Analysis of radial-flow packed beds for thermal energy storage Josh D. McTigue Alexander J. White 9 th June 2016 Department of Engineering, University of Cambridge
Summary Previous work on axial-flow packed beds Description of radial-flow packed beds Comparison of radial-flow and axial-flow stores Thermo-economic optimisation
HOT STORE (500 C)COLD STORE (-150 C) MaterialHeat Capacity J / Kg K Energy Density MJ / m 3 Heat Capacity J / Kg K Energy Density MJ / m 3 Al 2 O Fe 2 O SiO Typical Storage Densities Hydro(500m drop)5 MJ / m 3 CAES(100 bar)36 MJ / m 3
Previous work – axial-flow packed beds [1] A. J. White, “Loss analysis of thermal reservoirs for electrical energy storage schemes,” Applied Energy, vol. 88, pp. 4150– 4159, Nov [2] A. White, J. McTigue, and C. Markides, “Wave propagation and thermodynamic losses in packed-bed thermal reservoirs for energy storage,” Applied Energy, vol. 130, pp. 648–657, 2014.
Previous work – segmented stores [3] J. MacNaghten, J. S. Howes, and R. G. Hunt, “Improved heat storage apparatus,” Patent no. EP/ /2011, [4] J. McTigue and A. J. White, “Segmented packed beds for improved thermal energy storage performance,” IET Renewable Power Generation, Accepted
Previous work – integration with PTES [5] A. White, G. Parks, and C. N. Markides, “Thermodynamic analysis of pumped thermal electricity storage,” Applied Thermal Engineering, vol. 53, pp. 291–298, May [6] J. D. McTigue, A. J. White, and C. N. Markides, “Parametric studies and optimisation of pumped thermal electricity storage,” Applied Energy, vol. 137, pp. 800–811, Sept
Radial-flow packed beds [7] L. Bradley, “Regenerative stove,” US Patent 2,272,108. [8] R. Daschner, S. Binder, and M. Mocker, “Pebble bed regenerator and storage system for high temperature use,” Applied Energy, vol. 109, pp. 394–401, Sept
Radial-flow thermal fronts [2] A. White, J. McTigue, and C. Markides, “Wave propagation and thermodynamic losses in packed-bed thermal reservoirs for energy storage,” Applied Energy, vol. 130, pp. 648–657, 2014.
Radial-flow thermal fronts [2] A. White, J. McTigue, and C. Markides, “Wave propagation and thermodynamic losses in packed-bed thermal reservoirs for energy storage,” Applied Energy, vol. 130, pp. 648–657, 2014.
Radial-flow availability losses
Radial-flow availability losses - comparison
RADIAL AXIAL
Radial-flow availability losses - comparison RADIAL AXIAL
Radial-flow availability losses - comparison RADIAL AXIAL
Optimisation involves minimising Availability losses: Capital cost per availability output: Optimisation objectives
Packed bed capital costs CostValue k PV (£/m 3 bar)200 k pack (£/m 3 )1400 k ins (£/m 3 )1950
Optimisation parameters
Optimisation results – cold store
CONCLUSIONS A number of packed bed technologies have been investigated Radial-flow stores have comparable performance to axial-flow stores Radial-flow stores are typically more expensive due to larger volume requirements
Acknowledgements Dr. White and Dr. Markides Cambridge University Engineering Department St. Catharine’s College, University of Cambridge EPSRC Isentropic Ltd.