This paper summarizes the results of a comparative analysis of four models (the Kasten, Muneer, Zhang and Huang, and neural network-based models) used to predict hourly solar radiation for six tropical sites. All four models require cloud cover and nonsolar weather data to predict global, diffuse, and direct solar radiation. Predictions from the models are compared against measured solar data obtained for meteorological stations in the six tropical sites. Nonsolar weather data for the same sites were obtained from the National Climatic Data Center (NCDC).

Results of the validation analysis indicate that the Zhang and Huang model is suitable for predicting hourly solar radiation in tropical climates.

Units: SI