Evaluation on the photothermal conversion performance of SiC nanofluid for a direct absorption solar collector

In this study, the application possibility of SiC nanofluid in direct absorption solar collectors (DASCs), the dispersion stability, light absorption characteristics, and photothermal conversion performance of SiC nanofluid were experimentally investigated. In particular, the dispersion stability of SiC nanofluid according to pH concentration and the type of surfactant was evaluated using light transmittance. As a result, it was confirmed that the SiC nanofluid had the highest dispersion stability when the pH concentration was 7 and the PVP surfactant was used. Also, when the light transmittance was decreased with the increase in the extinction coefficient of light when the concentration of SiC nanofluid increased from 0.001vol% to 0.005vol%. However, even though the light absorption increased with increasing concentration, the photothermal conversion efficiency reached the critical value at 0.004vol%, and decreased at 0.005vol%. The photothermal conversion efficiency of the 0.004vol%-SiC nanofluid was improved by 81.6% compared to that of water.