Thermodynamic analysis of an integrated reversible solid oxide fuel cell system

To improve the efficiency of reversible solid oxide cell (rSOC) systems, an rSOC thermal management system architecture is proposed, achieving integrated and efficient operation of rSOC. A 20 kW level rSOC integrated thermal management system with fuel cell and electrolysis cell modes is established using ASPEN PLUS software. The system characteristics of different system operating parameters under fuel cell and electrolysis cell modes are studied. Exergy analysis and energy analysis are conducted on the system under different operating modes, The distribution of exergy flow, the exergy loss between the system and its components, and the influence of fuel utilization on the electrical efficiency and exergy efficiency of the rSOC integrated thermal management system are obtained. The results show that compared to traditional solid oxide electrolysis cell systems, the proposed rSOC integrated thermal management system can improve the electrolysis efficiency of the system to over 70 %. In addition, the exergy loss of the system and components mainly exists in heat exchanger 1 in the fuel cell mode, and mainly in the stack in the electrolysis cell mode. The system efficiency of both fuel cell and electrolysis cell modes increases with the increase in fuel utilization rate. Compared to electrolysis cell mode, the system's exergy loss in fuel cell mode is more sensitive to fuel utilization efficiency.