Single cooling type air conditioner and control method thereof

The invention discloses a single cooling type air conditioner and a control method thereof. The single cooling type air conditioner comprises a double-cylinder compressor, an outdoor heat exchanger, an indoor heat exchanger, a gas-liquid separator and a refrigerant radiator, a gas suction port of a first cylinder is communicated with a first liquid reservoir; the value range of an exhaust volume ratio of a second cylinder and the first cylinder is 1-10 percent; the gas-liquid separator is composed of a gas outlet, a first port and a second port; the gas outlet is connected with the second cylinder; a first throttling element with a fixed opening is connected in series between the first port and the outdoor heat exchanger; a second throttling element with a fixed opening is connected in series between the second port and the indoor heat exchanger; and the refrigerant radiator is connected in series between the outdoor heat exchanger and the first throttling element. According to the single cooling type air con