Tunable thermal and electricity generation enabled by spectrally selective absorption nanoparticles for photovoltaic/thermal applications

High-efficiency photovoltaic/thermal systems are being put forward to develop a low-carbon economy. Moreover, nanofluid-based beam splitters with excellent property of selective spectrum absorption have shown great potential to enable effective running of the solar cells and thermal collectors without any interference. In this work, a mathematic model to evaluate the performance of the nanofluid-based beam splitter was established. Ag@TiO₂ nanoparticles with selective absorption capability were suspended in water to generate high-efficiency beam splitters for photovoltaic/thermal applications. The nanoparticles exhibited high absorptivity in the visible light wavelengths and good transmittance in the spectral response range of silicon photovoltaic cell. Under the assumption that the relative worth factor was equal to 3, the 200 ppm nanofluid produced ~1.4 times of the overall efficiency compared to water. Furthermore, the merit function reached 2.16 when 100 ppm nanoparticles were suspended owing to high photothermal conversion efficiency of the Ag@TiO₂ nanofluid. Moreover, tunable nanoparticle concentrations were adopted to obtain high-efficiency solar energy utilization. Such being the case, differential distributions between electric and thermal energy demands can be realized to match the variable requirements of electricity and heat across geographical differences.