The effect of the pitch angle, two-axis tracking system, and wind velocity on the parabolic trough solar collector thermal performance

Abstract

In this study, heat transfer and airfield around a parabolic trough solar collector are simulated. The effect of the pitch angle, two-axis tracking system, and wind speed on the collector thermal performance is evaluated. Three-dimensional and turbulent flow equations are used. Simulations are performed at noon, for the 45th day of summer, for the geographical location of Isfahan. The effects of wind velocities from V = 1 to 3 m/s are studied. The results of this study are investigated for a single-axis tracking system at pitch angles 0°, 15°, 30°, and 45°, and for a two-axis tracking system for the angles of 45°–35°, 45°–25°, and 45°–15°, respectively. The results indicate that factors such as the change in the heat transfer coefficient, collector pitch angles, and amount of flow deviation between the upper and lower dome of the collector resulting in a distinction between the absorption of maximum radiation fluxes or the maximum heat transfer (heat loss) rate. Moreover, the higher the pitch angle, the higher the amount of received sunlight, but on the other hand, it causes the wind to affect all the collector surfaces (more heat loss). The drag force applied to the two-axis collector is lower than the one-axis collector. Therefore, using a two-axis system not only does not increase the structure size but also can decrease it, too.