Ray-leakage-free planar solar concentrator featuring achromatic hybrid collectors and innovative secondary optical elements

- A mathematical model of the ray-leakage-free concentration ratio is established.
- The concentration ratio reaches 5200x while no rays leak from the lightguide.
- Innovative secondary optical elements are designed for ray-leakage-free.
- Achromatic hybrid collectors are designed to reduce dispersion.

For high concentration ratio of the planar concentrator which is mainly used for photovoltaic or solar-thermal applications, the ray-leakage must be prevented during rays propagated in the lightguide. In this paper, the design of a ray-leakage-free planar solar concentrator is introduced with achromatic hybrid collectors and innovative secondary optical elements. The distance between two columns of dimple structures is larger because the collector width is irrelevant to the collector length, which prompts the ray-leakage-free propagating length can be raised greatly. Put differently, the proposed concentrator can obtain a high geometrical concentration ratio while achieving a high optical efficiency. To increase the ray-leakage-free propagating distance, a mathematical model between ray-leakage-free propagating length and the corresponding parameters is established, where the corresponding parameters include the parabola coefficient, the width of collector, the concentrator height and the small expanding angle of the dimple structure. Numerical results display that more than 5000x geometrical concentration ratio of the proposed concentrator is achieved without any leakage from the lightguide.