Enrichment and Thermal Performance of Solar-Based Heat Exchanger Featured With Alumina/Graphene Hybrid Nanofluid

Abstract The novel research intends to enrich the overall thermal performance and thermal efficiency behavior of solar-based heat exchangers configured with different concentrations of hybrid nanofluid composed of 50:50 ratios of alumina and graphene nanoparticles, whose particle dispersion and adhesive force are enhanced by the actions of the ultrasonication process and additions of 0.1% SDS (sodium dodecyl sulfate) surfactant. During the evaluation, a constant flowrate of 13 L/min is maintained. The influences of the ultrasonication process on the microstructural characteristics of the hybrid nanoparticle are confirmed via transmission electron microscopy analysis. The influences of hybrid nanofluid concentrations on the thermal performance of solar-based heat exchangers are investigated, and it is found that the heat exchanger operated with a 1.5% concentration of hybrid nanofluid shows significant improvements in heat transfer rates, convective heat transfer coefficients, outlet temperatures, and overall thermal and exergy efficiencies. These parameters demonstrate improvements of 10.6%, 20.3%, 13.7%, 13.2%, and 26% compared to the thermal performance of standard solar heat exchangers operating with water. Additionally, there is a minimal increase in pressure drop, measuring around 15.1% at the 1.5% volume concentration. The novel study highlights the potential of alumina/graphene hybrid nanofluids to enhance thermal performance in solar collectors while minimizing the impact on pressure loss.