Revenue assessment and visualisation of photovoltaic projects on building envelopes

Increased environmental and economic awareness, coupled with local government incentives, means that solar energy applications in buildings are crucial to sustainable urban development and commercial energy investment. Considering the large available areas on building rooftops and walls, and the application of building-integrated photovoltaic products, previous research has paid extensive attention to solar radiation estimation for roofs and vertical walls. This paper proposes a developed pixel method integrated with Net Present Value (NPV) analysis and applies the measurement to 3D visualisation of the revenue distribution of potential PV projects on building surfaces, including vertical and non-vertical facades. A building model derived from a real student accommodation building is then chosen as a case study in this paper. The developed algorithm extracts data built in SketchUp, exports instantaneous shadow images and estimates solar energy potential over building surfaces for each pixel unit. Coloured 3D radiation maps illustrate the distribution of solar energy potential on roofs and facades. 3D contour lines with NPVs are introduced to visually conduct PV installation strategies with desirable revenues over project lifetimes. The results reveal that facade installation is also worthwhile, as the corresponding project revenues are competitive with rooftop installation during specific periods. This study will benefit designers and construction managers in determining the optimal solution for implementing solar rooftop and facade systems in the design and construction phases.