Unraveling the role of the base fluid arrangement in metal-nanofluids used to enhance heat transfer in concentrating solar power plants

A comparative theoretical study of Cu, Ag and Ni nanofluids based on a heat transfer fluid used in concentrating solar power (CSP) plants is presented. The base fluid is a eutectic mixture of diphenyl oxide and biphenyl. The nanofluids based on Cu and Ag enhance thermal properties as thermal conductivity and isobaric specific heat of the systems as compared to the base fluid, while Ni nanofluid present a decrease in those properties. An inner layer of base fluid molecules around the metal were observed in which the interaction of the oxygen atom of diphenyl molecules with the metals play an important role. Thus, there are interactions of three, two, and one diphenyl oxide molecules around Cu, Ag and Ni nanoparticles whose trajectory and internal movements around the metals are analysed. Those analysis shown that the Brownian motion observed in the Cu nanofluid was directly related to its highest thermal properties.