Energy evaluation of an horizontal open joint ventilated facade

The term "open-joint ventilated facades" refers to a building system in which an external layer of slabs or tiles (metallic, ceramic, stone or composite) is hanged by means of a metallic-frame structure to the exterior face of the brick wall, creating an air cavity between wall and slabs. The arrangement of slabs is such that it forms open gaps between them, allowing the surrounding air to enter and leave the cavity all along the facade. In addition to aesthetic and constructive reasons, the main interest of open joint ventilated facades is their ability to reduce cooling loads. This is done by the buoyancy effect created by solar radiation inside the ventilated cavity. This paper focuses on the energy performance of a typical open joint ventilated facade, comparing its temperatures and heat transfer fluxes with those of a conventional sealed air cavity facade. The thermal and fluid-dynamic behaviour of both designs have been analysed with CFD techniques and the results of the simulations conclude that open-joint ventilated facades can help to achieve substantial energy savings in climates with hot summers and mild winters. (C) 2011 Elsevier Ltd. All rights reserved.