Building envelopes and outdoor comfort. Analysis and simulations to evaluate the contribution of opaque facades on outdoor comfort

The aim of this study is to investigate the contribution of building envelopes to outdoor comfort. Using current advanced energy simulation tools, the study proposes an evaluation of how and how much opaque facades with their thermal and optical properties affect outdoor comfort. Simulations of the universal thermal climate index (UTCI) and mean radiant temperature (MRT) are used in different configurations to compare and estimate the direct contribution of opaque facades. This study aims to highlight the specific benefits provided by interventions in building envelopes involving only constructive and material variations, changing the thermal behaviour of building components. The results of this study evidence the contribution of overheating conditions directly related to the thermal behaviour of building envelopes, highlighting the energy share directly depending on the properties of building components. Simulation results for outdoor UTCI and MRT with maps and data for the current status of an urban case study area as the reference scenario are compared to different intervention scenarios, changing the properties of building components and varying elevation configurations, showing and quantifying the increase or decrease of simulated indices. Ultimately the role of thermal behaviours of building components in the urban heat island is assessed.