Energy requalification of a hystorical building: a case study

The energy requalification of the "Real Albergo dei Poveri", a monumental building in Naples, unique both for its shape and dimensions (about 103.000 m2) and for its architectural features and original functions is here presented.The procedure of analysis of the thermal behavior of the building and the proposals of sustainable interventions to obtain an energy efficient ancient building are presented. The goal is to achieve environmental comfort conditions and at the same time reduce energy consumptions by applying sustainable strategies regarding both the building envelope components, and also by an appropriate choice of the heating system. As it will be shown in the results of the analysis, the building is a massive structure and its walls have very good thermal insulating and inertial properties. For this reason, only a high performance gas boiler with low temperature floor heating system could be proposed. Indeed, from the studies it can be inferred that an air conditioning system is not compatible with the monumental building. Low thermal transmittance of the walls and high inertial properties allow to obtain good thermal comfort conditions in summer time. Natural ventilation is granted thanks to air exchanges through manual devices. The massive features of the walls shift the attention towards the windows, which represent on one side the weak part of the envelope as regards thermal performances, but which, on the other side, allow to introduce the natural light, obtaining energy savings for lighting and achieving visual comfort conditions, provided they are associated with good controls of overheating in summer. Moreover, for the roof, photovoltaic technology has been chosen in order to produce energy from renewable resources and consequently to reduce CO2 emissions. All the proposed solution for restoration and energy requalification are respectful of the ancient building, its history, its already existing original materials and its shape. The research here presented started with the European project SARA (Sustainable Architecture applied to Replicable public Access) aimed to implement integrated and sustainable energy actions on a Europe-wide scale in order to contribute to future similar actions through replicability and promoting energy sustainability in buildings