Effect of mechanical ventilation on the improvement of the thermal performance of PCM-incorporated double external walls: A numerical investigation under different climatic conditions in Morocco

•The mechanical ventilation improves the contribution of PCMs.•Climatic conditions impact PCMs and mechanical ventilation performances.•The ventilation rates affect indoor temperatures and cooling energy.•Appropriate ventilation rate reduced the payback period of PCM. Improving the thermal storage capacity of buildings through the use of phase change materials (PCMs) is a promising solution to improve the thermal comfort of occupants and reduce energy consumption. In this study, the contribution of mechanical ventilation to the improvement of the thermal performance of double external walls incorporating PCM was investigated. The thermal and energetic performances of a typical residential dwelling in different climatic zones of Morocco were evaluated using recently collected weather data in typical meteorological year format. Several parameters that could impact the results were explored, including the melting temperature and thickness of the PCM, as well as the ventilation rate. The simulation results showed that the use of mechanical ventilation can lead to a considerable improvement in the thermal comfort and reduction in cooling energy consumption. In addition, an economic analysis revealed that mechanical ventilation can contribute to reducing the payback period of PCM investment.