Study on Performance Control of LaNi<sub>5</sub> Based Hydrogen Storage Reactor Coupled with Phase Change Materials

Metal hydride hydrogen storage materials (MH) represented by LaNi₅ have broad development prospects due to their advantages of low hydrogen absorption and desorption reaction temperature, easy activation, and strong reversible absorption and desorption performance. However, such materials still face problems of high heat transfer resistance and slow reaction rate in hydrogen storage reactors in practical applications. Thus, this paper proposed a novel array type hydrogen storage reactor coupled with phase change materials (PCM), which aims to construct a high specific surface area of heat transfer interface, enhance reaction heat transfer and hydrogen absorption reaction rate. In this paper, the coupled mathematical models of heat and mass transfer and reaction in hydrogen absorption process of three reactors with different structures are established. The heat transfer advantages of the coupled PCM reactor and the further enhancement effect of the array structure on its performance were compared and analyzed. The results indicate that the heat transfer effect of natural convection heat transfer between the outer wall and the surrounding air is poor, resulting in a slower absorption reaction rate. The coupling between PCM and reactor significantly enhances heat transfer and hydrogen absorption reaction rate. The construction of the array reactor further increases the heat transfer area between PCM and MH and enhances reaction heat transfer, and its average absorption rate is 46.4% higher than that of non-array coupled PCM reactors. In addition, the thermal properties of PCM are key factors affecting the performance of such reactors, and their heat transfer and absorption rates increase with the increase of PCM thermal conductivity and sensible heat, but decrease with the increase of melting point.