Thermo-physical Characterisation of Plasters Containing Phase Change Materials (PCMs)

Abstract

Abstract Phase change materials (PCMs) added into building materials largely demonstrated their effect in improving the overall thermal capacity, thus contributing to the reduction of the energy demand for heating and/or cooling. Knowing the thermo-physical properties of the enhanced materials is essential to maximize the achievable effect. The most used technique to do so is the Differential Scanning Calorimetry (DSC), but in case of inhomogeneous materials this method turns out to be poorly reliable, mainly due to the small amount of material usually needed to carry out the test. To overcome the main limitations, an alternative set up was realized, which allowed the characterization of different plaster samples enhanced with granular PCM. More specifically, plasters enhanced with 10% by mass of two different PCMs with melting temperatures of 28°C and 27°C, respectively, were considered. At first, a steady-state test was conducted and constant thermal gradients were maintained through which the thermal conductivity of the materials used was estimated. Then, an unsteady-state test was conducted through which the specific heat and the latent heat were estimated, showing a good agreement with values provided by the PCM suppliers. The estimated properties were then validated against experimental data acquired during the monitoring activity under real outdoor conditions of different wall samples on which the PCM-enhanced plasters were applied. With the estimated properties, RMSE values were lower than 1°C for temperatures and lower than 2.50 W/m2 for heat fluxes.