Coiled-tube heat exchanger for high-pressure metal hydride hydrogen storage systems – Part 2. Computational model

This second part of a two-part study presents a transient, three-dimensional numerical model for a high-pressure metal hydride (HPMH) hydrogen storage system that is cooled by a coiled-tube heat exchanger. The model uses the same geometry examined in the first part of the study and its predictions are compared to experimental results also discussed in the first part. The model involves solving coupled heat diffusion and hydriding reaction equations for Ti1.1CrMn. These equations are solved to determine the spatial distribution of hydride temperature as a function of time over the entire duration of the hydriding reaction, which is shown to agree favorably with the experimental data. The model also serves as an effective means for tracking the detailed temporal variations of the heat exchanger’s key performance parameters for different hydride locations relative to the coolant tube. These variations can aid in determining optimum placement of the coolant tube relative the hydride powder. Like the experimental study, the model proves that coolant temperature has the greatest influence on the time needed to complete the hydriding reaction.