Abstract: An air conditioning system includes a refrigerant circuit including a compressor, an indoor heat exchanger, a first expansion valve, a gas-liquid separator, a second expansion valve, and an outdoor heat exchanger which are sequentially connected together to perform a two-stage expansion refrigeration cycle. The refrigerant circuit further includes: a gas injection pipe through which intermediate-pressure gas refrigerant in the gas-liquid separator flows into an intermediate port of the compressor, and a liquid-gas heat exchanger configured to exchange heat between low-pressure gas refrigerant obtained by evaporating refrigerant in the outdoor heat exchanger and travelling toward the compressor and intermediate-pressure liquid refrigerant travelling from the gas-liquid separator toward the second expansion valve.

Abstract: A rotary compressor includes a cylinder having an annular cylinder space, a piston eccentrically disposed relative to the cylinder, and a drive shaft (53) connected to the piston. The piston has a piston portion eccentrically rotatable relative to the cylinder, and a piston end plate closing the cylinder space. The cylinder has an end plate storage space storing the piston end plate in an eccentrically rotatable manner. The cylinder space forms a main cylinder chamber, and the end plate storage space forms a sub-cylinder chamber.