Investigation of the stability of MgO nanofluid and its effect on the thermal performance of flat plate solar collector

Nanofluids are getting the utmost preference for heat transfer applications due to their excellent thermal properties over the base fluid. In the present study, the stability of Magnesium oxide/Ethylene Glycol-Distilled water nanofluid and its effect on the thermal performance of flat plate solar collector (FPSC) was experimentally investigated. Cetyltrimethyl ammonium bromide (CTAB) surfactant was added to the mixture and sonicated to stabilize the suspension. The stability was analysed at different nanoparticle concentrations (0.08%-0.4%) as a function of time. The thermal performance of FPSC was investigated at different particle concentrations (0.08%-0.2%) under varying flow rate (0.5-2.5 Lit/min). Nanofluid characterizations; zeta potential & UeV spectroscopy reveal that nanofluids were stable for more than 15 days up to 0.2 vol% concentration. At higher volume fraction (0.4 vol%), as a result of agglomeration, nanofluid become unstable. The highest thermal efficiency of the collector was achieved by 69.1% for 0.2 vol% at 1.5 Lit/min, which was 16.7% more than EG/DW solely. The results depict that the absorbed energy factor increased by 16.74% and heat loss parameter decreased by 52.2% at the identical parametric condition. The results encourage the use of MgO nanofluid in FPSC. (c) 2019 Elsevier Ltd. All rights reserved.