Analysis of the thermal response of a dual phase change material embedded in a multi-layered building envelope

Abstract

Mastering the thermal inertia of building envelopes is a key issue for properly handling the energy efficiency of buildings. The present study addresses the integration of a dual microencapsulated phase change material mixed with plaster as a coating layer on the inner wall of the building envelope. The purpose for using a hybrid PCM is to control the time shift of the heat load and its a posteriori impact on energy efficiency. The thermal response of the wall subject to different climatic conditions is investigated numerically using a finite volume method. A new mathematical model based on the enthalpy method is proposed, implemented and tested to analyze the effect of the dual PCM in depth. The predicted results demonstrate that the heat storage period is augmented by a factor of 57% when a dual PCM is used with plaster instead of a single PCM. The dual PCM also attenuates the decrement factor and lessens the heat infiltration into the building during the day by more than a 75% margin for the different climates investigated. In addition, the dual PCM contributes to reduce the temperature inside the building by lowering the indoor surface temperature by about 2 °C and also delays the peak in the heat infiltration beyond 3 hours. Consequently, usage of the dual PCM impacts positively on the energy consumption.