Ekmekçi, İsmailŞen, Y.2019-08-192019-08-192016https://hdl.handle.net/11467/2868In this study, horizontal global solar radiation estimation models and estimated values are reviewed and compared with measured national database for Istanbul. The mathematical models used are based on the sunshine duration data as common in the world. For comparisons, the most common statistical methods (MBE, MPE and RMSE) are also used. It can be briefly said that solar energy measurements in our country are not perfect and also are not reliable for any feasibility study then the results show that measurements cannot be used directly for any analysis. Those measurements also include wrong and missing data parts. Investors should have their own measurement station at the best location for the planned action, and the measured data also should be analyzed by specialists.eninfo:eu-repo/semantics/openAccessSolar EnergySolar Radiaton ModelsIstanbulGEPAAngström ModelArticle12