Performance of solar concentrator made of an achromatic Fresnel doublet measured with a continuous solar simulator and comparison with a singlet

A primary optics for solar concentrator made of an achromatic Fresnel doublet has been designed and manufactured. The achromatic Fresnel doublet combines the advantages of plastic lenses without being affected by chromatic aberrations. The performance has been determined experimentally using a homemade continuous solar simulator and compared to paraxial theory and ray-tracing simulations. Experimental results are in good agreement with theory and show that the achromatic Fresnel doublet is tolerant to manufacturing errors and uncertainty on the dispersion of the refractive index: the concentration factor remains above 1600× with an f-number of 2.