Design and analysis of an energy-efficient, large scale metal hydride hydrogen storage system using an extended multi-physics numerical model

This work proposes a large-scale, low-pressure metal hydride hydrogen storage system specifically designed for stationary applications, where an innovative thermal management approach is adopted by integrating the storage tanks with a heat pump. The system features a modular architecture, consisting of multiple cylindrical tanks operating in parallel, each equipped with an internal helical coil through which phase-changing heat transfer fluid circulates. An advanced numerical framework, which accounts for metal hydride porosity, permeability and thermal conductivity variations, was developed to simulate the hydrogen release process under a variety of operative conditions, with the aim of assessing system's performance and the impact of different thermal management configurations. The results provide the excellent performance of the proposed system in terms of hydrogen release capability, with hydrogen mass flow rates up to 6 kg/min, while also highlighting the dependency correlation of release rates on the initial hydrogen concentration. Moreover, the system demonstrates outstanding energy efficiency: the large storage capacity allows the exploitation of thermal inertia, while the integration with a heat pump significantly reduces the demand for active thermal management, leading to an energy consumption which is below the 5% of the hydrogen lower heating value. Overall, the study shows that the proposed system provides an effective and energy-efficient solution for stationary hydrogen storage, where minimizing energy losses and operational costs is crucial. These findings contribute to advancing the development of next-generation hydrogen storage technologies, outlining a promising pathway towards safer, more efficient, and sustainable solutions.