Copper-dispersed solar salt: An improved phase change material for thermal energy storage

Systems that store thermal energy efficiently are important for the adoption of solar thermal energy for industrial applications. This work attempts to modify the characteristics of an inorganic eutectic (solar salt) used as a phase change material. As one of the measures of improving the thermal conductivity of solar salt, composites containing copper nanoparticles (0-0.5 w/w%) in the solar salt matrix have been prepared and characterized. The thermal conductivity of the composite was elevated by 11% at the highest measurement temperature of 180 degrees C due to the presence of copper nanoparticles at 0.5 w/w% mass percentage. The presence of copper nanoparticles elevated the specific heat in the solid phase. The combination of a reduction in the time required for solidification and the increase in energy stored/released during phase change resulted in 24.7% and 42.4% increase in the rate of discharge for the composites with 0.25 w/w% and 0.5 w/w% copper nanoparticles respectively.