WEB Screening of natural zeolites as potential host matrices for the development of low-cost, high performance thermal energy storage materialsWednesday (23.09.2020) 17:35 - 17:50 P: Processing and Synthesis 1 Part of:
The widespread adoption of adsorption based thermochemical energy storage systems for residential heating will require the availability of low-cost thermochemical materials with higher thermal energy storage densities than currently commercially available adsorbents. Natural zeolites, which are globally abundant, possess interesting adsorption performance and are available at a fraction of the cost of synthetic molecular sieves such as zeolite 13X. This study aims to assess a sample of North American natural zeolites as potential host matrices for high performance composite materials comprised of zeolites and salt hydrates. The water uptake capacity, energy storage density and cost of the natural zeolites based composite materials are the main criteria for screening natural zeolites obtained from local material suppliers.
The natural zeolites analyzed in this study will be first introduced. They include different mesh of species from the analcime, chabazite and stilbite zeolite groups of sedimentary and flow rock origins. The methodology adopted to assess the performance of the tested natural zeolite samples as well as the composite materials based on the selected natural zeolites will be then discussed. Results obtained from the simultaneous thermal gravimetric analysis and differential scanning calorimetry (TGA-DSC) of the considered samples of natural zeolites originating from eight different North American mines and quarries will be summarized. The natural zeolites that have been selected as most promising matrices for further analysis in terms of suitability for composite material development will be presented. The water uptake and the energy storage capacity of these natural zeolites range between 0.11-0.13 g/g and 80-113 Wh/kg respectively. A brief economic case is presented, showing the capital cost reductions that can be realized at the system level in terms of $/GJ thermal energy storage. Furthermore, results are presented for composite materials developed from select natural zeolites and salt hydrates from the screening study. For example MgCl2·6H2O coupled with clinoptilolite shows over a 50% increase in energy storage capacity from 80 to 122 Wh/kg.