Performance improvement of a PV/T system utilizing Ag/CoSO4-propylene glycol nanofluid optical filter

Nanofluid-based spectral beam splitters (SBS) have become dramatically popular for PV/T applications due to it can achieve tunable optical properties inexpensively. In this paper, Ag nanoparticles suspended in hybrid CoSO4 and propylene glycol (PG) base fluids were prepared for both silicon and GaAs cells. Ag/CoSO4-PG nanofluid filters exhibited broad absorption outside solar wavelengths and showed high transmittance in wavelength range used by the two types of cells efficiently. The results from the indoor PV/T performance test indicated that Ag/CoSO4-PG nanofluid filters, paired with both silicon CPV cell and GaAs cell, enhanced the combined efficiencies more than five times compared to PV alone systems. Besides, the total efficiency for silicon CPV cell based PV/T system with Ag/CoSO4-PG nanofluid filters exhibited 9% higher than that of system with Ag/CoSO4-water nanofluid filters. Finally, results from validated models showed that the Ag/CoSO4-PG nanofluid filter for silicon based PV/T system presented the capability to enhance the market value of 30% at an optimum Ag nanoparticles mass fraction of 10 ppm and an optimum optical path-length of 15 mm. The peak merit function of 1.831 for GaAs based PV/T system was achieved when the nanoparticle fraction is 3 ppm and the optical path-length is 43 mm. (C) 2019 Elsevier Ltd. All rights reserved.