A novel building ventilated façade with integrated bifacial photovoltaic modules: Analysis of the electrical and thermal performances

The Energy Performance of Buildings Directive (EPBD) is, together with the energy efficiency directive, the main legislative instrument to promote the buildings energy performance and to boost renovation within the EU. EPBD requires that all new buildings have to reach the objective to be nearly Zero-Energy Buildings (nZEBs) by 2020. The concept of nZEBs focuses on firstly improving the energy performance of the building envelope and, then, integrating Renewable Energy Sources (RESs) to cover the remaining energy demand. In this context, photovoltaic (PV) systems provide a reliable solution for electricity supply either in existing or new buildings. Building Integrated Photovoltaic (BIPV) systems have the twofold advantage of increasing the prospects of renewable energy in the built environment, whilst providing savings in materials and construction time by replacing traditional building elements. Recently, bifacial PV cells have attracted interest because of their potential to increase PV modules power production. Integration of bifacial PV modules into a building façade represents a significant step forward in the application of this relatively new technology. Such façade can serve not only as a renewable source of electricity acting as an active system but also it contributes to reducing the building cooling needs acting as a passive system. In this paper, a multilayer one-dimension dynamic thermal model of monofacial glass-back sheet and bifacial glass-glass PV modules integrated into a building façade is presented. Given the geometry and PV technologies of the considered facades, as well as Catania (Italy) weather conditions, it has been shown that the bifacial glass-glass PV modules can produce an energy yield of about 5% more than the monofacial PV module.