Abstract: The wall-mounted air conditioners are becoming more and more popular among consumers, the improvement of people requirements for a healthy indoor fresh air sound quality is increased. In order to ensure the indoor fresh air sound quality experience, fresh air module is taken as the research object. Under the condition of size limitation, the aerodynamic noise is improved by optimizing the design of the blade runner and centrifugal air duct; By optimizing the matching of the parameters of the external rotor motor with the fresh air load, the electromagnetic noise is improved and the competitiveness of the product is improved. The verification results show that aerodynamic noise and electromagnetic anomaly noise are effectively improved by reducing the noise value of the same speed by 2.5 dB(A) when the performance of fresh air volume is met.

Key words: Fresh air system, Noise control, Aerodynamic noise, Electromagnetic noise