Performance assessment and optimization of the PEM water electrolyzer by coupled response surface methodology and finite element modeling

Proton exchange membrane water electrolyzer (PEMWE), integrated with renewable energy sources, is promising in green hydrogen production with its compact system design, high efficiency, and high-purity hydrogen production capacity. Renewable hydrogen production from PEMWE depends significantly on operational factors. This study optimized the process variables affecting the PEM electrolysis cell performance using the response surface methodology (RSM) of the Design-Expert 13 software (trial version) at a fixed temperature of 80 C. Water flow rate, cell voltage, and bolt torque were defined as the input factors of the model, while hydrogen flow rate and current were considered as the responses of the model. The statistical analysis showed that cell voltage, torque, and cell voltage-torque interaction significantly affected the current. Besides, it has been observed that the water flow rate plays a vital role in the hydrogen flow rate. The optimum conditions for green hydrogen production were a water flow rate of 2.45 mL/min, a cell voltage of 2.2 V, and a bolt torque of 10 Nm. In addition, a good match between the predicted and measured responses of the model was observed. This paper also includes finite element (FE) modeling and simulation of an experimental PEMWE. Based on the FE method, a three-dimensional simulation model of the PEMWE was established to investigate the effects of different bolt torques on the mechanical responses of the cell components. Numerical simulations were performed with a commercial code (ANSYS Mechanical). A pressure-sensitive film was placed instead of the catalyst-coated membrane (CCM) component of the single-cell PEMWE. The experimental results obtained from pressuresensitive films were compared with the numerical results, and it was observed that the results were in agreement with each other. The maximum equivalent stress on the CCM for a bolt torque of 10 Nm is around 116.3 MPa.