An innovative multi-zone configuration to enhance the charging process of magnesium based metal hydride hydrogen storage tank

High-temperature metal hydride (MH), such as magnesium hydride, is considered as one of the most promising technology to store hydrogen. However, there are two main bottlenecks, including the low rate of hydrogen absorption and low capacity of the MH reactor. In this regard, heat removal from the MH tank plays a crucial role in the hydrogen storage process. In the present study, to increase the hydrogen absorption performance, a novel configuration of the MH reactor is proposed and simulated using computational fluid dynamics (CFD). The study aims to assess the geometrical parameters of the proposed heat exchanger. Besides, a sensitivity analysis of the operating parameters of the reactor, including the Reynolds number and temperature of the air as well as hydrogen supply pressure is performed. The results indicate that the charging time drops significantly by increasing the number of air passages since the heat transfer rate improves dramatically. By raising the heat transfer fluid initial temperature, the charging time increases; however, as the heat transfer fluid Reynolds number and the inlet pressure of hydrogen increase, the absorption process accelerates. The recommended configuration is introduced by considering both charging time and manufacturing limitations. It is shown that the loading is approximately 30 minutes for the new multi-zone hydrogen energy storage using four passages for the air which provides a more applicable hydrogen fuel system.

Automated summary

High-temperature metal hydride (MH), such as magnesium hydride, is seen as a promising technology for hydrogen storage. However, low hydrogen absorption rate and reactor capacity are major challenges. This study proposes a novel MH reactor configuration to improve hydrogen absorption performance through CFD simulation and sensitivity analysis. Increasing the number of air passages significantly reduces charging time, and a recommended configuration using four air passages achieves approximately 30 minutes loading time.