Thermo-fluidic parametric study of cryogenic hydrogen storage in Fe-soc-MOF tanks – Part I: Assessment under operational constraints

Efficient hydrogen storage is important for developing a reliable and scalable H ₂ supply chain. This work presents the first part of a thermo-fluidic parametric study on cryogenic H ₂ storage in a Type I tank filled with a Fe- soc metal–organic framework (MOF). Numerical modeling is used to investigate temperature evolution, tank pressure, and hydrogen adsorption capacity. These parameters are analyzed under coupled operational constraints, such as the presence or absence of adsorbent material, tank volume, target stored hydrogen mass, and filling time. The results show that introducing adsorbent material decreases the equilibrium pressure by about 50 bar because approximately 338 g of H ₂ is stored in adsorbed form. At the same time, the adsorbent bed temperature rises by around 50 K within 0.5 h, due to the exothermic nature of adsorption. Expanding the tank volume from 10 to 12 L improves hydrogen adsorption capacity, lowering equilibrium pressure from 150 to 100 bar and increasing adsorbed mass to 364 g. Reducing the hydrogen storage target from 500 g to 433 g lowers temperature and final pressure by 50 bar. Finally, extending the filling time from 0.5 h to 6 h further reduces the temperature by up to 41 K and the pressure by more than 340 bar. In all cases, the simulations respected the mass balance, confirming the consistency of the numerical analysis. Overall, this work identifies thermo-fluidic and operational conditions governing cryo-adsorptive hydrogen storage and highlights the potential of Fe- soc -MOFs for improving storage efficiency under realistic operating constraints.