Parametric optimization of passive envelope design under 2020 and 2050 climate conditions: A case study of Marrakech

This study evaluates the thermal performance of passive building envelope strategies under current (2020) and future (2050 under Representative Concentration Pathway 8.5) climate conditions in Marrakech, a hot semi-arid city facing increasing cooling demand. Glazing types, including tinted glazing (AL-Tinted) and low-emissivity glazing (Low-E), are used in building envelopes, along with phase change materials (PCM). A dynamic simulation approach was employed to assess 27 configurations combining different levels of expanded polystyrene (EPS) insulation, glazing types including tinted glazing (AL-Tinted) and low-emissivity glazing (Low-E) used in building envelopes, and phase change materials (PCM). Results indicate that in 2020, the most insulated configuration (EPS 10 cm + Low-E glazing + 4 cm PCM) reduced cooling demand by 62.7% but increased heating demand by 76.9%. Under future climate conditions, a configuration with moderate insulation (EPS 4 cm), Low-E glazing, and 4 cm PCM achieved the highest cooling reduction (−65.8%) while avoiding overheating. Configurations without insulation led to significant heating penalties exceeding +100%. The influence of envelope parameters shifts under climate change, with insulation dominating current performance and PCM becoming more significant in future scenarios. The findings highlight the need for climate-responsive design strategies, supporting a transition from insulation-driven approaches to adaptive combinations of glazing and thermal storage for hot climates.