Abstract
In Europe, most of the final energy consumption is attributable to the building sector. During the last few years, the European Union has continuously tried to develop strategies to improve this situation. The main path followed was to give increasing importance to the energy efficiency improvement of the building stock, trying to reduce its impact on energy consumptions and harmful emissions. To do this, a series of directives have been issued with indications for the reduction of energy consumption and the abatement of greenhouse gas emissions. The regulations issued by the European Community have been transposed by the Member States into their regulatory bodies, trying to give shape on their territory to the European guidelines. In Italy, the problem of consumption deriving from the stock of buildings is amplified by the residential sector. Most of the residential buildings in Italy were built before 1970 when the issue of sustainability and energy efficiency became relevant. In the residential sector, few energy efficiency works have been carried out in the past decades, so much so that to reach the EU targets at 2030 and 2050, the current annual renewal rate should triple and maintain a constant growth in the coming years.
To address this issue, one of the main hurdles to overcome is the size of the sample under investigation. Given the sheer volume of buildings in need of energy retrofits, it is impossible to continue with the analysis of individual buildings. For this reason, there is a need to develop solutions to speed up the renewal process of the building stock with holistic strategies that allow to analyze and propose retrofit solutions at the level of an entire neighborhood.
This work aims to develop a methodological strategy to intervene on a large group of buildings, thus avoiding the "case-by-case" approach. In particular, the procedure starts from the study of the district for the energy diagnosis of buildings and then goes on to define a predictive process for planning energy efficiency scenarios for residential buildings at the neighborhood level. The process involves operators, policymakers, and stakeholders in cooperating to achieve a more sustainable future in a complicated context such as the one chosen for the case study. The approach is applied to a social housing neighborhood, similar to many others distributed homogeneously throughout the country. The proposed interventions are traditional efficiency measures with proven efficiency and cost-effectiveness. In this way the methodology is easily replicable in other contexts without having to make any particular changes, thus making it an example to be reproduced in other areas. Besides, a methodology is defined for the definition of the energy efficiency interventions that are most convenient from the point of view of costs and the results they obtain in terms of energy savings and reduction of harmful gas emissions. Likewise, a scenario of future development is proposed for the coupling of interventions on the buildings with interventions focused on the improvement of energy distribution networks’ sustainability. In particular, a possible increase in the use of woody biomasses to supply energy distribution systems is studied.
To carry out this kind of strategy, it has been underlined the lack of a database containing the necessary information for the thermophysical characterization of the Italian residential sector. A solution has been proposed by shaping a database of prototypes to be used in the development of strategies for the efficiency works of numerous buildings to avoid having to characterize the buildings under examination individually.
During the development of the work, some critical issues emerged that need further investigation. In particular, the combination of systems powered by sustainable energy sources and the efficiency of the building envelope presents complexities due to the restrictions imposed to safeguard the historical and architectural characteristics of the neighborhood studied. This factor represents an issue common to all Italian historical realities. These restrictions challenge the achievement of the best results in terms of energy recovery, comfort, and co-benefits.