Monitoring energy and comfort performance of transparent adaptive façades

The latest European energy policy aimed at reducing the energy demand and CO2 emissions due to the building sector has been pushing researchers, designers, manufacturers and contractors towards the development of novel concepts and technical solutions, with special emphasis on building envelope. Relevant improvements can be achieved by adopting a new approach, conceiving envelope components as “living” membranes, efficiently interacting with indoors and outdoors boundary conditions and with users’ needs thus performing an adaptive behaviour. Adaptiveness may be based on different driving factors, may perform at different timescales (from few minutes/ hours to diurnal/seasonal variations) and may take place at different components’/systems’ levels (macro or micro scale). This implies that adaptive façades are particularly complex to be comprehensively characterized. The lack of metrics and standardized procedure is one of the major barriers to promote their widespread adoption. In this paper some key aspects from the decennial experience gained by the Authors on dynamic building envelope components are presented. Through long-term experimental campaigns in test cells and field monitoring, energy and lighting performances of Active Transparent Façades, Switchable Glazing and Phase Change Materials integrated into glazing/shading devices have been widely investigated. Some case studies are presented, focusing on metrics adopted, measurements methodologies and post processing procedures, highlighting potentials and criticism.