DescriptionOver the past decade, energy storage has been identified by the European Commission as a topic of utmost importance for the ongoing transformation of the European energy system. Specifically, Thermal Energy Storage (TES) is expected to play an important role in increasing the overall efficiency of energy systems. This is particularly true for systems producing waste heat at temperatures below 100˚C, so-called low-grade waste heat, which according to the recent studies accounts for more than 45% of the global primary energy consumption. Large quantities of low-grade heat – both per weight and price - can be stored reversibly in a composite material containing expanded natural graphite (ENG) impregnated with SrCl2 upon exo-/endothermal ab-/desorption of ammonia. To achieve high efficiency of the ammonia-based heat storage system, particular attention must be taken in the realization of reactor design and heat exchanger. However, without the knowledge of material structure at nanoscale, which have a strong effect on heat and mass transfer within reaction volume, the design of the reactor cannot be accurate. Therefore, to study the material behavior over ammonia cycling at nanoscale, we performed two series of Small Angle Neutron Scattering experiments at the instruments Larmor and vSANS at the neutron sources ISIS (UK) and NIST (US), respectively. The results of the studies show that there are two characteristic sizes in our system within the probed range between 10 and 150 nm. Knowing the size as well as the shape of the particles, the nanostructure of the material was proposed. The next step of this study will be to link the structure with heat and mass transfer characteristics of the material, such as thermal conductivity and permeability.
|Period||16 Mar 2021 → 18 Mar 2021|
|Event title||The 15th International Conference on Renewable Energy Storage: IRES2021|
|Degree of Recognition||International|
- Heat storage
- thermochemical heat storage
- structural characterization