Abstract: In the process of developing a 1.5 HP room air conditioner, the refrigerant was changed from R32 to R410A. Under the condensation condition, there were small water droplets on the left side of the air duct of the indoor unit, which formed into large water droplets and drips. The theoretical analysis and experimental verification showed that the same evaporator diverting flow path, using different refrigerant, diverting uniformity was different. In the case of not changing the diverting flow path of the indoor evaporator of the mass production model, the circulation amount of R410A refrigerant in the system can be increased by reducing the target exhaust temperature to increase the opening of the electronic expansion valve during the system operation, and the uniformity of the diverting flow of the indoor evaporator can be improved by reducing the dryness of the evaporator inlet, so as to effectively solve the condensation problem. The research provides a feasible solution for solving similar problems in practical engineering, and plays a certain guiding role for refrigerant change and system optimization in the subsequent development process of cost reduction.

Key words: Room air conditioner, Refrigerant, Inlet dryness, Condensation