Conventional Methods of Defining of the Intensity of Solar Radiation on Horizontal Surface

The energy crisis, limited resources of fossil fuels, along with their negative environmental impacts in recent years have caused to increase the use of renewable energy sources, particularly solar energy. In order to evaluate the performance of solar systems, knowledge of the solar radiation intensity in each region is essential. In this study, solar irradiance components, diffuse and direct, for the city of Shahrekord, are measured. Solar power meter and Pyranometer are used for the experimental measurements. The Hattel radiation model, developed on gPROMS platform is used to calculate solar irradiance. Finally, in order to control the solar power meter results and the accuracy of Hattel model, radiation data recorded moment in Shahrekord solar radiation station has been used. The results indicate that around noon, good agreement exists between the measured results of solar power meter and those of pyranometer. While, during the early hours and the end of the day there is 23% difference between the measurement results. The Hattel model predictions for solar irradiance, agrees better with the measurements of pyranometer.