International Journal of Hydrogen Energy, Vol.41, No.11, 5361-5370, 2016
Performance investigation of thermal energy storage systems using metal hydrides adopting multi-step operation concept
The metal hydride based thermal energy storage (MHTES) technology is an attractive option for concentrating solar power. In this paper, a mathematical model was developed for MHTES systems. The charging and discharging processes of thermal energy were numerically analyzed. As shown in the simulation results, the temporal profiles of the average reacted fraction, the fluid outlet temperature and the hydrogen pressure appear to be repeated in a cyclic manner. The mean value of true temperature boost during the discharging process increases as the flowrate of the heat transfer fluid decreases. When the concept called multi-step charging/discharging operation modes was adopted instead of the conventional one-step reaction operation mode, the outlet temperature fluctuation of the heat transfer fluid of the MHTES system can be weakened. The system performance can be further improved by varying the fluid flow rate and optimizing the operation mode. Copyright (C) 2016, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Keywords:Thermal energy storage;Metal hydride;Multi-step operation concept;Concentrating solar power