Preliminary results on the assessment of using Venetian blinds as a solar thermal collector in double skin facades in Mediterranean climates

The global trend on energy integration and building efficiency is making both researchers and developers look for technical solutions to use façade surfaces for electricity and/or domestic hot water production. These applications improve the energy performance of the building, but the integration of solar photovoltaic panels or solar thermal collectors into the façade may block visibility to the exterior and may prevent natural light from entering the building, both important comfort factors for building users. This paper presents the preliminary results on the assessment of the thermal performance of a double-skin facade (DSF) with a venetian blind-type of structure used as a solar thermal collector to heat up a circulating fluid by means of computational fluid dynamics (CFD). This type of heat exchange structure would allow for energy recovery and exterior views simultaneously, and can be easily integrated into the façade aesthetical design. For the purposes of this study, the modeled façade is set to be located in Barcelona (Spain), where large solar gains are a constant condition throughout the year, and such large semi-transparent areas as this type of façades can produce significant over-heating in buildings, even during the winter. For the studied façade both the reductions in radiative heat gains entering the building and the heat recovery are evaluated for summer meteorological and solar radiation conditions and numerical results obtained are compared with previous results reported by our research group on a similar DSF model without a façade integrated thermal system