Dynamic, Modeling, Heat exchanger model, Frosting, Defrosting
In this paper, a dynamic heat exchanger model that unifies the frosting and defrosting analyses is presented. A novel scheme is proposed to solve the air flow redistribution due to non-uniform frost blockage. Unlike the existing defrost models which separate analysis for tubes and fins, the proposed defrost model unifies the analysis to maintain model consistency. The first-principles based frost and defrost models developed in this research allow for a more realistic assessment of the heat pump systems and greatly facilitate the design of controls. Utilizing the developed models, the transient behavior of a flash tank vapor injection heat pump under frosting and defrosting conditions is investigated and validated against experimental data.