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

Abstract

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 an MH reactor, with auxiliary gaseous storage for excess hydrogen, and 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.