Optical and structural optimization of a large aperture solar parabolic trough collector

Concentrating solar power is well established renewable energy technology. It involves the same heat engine cycle as the conventional power plants, and the heat produced can be stored effectively. However, expensive mirrors and structural support systems required to maintain high precision in the shape of reflectors for better optical and thermal efficiencies are the challenges involved in making it competitive with other solar power technologies. In the present work, a methodology is proposed based on the finite element method and Monte-Carlo ray tracing to design and optimize a parabolic trough collector. The effect of geometric and optical parameters such as rim angle, the width of the collector, tracking errors, and slope errors are analyzed. The effect of tracking errors in the East-West direction and slope errors are substantial compared to the other non-random errors. Loss of 25% and 7.1% in optical efficiency occurs for tracking errors of 20 mrad and slope error of 3.2 mrad, respectively. Based on the structural and optical study, an optimization method and optimum configurations are proposed. Using the proposed methodology, heat flux maps at the receiver can also be obtained for the structural health monitoring of the receiver tube.