Rotation and incidence angles for parabolic trough

Abstract

A geometrical method is utilized to derive the rotation angles and the incidence angles for a parabolic trough having different orientations. Using a least-squares method, a system of empirical equations is developed for calculating the solar radiation for Alexandria city, Egypt. A comparison between the empirical equations and experimental data shows good agreement. Another comparison between the obtained rotation and incidence angles shows excellent agreement with previous results. The equations for the incidence angle and rotation angle for trough orientation N-S and arbitrary tilt angle for the axis are new.