Experimental investigation of thermal performance of microencapsulated PCM-contained wallboard by two measurement modes

Abstract

Phase change materials (PCM) as a smart, feasible latent heat storage material has been utilized to reduce the energy demand and improve the thermal comfort of the buildings when incorporated into the building materials. Conventionally, the thermal behavior of the PCM mixed with the solid matrix (mortar or gypsum) is different with the bulk PCM. In this study, we designed an experimental apparatus to characterize the thermal performance of PCMs when they were utilized in their implementation state. Firstly, we investigated the effective thermal conductivity (λ) and the apparent specific heat (Cp) of the PCM-contained wallboard and the common gypsum wallboard, which were dependent on the temperature variation. Dynamic method was used to determine the phase change temperature, and the phase change process of the PCMs-wallboard was studied. Then, an “analogous step method” was proposed to determine the H(t) curves of the PCMs-wallboard, and the results were compared with the dynamic method. Finally, three methods of obtaining H(t) curves were compared and analyzed. From the obtained results, it can be concluded that when adopting the dynamic method appropriate heating rate (according to real application scenario) is necessary. When selecting the analogous step method, reducing the temperature interval can increase the accuracy of the H(t) even though it takes a lot of time. Anyway, both ways are more suitable for real wallboard test, comparing with the theoretical calculation method. The goal of our work is to investigate an appropriate method to evaluate the conductivities, apparent heat capacities, H(t) curves, and the phase change temperature of PCM-contained wallboards in their real application.