Assessing overheating and undercooling risks in existing public secondary schools in Mediterranean climate

Abstract

During the last years, there has been a significant increase in temperatures, as well as in the intensity and duration of heatwaves due to climate change, which noticeably affects summer, but also winter conditions. Thus, assessing overheating and undercooling risks in the existing stock is of the utmost importance, especially in highly occupied educational buildings with natural ventilation systems. These risks do not only affect students' thermal comfort but their health and academic performance. Besides, COVID-19 has highlighted the energy vulnerability of schools and the complexity to adopt adequate strategies to enhance indoor environmental quality. To assess overheating and undercooling risks in educational buildings in southern Spain, a parameterized and validated building simulation model has been constructed from a representative school using monitored data. Through sensitivity analysis techniques, the most critical variables on adaptive thermal comfort in summer and winter have been determined. The study highlights the difficulty of guaranteeing a balance between indoor air quality and thermal comfort, since not only infiltration and ventilation rate have a key impact on thermal comfort, but also and more importantly ventilation schedules. These conclusions are vital to propose retrofit strategies to mitigate climate change while tackling undercooling, using parameterized building-archetype models, which allow to simulate other representative case studies in the area.