Obtaining maximum input heat gain on a solar collector under optimum slope angle

In the present work, a mathematical model was used for estimating the total (global) solar radiation on an inclined surface faced to the south, and to determine the optimum slope angle for the solar collectors in a hot and dry part of Iran, based on the experimental data for a horizontal surface. The monthly, seasonal and yearly optimum slope angles were found. The gains in the solar radiation were calculated with respect to a solar collector inclined at the local latitude. The results showed that the yearly optimum slope angle for each city is close to the local latitude. The results also indicated that changing the monthly and seasonal slope angles causes us to achieve a significant yearly gain in the solar radiation for the region under investigation.