L’effetto della forma urbana sul guadagno solare delle facciate nella città compatta. Un approccio a scala urbana in un quartiere del XIX secolo

Within the variation of energy performance and microclimate conditions, the relation between urban form and solar irradiation takes a central role. In southern European cities, this relation takes on specific value due to climate conditions and urban texture features (built form, density, settings, etc.). The former determines a complex balance between solar gain and mutual shading, while the latter defines the model of the historical compact city. This study aims at determining the effect of the urban form of historical fabrics on solar access of façades, taken urban density parameters as indicators. A district-scale approach is proposed and tested in the case of different urban textures of a XIX century neighbourhood of Rome. The solar performance is assessed for direct gain passive solar systems on each of the building façades over a one-year period is calculated using Heliodon 2. Results show that this performance is more related to compactness (GSI) than building intensity (FSI). The study provides a contribution to the early-design stage solar energy assessment tools and fosters climate-sensitive urban regeneration in the historical compact city.