Numerical simulation of impact on wind load due to mirror gap effect for parabolic dish solar concentrator

Abstract

Parabolic dish solar concentrators are currently one of the most efficient solar technologies for the production of electricity. These systems are usually located in an open terrain where strong winds may be found and could affect their stability and optical performance. Mirror gap size has direct relation to thermal efficiency and construction cost. A tiny deformation of the concentrator under the action of a strong wind affects the focusing accuracy and increases the requirement of the structural strength of the dish. In this paper, different gap sizes (0–60 mm) between the mirrors of the dish are studied by numerical simulation. The results show that wind load on concentrator is sensitive to operation position, such as 30° pitch and 60° yaw angle. The gap causes an uneven distribution of the mean pressure coefficient on each facet, thereby increasing the risk of wind-induced vibration at the mirror edge. Besides, the drag coefficient on a parabolic dish increases along with the increase of the gap size between 0 and 60 mm when the dish is at the wind-resistant unfavorable conditions. For the overall wind force on a dish in the state of maximum drag force operation angle case, the mirror gap can reduce the wind force by about 3.54% with the gap size increased, which is mainly due to the significant reduction of the windward area. Therefore, the mirror gap should take as small a size as possible.