Dynamic modeling of heat and mass transfer in photovoltaic-electrolyzer systems: Implications for system design and safety

Ensuring robust heat transfer performance is vital for the safe and stable operation of photovoltaic-electrolyzer (PVE) direct coupling systems. This requires addressing the intricate challenge of dynamically integrating heat and mass transfer processes within these systems. In this work, a model is introduced that dynamically couples the multiphysics fields of the electrolyzer with the photovoltaic system to enhance PVE system efficiency and safety. Our simulations, closely corroborating experimental data, investigate the impacts of flow rate and electrolysis parameters on the temperature of the electrolyzer and chemical conversion rates. In comparison to the experimental values, the root mean square error of current density obtained by this method is 1.07 %. The temperature profile fluctuated within the experimental value range, with a root mean square error of 0.35 °C from the empirically fitted temperature curve. Furthermore, by utilizing the coupled heat transfer model, the electrolyzer's secure operating conditions were identified, requiring a minimum flow rate of 0.6 ml/s at 1.7 V to avoid exceeding the temperature safety limit of 353.15 K. The flow rate of the electrolyzer can be increased to circumvent the safety warnings for six times that were issued throughout the year. The optimized PVE system exhibits an annual average photovoltaic cell efficiency of 19.68 % and a solar-to‑hydrogen efficiency of 14.34 %. The solar-to‑hydrogen efficiency of the system has been enhanced by 2.2–13.3 % in comparison to non-optimal PV-PEM configurations. This research provides crucial guidelines for the design and safe operation of PV-electrolytic direct coupling hydrogen production systems.