Estimation of monthly mean hourly diffuse solar radiation

Measured hourly diffuse solar radiation data of Zhengzhou in 2004 were analyzed in this work. The solar model proposed by Liu and Jordan was used to estimate the monthly mean hourly diffuse solar radiation data at Zhengzhou in 2004. Comparison between estimated and measured values of the hourly diffuse solar radiation showed that Liu & Jordan model can predict the measured data with good accuracy during 8:00-17:00.