Design and fabrication of aspheric Fresnel-type lenses for solar energy by using a 3D printer

Traditionally, the Fresnel-type lens design often assumes thin lenses, since lenses of finite thickness cannot be completely described in analytical terms, then a numerical solution has to be found. We implement an exact ray trace considering a plane wavefront incident by reducing as much as possible the area of light concentration, while increasing the concentration ratio of energy. In such a way that we have mathematically determined a function to compute groove angles, to refract a bundle of rays from each planar echelon, which are propagated into a predetermined area of energy collection. In addition, we can evaluate the performance of the Fresnel-type lens design for a solar collector. Thus, an analytical formula to calculate the optical efficiency is obtained, in terms of the geometrical losses widely studied for nonimaging systems, such as blocking losses. Finally, the proposed aspherical Fresnel lens design is fabricated using a commercial 3D printer and subsequently polishing the surface for better performance. In this fashion we could test the performance of the manufactured prototype.