigerant connection pipe, the indoor heat exchanger, the gas refrigerant connection pipe, and the compressor, reduces a pressure of the refrigerant flowing through the liquid refrigerant connection pipe in such a way that the refrigerant is in a gas-liquid two-phase state,
• wherein an external expansion valve unit having an external expansion valve that further reduces the pressure of the refrigerant whose pressure has been reduced in the liquid pressure adjusting expansion valve is provided in the liquid refrigerant connection pipe,
• the indoor unit further has an indoor expansion valve in an indoor liquid refrigerant pipes that interconnect the liquid refrigerant connection pipe and a liquid-side end of the indoor heat exchanger, and
• a controller, that controls constituent devices of the outdoor unit, the indoor unit, and the external expansion valve unit, controls an opening degree of the external expansion valve to allow the refrigerant after being reduced in a pressure by the external expansion valve to flow in a portion of the liquid refrigerant connection pipe between the indoor unit and the external expansion valve unit when the refrigerant circulates in the order of the compressor, the outdoor heat exchanger, the liquid refrigerant connection pipe, the indoor heat exchanger, the gas refrigerant connection pipe, and the compressor and controls an opening degree of the indoor expansion valve to allow the refrigerant after being reduced in a pressure by the indoor expansion valve to flow in a portion of the liquid refrigerant connection pipe between the indoor unit and the external expansion valve unit when the refrigerant circulates in the order of the compressor, the gas refrigerant connection pipe, the indoor heat exchanger, the liquid refrigerant connection pipe, the outdoor heat exchanger, and the compressor.