Heat and mass transfer process simulation and structure design of a water-cooled fin solid metal hydride storage system

The heat transfer efficiency of a metal hydride reactor significantly affects its hydrogen absorption and desorption performance. Incorporating additional heat transfer structures can effectively enhance the heat transfer efficiency of hydrogen storage tank. To explore the impact of internal heat transfer structure on the hydrogen absorption capability of the reactor, a novel designed hydrogen storage tank with multi-ring hollow heat transfer fins was proposed. Firstly, a mathematical model is developed to describe the heat and mass transfer process during the hydrogen absorption, and the model is verified by hydrogen absorption experiments. Secondly, the heat transfer structure of multi-ring hollow fin reactor with three-fin structure is determined by comparing the effects of the structure of heat exchanger pipe and the number of heat exchanger fins on the heat transfer efficiency and hydrogen absorption rate of the system. Finally, the effects of flow velocity, temperature of heat transfer fluid and hydrogen absorption pressure on the hydrogen absorption efficiency of the system were compared. The numerical results show that the proposed reactor has shown an improvement in average heat exchange efficiency and average hydrogen absorption rate by 75.49% and 55%, respectively, compared to the initial reactor. The flow velocity and temperature of the heat transfer fluid have an influence on the heat exchange performance of the system, with an impact ranging from 7.69% to 62%, but little effect on the average hydrogen absorption rate of the system, and the hydrogen absorption pressure significantly affects the hydrogen absorption rate. The higher hydrogen absorption pressure can effectively extract the hydrogen absorption rate of the system, but the higher hydrogen absorption pressure imposes greater requirements for the heat transfer conditions of the system.