Abstract
A wide selection of energy efficiency measures (EEMs) are technically available to improve the energy performance of existing buildings, each of which can be applied to a different extent. The definition of the best combination of retrofit strategies is generally pursued through the balance of economic and energy targets. What this approach does not consider are some different performance aspects, although related to the same EEMs, and in particular the occupant well-being. In this framework, the definition of the best retrofit strategies should consider three objectives characterized by a competing nature: the energy savings, the economic advantage and the indoor thermal comfort.
Government incentives play a crucial role in promoting retrofit projects. This financial subsidies should be
addressed to incentive solutions not economically attractive but optimal in terms of energy savings and indoor thermal comfort. The aim of this work is to evaluate a large range of EEMs for different starting building modules. In particular it is investigated the entity of government subsidies required to improve the profitability of the optimal solutions in relation with different initial starting conditions. In order to define the optimal solutions, a multiobjectives optimization-based approached is implemented through an Evolutionary Algorithm coupled with the simulation code. Subject of the study is a set of building modules obtained by varying the initial characteristics of a reference residential module: windows orientation, compactness ratio and thermal characteristics of the envelope. Two different southern European climatic contexts are considered: Milano and Messina.