Modified computational methods using effective heat capacity model for the thermal evaluation of PCM outfitted walls

摘要

Some modified computational methods when using two-dimensional effective heat capacity model for predicting the transient heat transfer process of the building envelopes outfitted with phase change materials (PCMs) were presented. In the methods, some important improvements were performed, such as considering different melting and solidification temperature ranges, multiple temperature turning points and PCM's liquid fraction during phase change process. The experiments were conducted to verify the accuracy of the proposed methods. Based on the experimental data, the comparative analysis of the presented methods together with the original methods using enthalpy model and effective heat capacity model were conducted. The deviations produced by the original methods were found to be markedly larger than the presented ones. The standard and the maximum deviations of the modified methods were less than 0.25 degrees C and 0.55 degrees C, and the corresponding relative errors were under 2.5% and 4.0%.