Thermodynamic analysis of a supercritical CO2 Brayton cycle integrated with solid oxide fuel cell.

Two crucial challenges in energy production are emissions and efficient energy utilization. Renewable energy sources and the harnessing of waste heat are important solutions to address these issues. This study focuses on investigating the applicability of the supercritical CO 2 (S–CO 2) Brayton cycle in conjunction with an intermediate-temperature solid oxide fuel cell (IT-SOFC) as a waste heat source. A system is designed and its performance is analyzed using the first law of thermodynamics. Initially, the operating parameters are determined, and then the effects of variations in compressor inlet parameters and turbine inlet temperature on the efficiency and performance of the Brayton cycle are investigated. The performance of the S–CO 2 cycle and the heat transferred from the waste heat source to the fluid are examined from the thermodynamic point of view at these intermediate-temperature levels. The findings demonstrate the usefulness of considering the waste heat from the commercialized IT-SOFC in the S–CO 2 Brayton cycle. Furthermore, it is observed that the efficiency of the Brayton cycle improves at the critical pressure and temperature points. The system's performance parameters are determined with a turbine inlet temperature of 823 K (550 °C). Through thermodynamic analysis, it is determined that the S–CO 2 cycle generates 125.6 kW of power with a thermal efficiency of 16.34%. It is shown that an IT-SOFC with an electrical power output of 163 kW can supply the necessary heat to this system. • S–CO 2 basic Brayton cycle is used as a bottoming cycle of the SOFC. • IT-SOFC/S–CO 2 Brayton cycle hybrid system is analyzed thermodynamically. • Effects of different operation parameters on efficiency are investigated. • S–CO 2 Brayton cycle thermal efficiency is 16.34% at 550 °C turbine inlet temperature. • The highest cycle efficiency is obtained at the critical point of CO 2. [ABSTRACT FROM AUTHOR]