Photothermal Conversion Performance of Fe3O4/ATO Hybrid Nanofluid for Direct Absorption Solar Collector

In order to enhance the efficiency of direct absorption solar collectors, this study carried out an experimental analysis about the optical and photothermal conversion performance of Fe3O4, ATO and Fe3O4/ATO nanofluids with total concentration of 0.1wt%. According to the results of experiments, Fe3O4 nanofluid outperform ATO nanofluid in terms of optical absorption; nevertheless, at wavelengths shorter than 600 nm, it also shows significant scattering reflection. The solar-weighted absorption coefficient of Fe3O4/ATO nanofluid rose from 0.863 (mFe3O4mTotal= 0.2) to 0.932 (mFe3O4mTotal= 0.8) when the optical path length increased from 0.01 m to 0.06 m. Additionally, the photothermal conversion efficiency of Fe3O4/ATO hybrid nanofluid was attained 0.932 at (mFe3O4mTotal= 0.2), above the 0.892 and 0.898 photothermal conversion efficiencies recorded for 0.1 wt% ATO and Fe3O4 nanofluids, respectively. When present together, the opposing optical characteristics of Fe3O4 and ATO boost photothermal conversion performance, which is anticipated to raise the efficiency of direct absorption solar collectors.