Methodologies for Analyzing the Solar Energy of Historical Centres and the Identification of New Scenarios for Sustainability

Sustainable energy is no longer a technological challenge, as many of its aspects have now been analysed and solved. However, this is not true when looking for sustainable systems that are technologically compatible with the characteristics of the historical city; in fact, the use of alternative energy supply systems in historical city centres has not yet been dealt with in a satisfactory manner. Complete overall views were not protected, and only in some cases have we opted for a viewpoint that is more attentive to conserving values. The research was first aimed at investigating the nature of solar-energy-system coverage in the old part of the city by directly assessing its specific features and checking for areas of dissonance and balance. We then analysed the historical buildings in order to define the city’s energy characteristics, environmental site specifics, and latent potential related to the case study. This analysis started by estimating the solar radiation and evaluating useful microclimate parameters such as the sky view factor, shadows, and thermo-hygrometric parameters. In order to provide useful services to citizens in the environmental field and to reduce energy consumption, we have developed a web application that identifies renewable energy systems that have already been constructed in the municipal area and assesses the benefit of installing solar panels on the roofs. The study has allowed us to establish several criteria in defining a scientifically based methodology, presented as “guidelines for historical centres” to be used by authorities in order to determine the most suitable installation mode. Sustainability still represents a challenge in that it tests a city’s resilience, that is “the capacity of an ancient urban system to absorb a disturbance and adapt itself as the change takes place in such a way as to maintain the same essential functions, the same structure, and its own identity”; to ensure the continuity of its history even with new energy scenarios.