Ricerc@Sapienza

Urban heat island is an anthropogenic phenomenon affecting urban outdoor thermal comfort conditions
and energy utilization. This is even truer in urban canyon con?gurations, characterized by low sky view
factor and where the effect of short-wave and long-wave solar radiation on construction surfaces is able
to produce massive outdoor local overheating. Traditional solutions cannot always be applied in urban
historical canyons, where the exteriors of buildings cannot be modi?ed due to preservation. Here, the
capability of innovative cool materials to mitigate local microclimate of historical urban canyons is
investigated. A preliminary experimental characterization of the materials is performed. A numerical
simulation of the microclimate effect generated by the application of such materials is performed. Results
show that the proposed materials improve the microclimate without neglecting preservation constrains.
Such materials set the best scenarios in terms of thermal comfort, by enhancing albedo on canyon
surfaces. Their application on the vertical surfaces of narrow canyons can lead to deleterious effects on
outdoor thermal comfort. Such ?ndings are con?rmed by PMV and MOCI analyses. Energy ef?ciency
solutions may be effectively implemented in historical districts, opening the doors to other tailored
solutions, such as integrated renewables, to make these environments more sustainable and comfortable.