Ricerc@Sapienza

Urban heat island (UHI) can considerably affect the thermal quality of the urban environment, especially within urban canyons, that have typically low sky view factor and limited surface heat re-emission capability. A huge research effort has been registered to develop mitigation solutions for UHI, such as cool materials and greenery. Nevertheless, it is not always possible to apply such strategies in historical urban environments due to constrains for the preservation of their cultural value that do not allow to modify the exterior architectural appearance of heritage buildings.

While urban areas expand both in terms of population and built/paved surfaces, cities are facing growing challenges. In particular, the wellbeing and comfort of urban population is of primary importance, and has to be pursued together with other objectives, such as the reduction of energy consumptions and emissions. These issues are all related, since energy consumptions lead to higher emissions, which translate into higher temperatures in cities, thus reduced thermal comfort for pedestrians, and air quality deterioration.

Nowadays, passive strategies are identified among the preferred solutions to reduce energy consumption and to increase comfort in the built environment. Indeed, such strategies allow energy saving by exploiting the intrinsic characteristics of materials. In this work, an innovative cool, photoluminescent paint is considered for application in the built environment, as a passive strategy to (i) reduce energy for cooling in the hot season, (ii) maintain lower surface and air temperatures, thus benefiting comfort and (iii) contribute to the lighting of the outdoor public space.