Opportunities for energy savings with interventions on the lighting systems of historical buildings: The case of Palazzo Medici in Pisa, Italy

The energy audit for a building is a procedure designed mainly to obtain adequate knowledge of the energy consumption profile, identify and quantify opportunities for energy savings by a cost-benefit analysis and report, clearly and comprehensively, about the obtained results. If the audit is referred to a building with a significant historical and artistic value should be also developed a compatibility evaluation of the energy saving interventions with the architectural features. In this paper, discussing the energy audit carried out for the historical building named 'Palazzo Medici' in Pisa (Italy), the Authors analyses, from a techno-economic standpoint, different possible interventions on the lighting systems aimed to obtain significant energy saving. The total of six interventions on indoor and outdoor lighting systems, analyzed in the paper, allow a reduction of about 35% of the electrical energy demands for the artificial lighting of indoor and outdoor spaces, with a very short payback times. From the results obtained by the Authors, it is possible to show that, for historical buildings used for public functions, interventions to improve energy efficiency of lighting systems may allow significant reductions in the electrical energy consumption, which, in some cases, may reach or exceed the 20% of the overall electrical energy consumption.