Advanced NanoMaterials and Technologies for Energy Sector – AdvNanoEnergy 2020; Vol 4; Issue 1
An important class of materials that contribute substantially to the efficient use and conservation of waste heat and solar energy is the phase change materials (PCMs) used for thermal energy storage. Higher energy storage density is provided by latent heat storage, with a lower temperature difference between storage and release heat than the sensitive heat storage method. The thermal properties of different PCM systems mentioned in the literature for application in thermal energy storage, focusing on the properties of PCM materials encapsulated in different shells are presented. Some original results on the thermal properties of materials based on KNO3-NaNO3 system micro-encapsulated in ZnO shell by a hydrothermal process are presented and the values obtained for melting and crystallization temperatures and enthalpies vs. composition have been modelled by simple fitting equation. The application foreseen is in designing a pilot tank to test the thermal behaviour of micro-encapsulated PCMs with working temperature in the range 300-500oC used in thermal energy storage for concentrated solar systems.