A toolchain to evaluate the impact of urban heat island and climate change on summer overheating at district level

This paper aims to quantify and analyse the impact of urban heat island and climate change on summer indoor thermal comfort in buildings at district level. By leveraging the models of outdoor climate and dynamic building simulation, a toolchain is developed to quantify the overheating hours under different outdoor climate scenarios in rural and urban context. Future climate data are generated for the city of Roeselare (Belgium) under RCP4.5 and RCP8.5 scenarios in 2030 and 2050 respectively, and a residential district with 265 buildings is analysed by incorporating characteristics data of individual buildings, instead of using a traditional archetype approach. The results clearly demonstrate that overheating risks exist in most of the buildings of the analysed district under all climate scenarios. Mutual shading plays a non-negligible role in the overheating analysis. Scheduled opening of operable windows and controlled solar shading devices can effectively reduce the overheating hours at the district level under all climate scenarios. The impact of urban heat island is less important for the situation with adaptation measures, and the number of overheating hours could be even larger in rural areas in certain circumstances. The results of overheating hours could be different by using different quantification methods.