Development and Experimental Researches on A Multi-Connected Air-Conditioning System

A multi-connected air-conditioning system having one outdoor unit and four indoor units, with 5 HP constant speed scroll compressor paralleled with 4 HP frequency inverter scroll compressor, was developed. Many experiments were taken under different working conditions and different system parameters. The performances and the operating characteristics were obtained. The oil-back ability was validated and the necessary oil-back/oil equilibrium operation modes were improved. The influences of the connection pipeline on the performances and the operating parameters were also analyzed. The different charge amount of refrigerant and its influence were tested and analyzed. In the end, according to the state standard of multi-connected air-condition (heat pump) unit, the IPLV of this system with double compressors was calculated based on the part load performances.