Optimum tilt and azimuth angles of heat pipe solar collector, an experimental approach

The application of solar energy as the widest, clean and free source of thermal energy requires the solar collector. As one of the common types of solar collector, heat pipe solar collector has been investigated. The thermal performance of a solar heat pipe collector was simulated using the anisotropic sky radiation model in eight different tilt angles and thirteen azimuth angles at the location of Isfahan City, Iran. The obtained theoretical results were compared with experimental ones and an average discrepancy of 5 % was obtained. After approving the chosen model, the optimum seasonal and yearly tilt angles were calculated and the correlations also were drawn from a written subroutine. The results show that through spring and summer, the optimum tilt angle is somewhat less and through autumn and winter the optimum tilt angle is beyond the latitude angle with the largest difference in spring and autumn. For the whole year and under the conditions of the present study, the optimum tilt angle is nearly the same as the latitude angle of the location.