The hydrogen absorption of metal hydride (MH) is an exothermic process. For a cylindrical MH hydrogen storage reactor with a concentric tube heat exchange, the hydrogen adsorption heat is discharged by the heat transfer fluid (HTF), and the absorption reaction proceeds along the radial direction from the center to the periphery, which leads to the non-uniformity of the reaction process and limits the average reaction rate. In order to improve the hydrogen storage rate, the phase change material (PCM) is used to assist in heat transfer by surounding the reactor. This paper establishes a mathematical model to describe the heat and mass transfer process within the reactors. The results show that the surrounding PCM can absorb the reaction heat at the periphery of the reactor, and promote the reaction proceeding in this region. Thus, the average hydrogen absorption rate of the reactor surrounded by PCM is increased by about 1.5 times owing to the assisted heat transfer of PCM.
Keywords Metal hydride, Hydrogen storage, Phase change materials, Heat transfer fluid, Heat transfer