Dynamic mass and energy balance model of a 50 kW proton exchange membrane electrolyzer system

This paper presents a parameter-adjustable dynamic mass and energy balance process model for a 50 kW proton exchange membrane (PEM) electrolyzer plant. Energy and mass balances are derived for the electrolyzer stack, heat exchangers, and gas–liquid separation vessels. These balances, along with semiempirical submodels, are integrated and solved within MATLAB system blocks connected through a Simulink environment. The model is validated using experimental data obtained from a comparable industrial plant with similar pressure, power, and system design parameters. The PEM plant is capable of operating within a pressure range of 5–55 bar. The electrochemical and thermal behaviors, along with hydrogen production, are compared between the process model and the actual PEM plant to assess the accuracy of the simulations. The results demonstrate a satisfactory agreement between the model predictions and experimental data. In nominal operation, 68.5% of the total power supplied to the stack is converted into hydrogen, while the remaining power is dissipated as heat due to overvoltages. This excess heat is primarily transferred through the heat exchangers to the secondary leg.