Abstract: When the heating function of air conditioner is turned on, especially in low temperature and high humidity, the outdoor condenser of air conditioner is easy to frost by ice. The effect of defrosting, the noise and the impact of defrosting of the heating ability have a great impact on the user experience. Especially in the case of low temperature and high humidity in the south, frost formation is serious. It is difficult to remove and affects the heating ability, affecting the user's heating experience. Optimizes the defrosting control logic of air conditioner in low temperature and high humidity environment. Through the outdoor coil temperature and outdoor ambient temperature, the frosting degree is intelligently judged. The defrosting effect of air conditioner outdoor heat exchanger in low temperature and high humidity condition is improved. The system can make intelligent judgment and timely defrosting, improve the heating effect under the same working conditions, and realize the significant improvement of user experience in heating. The action of electronic expansion valve and four-way valve in defrosting is optimized, which reduces the noise of defrosting.

Key words: Air conditioner, Optimization of defrost function, Noise, Heating capacity