Retrofit of Massive Buildings in Different Mediterranean Climates. Interactions Between Mass, Additional Insulations and Solar Control Strategies

In temperate climates, such as in most parts of Italy, it is necessary to limit both winter heat losses of buildings and their overheating in other periods. Moreover, in warmer Mediterranean climates the convenience of insulation against the building’s thermal inertia must also be evaluated. Therefore, when the energy renovation of an old building with heavy masonry is performed the problem is to optimize the position and the thickness of the additional insulation. In presence of extended glazed surfaces, the most appropriate solar control strategy should be defined too. Both issues are present in many old Italian public buildings. This paper deals with a computerized methodology for optimizing these choices by taking into account the interactions between thermal mass, additional insulation as well as internal and solar gains. The case study consists in a typical school building from the early 1900s. Building’s thermal behavior was simulated in different Italian climates: Bologna, Roma and Palermo. The effects of various solutions on energy demand and comfort were compared. The possible effects of different types of masonry, different building’s orientations and various intended uses were also explored. Simulation results show that the optimal intervention strategy, for the considered type of building, depends not only on the climate but also on the building’s intended use, which determines the internal gains and the time profile of use.