Study of a proton exchange membrane fuel cell and metal hydride system based on double spiral structure coupling

The coupling system of a Proton Exchange Membrane Fuel Cell (PEMFC) and Metal Hydride (MH) canister was investigated, employing a double spiral structure to redirect waste heat from the PEMFC to the MH. The remaining heat was harnessed for seawater desalination via a Multi-Stage Flash Desalination (MSF) apparatus. By analyzing the operation of the PEMFC at various power points and dividing the hydrogen release process into stages A, B, and C, we investigate the time evolution law of each parameter of the MH bed. We evaluate the effects of the PEMFC operating parameters and the double spiral geometry parameters on the system's stable operation duration. The results reveal that the current density of the PEMFC significantly affected the system performance, while its operating temperature exerted a limited impact; the system exhibits greater suitability for long-term, low-power operation mode. Furthermore, the system's efficiency can reach up to 81.7%, with a stable working time of 6790 seconds. Considering the heat exchange in the MH canister, the double spiral heat exchanger's position occupancy problem, and the double-tube synergistic effect together, the MH is divided into α, β, and γ zones, and the heat exchanger geometrical parameters are optimized for the study. It is recommended to employ a tube diameter of 0.015 m and a coil spacing of 0.030 m for the heat exchanger.