Improving powder bed properties for thermochemical storage by adding nanoparticles

Thermochemical storage offers interesting potential to store thermal energy, especially in the field of industrial waste heat utilization or for concentrated solar power (CSP) plants. However, at present the development of thermochemical storage technology is in its initial stage with investigations mainly on material aspects or small lab-scale systems. With regard to its thermodynamics and kinetics, it has been shown that the CaO/Ca(OH)(2) reaction system is suitable for thermochemical heat storage at a temperature range of 400-600 degrees C. However, the behaviour in a small lab-scale system was mainly dominated by heat and mass transfer limitations originating from the small particle size and changes in the bulk properties. It is shown that by the addition of small amounts of additives like nanoparticles of SiO2 (Aerosin (R)), the bulk properties can be stabilized and consequently the cycling stability ensured. In addition, channelling effects can be minimized resulting in a more homogeneous flow through the reaction bed improving the overall reaction behaviour of the thermochemical storage. (C) 2014 Elsevier Ltd. All rights reserved.