Comparison of multi-inlet and serpentine channel design on water production of PEMFCs

Two flow field designs, a new multi-inlet design and a conventional serpentine design, for a PEMFC together with relative humidity (RH) and porosity of the gas diffusion layer (GDL) are studied in relation to net water production using a 3-dimensional computational fluid dynamics simulation. The results show that (1) with increasing GDL porosity, discharged water in the serpentine design slightly increases, because accumulated water decreases, whereas discharged water in the multi-inlet design decreases due to a reduction of generated water; (2) although fuel cell power performance improves as RH increases, net water production decreases in both designs, because more water is accumulated; and (3) comparatively higher power and net water production are observed with the multi-inlet design, owing to uniform distributions of reactant gas and water. It is determined that, for net water production without compromising power production, input water should be decreased and, for higher cell performance, flow field design like multi-inlet design should be developed.