Characterization, optimization and efficient implementation of active façades in social housing buildings E.Iribar * ,*** , I. Ruiz de Vergara *,*** , C. Escudero *,*** , D. Perez-González *,*** , J.M. Hidalgo ** , J.M. Sala * . * ENEDI group, Department of Thermal Engineering, University of the Basque Country, Alameda. Urquijo s/n, Bilbao 48013, Basque Country (Spain) ** ENEDI group, Department of Thermal Engineering, University of the Basque Country, Europa 1, Donostia-San Sebastian 20018, Basque Country (Spain) *** Basque Government LQCB, Aguirrelanda 10, Vitoria-Gasteiz 01013, Basque Country (Spain) ABSTRACT The goal of this research project is to provide free heating by using active façades in a social housing building with 32 dwellings that is located in the North of Spain. Thereby, it was necessary to characterize the thermal performance of AFs so as to optimize their implementation in the building. The analysis was carried out by both virtual and experimental characterizations of a façade model and a monitored building. Keywords: active façades, Paslink Test Cell, Building Simulation, Free Heating, Building Energy Efficiency 1 INTRODUCTION In order to meet with NZEB requirements for the climate zone of Northern Spain, it is not sufficient to build designs with high insulation That is because ventilation demands due to salubrity reasons create a significant heating demand. Furthermore, it also must take into account the operational cost of facilities and common services. Nevertheless, it is possible to reach the scope with an extra renewable energy contribution obtained through the building envelope system based on solar energy uptake surfaces (AFs). 2 METHODOLOGY In this study some AFs were tested in sample-scale. The evaluated AFs group was composed from conventional active systems, such as TW, through solutions such as PV façades. These facades were tested in outdoor conditions using a traceable and precise methodology. The testing equipment used is a PASLINK test cell developed by the DYNASTEE (DYNamic Analysis, Simulation and Testing applied to the Energy and Environmental performance of building) network at the Basque Government LQCB. Accordingly, these tests not only showed the efficiency of different AF, but they also provided detailed information to define a mathematical model of an active performance (such as ventilated cavity’s convective behavior) [2-4] to introduce them in building scale simulation. In this way, a considerable amount of dynamic simulations were conducted by TRNSYS to evaluate the studied cases. In this preliminary stage of characterization, the design principles were corrected in order to improve the thermal performance of these AFs. Both the tests and simulation results demonstrated that the AF optimization should be carried out focusing on the use of the evacuated heat by convection in the ventilated cavity through an AEFS. Finally, these design principles were applied in the construction of the aforementioned social housing building. Three different types of façades were installed along the Southern orientation of the building with different use of energy generated in the implemented AFs. Furthermore, a relevant criteria has been defined to adjust the operation of these active elements and, in consecuence, to find the optimal renewable system that provides free heating to tenants. 3 PASLINK TEST CELL To get a proper characterization of AFs by testing, 3 requirements are needed: reliable equipment, a fully representative sample and finally an accurate and confident process of calculation and analysis of the obtained data. All these points are reached working with PASLINK cells and its test methodology. The test was created by The European Project PASSYS (Passive Solar Systems and Component Testing) which was developed from the mid-1980s to the mid-1990s. In 1994 a European Economic Interest Group was created: the PASLINK EEIG [1]. Nowadays all the experience of the PASLINK group has been integrated in the DYNASTEE (DYNamic Analysis, Simulation and Testing applied to the Energy and Environmental performance of buildings). There are two PASLINK test cells in the LQCB facilities; they are called EGUZKI and ILARGI. They were upgraded following the indications provided by Dr. J.J. Bloem of the European Institute DG Joint Research Centre, Institute for Environment and Sustainability in Ispra-Italy. The PASLINK test cell consisted of a well-insulated structure of 8 x 2.7 x 2.7 m with two spaces [5]. One called Materials for Energy, Efficiency and Sustainability: TechConnect Briefs 2016 275