Optimal measures for energy retrofit on the university building “Ex Cotonificio Olcese” in Venice

Interventions on existing building represent a great potential for energy saving in Italy, where most of the envelopes have low thermal resistance. National regulations on energy savings have been developed over the last years consequently the normal practice has led to the introduction of remarkable thicknesses of insulation materials, without considering the effect on comfort and on cooling energy loads. The European Directive 2012/27/EU established a comparative methodology framework for calculating cost-optimal solutions of intervention considering the internal comfort and the global cost and giving also great relevance to referring to the local climate conditions. This paper presents a detailed analysis of a monitored case study, the university building “Ex Cotonificio Olcese” in Venice, an historical building already listed by regional Superintendence. The aim is a proposal of an optimal retrofit balancing costs and reduction of energy use and CO2 emissions, by respecting also the historical identity. The workflow is organized into several steps: the first one presents the state of the art of the building, making a survey and collecting data (such as geometry and energy consumption). Then a mathematical model is developed and calibrated with real energy consumption by bills. Next phase concerns on the individuation of technological components with major thermal loss, in order to propose some energy efficient measures to intervene in the envelope, based on the methodological guidelines of the Annex 56 "Cost-Effective Energy and Carbon Emissions Optimization in Building Renovation". The proposal considers constrains as the school normative (for energy tandards, safety and users comfort) and also the morphological respect of the existent external façade.The paper presents at least some best solutions combined with different kind of materials and estimates the availability of the financial application of “Conto Termico 2.0” government incentives.