Computational Fluid Dynamics Analysis for Evaluating the Urban Heat Island Effects

In this study an urban geometry, constituted by three urban street canyons with a canyon aspect ratio H/W of 1.0, has been examined. CFD simulations were performed to evaluate the fields of temperature and velocity of the air within the urban canyons and their surroundings. Several scenarios were examined considering alternatively the leeward or the windward walls hitted by the sunrays, while the opposite façade was shaded, as well as varying the reflective properties of the surfaces and the wind velocity. The results of simulations evidence that the adoption of materials of the building envelope with high albedo coefficient guarantees a decrease of the temperatures at least of 1.5°C. Therefore, an increase of the knowledge of urban climate may provide valuable contribution to promote energy efficiency in the built environment.