M Abdolzadh - Department of Mechanical Engineering, Islamic Azad University Kerman Branch, Kerman
M.A Mehrabian, - Department of Mechanical Engineering, Shahid Bahonar University of Kerman,Kerman,
A Zare - Department of Mechanical Engineering, Shahid Bahonar University of Kerman, Kerman

One of the important parameters influencing the performance of a solar collector is its slope angle, because the variation of slope angle makes the amount of solar radiation intensity reaching the collector surface change. A mathematical model was used for estimating the total (global) solar radiation intensity on an inclined surface faced to the south, and to determine the optimum slope angle for the solar collectors in hot and dry part of Iran based on experimental data for a horizontal surface. The monthly, seasonal and yearly optimum slope angles were found. The slope angle was calculated for different intensities of total radiation on the collector surface and the corresponding values for maximum total radiation were specified as the optimum slope angles. 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, seasonal and yearly slope angles causes to achieve a significant yearly gain in solar radiation intensities for the region under investigation. These yearly gains were calculated with respect to a solar collector fixed at zero slope angles.

Global solar radiation intensity, Optimum slope angle, Solar collectors, Zero slope angle, Hot and Dry