Numerical study on hydrogen desorption performance of a new MgH2 solid-state hydrogen storage device.

To explore the factors affecting the hydrogen evolution performance of a new MgH 2 solid-state hydrogen storage heat exchanger, this paper designs the MgH 2 solid-state hydrogen storage device. The study numerically investigates the influence of operating parameters and structural parameters on the hydrogen release reaction. The results demonstrate that the hydrogen desorption rate increases as the pressure decreases from 0.3 MPa to 0.1 MPa. Moreover, the hydrogen evolution reaction rate significantly rises with an increase in the inlet temperature of the heat transfer fluid (HTF) from 600 K to 700 K. Similarly, the rate of hydrogen evolution reaction increases with an increase in the flow rate of the HTF from 0.5 m/s to 1.25 m/s. The hydrogen evolution reaction time can be notably reduced by increasing the thickness of the annular HTF layer. Compared to no annular fluid layer, the completion time of the hydrogen desorption reaction is shortened by 558 s with a 5 mm thickness. The arrangement of heat exchanger pipes plays a crucial role in the hydrogen evolution reaction, and thus a comprehensive index M is defined to evaluate its influence. A higher M value indicates slower hydrogen release efficiency of the device. By optimizing the operating conditions, the hydrogen desorption time can be shortened by 93.4 %. • A new type of solid-state hydrogen desorption system is designed. • The effect of working and structural parameters on hydrogen desorption performance is discussed in detail. • The paper defines a comprehensive performance index M to compare different bed designs. [ABSTRACT FROM AUTHOR]