Study on the impact of heat exchange structures on hydrogen storage performance in magnesium-based hydrogen storage reactors

Magnesium-based metal hydride alloys have garnered significant attention in recent years due to their high hydrogen storage density and excellent safety profile, emerging as a focus in hydrogen storage. This paper presents the design of hydrogen storage heat exchange structure that integrates spiral and straight tubes, incorporating double-layer fins. The objective is to enhance the heat transfer performance of the hydrogen storage reactor, thereby improving its hydrogen storage capacity. Through numerical studies, the effects of various factors, including the flow direction of the heat transfer fluid, fins material, quantity, and dimensions, on the hydrogen absorption performance are analyzed. The results indicate that the outlet temperature of the heat transfer fluid varies with the direction of flow. During the entire hydrogen absorption, the inflow through the outer spiral tube provides greater heat exchange capacity, resulting in slightly superior hydrogen storage performance. However, the structural parameters of the fins significantly impact hydrogen storage efficiency. Specifically, under the same volume fraction, comprehensive adjustments to the height, width, thickness, and quantity of the fins lead to a reduction in the hydrogen storage reaction time from 506 s to 460 s, representing a nearly 9.1% decrease in the time required to complete the hydrogen absorption.