Thermodynamic Evaluation of Temperature and Hydrogen Concentration Effects on the Performance and Efficiency of SOEC Systems with Different Support Types

Solid oxide electrolysis cells (SOEC) offer advantages in efficiency and energy utilization, making them a focal point of research in the hydrogen energy field. SOEC performance is closely tied to the support structure type, operating temperature, and feedstock atmosphere ratio, which are key areas of current research. However, the high-temperature, enclosed operational environment of SOEC results in costly research. In contrast, numerical simulations provide advantages in cost and ease of operation. This study uses MATLAB/Simulink software to develop a mass-energy balance analysis model for anode supported cells (ASC) and electrolyte supported cells (ESC). The model examines the thermal balance and energy consumption of each component within a 30 cell stack and the system, including balance-of-plant components, and investigates the impact of operating temperature and H2/H2O feedstock mixture ratio on system efficiency, providing valuable reference for future system design. The results indicate that, compared to ASC-type stacks, ESC-type stacks are more significantly affected by temperature. When the temperature is increased from 750°C to 850°C, the electrolysis voltage decreases by 49.8% for ESC and 13.8% for ASC. In terms of system analysis, the efficiency of the ASC system decreases with increasing temperature, while the efficiency of the ESC30 system increases with temperature. This phenomenon can be attributed to the higher waste heat power generated by the ESC-type stacks, which reduces the electrical energy consumption of the electric heater. In this analysis, the optimal operating conditions for system efficiency were found in the ASC30 system, with an operating temperature of 750°C and an H2/H2O mixture ratio of 0.1/0.9, achieving a system efficiency of 68.7%.