Recupero sostenibile nel centro storico di Petralia Soprana: strategie per il retrofit energetico.

The valorization of building in the historical centers of limited territorial environment, such as the ones in the Madonie’s Park, represents a requirement of mountain communities, which are the witnesses of a gradual abandonment of historical buildings, representative of the local cultural heritage, mainly because they are inadequate to ensure indoor comfort. Also for the recovery of these buildings, technological, energy and economic issues have to be evaluated, compatibly with the historical value. In particular this urban area, typical of the Madonie’s Park, is an architectural, historical and material heritage that merges with the natural and scenic values of the area, representing the result of a long evolutionary process of successive layers, in which individual buildings and urban spaces improve as part of an area characterized by specific structural conditions, closely related to the use of local materials and integrated with the territory. In this context, the Town of Petralia Sottana decided to recover uninhabited existing buildings, creating council housing units in order to reduce the environmental degradation and slow down the process of urban abandonment. The focus for certain types of buildings can be a starting point not only to build up an urban identity, but also to start a social and economic process for the different types of development that this can induce. The paper will present the results of a study started during the Master “Innovative Materials and Techniques for Sustainable Building”, organized by the University of Palermo, during which it was developed, in collaboration with the Technical Office of the Town of Petralia Sottana, a strategy of environmental and technological redevelopment, in order to improve the indoor comfort with targeted actions, involving both the technological system and the building energy management, and fundamentally concerning the improvement of the performance of the building envelope (increase of thermal insulation, replacement of windows, etc.). In particular, the critical technical elements have been identified, analyzing the nature and the thermophysical characteristics of the constituent materials. The evaluation of possible hypotheses, in accordance with the regulations, is supported by a technical and economic analysis that takes into account the cost/benefit results of the proposed solutions. The aim was the developing of strategies and practices of intervention that allowed an energy reclamation, resulting in a reduction of CO2 emissions and costs assessed in terms of scale economy, in order to consider aspects of planning, design and production.