Photothermal conversion characteristics and exergy analysis of TIN@h-BN composite nanofluids

The widespread application of solar-thermal absorbers is currently hindered by their low absorption efficiency and high capital cost. Therefore, many initiatives, including direct absorption solar collectors (DASCs), are currently under way to improve the efficiency of the absorbers. In this regard, the application of TiN-modified h-BN nanosheets in DASCs is studied in this paper. Their superior solar absorptivity and thermal conductivity are based on the plasma plasmon effect of nanoparticles and the high thermal conductivity of h-BN nanosheets, respectively. In the experiment, five different concentrations (20, 40, 60, 80, 100 ppm) of TiN@h-BN composite nanofluids were prepared by a two-step method. The stability and optical properties of the nanofluids were analyzed. In addition, thermal loss and exergic efficiency of photothermal conversion system were analyzed and discussed. Combined with localized surface plasmon resonance (LSPR) of TiN nanoparticles and h-BN light reflection properties, the photothermal conversion of TiN@h-BN composite nanofluids was improved in DASCs. The 80 ppm nanofluid showed the best exergic efficiency, with an average exergic efficiency of 83%. Meanwhile, the photothermal conversion efficiency of 80 ppm TiN@h-BN composite nanofluid reaches the maximum 78%. This work provides new strategies for harnessing the full spectrum of solar energy and controlling the photothermal properties of nanofluids. [GRAPHICS] .

Automated summary

This paper studies the application of TiN-modified h-BN nanosheets in direct absorption solar collectors (DASCs) to improve the efficiency of solar-thermal absorbers. The nanosheets exhibit superior solar absorptivity and thermal conductivity due to the plasma plasmon effect of nanoparticles and the high thermal conductivity of h-BN nanosheets. Five different concentrations of TiN@h-BN composite nanofluids were prepared and analyzed for stability, optical properties, thermal loss, and exergic efficiency. By combining localized surface plasmon resonance (LSPR) and h-BN light reflection properties, the photothermal conversion efficiency of the nanofluids in DASCs was improved. The study provides new strategies for utilizing solar energy and controlling the photothermal properties of nanofluids.