Abstract: The structure of the heat exchanger of the room air conditioner is becoming more and more compact. At the same time, the demand for the refrigeration capacity is increasing. It is very important to ensure that the air conditioner can give full play to its refrigeration capacity and operate reliably by analyzing the thermal properties of the refrigerant, reasonably adjusting and setting the parameters of the refrigeration system. Theoretically and experimentally analyzes the change of system operation characteristics with outdoor air volume when the room air conditioner in R32 refrigerant is at high frequency output. The change of air volume affects the change of system pressure and refrigerant flow. Excessive external air volume causes low evaporation temperature and overheating. Part of the area in the evaporator is superheated gas, the effective heat exchange area becomes smaller, and the refrigeration capacity of the system decreases. In the actual design and commissioning of the refrigeration system, it is necessary to adjust the temperature difference between the inlet and outlet of the indoor evaporator reasonably to achieve the optimal operation of the system.

Key words: Room air conditioner in R32 refrigerant, High frequency operation, System characteristics