Ventilated façade as building retrofit solution: preliminary thermal model and comparison of energy performance in different climatic regions

The construction industry significantly contributes to energy consumption and greenhouse gas emissions. To mitigate these impacts, enhancing building envelopes by increasing thermal inertia is a global goal. Ventilated façades are promising, reducing thermal flux and mitigating solar overheating. However, recent studies highlight that assessing their thermal transmittance using UNI 6946 standards is often unrealistic. The proposed model analyzes a ventilated façade system, using heat transfer and airflow network analysis. This façade features a base inlet for airflow, exploiting the chimney effect for cooling. The energy balance equations consider various façade interfaces and the air volume in the cavity. Model validation was performed by comparing results with experimental data from the literature. Parametric analyses varied solar radiation, external temperature, and inlet air velocity. The system was applied to a 1970s building archetype modeled with quasi-steady-state software, located at three different latitudes in Italy to evaluate geographical and climatic effects.The model showed that ventilated façades can reduce thermal transmittance by up to 45%, improving energy efficiency. High solar radiation and low external temperatures enhance the chimney effect. Applying the ventilated system reduced heating energy consumption by up to 75%, though cooling consumption might increase in highly insulated buildings.