The impact of thermal comfort in multi-objective optimization of buildings refurbishment

The European Committee is encouraging the Member States to adopt the so-called “cost optimal approach” to define new energy performance requirements for new and existing uildings. However, the cost-optimal should not neglect the indoor thermal comfort. The improvement of the building energy performance, especially if related to the addition of high insulation thickness, can increase the risk of overheating. A small energy input raises the internal temperature considerably. Therefore, in order to move beyond the mere economic optimization of retrofit interventions, it is important to understand what the solutions able to enhance the performance of the buildings are, also in terms of thermal comfort. In this paper, this problem has been investigated. The analysis has been carried out on a set of different residential building modules, representative of different building typologies and construction periods, located in two different climatic contexts. By means of a multi-objective optimization approach, the best combination of EEMs has been defined first optimizing only the energy and economic aspects, then the indoor thermal comfort has been added and the optimization re-run. A Genetic Algorithm (NSGA-II) coupled with a simulation tool has been used to optimize the different objectives.