Mitigation of the impacts of heat islands on energy consumption in buildings: A case study of the city of Tehran, Iran

Abstract

• Strategies were proposed to mitigate the impact of urban heat islands (UHIs) on the energy performance at residential building level. • High-albedo materials and vegetation were incorporated in the simulations. • UHI in Tehran can be reduced by 2.1 °C through a combination of high-albedo material and vegetation. This research investigates several strategies that can be used to mitigate the impact of urban heat islands (UHIs) on the energy performance of residential buildings. In this context, the UHI in Tehran's city was first analysed by comparing weather data from two synoptic stations: Mehrabad in an urban area and rural Karaj. Furthermore, to improve thermal comfort and assess the effects of UHI mitigation strategies on microclimate, high-albedo materials, vegetation, and a combination of these two strategies were simulated using the ENVI-met tool. The time span was based on peak yearly temperature. After investigating the most commonly used scenarios, which are the most effective on ambient air temperature, the impact of ambient air on residential building energy consumption was calculated. The results illustrated that the UHI in Tehran is around 3–6 °C, which can be reduced by 2.1 °C through a combination of high-albedo material and vegetation; subsequently, the cooling load decreases by 29% under the same scenario. Consequently, implementing these optimal strategies leads to better thermal comfort being achieved and savings in energy consumption.