A method to obtain daily total solar insolation (kwh/m~2 ) from daily total output current (Ah) of a PV array

摘要

To determine solar energy potential in a certain location and to realize studies of economics and sizing of photovoltaic system applications to be established in this certain location, solar radiation measurement corresponding to this site is critically important. Solar energy atlas of Turkey is extracted using ESRI Solar Radiation Model whose parameters are calibrated with measurements, which cover period of 22 years between 1985 and 2006, by the study made by EIE in 2008. Applicators of solar energy technologies use solar radiation data in studies such as suitability of the site, economics and sizing of the application. For large-scale applications of solar energy conversion technologies, most experts agree that solar radiation data should be accurate to within 5% to assess the resource, estimate the output of a solar system, and determine whether the system can reliably and economically meet daytime demand and energy requirements. It is stated that the atlas extracted by EIE may include 10% error. Additionally data for some cities at the atlas completely depend on the model estimation. So these data include error more than 10%. For these cities with error more than 10%, the performance and economic goals may not be met in the applications. In this study, a method is presented to evaluate the daily total solar insolation (kWh/m~2) from the knowledge of daily total PV array output current (Ah) given by the data logger device of photovoltaic system composed from four strings each having two modules occupied in Karabuk University Renewable Energy Engineering Research and Application Center. Universities with similar small systems can collect solar energy data corresponding to their sites using presented method in this study.