Efficiency and Performance Analysis of SOFC Integrated With S‐CO ₂ Brayton Cycles: A Comprehensive Study on Waste Heat Utilization

ABSTRACT Addressing global energy challenges demands advanced strategies for efficient waste heat utilization and system integration. This study focuses on converting waste heat from an intermediate‐temperature solid oxide fuel cell (IT‐SOFC) into useful work and investigates the performance of hybrid systems that couple the IT‐SOFC with various supercritical carbon dioxide (S‐CO 2 ) Brayton cycle configurations. At the standard operating conditions of the IT‐SOFC (600°C, 0.3 A/cm 2 ), the efficiency of the isolated solid oxide fuel cell (SOFC) stack is 34.75%. The efficiencies of the novel hybrid systems are as follows: the SOFC/S‐CO 2 basic Brayton cycle (SBBC) hybrid system at 43.93%, the S‐CO 2 recompression Brayton cycle (SRCBC) hybrid system at 49.8%, and the SOFC/S‐CO 2 regenerative Brayton cycle (SRBC) hybrid system achieving the highest at 54.66%. Different cycles favor different temperature ranges: the SRCBC is more efficient below 600°C, whereas the SRBC performs better above 600°C due to the temperature sensitivity of its heat recovery unit. The SOFC/SRBC hybrid system offers high efficiency with reduced complexity, making it a promising approach for effective waste heat utilization.