Abstract: Frosting has the most significant impact on the heating capacity and thermal comfort of heat pump air conditioners. Developing dynamic model of air conditioners under frosting condition is an effective solution to optimize control strategy to improve the heating capacity and thermal comfort of heat pumper air conditioners. A dynamic model of air conditioners under frosting condition is established, where the frost accumulation is calculated by the difference of air humidity through heat exchanger based on the heat exchanger surface temperature at first, and then a relation is built between the frost accumulation and air flow rate to couple the frosting and heat and mass transfer in air conditioning system. The experiment validations show that the new dynamic model can predict the attenuation of air flow rates and the attenuation of heating capacities under the frosting condition, where the maximum real-time deviation of air flow rates are less than 5%, and the calculation error of cumulative heat capacities are less than 5%.

Key words: Air conditioner, Heat pump, Heat exchanger, Frosting, Dynamic modeling