Assessment of green roofs performance with numerical simulation tools and experimental measurements

The application of green roofs is spreading all over the world due to the many benefits they provide at both building and city scale. The continuous cities growth leads to an increasing heat island effect with important consequences for the inhabitants comfort. Countermeasures such as vegetative roof covers can mitigate the urban microclimates thanks to evapotranspirative cooling and roof shading, thus reducing the roof surface temperature and hence the surrounding air temperature. To quantify these potential benefits, a key aspect is the availability to designers and green roof systems developers of advanced numerical simulation tools, capable of modeling all the complex interacting phenomena that influence the performance of a green roof. This paper focuses on the analysis of surface and near surface green roof temperatures with two well-known and validated simulation models, WUFI and EnergyPlus, for two different locations, Holzkirchen (Germany) and Milano (Italy), during the summer