ANALYSIS OF MULTI-FUNCTIONAL VENTILATED FACADES. AN EUROPEAN JOULE PROJECT M. Costa Centre Tecnològic de Transferència de Calor (CTTC) Lab. Termotècnia i Energètica, Universitat Politècnica de Catalunya (UPC) Colom n. 11, Terrassa, Barcelona, 08222, Spain, Phone: 34-937398287, Fax: 34-937398101, labtie@labtie.mmt.upc.es O. Aceves Teulades i façanes multifuncionals SA, P. Ind. Pla d’en Coll, C/Gaià n.5, Montcada i Reixac, Barcelona, 08110, Spain Phone: +34-935753666, Fax: 34-935753442, tfm@filnet.es F. Sen Robertson Española S.A., Crta. De Barcelona da Ribas, km. 25.6, Granollers, Barcelona, 08400, Spain, Phone: +34-938494411, Fax: +34-938400309, Robertin@intercom.es W. Platzer Fraunhofer Institute für Solare Energiesysteme/*PSE GmbH, Oltmannsstr., 5, Freiburg, 79100, Baden Wuerttemberg, Germany, Phone: +49-7614588131, Fax: +49-7624588132, platzer@ise.fhg.de A. Haller Ernst Schweizer AG Metallbau, Hedingen, 8908, Switzerland, Phone: +41-17636111, Fax: +41-17618851, andreas-haller@schweizer-metallbau.ch M. Indetzki Deutsche Amphibolin-Werke, Robert Murjahn Gmbh & Co. KG, RoBdörfer Strasse 50, Ober-Ramstadt, 64372, Germany, Phone: +49-615471655, Fax: +49-615471606, Markus.indetzki@caparol.de T. Ojanen Technical Research Centre of Finland, Building Technology, VTT Lämpömiehenkuja 3, Spoo, 02044, Finland, Phone: +358-94564720, Fax: +358-94552408, Tuomo.Ojanen@vtt.fi Abstract – The name Multi-Functional Ventilated Facade (MFVF) has been used in the project as a generic name to refer to a facade characterized by an inner ventilated air layer along with the incorporation of some additional technological elements. The elements here studied have been the following: the use of phase change materials (PCM) in the opaque walls to provide thermal inertia, the use of transparent insulation (TI) to reduce the convective losses in the semi-transparent areas and, finally, the incorporation of photovoltaic cells (PV) at the skin of the building to provide electrical power. The flux air developed in the channel provides not only an additional thermal resistance but a heat flux which can be driven outdoors or indoors conveniently according to the building energetic load. Different MFVF prototypes adapted to the different European climates have been experimentally tested in cabin test cells under real outdoor conditions and for long time periods. Also, an specific computing code has been adapted to analyze the thermal behavior of this kind of facades. The code has been partially validated with the experimental information provided by the prototypes. Finally, the code is been used to optimize the main design variables of these facades. 1. INTRODUCTION A MFVF pretends to be an architectural solution for solar oriented facades. The ventilated channel, which is one of the main features of these facades, provides a double skin to the building which allows to have large solar heat gains together with small thermal losses. The ultimate goal is to reduce the building thermal load without decreasing some important building design aspects such as the daylight gains and the outdoor aesthetic of the building. Solar heat gains at the ventilated channel are driven outdoors to prevent indoor overheating which occur when glass facades are used in Southern and Central Europe. These heat gains can be driven indoors in Northern European climates to produce a preheating of the ventilation air. The industrial objective of the project is to study ventilated glass facades with new elements coming from