Urban Heat Island intensity and buildings’ energy needs in Duran, Ecuador: Simulation studies and proposal of mitigation strategies

Abstract

Urban Heat Island (UHI) is a phenomenon that is affecting cities across the world. In tropical climates, an increased UHI intensity can cause a significant rise in heat stress probability, both indoors and outdoors. A general increase in the air-conditioning energy consumption of buildings should also be expected as a consequence. This paper evaluates the case of Duran, Ecuador. It estimated, through a spatial distribution analysis, urban morphology parameters, properties of materials, and anthropogenic heat emissions in the streets. Twenty-eight urban, randomly selected samples were classified using the k-means clustering technique, which resulted in four preliminary clusters. Exploratory UHI simulations were carried out in the Urban Weather Generator tool (UWG) using the four clusters to investigate the relevance of the main UHI driving factors through a sensitivity analysis. Urban samples were weighted, considering the sensitivity analysis, for better classifying the driving factors. Results indicate that Duran city is strongly affected by UHI, especially in informal settlements with high anthropogenic heat release. The urban temperatures obtained by the model were compared to the experimental measurements in different locations in the city. Besides, the building cooling needs were simulated by using the TRNSYS v. 17 tool for residential and commercial buildings of the city, showing that UHI is increasing cooling-related energy consumption in a 30–70 % for residential buildings and a 10–20 % for commercial buildings. Finally, general mitigation strategies and policy implications to reduce the UHI intensity are proposed, and a set of scenarios is tested for the cluster with the highest UHI intensity.