Characterization of an opaque ventilated façade applied to a living laboratory: A seasonal experimental thermal performance analysis under real conditions

The present work focuses on a long-term, experimental monitoring analysis of an Opaque Ventilated Façade (OVF) system applied to a dry-assembled, wood-based wall technology. The real-scale prototype of the façade was installed in the full-scale facility developed under the MEZeroE, H2020 EU funded project. A detailed monitoring campaign has been conducted during summer and winter to assess the OVF performance under real operation. The experimental study allowed the characterization of the main OVF variables: i) temperature of the OVF layers, ii) air speed inside the cavity, iii) air temperature inside the cavity, iv) heat flux across the OVF and a reference non-ventilated façade, v) correlation between the different key variables. During summer days, the minimum and maximum cavity air speed is respectively 0.6 m/s and 1.2 m/s; during winter days the cavity air speed is stable and around 0.4–0.5 m/s. In summer the OVF shows a linear correlation between the air speed and the temperature of the air cavity (R2 = 0.76) and between the air cavity and the external air temperature (R2 = 0.96). From an energy efficiency perspective, the OVF contributes to a reduction in peak cooling loads by approximately 2.0–3.0 W/m2 and peak heating loads by approximately 0.9–1.0 W/m2. Architects and engineers can use the experimental results as a reliable scientific basis to design and accurately predict the performance of similar façade systems.