Abstract

Molten salt based nanofluids are of special interest in the scientific community due to the increments reported in thermal properties, as well as for their practical application in Thermal Energy Storage systems. Conflicting results of heat transfer properties measurements are yet to be explained. The contact angle and the viscosity of the solar salt with various concentrations of SiO2 was measured throughout the liquid phase. Additionally, the effect of the temperature on its internal structure was investigated through dynamic laser scattering for a single silica concentration. Addition of small amount of nanoparticles, significantly alters the values of the contact angle and viscosity of the solution. The values remain stable at higher values compared to the base fluid, between 220 and 300 °C and then rapidly decrease between 300 and 350 °C to reach the ones of the base fluid at higher temperatures. Mean nanoparticle diameter has been found to increase significantly between 330-340 °C for the single concentration. Both contact angle and nanoparticle diameter values have been found to be stable with respect to time.