Solar Architecture in Rome. The refurbishment of historic buildings with active solar technologies

The European (EU) Climate Goals Plan for 2030 underlines the strong need to build a modern, sustainable, and resilient Europe, and this high goal means, among other, more energy efficient buildings. Looking at this EU Directive, Italy has signed the Piano Nazionale Integrato per l’Energia e il Clima (PNIEC), which intends to pursue an indicative target of reducing consumption by 2030 equal to 43% of primary energy and 39.7% of final energy, compared to the scenario of 2007. But the Italian commitment to the integration of energy production systems from renewable sources in existing buildings has already been going on since the early nineties. Thus, this study focuses on some historic buildings of the architectural heritage in Rome (Italy) that have undergone technological and energy redevelopment from the 1990s to today, with particular attention to active solar solutions. To this purpose, five historic buildings located in the centre of Rome and characterised by different construction and refurbishment periods, functions, and architectural approaches are analysed to highlight their morphological, technological, and typological characteristics. These case studies are discussed and assessed with the support of some Conservators of the Italian Heritage Authorities in the framework of the Interreg Italy-Switzerland Research Project "BIPV meets history", to understand the pros and cons of the different approaches. Finally, risks and benefits for their aesthetic, technical, and energy integration are highlighted following a scheme developed in the International Energy Agency (IEA) Task 59 for verifying the heritage-compatibility of each solution.