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Title: Modeling of a thermal energy storage system based on coupled metal hydrides (magnesium iron – sodium alanate) for concentrating solar power plants

Concentrating solar power plants represent low cost and efficient solutions for renewable electricity production only if adequate thermal energy storage systems are included. Metal hydride thermal energy storage systems have demonstrated the potential to achieve very high volumetric energy densities, high exergetic efficiencies, and low costs. The current work analyzes the technical feasibility and the performance of a storage system based on the high temperature Mg 2FeH 6 hydride coupled with the low temperature Na 3AlH 6 hydride. To accomplish this, a detailed transport model has been set up and the coupled metal hydride system has been simulated based on a laboratory scale experimental configuration. Proper kinetics expressions have been developed and included in the model to replicate the absorption and desorption process in the high temperature and low temperature hydride materials. The system showed adequate hydrogen transfer between the two metal hydrides, with almost complete charging and discharging, during both thermal energy storage and thermal energy release. The system operating temperatures varied from 450°C to 500°C, with hydrogen pressures between 30 bar and 70 bar. This makes the thermal energy storage system a suitable candidate for pairing with a solar driven steam power plant. The model results, obtained formore » the selected experimental configuration, showed an actual thermal energy storage system volumetric energy density of about 132 kWh/m 3, which is more than 5 times the U.S. Department of Energy SunShot target (25 kWh/m 3).« less
 [1] ;  [2] ;  [2] ;  [1] ;  [1] ;  [2]
  1. Savannah River Site (SRS), Aiken, SC (United States)
  2. Savannah River Site (SRS), Aiken, SC (United States); Greenway Energy LLC, Aiken, SC (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 0360-3199; PII: S036031991731683X
Grant/Contract Number:
Accepted Manuscript
Journal Name:
International Journal of Hydrogen Energy
Additional Journal Information:
Journal Volume: 42; Journal Issue: 35; Journal ID: ISSN 0360-3199
Research Org:
Savannah River Site (SRS), Aiken, SC (United States)
Sponsoring Org:
USDOE Office of Environmental Management (EM)
Country of Publication:
United States
14 SOLAR ENERGY; 25 ENERGY STORAGE; 29 ENERGY PLANNING, POLICY, AND ECONOMY; Metal hydrides; Concentrating solar power plants; Thermal energy storage; Transport models; Efficiency
OSTI Identifier: