Evaluating the solar potential of rooftops on campus San Joaquín, Santiago - Chile using opensource GIS
Abstract
Over recent years, photovoltaic systems have become increasingly popular for the installation on buildings' rooftops. Due to the increasing demand for electricity through Photovoltaic (PV) systems, it is necessary to evaluate the solar potential on roofs in the first place. Since from these values, it is possible to analyze which rooftops are suitable for the installation of photovoltaic systems to produce the maximum electrical energy but estimate the actual solar potential for applications in the dense urban environment is a difficult mission. In this work, the solar potential in roofs is calculated in Santiago de Chile using opensource GIS. The Global Horizontal Irradiance (GHI) used for this analysis was taken from the Solar Laboratory of Pontificia Universidad Católica de Chile. The other components of radiation: Direct Normal Irradiance (DNI) and Diffuse Horizontal Irradiance (DHI) were obtained although of the BRL model for Santiago de Chile. Using the method of Sandia National Laboratory, a typical meteorological year (TMY) was built to handle like input in the process of calculation of the solar potential on the rooftops. A Digital Surface Model (DSM) is used to describe urban geometry. Another sensitivity analysis done in this research was with the albedo, where it was changed in 6 values assuming that exist several buildings with different materials around of building chosen as the case of study. The methodology was validated against measurements made on-site, showing a slight overestimation in the winter months compared to the summer months. An albedo sensitivity analysis was also performed, in which it is evident that the increase of the estimated radiation in the rooftops is linear. Still, the differences in the rise between albedos 0.2 and 0.4 tend to remain constant, therefore, because the compactness effect is relatively meaningless, to use very high albedos.