Reuse of an ancient church: thermal aspect for integrated solutions

The definition of intervention strategies for the restoration and the functional actualization of historic and high artistic quality artifacts, postulates a systemic approach for the different variables that contribute to the definition of the project. This paper presents an emblematic case study of an historic building, the church of St. Francis in San Giovanni in Persiceto near Bologna, one of the most representative of the architectural construction of Bolognese Baroque, built by Alfonso Torreggiani. The expected new functions as exhibition hall and/or concert activities, requires a search for integrated strategies to ensure indoor comfort requirements (thermo-hygrometric, acoustics) and to define HVAC plant equipment for the reduction of energy consumption without affecting the historic values and artistic perception of the building. Therefore, the analysis of the church in the survey phase, besides the usual historical and architectural investigations, should investigate the potential issues and the critical aspects of structures, like the multilayered floor and refined decorations that lines the walls of the nave. Understanding the intimate rationality of the building (presence of any shafts, steps etc .) is a prerequisite for the inclusion of plant components without altering the visual perception and to optimize the acoustic and the climatization plant systems. Although the use of renewable energy are required today for all new plant systems, in this case it was decided to exclude invasive elements that could have altered the image of the entire monumental complex of which the church belongs. The proposed HVAC plant, after an analysis of dynamic thermal behaviour of the building, is an air-conditioning system coupled to radiant heating system to ensure, in a climate context with high humidity levels, the optimal temperature and humidity not only for comfort conditions but also for preservation of the building itself and of artistic works