Abstract
The integration between solar energy systems and building components is highly critical in sensitive heritage contexts. On the one hand there is the need for finding a balance between the preservation of the aesthetic appearance and the historical values, but on the other hand, finding the space where to effectively integrate the systems might be quite challenging. The solar systems can be divided in photovoltaic (PV) and solar thermal (ST) systems. Building Integrated Photovoltaics (BIPV) and Building Integrated Solar Thermal (BIST) are PV or ST panels integrated into the building envelope, combining the energy generation with other functions, such as noise, weather protection, thermal insulation, sun shadow, and other aspects. Nowadays, the dynamism of the market allows to design highly compatible products which look like traditional architecture materials. This situation fosters the integration of these products in the BIPV and BIST systems within the heritage sites, especially thanks to the use of advanced customisation processes, special and low-reflecting glasses, and innovative cost-competitive coatings. There is a limited number of studies on the application of these technologies in heritage contexts, due to the presence of architectonic, conservative, and cultural barriers. This paper aims to conduct a comprehensive review of the available literature on the integration of renewable energy sources (RES) in heritage sites and buildings, which would foster the preservation of their cultural and natural values as well as reducing primary energy consumption, increasing comfort levels, minimizing environmental impacts, and improving technical quality and economical outlays. A common framework will thus defined to support restorers, historic conservators, and energy experts and to facilitate the diffusion and application of RES in heritage contexts. This conceptual framework will provide industries and academics with operative strategies and will encourage their diffusion and application in sensible contexts.