Algorithmized Modelling, Simulation and Validation of Clearness Index in Four Regions of Uganda

Uganda as a developing nation, needs to exploit her renewable energy potential to maximum through extensive research in the field of solar engineering. Thus, this work tries to build up a comprehensive clearness index model at three categories; national, regional and district on periodic (monthly) and non-periodic (yearly) basis for this purpose. Approximately, this quest is proceeded with the acquisition of quadragenarious data from both National Aeronautics and Space Administration (NASA) and the on-station data from four locations in Uganda. The data were arranged in the structural order of the proposed clearness index (CI) model in the MS-Excel spread sheet and later exported to OriginLab to obtain the coefficients of the CI models. The statistical inference; the coefficient of determination ( R2 ), were all tending to unity (1) which indicates the strength of the models obtained. It is observed that clearness index ranges for the different regions of Uganda: Northern (0.5288 – 0.6077), Eastern (0.5609 – 0.6077), Central (0.5123 – 0.6224) and Western (0.5123 – 0.5893). Besides, the empirical validation of the model results with the on-station data was carried out. There was good agreement between the simulated and on-station data with the trace of deviations which could be attributed to the impact of latitude and longitude of the failed locations. Furthermore, the present models were compared with the existing models, the deviation between the measured and the present model was insignificant compared to the existing models. Therefore, the present model could be employed in the advancement of solar technologies in Uganda.