Development of a high-performance metal hydride tank with novel heat-medium/hydrogen flow paths for off-site hydrogen use in urban areas

In this study, we significantly enhanced the performance of metal hydride (MH) tanks without incurring substantial costs by adopting commercially available heat exchangers, optimizing heat-medium flow paths, and incorporating structures to improve hydrogen diffusibility. The significance of this study lies in the fabrication of a practically sized MH tank that achieves high hydrogen absorption and release performance below 1 MPaG, using commonly available heat exchangers and TiFe-based MH. Even when the flow velocity through the heat-medium path of the exchanger was low, optimizing the flow path design enabled excellent absorption and release performance. Furthermore, the adoption of an original hydrogen diffusion structure within the MH tank improved hydrogen diffusibility, thereby enhancing absorption and release performance. The developed tank demonstrated the hydrogen absorption and release capabilities required for off-site hydrogen utilization. The tank was also successfully scaled up to a size capable of storing approximately 88 Nm³ of hydrogen. The findings of this study are significant both academically and practically, and the integration of the fabricated tank into buildings has the potential to contribute substantially to the decarbonization of urban areas.