Estimation of hourly global solar radiation in the plane areas of Uttar Pradesh, India

The hourly global radiation on a horizontal surface can be evaluated for the plane areas of Uttar Pradesh using regression constants based on the model proposed by Al-Sadah et al. (1990). Comparison between estimated and measured values shows that the constants derived for Lucknow (latitude 26.75 degrees N, longitude 80.50 degrees E) provide good estimates of the hourly global radiation except for the sunrise and sunset hours. The present results are comparable with the estimates of the Liu and Jordan (1960) and Collares-Pereira and Rabl (1979) models which also correlate hourly values and daily totals of the global radiation. (C) 1997 Elsevier Science Ltd.