An experimental study of the efficacy of integrating a phase change material into a clay-straw wall in the Drâa-Tafilalet Region (Errachidia Province), Morocco. (November 2020) - Ben Zaid, Zaineb
Abstract: The objective of this new study is to integrate a Phase Change Material (PCM) into a clay-straw wall in order to reduce the energy consumption of buildings in Morocco's Drâa-Tafilalet Region. The underlying notion is to fully utilize the storage capacity in the walls built with clay and straw. Furthermore, to raise the thermal energy stored in the building envelope, a PCM was integrated into the walls. In this experiment, a reduced-scale cavity with replaceable sidewalls was used to study the thermal transfer taking place in walls. The effect of PCM location was also investigated by considering the reduction in both wall surface temperature and surface heat flux. Both the inner and outer wall layer temperatures were measured, while the heat flux through the walls and the heat stored in the walls were estimated. Results show that by integrating PCM into the clay-straw wall, the surface temperature can be reduced by up to 3 °C. In addition, the location of the PCM adjacent to the heat source considerably lowers the surface temperature, by a value of 1 °C compared to when PCM is placed on the outer wall layer. The peak heat flux of the PCM-integrated wall drops by 31.95% compared to the clay-straw wall without PCM. However, for the clay-straw wall with PCM on the outer layer, the peak heat flux is reduced by 26.5%. Moreover, the PCM-integrated wall stores 14.17 W/m 2 on average of the inlet heat flux. On the other hand, the clay-straw wall with PCM on the outer layer and the wall with PCM embedded in the middle are both able to reduce the peak heat flux by 30.41%. Highlights: A PCM-integrated, clay-straw wall performs satisfactorily on a reduced-scale cavity. The time delay in heat transfer is improved compared to the non-PCM clay-straw wall. The effect of PCM location on the inner wall layer serves to reduce heat transfer. The wall with PCM on the inner layer improves thermal storage performance.