Thermal comfort assessment of secondary school building stock in southern Spain using parametric numerical models and applying different climatic and ventilation scenarios

Climate change is accelerating global warming, leading in turn to increased thermal stress and indoor overheating, particularly in buildings with high occupancy in southern Europe. This study examines the thermal performance of secondary school buildings in southern Spain, focusing on the influence of ventilation on thermal comfort. Given the reliance on natural ventilation of a significant portion of the Mediterranean school building stock, this research aims to characterize thermal comfort conditions using validated parametric simulation models on a regional scale. The study analyses current and future comfort conditions across different climatic zones, incorporating climate change projections, and assessing overheating and undercooling risks. Results show how ventilation without thermal treatment plays a crucial role in both overheating and undercooling. Higher ventilation rates generally lead to discomfort during winter but improve comfort in summer. Building orientation and solar exposure further influence comfort, with south-facing buildings benefiting from solar gains. Projections for 2050 suggest an increase in overheating risks, particularly in cities with higher cooling degree days (CDD). Despite the benefits of higher ventilation rates, these may not fully mitigate the anticipated increase in overheating, which showcases the need for additional strategies, such as active ventilation systems, to address these challenges. The findings highlight the need for improved adaptation strategies to mitigate the effects of climate change. • Influence of natural ventilation on thermal performance of Mediterranean schools • Overheating and undercooling risk under current and future climate change scenarios • Orientation and use of blinds influence thermal comfort through solar gains • Higher ventilation rates reduce summer discomfort but worsen winter conditions • Adaptive natural ventilation strategies are needed to face future climates