TY - JOUR
TI - Modeling of the hourly horizontal solar diffuse radiation in Sanliurfa, Turkey
AU - Beyazıt Nesrin Ilgin
AU - Ünal Fatih
AU - Bulut Hüsamettin
JN - Thermal Science
PY - 2020
VL - 24
IS - 2
SP - 939
EP - 950
PT - Article
AB - Horizontal diffuse solar radiation has been calculated over various models by  using the total radiation data obtained from the horizontal surface due to  reasons such as lack of adequate measurements and expensive measuring  instruments. In this study, the measurements were calculated using the  obtained data between the years 2009 and 2016 from solar radiation  measurement system with solar tracking system, which belongs to the  Department of Mechanical Engineering, Şanlıurfa Harran University (Turkey).  Three horizontal solar diffuse radiation models have been proposed by using  the relationship between the diffuse radiation ratio and the clarity index  obtained by 8 years’ data. Horizontal solar diffuse radiation values were  calculated and compared with the measurement data for Şanlıurfa by using 15  models of diffuse radiation given in the literature and the results obtained  from the models. The statistical errors of the proposed models and 15  different diffusive radiation models were calculated. As diffuse radiation  varies with time, it is determined that modeling of Model 1 and Model 2  obtained from Şanlıurfa data gives better results in terms of clarity index  constraints. Furthermore, although the desired success cannot be achieved  with Model 2 in terms of tstat, it has been determined that the relevant  model provides better results than many models when compared to statistical  errors. With the improvements to be made on Model 2, a local estimation  model is thought to give better results.