Reviewing thermal conductivity aspects of solar salt energy storage

Abstract

In recent years, nanoparticles have gained significant attention as additives in thermal energy storage materials for concentrated solar power plants. Depletion of fossil fuels and environmental concerns have prompted a shift towards clean renewable energy sources, like solar energy that is available in abundance. To harvest solar energy using thermal energy storage (TES) materials and enhancing such a materials thermal conductivity using nanoparticle additives, has emerged as a key research area. Hence, this review provides a comprehensive consideration of the thermal conductivity of solar salts with different nanoparticle additives; and the measurement techniques and various models that are used to study them experimentally and theoretically. Furthermore, the various factors that can influence the thermal conductivity are also analyzed and some issues – like high concentrations leading to high viscosity and agglomeration of nanoparticles in TES materials – are discussed. The different results show that thermal conductivity exhibits a linear relationship with the concentration of nanoparticles in TES materials at a certain level.