Air conditioner

An air conditioner comprising:

• a refrigerant circuit including:
• a compressor;
• an outdoor heat exchanger;
• an expansion valve;
• and an indoor heat exchanger all of which are connected in a stated order;
• a cycle controller causing either (i) the outdoor heat exchanger to function as an evaporator and the indoor heat exchanger to function as a condenser to create a heating cycle in the refrigerant circuit or (ii) the outdoor heat exchanger to function as the condenser and the indoor heat exchanger to function as the evaporator when a reverse cycle executing condition is met, to create a reverse cycle in the refrigerant circuit, so that the refrigerant circulates in reverse of the heating cycle;
• a rotation speed controller adjusting a rotation speed of the compressor in the reverse cycle, depending on an index correlated with an amount of frost on the outdoor heat exchanger at a start of the reverse cycle;
• and
• an opening adjuster adjusting an opening of the expansion valve, depending on the index at the start of the reverse cycle,
• the rotation speed controller decreasing the rotation speed of the compressor in the reverse cycle as the index at the start of the reverse cycle indicates that the amount of the frost on the outdoor heat exchanger is smaller, and
• the opening adjuster decreasing the opening of the expansion valve in accordance with the amount of the frost on the outdoor heat exchanger, so that the opening decreased becomes smaller than the opening when the compressor runs at a highest rotation speed in the reverse cycle, as the index at the start of the reverse cycle indicates that the amount of the frost on the outdoor heat exchanger is smaller.