Title:	How to "Display" the Angle-Resolved Transmission Efficiency of a Solar Concentrator Reversing the Light Path
Author(s):	A. Parretta, A. Antonini, M.A. Butturi, P. Di Benedetto, E. Milan, M. Stefancich, D. Uderzo, P. Zurru, D. Roncati, G. Martinelli, M. Armani
Keywords:	Oblique Incident Sunlight, Modelling / Modeling, Characterisation, Characterization, Concentrator
Topic:	Advanced Photovoltaics
Subtopic:	Fundamental Studies
Event:	23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain
Session:	1AO.6.6
Pages:	95 - 98
ISBN:	3-936338-24-8
Paper DOI:	10.4229/23rdEUPVSEC2008-1AO.6.6
Price:	0,00 EUR
Document(s):	paper

Abstract/Summary:

---

A novel, powerful method for the optical characterization of solar concentrators is presented. It requires the reversing of light path, realized through the backward illumination of the concentrator from the receiver surface, and the measuring of intensity distribution of light projected on a far, diffusive screen. If the source of back illumination is spatially uniform and has a Lambertian angular distribution, then the angle-resolved relative radiance derived from the projected light intensity perfectly coincides with the relative angle-resolved transmission efficiency of the concentrator operating in the normal, direct mode. Respect to the conventional method for deriving the angleresolved efficiency, which requires an expensive apparatus and long measurements at different orientations of the concentrator respect to a parallel beam, the presented, inverse, method is extremely simple to apply and requires only the recording of an image, that displayed on the screen, by a camera or a CCD. The inverse method, previously validated with simple ideal, reflective non-imaging (CPC) concentrators, is here applied to real (absorbing) reflective non-imaging and refractive Fresnel lens systems.