Indoor characterization and comparison with optical modelling of four Fresnel-based High-CPV units equipped with secondary optics

Numerous works analyze the refractive secondary optical elements (SOEs) in their application to HCPV modules, since the improvement in their optical tolerances, specifically, in the acceptance angle. Comparative theoretical and some experimental works are already published about this matter. However, this work also provide the validation of an optical modelling previously published, in which key features of the HCPV units were taken into account. Specially, that modelling considered wavelength-dependent properties in the light-matter interaction, like in the optical polychromatic efficiency of the solar cell (through its spectral response), or in the light absorption coefficient of the PMMA material. Then, four SOEs are manufactured and utilized to assemble different HCPV units to be characterized under controlled conditions in a CPV Solar Simulator. The four SOEs are: (i) SILO-Pyramid (SIngle-Lens-Opical elment), (ii) DCCPC (dielectric-cross compound-parabolic-concentrator), (iii) RTP (refractive truncated pyramid) and (iv) Trumpet. The correspondent HCPV units are characterized at 1000 W/m² and at spectral conditions SMR = 1 under normal alignment respect to the simulated light and also at different tilted orientations. This last allows to measure the acceptance angle of each HCPV unit. These values are compared to those simulated by ray tracing. The results show measured acceptance angle values are in general similar to the simulated ones, with a deviation lower than 8%, except for the case of the SILO-Pyramid unit.