Models for the estimation of building integrated photovoltaic systems in urban environments

Growing concerns of global warming has spurred a rapid growth in micro-renewable technologies. Technologies, which can be integrated into building structures, such as photovoltaic and solar thermal systems, are a popular choice with clients and installers. Traditional solar energy models are often used when designing building integrated photovoltaic (BIPV) systems. Problems are often encountered in urban locations where BIPV systems do not meet their design performance. This is because the solar energy models used in the design process include only the effects of shading caused by the blockage of the beam component, but do not consider the effects of overall global dimming, caused by the reduction of the diffuse component emanating from the sky hemisphere due to surrounding obstacles, such as buildings and trees. The current paper presents two models, which have been developed to incorporate the effects of shading of either the beam component, or the shading of both the beam and the diffuse components on BIPV output.