Alternative cooling solutions for hydrogen storage in metal hydride bed: PCM and baffled cooling channels

The improvement of hydrogen storage depends on effective cooling and novel thermal management techniques. New thermal management solutions have emerged from studies focused on refining hydrogen sorption processes. This study investigates the thermal management of hydrogen storage by evaluating cooling channels and Phase Change Materials (PCM) both as individual solutions and as an integrated hybrid system. Considering the thermal contribution of the PCM, several distinct configurations are examined. In addition to conventional arrangements such as encapsulating the MH domain or utilizing a sandwich-structured MH-PCM layout, this study introduces an innovative design. Baffles of various geometries are positioned on the interior surface of the cooling channel and are covered in PCM, thereby establishing a direct thermal contact zone between the MH bed and the heat transfer fluid. A single wavy baffle and multiple plain baffles are employed for Case 4 and Case 5, respectively. In these configurations, the hydrogen absorption capacity (wt.%) and the temperature distributions within the MH bed are evaluated. Numerical findings demonstrate that the incorporation of optimized baffle geometries and phase change materials (PCM) within the cooling channel substantially overcomes the heat transfer limitations of solid-state hydrogen storage. Specifically, compared to the reference only cooling channel configuration (Case 1, showing a final hydrogen capacity of 0.325 wt% at t = 4000 s), the integration of 8 plain baffles combined with PCM (Case 5) achieves a maximum hydrogen sorption capacity of 0.549 wt%, representing a 68.9 % enhancement (t = 4000 s) Furthermore, the evaluation reveals that Case 4 (wavy-structured baffle) accelerates early-stage reaction kinetics, delivering a final sorption capacity of 0.496 wt% (52.6 % increase over Case 1) while closely matching the performance of conventional sandwich designs. Thermal performance metrics further indicate that Case 5 successfully reduces the average bed temperature by approximately 10 % (suppressing local peaks down to 275.5 K), thereby verifying that optimized secondary fluid mixing and latent heat buffering provide an effective engineering solution for rapid and safe hydrogen storage. These results offer valuable insights for improving alternative cooling systems and optimizing effective thermal solutions for metal hydride hydrogen storage.