Abstract: The volume of the compressor directly affects the volume, as well as the installation, safety, and heat dissipation of the outdoor unit of the air conditioner. At present, there are limited methods in the industry to reduce the volume of compressors, especially in aspect of the gas-liquid separator. A miniaturized rotary compressor with a gas-liquid separator installed underneath has been proposed, which reduces the main body width of the compressor by 45% compared to conventional compressors in the same capacity range. By combining simulation and experiment, the heat transfer, gas-liquid separation, and oil return processes inside the gas-liquid separator were analyzed, and the optimal structural design of the gas-liquid separator was confirmed. The results showed that after adopting the innovative "near stagnation refrigerant insulation" technology, the compressor capacity increased by 2.2% and the energy efficiency increased by 3.3%. By reasonable designing of the internal pipe positions, pipe diameters, and oil return holes, the liquid refrigerant amount flush into the cylinder is reduced by 93%, the energy efficiency of the air conditioning system is improved by 0.2% to 3.3%, and the oil level height is guaranteed under various operating conditions. The above research guarantees the small width, high efficiency, and high reliability of the rotary compressors simultaneously, also provides favorable support for the design and development of such kind of compressors.

Key words: Rotary compressor, Miniaturized, Heat transfer, Gas-liquid separation, Oil return