Experimental study on optimal operation control strategy of quasi-two-stage compression heat pump air conditioning system based on full micro-channel heat exchanger

In environments with significant temperature variations, the quasi-two-stage compression heat pump air conditioning system demonstrates notable advantages in mitigating key challenges such as high compressor exhaust temperature, exhaust pressure, low system heat exchange, and COP. This study optimizes the optimal refrigerant charge amount and superheat set-point control strategy of the electronic expansion valve for the system. By adjusting the method of supplying the gas and the superheat set-point of the electronic expansion valve, the system is able to achieve stable and efficient operation. The experimental findings indicate that following the optimization of operational control strategies, the system heat exchange capacity increased by 18.8%, the COP improved by 12.3%, and the compressor exhaust temperature decreased by 11.3?C.