A Method for Sustainable Lighting, Preventive Conservation, Energy Design and Technology—Lighting a Historical Church Converted into a University Library

Many ancient libraries in Italy are housed in historical buildings, only a few in former churches and monasteries. Newly built libraries mostly comply with the requirements of sustainability, energy saving and renewable energy use, but this does not occur for existing ones, especially when they belong to the historical cultural heritage. Historical library buildings have good mass and thermal inertia but often have inadequate windows with low light transmission value. Lighting systems are often without control and thus cause poor lighting conditions. Our present research concerns the energy sustainability assessment of retrofit operations for lighting in an existing historical university library, focusing on lighting quality, adequate lighting conditions for visual tasks, vision ergonomics and well-being, and guaranteeing the preventive conservation and protection of heritage books. This case study is very particular, because it concerns a Florentine historical monastery which is now a university library. Our proposed method introduces an optimal toolset for lighting design solutions with the aim of sustainability. The library indoor space was procedurally decomposed into illumination volumes according to different occupant activities and visual tasks and different use areas. This method is extensible to all similar cultural heritage case, but also existing old buildings and current designs.