Resumen de Calculating solar radiation for horizontal surfaces—I. Theoretically based approaches

J. E. Hay

• This paper reviews the theoretical basis of relatively simple models that use widely available meteorological data to determine the solar irradiation at the earth's surface. Spectral and non-spectral models for clear and cludy sky conditions are considered. A sample of validation results is presented. These indicate that most of the models studied are capable of estimating the global irradiation with acceptable accuracy, especially for time intervals of a month of more.