On the optimization of hydrogen storage in metal hydride beds

This work presents a novel systematic approach for the optimal design and control of metal hydride beds used for hydrogen storage. A detailed 2-D mathematical model is developed and validated against experimental and theoretical literature results. Based on recent advances in dynamic optimization, the objective is then to find the optimal process design (e.g. cooling systems design) and operating strategy (e.g. cooling fluid profile over time, hydrogen charging profile, etc.) so as to minimize the storing time, while satisfying, a number of operating constraints. Such constraints account for pressure drop limitations, cooling fluid availability and maximum tank temperature. Optimization results indicate that almost 60% improvement of the storage time can be achieved, over the case where the system is not optimized, for a minimum storage capacity of 99% of the total bed capacity. Trade-offs between various objectives, alternative design options and optimal cooling control policies are systematically revealed illustrating the potential offered by modern optimization techniques.