Patent ID: 8402779

Claim:
An air conditioner comprising: a refrigerant circuit including a heat source unit having a compressor and a heat source side heat exchanger exchanging heat between refrigerant and air, a utilization unit having a utilization side expansion mechanism and a utilization side heat exchanger, and a liquid refrigerant communication pipe and a gaseous refrigerant communication pipe connecting the heat source unit to the utilization unit, the refrigerant circuit being configured to perform at least a cooling operation in which the heat source side heat exchanger functions as a condenser of the refrigerant compressed in the compressor and the utilization side heat exchanger functions as an evaporator of the refrigerant condensed in the heat source side heat exchanger; a shutoff valve being disposed at a position downstream of the heat source side heat exchanger and upstream of the liquid refrigerant communication pipe in a refrigerant flow direction in the refrigerant circuit in the cooling operation, and configured to shut off the refrigerant flow; and a refrigerant detection unit being disposed upstream of the shutoff valve in the refrigerant flow direction in the refrigerant circuit in the cooling operation, and configured to detect the amount or the amount-related value of refrigerant that exists upstream of the shutoff valve by detecting the liquid surface height of the refrigerant in the heat source side heat exchanger.