Abstract: In order to reduce the pipeline vibration and noise in the process of air conditioning defrosting and improve the capacity of air conditioning heating cycle, the control technology of defrosting is experimentally studied. Firstly, the single factor tests of each actuator of air conditioner such as indoor fan, four-way valve, compressor and outdoor fan are carried out, determined the impact of each actuator on the air conditioning system. Then, the actuators are jointly controlled to form an optimized program, which is compared with the original program. Experiments show that the optimized defrosting program can reduce the high and low pressure difference by 0.061 MPa and the pipeline vibration and noise are effectively reduced when the four-way valve is reversing. The optimized scheme can also improve the heating capacity 134 W and energy efficiency ratio, which is helpful to improve the heating comfort of users. The research results have guiding significance for the control strategy of defrosting.

Key words: Variable frequency air conditioner, Defrosting, Control technology, Optimization