An Optimization Model for the Selection of Renovation Actions in a Building

In Portugal, as in all of Europe, there has been a growing concern about energy poverty and its impact on people’s health and well-being. Rehabilitating and making buildings more energy efficient allows for the reduction of energy consumption, that is, transforming existing buildings into near-zero energy buildings (nZEB). Energy consumption in buildings can be reduced by implementing measures to improve energy efficiency. However, the choice of improvement measures to be implemented needs to be optimized since, in general, they require investments, despite causing a decrease in energy costs. The research provides a linear programming optimization approach based on a bi-objective knapsack model to pick the portfolio of actions to undertake while analysing energy consumption reductions and investment payback periods. The model enables the selection of the investments required for the building to achieve nZEB certification. A case study is used to illustrate the model.