Optical Tests on a Curve Fresnel Lens as Secondary Optics for Solar Troughs

Table 2

Concentration factor C as a function of α for lens_B.

α (°)	mm	mm	mm	mm	mm
40	1.96	2.03	2.07	2.07	2.05
35	1.98	2.05	2.09	2.10	2.06
30	1.98	2.06	2.11	2.12	2.08
25	2.00	2.07	2.11	2.11	2.09
20	2.02	2.11	2.15	2.13	2.10
15	2.00	2.11	2.16	2.16	2.13
10	1.98	2.07	2.13	2.13	2.10
5	1.97	2.06	2.10	2.10	2.08
0	2.00	2.09	2.15	2.15	2.13
−5	2.03	2.13	2.19	2.19	2.16
−10	2.04	2.13	2.18	2.17	2.13
−15	2.02	2.11	2.17	2.17	2.15
−20	2.03	2.13	2.18	2.17	2.14
−25	2.02	2.11	2.15	2.15	2.12
−30	2.01	2.08	2.13	2.13	2.10
−35	1.99	2.07	2.12	2.12	2.07
−40	2.00	2.07	2.10	2.09	2.05