Single-cold air conditioner and control method thereof

The invention discloses a kind of single cold type air-conditioner and control method thereof.Single cold type air-conditioner includes: duplex cylinder compressor, outdoor heat exchanger, indoor heat exchanger and gas-liquid separator, duplex cylinder compressor includes the first cylinder, the second cylinder, the first reservoir and the second reservoir, the air entry of the first cylinder and the connection of the first reservoir, the air entry of the second cylinder and the connection of the second reservoir, the span of the delivery space ratio of the second cylinder and the first cylinder is 1%～10%；Gas-liquid separator includes gas outlet, first interface and the second interface, gas outlet is connected with the second reservoir, it is in series with the adjustable first throttle element of aperture between first interface and outdoor heat exchanger, between the second interface and indoor heat exchanger, is in series with the adjustable second section fluid element of aperture.Single cold type air-conditioner according to the present invention, is effectively improved energy efficiency of air conditioner.