Sensitivity analysis of electrodes spacing media for evaluating alkaline electrolyzer performance through CFD modeling

Abstract

Alkaline Water Electrolyzer (AWE) technology shows promising potential for shifting towards green hydrogen production. With the growing global interest in green hydrogen, understanding the dynamics of AWE systems becomes crucial to improving their performance. Therefore, this paper aims to provide a novel sensitivity analysis aspect to investigate the correlation within parameter variables associated with AWE's electrode separation media. These parameters include electrode-diaphragm gap, temperature, diaphragm thickness, and porosity, aiming to evaluate their impact on AWE current density. The methodology involves the development of a Computational Fluid Dynamics (CFD) model, conducting a parametric study, performing Analysis of Variance (ANOVA), and sensitivity testing within specified parameter ranges. The findings show that diaphragm porosity has a considerable effect, especially between 15 % and 60 % porosity, where the trend levels off at higher values. The electrode-diaphragm gap trend reveals a sensitive, nonlinear increase in cell current density as the gap decreases from its average, with a 75 % decrease yielding over 100 % higher current density, while adjustments beyond 10 mm have minimal impact on current density despite significant variations in other parameters. A 50 % temperature rise increases current density by 40 %, while a 50 % diaphragm width reduction modestly boosts current density by around 10 %. Understanding these sensitivities is vital for optimizing AWE's performance.