Adiabatic Compressed Air Energy Storage with packed bed thermal energy storage
journal contributionposted on 27.02.2019 by Edward Barbour, Dimitri Mignard, Yulong Ding, Yongliang Li
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The majority of articles on Adiabatic Compressed Air Energy Storage (A-CAES) so far have focussed on the use of indirect-contact heat exchangers and a thermal fluid in which to store the compression heat. While packed beds have been suggested, a detailed analysis of A-CAES with packed beds is lacking in the available literature. This paper presents such an analysis. We develop a numerical model of an A-CAES system with packed beds and validate it against analytical solutions. Our results suggest that an efficiency in excess of 70% should be achievable, which is higher than many of the previous estimates for A-CAES systems using indirect-contact heat exchangers. We carry out an exergy analysis for a single charge-storage-discharge cycle to see where the main losses are likely to transpire and we find that the main losses occur in the compressors and expanders (accounting for nearly 20% of the work input) rather than in the packed beds. The system is then simulated for continuous cycling and it is found that the build-up of leftover heat from previous cycles in the packed beds results in higher steady state temperature profiles of the packed beds. This leads to a small reduction (<0.5%) in efficiency for continuous operation.
This work was supported by the Engineering and Physical Sciences Research Council under the grants EP/K002252/1 (Energy Storage for Low Carbon Grids) and EP/L014211/1 (Next Generation Grid Scale Thermal Energy Storage Technologies).
- Mechanical, Electrical and Manufacturing Engineering