Sustainable church heating: The Basilica di Collemaggio case-study

Historic building heating and, in particular, church heating represents a challenging task because many objectives have to be reached simultaneously; in facts, adequate thermal comfort levels have to be guaranteed for the occupants while ensuring an optimal internal climate suitable for the preservation of valuable and often fragile building components and artworks. Moreover, current requirements for sustainability impose to make efforts, where possible, to minimize the amount of energy needed and the consequent environmental impact. For such reasons, the present work addresses in detail the church heating topic, by analysing different feasible strategies and developing subsequently an original technology, able to combine energy efficiency and cultural heritage preservation aspects. The application field of the study is represented by the Basilica di Collemaggio (L'Aquila, Italy), a church of worldwide relevance, currently under restoration. In detail, traditional heating strategies were compared with solutions for the local-comfort, such as the pew-based heating, and a novel hydronic high-efficiency pew-based system was proposed and deeply analyzed. The work demonstrated that such solution is able to combine the advantages obtainable from electric benches with those of a hydronic heating system coupled with ground-source heat pumps, combining good local comfort levels to significant energy savings and low or no impact on the artworks and building structures. The system design was based on a local-comfort assessment, supported by experimental and CFD analyses.