Nonideal concentration of nonimaging linear Fresnel lenses

Our paper discusses geometrical and optical concentration ratios of the optimum nonimaging arched linear Fresnel lens which we designed earlier. This is a fundamental issue, with practical implications for the design of refractive nonimaging concentrators. The deliberations yield a better understanding of the way the refractive index of the thin lens, and the refractive index of the possible dielectricum between lens and receiver, as well as light incident in the plane of the secondary acceptance half angle psi, influence the performance of the nonimaging concentrator. Theoretical results are compared with tests of the existing prototypes of the nonimaging lens, used for the concentration of solar radiation. The novel nonimaging lens is put into the context of historic research, and is made comparable to other nonimaging concentrators, notably the Compound Parabolic Concentrator. We propose the use of a linear kaleidoskope-based secondary concentrator to achieve a uniform flux distribution and the reproduction of the spectrum of the incoming light.