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Propagation of white light through optical fibres for CPV systems

Optical fibres as sunlight harvesting waveguides for use in concentrating photovoltaic (CPV) systems are proposed. Results of ray tracing simulations and experimental measurements in feasible optical fibre configurations are presented in this paper. The configurations incorporate spherical as well as aspheric lenses, a simpler precursor of the Fresnel lens. Step index fibres with SiO2 as core material and preferably high numerical apertures and high incidence angles are utilised initially. Scenarios with sources of monochromatic and 1000 W/m2 irradiance are considered on simulations. Although high concentrations can be achieved in practice, for CPV applications uniformity at the end receiver is also considered as a key factor to realise acceptable cell performance. We obtained more than 99% uniformity at the end receiver of the proposed configurations for flux concentration of 2000 suns.