Research on frost formation in air source heat pump at cold-moist conditions in central-south China

►A dynamic evaporator model is built up. ► The model involves the ratio of the latent heat to sensible heat of wet air. ►A correlation considering deq is shown below to predict frost accumulation: Mfrv3Ψdeq2=(TaTw)0.1(vτdeq)0.7(ldeq)1.378Xa1.228. ►The changing ratio can characterize the early development of system performance. ►The changing ratio can characterize the early development of frost accumulation.