22. Urban Microclimate and Thermal Comfort in the Social Housing Districts of Rome: The Combined Effect of Built Form and Urban Materials

This work explores the interdependencies, at the neighbourhood scale, between the built form and the urban materials with microclimate and thermal comfort in the social housing districts of Rome (Italy). Indeed, in Italy, as well as in other European countries, most of the urban expansions happened during the second half of the twentieth century thanks to public investments. Therefore, these neighbourhoods represent nowadays a relevant part of the built-up footprint and they accommodate many inhabitants. Moreover, these suburban social housing districts, designed by important architects, have been widely investigated by researchers, architects and practitioners focusing on sustainable transformation and regeneration. This attention was due to the observation that such public building stock is the ideal environment to test urban renewal strategies and sustainable design methods based on thermal analysis tools at urban scale for Mediterranean climate since each district is distinguished by unitary design that gives it morphological, typological and technological homogeneity. Furthermore, in Southern Europe, outdoor areas and public spaces are culturally considered as the extension of one’s living spaces and for this reason are of fundamental importance for mankind social life and inhabitants’ living quality. This is even more significant, given the urban population growth. Such growth poses serious issues, e.g. urban heat island effect on urban areas, and, for this reason, urban microclimatic conditions and inhabitant well-being in the existing city are of primary importance. The effects of urban materials and built form on microclimate and outdoor thermal comfort have been widely investigated by building physics and urban physics but more often without approaching the interdependencies between the two disciplines at multi-scale level. In parallel to these, work on the environmental performance of built form has progressed in recent years to include not only the building itself but also other components of the urban space scaling up to a wider scale of analysis. Key urban form and material-related microclimatic consequences of existing suburban social housing districts of Rome are explored and strategies to optimize their interdependencies towards better outdoor thermal environment performance are presented. Thus, this study investigates the effectiveness of different design strategies in order to improve outdoor comfort conditions with respect to microclimatic factors. Simulations of three case study districts are performed with ENVI-met model v.4 software. Results demonstrated a significant variation of microclimatic conditions and thermal comfort index (PMV) due to the implementation of specific site-appropriate design strategies, such as green and blue surfaces, and cool materials, on both buildings and public space. These findings will contribute to promoting a climate-sensitive design perspective towards urban renewal strategies, taking into account the Mediterranean climate and distinctive features of the above-mentioned districts.