Broad-band absorption and photo-thermal conversion characteristics of rGO-Ag hybrid nanofluids

• Published in: Journal of molecular liquids 2024-08, Vol.408, p.125347, Article 125347
• Main Authors: Huminic, Gabriela, Vărdaru, Alexandru, Huminic, Angel, Fleacă, Claudiu, Dumitrache, Florian
• Format: Article
• Language: English
• Subjects: Hybrid nanofluids; Optical properties; Photo-thermal conversion
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2024.125347

•A new hybrid nanofluids, rGO-Ag/water and rGO-Ag/water + ethylene glycol were prepared.•Optical and photo-thermal properties of hybrid nanofluids were experimentally tested.•Both hybrid nanofluids achieve superior solar absorption.•The PTE performance was enhanced at low concentrations of hybrid nanofluids. In the current paper, the thermo-physical, optical and photo-thermal conversion characteristics of reduced graphene oxide nanosheets and silver nanoparticles suspended in water and water + ethylene glycol solution (1:1) were experimental investigated under indoor conditions. The results indicated that the hybrid nanofluids have a good solar absorption in both visible and near-infrared regions (220–1400 nm). Comparing transmission spectra and extinction coefficients of rGO-Ag/water and rGO-Ag/W + EG hybrid nanofluids it is found that the use of rGO-Ag/W + EG hybrid nanofluid is much more beneficial than the rGO-Ag/water nanofluid in solar applications. The rGO-Ag /water and rGO-Ag /W + EG hybrid nanofluids with 0.10 wt% exhibit a relative increase in the temperature difference by about 21 % and 37 % compared to the base fluids and also stored energy values of 4989 J and 5432 J respectively, after an irradiation time of 60 min. This study emphasized the solar potential of rGO-Ag hybrid nanofluids for improving the direct absorption solar collectors performance.