Various tools for optimizing large scale magnesium hydride storage

• A Phase Change Material (PCM) for hydrogen storage on magnesium hydride is reported.
• Two numerical models are presented and successfully compared to the experiments.
• Analytical formulae giving the loading time of the tank are proposed.

Hydrogen storage on magnesium hydride is considered in Grenoble laboratories since almost 10 years. Several high capacity tanks have been built and tested up to a hydrogen quantity equal to 0.6 kg. Magnesium hydride has a relatively high absorption (or desorption) enthalpy which places the heat exchange problems at the center of the tank design. A fair increase of the storage efficiency can be achieved when the absorption energy is stored in a Phase Change Material (PCM). We present here some modeling tools for the prediction of the time evolution of the various physical parameters such as front position, temperature, stored hydrogen volume, and fraction of the PCM which has been melted. The results are compared to experimental data. Analytical expressions of the loading time for various geometries are given either in rectangular or cylindrical coordinates.