Energy and cost efficiency of phase change materials integrated in building envelopes under Tunisia Mediterranean climate

Abstract

An extensive study, including energy and economic analyses has been proposed to assess the benefits of the phase change materials (PCMs) when integrated into building envelopes under the Tunisian climate. Sensitivity analyses have been presented in order to investigate the PCM interaction with the thermal insulation and the cool roof measures. Numerical simulations with EnergyPlus highlighted the crucial selection of an optimal phase change temperature. The PCM applied on the outside face of a brick wall provided better energy efficiency, with the highest energy savings up to 13.4% achieved for the south orientation. The integration of the PCM improved the thermal inertia of the wall with an increase of 2 h in the time lag for the east orientation. A 30-year life cycle cost analysis showed that the integration of the PCM in a brick wall is not cost-effective. The interaction between the PCM and the thermal insulation in a brick wall showed a better efficiency of the PCM in the absence of insulation, providing the highest rate of energy consumption reduction, estimated to 12.21%. The integration of the PCM in a concrete-based cool roof compensated the wintertime penalties and reduced the daily surface temperature fluctuation by up to 5.35 °C.