Energy effectiveness of passive cooling design strategies to reduce the impact of long-term heatwaves on occupants’ thermal comfort in Europe: Climate change and mitigation

Many newly built, energy-efficient terraced houses are characterised by high indoor air temperatures and thermal comfort issues, because these state-of-the-art houses were designed and built without considering the warming climate conditions in the summer. As a result, many of these residential buildings are at risk of overheating and require careful implementation of passive cooling design systems when retrofitting. This study reviews the overheating risk and energy effectiveness of six passive design strategies tested and implemented in an innovative terraced house located in southeast London during the long-term heatwaves experienced in both the UK and continental Europe in the summer of 2018. A quantitative research methodology is employed based on an extensive monitoring campaign conducted to measure environmental conditions, including indoor air temperature, relative humidity and CO2 of each occupied space in a prototype base-case building. In the subsequent phase of the research, retrofit strategies were investigated by modelling and simulation using the Integrated Environmental Solutions (IES) software suite for data validation. The preliminary results of the modelling and simulation confirmed the survey findings of high levels of occupant discomfort and relatively high cooling loads. The internal operating temperatures of the simulated rooms remained high throughout the day and night during the long-term heatwaves, ranging from a minimum of 24.7 °C to a maximum of 32.1 °C. The results highlight significant deviations in the estimated energy consumption of the base-case building as well as in the energetic and environmental indexes of the passive cooling design strategies. The study will contribute to the strategic design of retrofit interventions to effectively reduce cooling energy consumption by considering occupants’ thermal comfort, thermal adaptation and energy use.