Heliodon prediction of shading on building integrated photovoltaic systems

Extensive shading of building integrated photovoltaic (BIPV) power systems causes high performance losses, often much higher than originally estimated. In the urban environment, shading cannot be avoided and therefore methods to accurately predict PV facade and/or roof system shading patterns must be developed. By utilising a Heliodon, normally used by architects to predict natural interior lighting effects, accurate seasonal shading by surrounding structures can be assessed on a 3D scale model of the proposed PV generator, or array. In order to test this Heliodon prediction method, comparisons are made between photographs of the shading on both the model of and an actual Northumberland building PV facade in the UK.