Progress on use of nanoparticles in salt hydrates as phase change materials

Salt hydrates are considered to be promising materials for thermal energy storage (TES) and are being widely used in different areas. However, these compounds have several drawbacks that are currently targeted to be improved. In this regard, the use of nanoparticles for dealing with low thermal conductivity and high subcooling degree of salt hydrates has been recently proposed. In consequence, the objective of this review was to analyze and compare the enhancement of the properties of salt hydrates and their eutectic mixtures by nanoparticles. The methods of addition of nanoparticles into salt hydrates were also classified and discussed. Additionally, the influence of nanoparticles on thermal and physical properties, such as viscosity and latent heat, was discussed. Thermal conductivity and subcooling are among the properties that show great profit from nanoparticles. Hence, the enhancement of PCM with nanomaterials can encourage their application in buildings, heat exchangers, solar power plants and solar cookers, among others. These improvements achieved for the salt hydrates project them as excellent PCM, making them suitable for the market.