Evaluation of Solar Energy Calculation Methods for 45° Inclined, South Facing Surface

For active solar systems, such as solar collectors and PV panels it is important to estimate the possible thermal or electric energy production. The energy output of these devices depends on several factors. In this paper different models for estimating the available solar radiation were analyzed. The models selected for evaluation were the Liu-Jordan, the Hay and the Reindl et al. models.There are studies evaluating such models, but evaluations were not performed for Central and Eastern European locations, only for regions with different climatic conditions. Present study focuses on the Central and Eastern European region with it's specific continental climate. In order to evaluate the models, a major city of the region, Budapest, was selected. In Eastern Europe usually only the monthly and yearly values of solar radiation are available and applied in engineering practice. However, in many cases more detailed data are required. Hence the aim of this paper is also to highlight the importance of available daily data for modeling.For solar collectors and PV panels, the optimal orientation is to the south and the optimal tilt angle is assumed to be approximately 45° in the region. The calculated daily values were compared to measured data. The solar radiation was measured on a 45° tilted, south oriented surface in Budapest. The dataset used for the global radiation calculations was provided by the Hungarian Meteorological Service.