Abstract:

Based on optical principle of arched Fresnel lens, calculation models for lens geometrical parameters such as serrated groove angle and height are set up, and calculation models for parameters of concentrating performance including lens transmittance, concentrated flux density distribution, target width are established. Structural parameters and concentrating performance are calculated and analyzed in comparison with flat Fresnel lens. Besides, effect of the factors such as transverse tracking errors（0°～2°）,slight defocusing on arched Fresnel lens characteristics is analyzed. The results indicate arched Fresnel lens can both decrease the target width effectively and increase the concentrating ratio. Furthermore, sensitivities to transverse tracking error of arched Fresnel lens are substantially decreased. Different curvature radii of arched Fresnel lens have little effect on the transmittance, which keeps its value range between 85.89%～ 87.91% .  Compared with a flat Fresnel lens, when defocusing and transverse tracking error exist, the arched Fresnel lens can sustain optimum optical performance while its F number is between 0.8 and 1.0, and R/f≤1.0. Research results above provide a significant design guidance for arched Fresnel lens application in spacial concentrating solar arrays.

Key words: Arched Fresnel lens, Serrated groove angle, Transmittance, Concentrated flux density distribution, Target width