Heat pump air conditioner

A heat pump air conditioner through which a refrigerant flows, the heat pump air conditioner comprising:

• a compressor for compressing and discharging a refrigerant;
• a first heat exchanger for radiating heat of the gas refrigerant discharged from the compressor;
• a decompressing unit for decompressing the refrigerant having passed through the first heat exchanger, the decompressing unit having a throttle portion with a fixed opening degree;
• a second heat exchanger for evaporating the refrigerant having passed through the decompressing unit;
• a separator for separating the refrigerant having passed through the second heat exchanger into gas refrigerant and liquid refrigerant and storing the liquid refrigerant therein, the separator having a gas suction pipe through which the gas refrigerant in the separator is sucked into the compressor, the gas suction pipe having an oil return hole through which at least oil is sucked and mixed with the gas refrigerant to be returned into the compressor, the oil return hole being formed at a bottom of the gas suction pipe;
• and
• a control unit for controlling an operation of the compressor, the control unit having judging means for judging whether a specific condition that a surface of the liquid refrigerant in the separator is rapidly lowered toward the oil return hole is satisfied, wherein:
• the control unit forces the refrigerant to flow bypassing the decompressing unit at the time of starting the compressor when the judging means judges that the specific condition is satisfied.

A heat pump air conditioner through which a refrigerant flows, the heat pump air conditioner comprising:

• a compressor for compressing and discharging a refrigerant;
• a first heat exchanger for radiating heat of the gas refrigerant discharged from the compressor;
• a decompressing unit for decompressing the refrigerant having passed through the first heat exchanger, the decompressing unit having a throttle portion with a variable opening degree;
• a second heat exchanger for evaporating the refrigerant having passed through the decompressing unit;
• a separator for separating the refrigerant having passed through the second heat exchanger into gas refrigerant and liquid refrigerant and storing the liquid refrigerant therein, the separator having a gas suction pipe through which the gas refrigerant in the separator is sucked into the compressor, the gas suction pipe having an oil return hole through which at least oil is sucked and mixed with the gas refrigerant to be returned into the compressor, the oil return hole being formed at a bottom of the gas suction pipe;
• and
• a control unit for controlling an operation of the compressor, the control unit having judging means for judging whether a specific condition that a surface of the liquid refrigerant in the separator is rapidly lowered toward the oil return hole is satisfied, wherein:
• the control unit increases the opening degree of the throttle portion to a value larger than that in a normal state at the time of starting the compressor when the judging means judges that the specific condition is satisfied.