The acquisition of accurate knowledge of diffuse solar radiation is essential for the conversion and application of solar energy. Nevertheless, most regions around China lack the accurate measured diffuse solar radiation. The main purpose of this study is to establish reliable models for estimating diffuse solar radiation based on the clearness index for both annual and seasonal scenarios. For this purpose, 15 existing diffuse solar radiation models, including nine existing diffuse fraction and six existing diffuse coefficient models, were calibrated for estimation of daily diffuse solar radiation. Long-term, continuously measured global and diffuse solar radiation data were utilized as calibration and validation models. Five statistical parameters such as the mean absolute error (MAE), root mean square error (RMSE), uncertainty indicator at 95% (U95), mean absolute percentage error (MAPE), the correlation coefficient (R), and a global performance indicator (GPI) were used for evaluating the performance and accuracy of the calibrated models. The results showed that the calibrated best-performing models can estimate the daily diffuse solar radiation on a horizontal surface with good accuracy for both annual and seasonal scenarios. Moreover, the calibrated best-performing models can be used for estimating the daily diffuse solar radiation in regions like Wuhan.
Diffuse solar radiation Clearness index Empirical model
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The project is supported by National Key R&D Program of China (No. 2018YFD1100700). We sincerely thank the National Meteorological Information Center of China Meteorological Administration for providing the diffuse solar radiation data.
Yilmaz, F.: Thermodynamic performance evaluation of a novel solar energy based multigeneration system. Appl. Therm. Eng. 143, 429–437 (2018)CrossRefGoogle Scholar
Halawa, E., et al.: Empirical correlations as a means for estimating monthly average daily global radiation: a critical overview. Renew. Energy 72, 149–153 (2014)CrossRefGoogle Scholar
Khorasanizadeh, H., Mohammadi, K.: Diffuse solar radiation on a horizontal surface: reviewing and categorizing the empirical models. Renew. Sustain. Energy Rev. 53, 338–362 (2016)CrossRefGoogle Scholar
Liu, B.Y.H., Jordan, R.C.: The interrelationship and characteristic distribution of direct, diffuse and total solar radiation. Sol. Energy 4(3), 1–19 (1960)CrossRefGoogle Scholar
Khorasanizadeh, H., Mohammadi, K., Goudarzi, N.: Prediction of horizontal diffuse solar radiation using clearness index based empirical models; A case study. Int. J. Hydrog. Energy 41, 21888–21898 (2016)CrossRefGoogle Scholar
Orgill, J.F., Hollands, K.G.T.: Correlation equation for hourly diffuse radiation on a horizontal surface. Sol. Energy 19(4), 357–359 (1977)CrossRefGoogle Scholar
Lam, J.C., Li, D.H.W.: Correlation between global solar radiation and its direct and diffuse components. Build. Environ. 31(6), 527–535 (1996)CrossRefGoogle Scholar
Erbs, D.G., Klein, S.A., Duffie, J.A.: Estimation of the diffuse radiation fraction for hourly, daily and monthly-average global radiation. Sol. Energy 28(4), 293–302 (1982)CrossRefGoogle Scholar
Jiang, Y.: Estimation of monthly mean daily diffuse radiation in China. Appl. Energy 86(9), 1458–1464 (2009)CrossRefGoogle Scholar
El-Sebaii, A.A., et al.: Global, direct and diffuse solar radiation on horizontal and tilted surfaces in Jeddah, Saudi Arabia. Appl. Energy 87(2), 568–576 (2010)CrossRefGoogle Scholar
Younes, S., et al.: Quality control of solar radiation data: present status and proposed new approaches. Energy 30(9), 1533–1549 (2005)CrossRefGoogle Scholar
Bailek, N., et al.: A new empirical model for forecasting the diffuse solar radiation over Sahara in the Algerian Big South. Renew. Energy 117, 530–537 (2018)CrossRefGoogle Scholar
Collares-Pereira, M., Rabl, A.: The average distribution of solar radiation-correlations between diffuse and hemispherical and between daily and hourly insolation values. Solar Ener-gy 22(2), 155–164 (1979)CrossRefGoogle Scholar
Despotovic, M., et al.: Review and statistical analysis of different global solar radiation sun-shine models. Renew. Sustain. Energy Rev. 52, 1869–1880 (2015)CrossRefGoogle Scholar