A binational team led by Imperial College London and Tecnológico de Monterrey has modelled, designed and numerically tested a parabolic-trough spectral-splitting CPV-T (SSCPV-T) collector that integrates:
• a commercial 10× parabolic concentrator (aperture 1.088 m, focal length 0.34 m);
• a triangular primary receiver with c-Si PV cells attached to its sloped faces;
• a secondary liquid filter channel placed between the mirror and the cells, and enclosed in a glass envelope that absorbs UV/IR while transmitting the 400–1100 nm waveband optimal for c-Si PV cells.
Three filter fluids for the liquid filter channel were compared: water, Therminol-66, and an AgSiO₂-ethylene-glycol (AgSiO₂-eg) nanofluid. Fully coupled 3-D ray-tracing, electrical and CFD sub-models—each validated against literature data to within 10 %—were solved in COMSOL Multiphysics 6.1.

Key results
• At an irradiance of 1000 W m⁻², a wind speed of 1 m s⁻¹, and a filter-to-primary mass flowrate ratio of 0.2, the proposed collector delivered:
– an electrical efficiency of 15 %
– an overall, maximum thermal efficiency of 45 % (primary: 30 %; filter: 15 %)
– a filter channel outlet flow temperature of 100 °C at 5 % efficiency, allowing direct steam or process-heat applications.
• Use of the AgSiO₂-eg nanofluid filter raised the filter’s thermal efficiency to ≈ 41 %—a 25 % absolute improvement over water or Therminol-66—pushing the overall thermal efficiency to ≈ 60 %, while the electrical efficiency dropped by only ≈ 5 % absolute (≈ 10 % vs 15 %), showing effective spectral decoupling.
• Parametric studies revealed a plateau in performance above a 0.24 mass flowrate ratio, beyond which pumping penalties outweigh gains.

Research significance
By developing the first fully-validated 3-D SSCPV-T collector design tool and using this to quantifying the performance of a proposed SSCPV-T collector, the study provides designers with a validated tool and a blueprint for next-generation, high-performance total-solar-utilisation cogeneration systems. The AgSiO₂-eg nanofluid configuration is particularly attractive for industrial users prioritising high-grade heat, while the water-based design remains cost-effective for medium-temperature applications. All modelling tools and optical/thermal correlations are being released open-source to accelerate commercial uptake.
DOI: 10.1007/s11708-025-1028-y