Experimental Assessment of PCM Roof Layers on Thermal Comfort in a Hot Semi-Arid Climate.

Nowadays the building sector consumes more than a quarter of total energy production worldwide, holding an immense contribution to the environmental crisis. For that, applying energy efficiency measures in early building design, such as improving building envelope, continues to strike attention among decisionmakers. This study presents the experimental evaluation of two configurations for a building roof, which include Phase Change Material (PCM) close to the inner layer. Two experimental modular rooms were built, one as a base case without PCM and the other as a PCM case. The evaluation was carried out under free running evolution and in semi-arid climatic condition during summer period in Monterrey, Mexico. The thermal performance of the modular rooms was evaluated based on indoor air and sol-air temperatures, whereas the time within comfort range was analyzed under an adaptative thermal comfort model. A comprehensive assessment of results showed that for the selected period, the reduction of maximum indoor temperature was between 3.94 and 7.02%. In addition, even though the PCM was only placed on the ceiling, it had a notable impact on the temperature decrease on the walls and floor. Regarding comfort, it was found that an increase in comfort time by 50 min for setting A and 70 min for setting B in comparison with the base case. Finally, the results showed the highest reduction in indoor air temperature of 2.06 degrees C for setting B with 30 cm of air chamber.