An experimental sensitivity analysis on the summer thermal performance of an Opaque Ventilated Facade

摘要

In the last few years opaque ventilated facades (OVFs) have reached an increasing diffusion in the Mediterranean area for their capability of reducing the heat flux across the building envelope in summer conditions as well as preventing the condensation and infiltration risk in the winter period providing wind and rain protection, thus increasing the durability of the facade. Moreover, the possibility to host different cladding allows architects to explore a wide range of facade combinations. In the framework of a regional funded project, an extensive in-field experimental campaign was carried out in the summer period on different full-scale OVF configurations, with the aim of assessing the thermal performance of a newly developed OVF based on hollow clay claddings technology.A sensitivity analysis was thus performed, in order to evaluate, on the one hand, the effect on the performance of the main facade features, e.g. ventilation channel height, solar absorption coefficient and ventilation grills openings ratio, and on the other hand, the influence of the outdoor boundary conditions, e.g. solar radiation and external air temperature.The experimental results highlight that the facade configuration and the design features significantly affect the capability of OVFs on minimising the solar heat loads across the wall (between similar to 30% and similar to 70%) if compared to an unventilated facade (representing the reference configuration). These results allow providing general guidelines for an optimised OVF design. Moreover, the assessment of the effect of the outdoor boundary conditions allowed to identify the conditions in which the facade shows the higher exploitation of natural ventilation. (C) 2020 Elsevier B.V. All rights reserved.