Properties of Al2O3-MWCNT/radiator coolant hybrid nanofluid for solar energy applications

Abstract

As a unique approach to enhance the heat transfer properties of fluids with the inclusion of multiple solid particles with sizes less than 100 nm is called hybrid nanofluids (HNF). Due to the exceptional heat transfer capabilities of HNF, they are being evaluated as prospective working fluids for high heat flux systems such as solar collectors. In this paper, the effect of volume fraction and temperature on thermal conductivity (TC), viscosity, and density of Al2O3-MWCNT/radiator coolant hybrid nanofluid are experimentally investigated. X-ray diffraction was used to characterize the Al2O3 and multiwalled carbon nanotube. The experiment was carried out at different volume fractions (0.1–0.5 vol%) and different temperatures (20–60 °C). The experimental results found that the TC, viscosity, and density of Al2O3-MWCNT/radiator coolant hybrid nanofluid increase as a function of vol% of nanoparticles. However, the viscosity and density decrease with an increase in temperature. The maximum enhancement of TC was found to be 11% at 0.5 vol% and 60 °C. Therefore, the Al2O3-MWCNT/radiator coolant hybrid nanofluid enhances thermal properties over the base fluid. Thus, the results encourage to use of Al2O3-MWCNT/radiator coolant hybrid nanofluid in solar applications.

Keywords

• Hybrid nanofluids
• Solar energy
• Thermal conductivity
• Viscosity
• Temperature