Thermal energy storage is regarded as an enabling technology with a variety of applications, especially regarding energy efficiency and usage of renewable and waste heat. Thermochemical storage materials, in this aspect, provide much higher storage capacities per mass or volume compared to sensible or latent heat storage, often by a factor of 10 or more compared to water storage, the most often used storage type [1]. Moreover, thermochemical storage materials can store the heat for infinite time without insulation and are regarded as a key technology for heat transport and long term storage, although short term storage concepts presently seem to be more feasible in terms of economy [2].
However, as with latent heat storage materials too, the storage design has to meet a number of key parameters, the power density and cycle efficiency as well as cycling stability being of highest importance in addition to the storage capacity. In order to assess these key parameters, a method for
TGA/DSC measurements of hydration and dehydration processes has been developed. Using this method, properties of thermochemical storage materials that are making use of hydration/dehydration processes can be determined directly. We were able to investigate power densities dependent on water
vapour partial pressure and layer thickness, as well as maximum storage efficiencies and cycling stability of various materials and composites.