Mitigating undercooling and overheating risk in existing desert schools under current and future climate using validated building simulation model

Abstract

In Palestine and neighboring regions, buildings are constructed without insulation and mechanical heating and cooling systems, leading to significant thermal discomfort for occupants. To address this issue, the paper introduces a robust methodology that utilizes a validated building simulation model (BSM) created based on hourly indoor air temperature to assess indoor thermal comfort during winter and summer seasons under both current and future climates. This methodology is applied to an existing school built in 1990 in Jericho-Palestine, which has a hot desert climate. Classrooms rely on the thermal mass to increase the indoor temperature in the winter, and natural ventilation to reduce it in the summer. The effect of climate change on indoor thermal conditions is evaluated using typical warmer and colder future years based on the latest SSP5-8.5 scenario. The results showed that the calibrated and validated BSM achieved a highly accurate prediction of indoor air temperature compared to indoor air measured temperature. The validated BSM showed extreme cold for 880 h (91% of wintertime) and excessive heat for 90 h (19% of summertime) during school days. Passive winter measures, including high insulation and airtightness level, and using double glass windows, reduce undercooling to less than 40 h but increase overheating to 180 h. Passive summer measures, including night cooling and exterior shading, are necessary to reduce overheating to around 40 h. These measures are still effective in resisting the cold future years, but more creative passive summer measures and/or a mechanical cooling system are needed.