A nanofluid composed of a base fluid and a solid nanocomposite particle, where the solid nanocomposite particle consists of a carbon nanotube and a metal oxide nanoparticle selected from the group consisting of Fe2O3, Al2O3, and CuO. The metal oxide nanoparticle is affixed inside of or to the outer surface of the carbon nanotube, and the solid nanocomposite particle is homogeneously dispersed in the base fluid. The heat transfer and specific heat capacity properties of the nanofluid are measured using differential scanning calorimetry and heat exchanger experiments with different nanocomposite concentrations and different metal oxide percent loadings.