Investigating the effect of graphene on eutectic salt properties for thermal energy storage

Abstract Enhancement of heat capacity and thermal conductivity with the dispersion of graphene nanoparticles into low-temperature eutectic salt was investigated. Three different nanoparticle concentrations (0.01, 0.05 & 0.1 wt. %) were dispersed into a eutectic salt mixture composed of 5.66% NaNO3, 21.25% KNO3, 24.75% Ca(NO3)2, 41% CsNO3, & 7.34% LiNO3 by weight. The results show that the graphene doping resulted in enhanced heat capacity ranging from 5 to 13%, whereas thermal conductivity increased marginally by ˜3%, with respect to graphene concentration. Various theoretical models were tested to predict the thermal conductivity and heat capacity of the graphene-doped eutectic salt. The Maxwell and Hamilton-Crosser thermal conductivity models showed good agreement with experimental results, with a deviation of ±3%, while Nan’s thermal conductivity model over-predicted the thermal conductivity value. The conventional heat capacity equation fits well with the experimental data, with deviation