Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1016/j.apenergy.2014.08.104
Title (Primary) The influence of gas–solid reaction kinetics in models of thermochemical heat storage under monotonic and cyclic loading
Author Nagel, T.; Shao, H. ORCID logo ; Roßkopf, C.; Linder, M.; Wörner, A.; Kolditz, O. ORCID logo
Source Titel Applied Energy
Year 2014
Department ENVINF
Volume 136
Page From 289
Page To 302
Language englisch
Keywords Thermo-chemical heat storage; Calcium hydroxide/oxide; Porous media; Reaction kinetics; Finite element method; OGS
UFZ wide themes RU5;
Abstract Thermochemical reactions can be employed in heat storage devices. The choice of suitable reactive material pairs involves a thorough kinetic characterisation by, e.g., extensive thermogravimetric measurements. Before testing a material on a reactor level, simulations with models based on the Theory of Porous Media can be used to establish its suitability. The extent to which the accuracy of the kinetic model influences the results of such simulations is unknown yet fundamental to the validity of simulations based on chemical models of differing complexity. In this article we therefore compared simulation results on the reactor level based on an advanced kinetic characterisation of a calcium oxide/hydroxide system to those obtained by a simplified kinetic model. Since energy storage is often used for short term load buffering, the internal reactor behaviour is analysed under cyclic partial loading and unloading in addition to full monotonic charge/discharge operation. It was found that the predictions by both models were very similar qualitatively and quantitatively in terms of thermal power characteristics, conversion profiles, temperature output, reaction duration and pumping powers. Major differences were, however, observed for the reaction rate profiles themselves. We conclude that for systems not limited by kinetics the simplified model seems sufficient to estimate the reactor behaviour. The degree of material usage within the reactor was further shown to strongly vary under cyclic loading conditions and should be considered when designing systems for certain operating regimes
Persistent UFZ Identifier
Nagel, T., Shao, H., Roßkopf, C., Linder, M., Wörner, A., Kolditz, O. (2014):
The influence of gas–solid reaction kinetics in models of thermochemical heat storage under monotonic and cyclic loading
Appl. Energy 136 , 289 - 302 10.1016/j.apenergy.2014.08.104