(151c) System Modeling Methodology and Analyses for Materials-Based Hydrogen Storage

In the global efforts to develop advanced materials-based hydrogen storage, the various on-board reversible hydrides, adsorbents and chemical storage candidate materials and systems each have their individual strengths and weaknesses. An overarching challenge in associated research and development is to devise material/system architectures which satisfy all requirements for viability in a particular application area, such as light duty vehicular transportation. System modeling at the level which encompasses not only the storage material and vessel/reactor, but also integration with a fuel cell and balance-of-plant components, provides a more complete assessment of viability and guides options for improvement. The current work will cover the methodology developed for conducting such system modeling consistently across multiple organizations and will present performance results from studies focused on reversible hydride systems. Connecting this high level modeling to more detailed finite element design simulations will be one aspect of the framework approach discussed. The complex hydride NaAlH₄ is representative of novel materials under development and will be used as the basis for properties, such as temperature dependent kinetics, which influence the integrated system configurations and component sizing. While system charging is included, emphasis is placed on the discharge step in the storage process, interrogated through both simplified operation conditions (ex. constant fuel rate demand) and drive cycle transients. Comparisons of performance relative to requirements, including effective gravimetric capacity, effective volumetric density and energy utilization, will be given for the baseline material and for sensitivity studies on key material properties.