Performance of empirical correlations for predicting monthly mean daily diffuse solar radiation values at Kampala, Uganda

SummaryExisting literature lacks information on formulation and performance assessment of diffuse solar radiation models in the Eastern African region yet this region has a high potential for the utilization of solar energy. The objective of this paper is to assess the performance of seventeen diffuse solar irradiation empirical correlations, at Kampala, Uganda. The best performing correlations were determined using the ranking method. The normalized absolute mean bias error and root mean square error were computed and utilized in the ranking process. The results indicated that the correlations relating diffuse transmittance $(\bar{H}_d/\bar{H}_0)$ with relative sunshine duration $(\bar{S}/\bar{S}_0)$ are more reliable for diffuse solar radiation predictions at least in the Uganda environment. These models are expressed in terms of first, second and third order polynomials of the relative sunshine duration and are particularly recommended for their simplicity and worldwide applicability.

[1]  A. Angstroem.  Solar and terrestrial radiation , 1924 .

[2]  Benjamin Y. H. Liu,et al.  The interrelationship and characteristic distribution of direct, diffuse and total solar radiation , 1960 .

[3]  R. Tuğrul Oğulata,et al.  Solar radiation on Adana, Turkey , 2002 .

[4]  M. Hijazin.  The diffuse fraction of hourly solar radiation for Amman/Jordan , 1998 .

[5]  M. Tiris,et al.  Analysis of solar radiation data for Gebze, Turkey , 1997 .

[6]  M. Chendo,et al.  Atmospheric turbidity and the diffuse irradiance in Lagos, Nigeria , 1997 .

[7]  Kamil Kaygusuz,et al.  The Comparison of Measured and Calculated Solar Radiations in Trabzon, Turkey , 1999 .

[8]  A. Angstrom.  Solar and terrestrial radiation. Report to the international commission for solar research on actinometric investigations of solar and atmospheric radiation , 2007 .

[9]  Josep Calbó,et al.  INFLUENCE OF THE GLOBAL RADIATION VARIABILITY ON THE HOURLY DIFFUSE FRACTION CORRELATIONS , 1999 .

[10]  A. Kume,et al.  Evaluation of direct and diffuse radiation densities under forest canopies and validation of the light diffusion effect , 2003, Journal of Forest Research.

[11]  Joseph A. Jervase,et al.  Monthly average daily solar radiation and clearness index contour maps over Oman , 2003 .

[12]  M. Bashahu,et al.  Statistical comparison of models for estimating the monthly average daily diffuse radiation at a subtropical African site , 2003 .

[13]  L. Hadjioannou,et al.  On the diffuse fraction of daily and monthly global radiation for the island of Cyprus , 1996 .

[14]  Richard H. Grant,et al.  Ability to predict daily solar radiation values from interpolated climate records for use in crop simulation models , 2004 .

[15]  C. P. Jacovides,et al.  Application of SPCTRAL2 parametric model in estimating spectral solar irradiances over polluted Athens atmosphere , 2004 .

[16]  Zhou Jin,et al.  Estimation of daily diffuse solar radiation in China , 2004 .

[17]  M. Muselli,et al.  Stochastic study of hourly total solar radiation in Corsica using a Markov model , 2000 .

[18]  W. Beckman,et al.  Solar Engineering of Thermal Processes , 1985 .

[19]  Arif Hepbasli,et al.  Solar Radiation Models. Part 1: A Review , 2004 .

[20]  Michael Geiger,et al.  A Web service for controlling the quality of measurements of global solar irradiation , 2002 .

[21]  Amauri Pereira de Oliveira,et al.  Correlation models of diffuse solar-radiation applied to the city of São Paulo, Brazil , 2002 .

[22]  A. Bahgat,et al.  Computation of the Solar Energy Captured by Different Solar Tracking Systems , 2000 .

[23]  T. O. Aro,et al.  The Diffuse Fraction of Global Solar Irradianceat a Tropical Location , 1998 .

[24]  Javier Almorox,et al.  Global solar radiation estimation using sunshine duration in Spain , 2004 .

[25]  K. Gopinathan.  Empirical correlations for diffuse solar irradiation , 1988 .

[26]  Chakradhar Lingamgunta,et al.  A universal relationship for estimating clear sky insolation , 2004 .

[27]  Francesco Danuso,et al.  Climak: a Stochastic Model For Weather Data Generation , 2002 .

[28]  A. A. El-Sebaii,et al.  Estimation of horizontal diffuse solar radiation in Egypt , 2003 .

[29]  M. Iqbal,et al.  Correlation of average diffuse and beam radiation with hours of bright sunshine , 1979 .