Application of GIS tools to the improvement of energy supply in PV rooftop installations

Abstract

Present work studies the energy supply from photovoltaic (PV) installations in industrial conglomerates using the rooftops as a surface to install the PV panels. The study is based on a modelling procedure that takes into account the specific characteristics of the rooftop, shape, size, azimuth and inclination, using GIS tools to identify these parameters for every single rooftop. Modelling has been developed modifying the tilt angle of the PV panel for vertical and horizontal PV panel layout and analyzing which one of the two configurations generates more energy. The study has been extended for tilt angles from the horizontal plane to the latitude of the location. The methodology uses a previous study in determining the optimum number of PV panels that can be placed on the rooftop. Shading effects have been taken into account for energy supply calculation, resulting in a variation with the tilt angle of the PV panel that depends on the range of the tilt angle; three ranges have been identified, low (0≤β/ϕ≤0.3), medium (0.3≤β/ϕ≤0.8)and high (0.8≤β/ϕ≤1). Maximum variation, 1.6%, has been observed in the low range, while for the high range energy supply does not seem there is no blocking to depend on the tilt angle. The results show that the modelling matches theoretical predictions within accuracy higher than 99.4%. Modelling has also been developed for two different configurations of the PV panel positioning, vertical and horizontal. Tests have been applied to the largest and smallest rooftop; the similar trend in the evolution and the close values of the energy supply with tilt angle proves that the methodology can be applied to any of the industrial building rooftops. The results of the modelling show that there is no much difference between the two configurations; however, horizontal configuration works better for larger areas while vertical one is more suitable for smaller areas. Additional row has been added to the layout provided the shadow is out of rooftop bounds. The increase of the energy is not very relevant, barely 1% for the vertical configuration and 0.2% for the horizontal one.