Calculation of transient phase change heat transfer through building envelopes: an improved enthalpy model and error analysis

Abstract To accurately predict the transient heat transfer process through building envelopes that have been enhanced with phase change materials (PCMs) is important. An improved two-dimensional (2D) model, based on the enthalpy method, is presented in this paper. The proposed model handles, among other features, PCM's thermo-physical parameters, various melting and solidification temperature ranges, and multiple temperature turning points during phase change, more precisely than the existing models [ 1 , 2 , 3 ]. The model was verified against the experimental data from the measurement of a wall constructed using concrete masonry units (CMUs) and enhanced with PCMs. The results of the verification indicated that the deviations of the proposed model were less than 0.40 °C for standard deviation and 0.80 °C for maximum deviation under the studied conditions. And the corresponding relative errors were less than 2.9% for standard deviation and 5.7% for maximum deviation. The proposed model is necessary for the accurate calculation of transient heat transfer in the presence of PCMs.