Abstract
•Simple approach to predict the optical efficiency and optical concentration ratio experimentally.•Single and multi-junction solar cells has been utilized for optical products predications.•Focal spot area to solar cell area were considered in the measurements.•Analysis for UHCPV optics were investigated to theoretically estimate the optical losses.
This article investigates the discrepancy between the theoretical and the experimental optical characterisation results of a Fresnel Lens - silicon on glass (SOG), as a primary optical component toward UHCPV of >3000 suns design (Shanks et al., 2018). All the equations were elaborated for single- and multi-junction solar cells, emphasising the performance when the focal spot area is larger or lesser than the solar cell area. This simple prediction approach of optical characterisation has shown a strong agreement between the theoretical and experimental results of the multi-junction solar cell with a discrepancy of 2% at 7.7 W (77 suns) and 6% on the average cross a solar irradiance on the cell from 3.1 W to 7.7 W corresponding to 31 suns – 77 suns in concentration ratio. A theoretical analysis of the optical performance for a 1/4 of the system grouping three optical interfaces is performed to estimate the optical loss and its influence on the optical efficiency and optical concentration ratio.