Three-zone multifocus hybrid Fresnel lens concentrator.

In this paper, we designed a three-zone multifocus hybrid Fresnel lens concentrator without a homogenizer. This concentrator uses three types of prisms: a refractive prism, a single total internal reflection (STIR) prism, and a double TIR (DTIR) prism. In order to achieve a uniform irradiance distribution, the Fresnel lens is cut into four quadrants and reconnected. Moreover, by decreasing the angle of the edge ray, the hot spot effects caused by the STIR and DTIR prisms can be reduced. Finally, the three-zone multifocus hybrid Fresnel lens concentrator can achieve a geometric concentration ratio of 2121X, f-number of 0.441, optical efficiency of 76.570%, acceptance angle of ±0.268, uniformity of 57.002%, and hot spot criteria of 1.369.