Experimental study on integrated hydrogen-based cooling, heating, and power generation

To address rising energy demand and global warming, green hydrogen-based energy systems offer a promising alternative to fossil fuels. This study investigates the coupling of an anion exchange membrane (AEM) electrolyser, metal hydride (MH) storage, and a proton exchange membrane fuel cell (PEMFC) for integrated hydrogen storage, power generation, and thermal management. Hydrogen produced at approximately 35 bar by the electrolyser is stored in a MH reactor, and 1.0 m3 storage vessel. The hydrogen is then supplied to a 4 kW fuel cell (FC) operating at loads between 1 and 3.5 kW. The MH reactor, based on a shell-and-tube heat exchanger design, contains 20 kg of AB5 alloy with a hydrogen storage capacity of ∼300 g (∼1.5 wt.%). Experimental results demonstrate stable system operation, with heating output during the absorption half cycle ranging from ∼3.5 to 4.4 MJ for various absorption conditions, and cooling output during desorption varying from ∼0.2 to 0.75 kW for load conditions ranging between 1.0 and 3.5 kW. With MH coupling, the FC efficiency reached 53%, with optimal performance observed above 50% load. The results confirm the feasibility of MH-based hydrogen storage systems for combined power, heating, and cooling applications, particularly in transport energy systems.