Innovative façades: lightweight and thin systems with high inertia for the thermal comfort. Application in office buildings in Southern Europe

This research demonstrates that lightweight, thin façade systems with innovative materials can combine a higher thermal inertia with a lower energy demand for heating and cooling as compared to massive façades. It is therefore very possible to use innovative light materials (originally developed in and for Central Europe) also in Southern Europe, where the main problem is the energy demand for cooling in summer (in contrast to the energy demand for heating in northern latitudes). Three of those systems were selected and investigated for three different climatic conditions in middle latitudes with respect not only to static energy performance parameters imposed by the Italian legislation (thermal transmittance U and superficial mass MS), but also checking two dynamic energy performance parameters defined particularly for non massive structures (phase delay fa and decrement factor φ). Additionally a recently introduced by European standard UNI-EN-ISO-13786 parameter (periodic thermal transmittance Yia) was considered. Verification of the energy performance of the façade systems was performed using thermodynamic simulations. The results are: • Development and application of an experimental / simulation procedure for the evaluation of the thermal performance of façade systems in use (annual energy demand: [kWh], costs [€] and CO2 produced [kg]). • Demonstration that energy performance of new lightweight systems is better than the one of a traditional Italian reference façade system with high MS. • Proposal of possibilities for improving the analyzed façade systems with respect to their application in middle latitudes. • Development of design criteria for the application of the analyzed façades in three climatic zones in Italy.