Application of PEG-Fe3O4 nanofluid in flat-plate solar collector: An experimental investigation

In the present study, novel in-situ oxidation precipitation of ferrous hydroxide method is used to synthesized Fe3O4 nanoparticles and Polyethylene glycol 200 is used for covalent functionalization. Various characterizations tests (FESEM, EDX, XRD, FTIR, HRTEM) were performed, and the Polyethylene glycol treated Iron oxides functionalization was confirmed. Thermal conductivity, density, specific heat, and viscosity were experimentally assessed and validated using the correlations that were available. The corresponding improvements in thermophysical characteristics were 13.35%, 0.06%, 0.37%, and 20.9% at 0.1 wt% and 35°C. UV–vis spectroscopy and Zeta protentional was used to check the stability of nanofluids and found that nanofluid was stable for 30 days. A flat plate solar collector was experimentally installed, and the thermal performance of collector was calculated using ferrofluid under ASHRAE standard 93–2003 at different heat flux intensities (597,775,988 W/m2), mass flow rates ((0.0133, 0.0200, 0.0266 kg/s), inlet fluid temperature (30–50°C) and weight concentrations (0.025,0.05,0.075,0.1%). The highest thermal efficiency enhancement of 13.83% was noticed. Moreover, the ANSYS-CFD model was used for the numerical analysis of the thermal performance of flat plate collector at the same environmental conditions, and a maximum difference of 8.33% at 0.1 wt% was noticed in comparison with experimental data. •Nanofluid was synthesized using in-situ oxidation method and confirmed with different characterization technique.•Thermophysical properties of Nanofluids with different weight concentrations were measured experimentally.•Thermal performance of FPSC was evaluated using ferrofluid and found 13.83% enhancement.•A maximum difference of 8.33% at 0.1 wt% was noticed in comparison with experimental data when ANSYS-CFD model was used.