On the Compromises Between Form and Function in Grid-Connected Building-Integrated Photovoltaics (BIPV) at Low-Latitude Sites
Abstract
The integration of photovoltaic (PV) modules on building façades and rooftops is an ideal application of solar electricity generators in the urban environment. Maximum annual performance of grid-connected PV is usually obtained with modules tilted at an angle equal to the site latitude, facing the equator. The performance of PV systems not tilted or oriented ideally can drop considerably, depending on site latitude. With grid parity - when the cost of solar electricity becomes competitive with conventional electricity – expected in many countries in the present decade, a more widespread application of PV on buildings is expected, and in this context, the main goal of this paper is to show that good compromises between form and function can be reached. In this work we compare the annual energy generation of a curved BIPV system installed as a carport rooftop, with an ideally-oriented and tilted, flat BIPV system installed as a building’s rooftop cover at a low-latitude site (27oS). For the one-year period analysed here (Jun/2009 to May/2010), the curved-shaped BIPV annual yield was 12% lower than the reference BIPV system, and, for summer months (Nov/2009 to Feb/2010), the BIPV curved-shaped system presented superior monthly yield (the difference was +15% for Nov/2009). From these results it was possible to show that one can reach a good compromise between form and function in BIPV systems.