Numerical analysis and performance assessment of metal hydride-based hydrogen storage systems

This paper presents a detailed analysis of low-temperature, metal hydride-based hydrogen storage systems by means of a lumped model previously developed by the authors. In the first part of this study the model is applied to simulate experimental systems described in the literature, where the absorption and desorption of hydrogen under constant-pressure conditions are studied. The numerically evaluated time evolution of several key parameters (such as hydrogen mass flow, temperature and pressure) is reported and its accordance with experimental results available in the literature is discussed, in order to identify the model's strengths and limitations and its validity range, and to offer analytical insight into the behavior of the storage system as different operating parameters are varied. The model is then used as a tool to predict the performance of metal hydride hydrogen storage devices operating in FC-based energy systems. This is accomplished by analyzing the storage system response to a constant flow condition, i.e. when the FC operates under a constant external load.