Estimating beam and diffuse solar irradiance components using multiple solar irradiance meters

Sammanfattning: In recent years, different renewable energy sources have been on the rise. Among these, solar power has shown great potential in both small and big scale. Since solar irradiance is the main input for solar power systems, it is of great importance to examine how much of the solar irradiance actually reaches a certain location, and how much of the total solar irradiance consists of direct (beam), diffuse and reflected irradiance. This is usually done with expensive measurement meters, such as pyranometers and pyrheliometers. In this thesis, incident solar irradiance data from a cheap sensor network is analyzed, a new proposed model for estimating beam and diffuse fraction is examined and the results are compared to another estimation model, namely Erbs model. The comparison between the two models shows high correlation for beam irradiance, regardless of weather conditions, whereas the correlation for diffuse irradiance shows a highly varying result, much dependent on the weather conditions. It is difficult to motivate how well the proposed model is performing on a broader scale, since the study is limited to a specific area during a short period of time.