Harmonic model of hourly fractions of daily global and diffuse solar radiation

الملخص EN

A harmonic model for the hourly global and diffuse solar radiation fractions is developed.

The Fourier coefficients of the model are determined by using measured data.

In testing the generality of this approach, similar analysis is applied to data collected in five cities in different countries.

The results demonstrate a consistency in the level of accuracy of the model.

Computations by the model are in excellent agreement with the data.

The percentage error between the data and the Fourier coefficients are used in the model to make it general.

The errors of the general model remain within acceptable limits, especially for time range of about ten hours around the solar noon.

Computations of the hourly global and diffuse solar radiation fractions by the harmonic model developed in this research demonstrate a significant improvement over computations by existing models.