Estimation of the influence of Fresnel lens temperature on energy generation of a concentrator photovoltaic system

Recent investigations of Fresnel lens concentrator optics have shown that optical efficiency and module performance depend on lens temperature. In former works we have succeeded in modeling these effects, achieving very good agreement with measurements of silicone on glass (SOG) Fresnel lenses. In the work presented here, we combine this lens model with irradiation spectra and ambient temperature data at typical sites for concentrator photovoltaic power plants for a whole year of operation. The solar cell is simulated with a model based upon the detailed balance limit introduced by Shockley and Queisser. This concentrator photovoltaic system consisting of a triple junction solar cell and a Fresnel lens concentrator is simulated including changes in temperature and spectrum over daytime and during all seasons. Comparing two simulations, one with the Fresnel lens kept at constant temperature and one with a realistic temperature variation of the lens, allows us to analyze the impact of Fresnel lens temperature on system efficiency under realistic environmental conditions. In our analysis poly(methylmethacrylate) (PMMA) Fresnel lenses and SOG Fresnel lenses show comparable energy harvesting efficiency at close to market locations.

► Systems with Fresnel lens concentrator and idealized solar cell.
► System using silicone on glass (SOG) lens compared to PMMA lens.
► Four close-to-market and two extreme potential power plant sites are studied.
► Average annual efficiency loss due to temperature lower for PMMA than for SOG lens.
► Overall performance comparable for PMMA and SOG lenses at close-to-market locations.