Comfort and building performance analysis of transparent building integrated silicon photovoltaics

Within this paper an annual performance and daylight comfort analysis of building integrated photovoltaic (BIPV) is discussed, evaluated and compared to a common façade solution. The daylight comfort analysis includes annual illuminance, glare evaluations, and further daylight factor calculation. Secondly, dynamic thermal simulations are performed. The energy consumption of the luminaries is considered as part of the thermal internal gains. Both, the heating and the cooling energy demands are investigated. Different solar cell types (such as multicrystalline cells and monocrystalline cells), integrated in a sandwich-glazing substrate, already existing on the market, are investigated. They are categorized as shading systems differentiating only in their shape, size and therefore transparency ratio. The efficiency per cell as well as their visual comfort performance is exemplarily evaluated for a typical office located in Freiburg, Germany. The impact of the PV area ratio (ratio of PV coverage to fenestration area) on the façade both on the thermal and on the visual comfort are investigated in this paper. The annual simulation results show that a façade with integrated photovoltaics has the potential to improve overall energy performance of buildings when com-pared with the reference system Venetian blind due to the significant electric yield benefits. The shape and the adopted technologies have also an impact on the visual contact to the ambient and on the energy generation. Nevertheless, none of the investigated systems with the given conditions complies with the criteria for glare protection - therefore an additional (internal) glare protection is needed.