A novel waste heat-powered intercooled sCO2–tCO2 cogeneration cycle supplying energy to a direct air capture system: exergoeconomic and lifecycle assessment

This study presents a comprehensive exergoeconomic and life cycle assessment of a supercritical CO2-based cogeneration cycle. A detailed exergy analysis was conducted to identify system inefficiencies, followed by an exergoeconomic evaluation to quantify the capital costs of exergy streams and their distribution across system components. Furthermore, a life cycle assessment (LCA) was performed to evaluate the environmental performance and long-term sustainability of the system. The base-case results indicate a total cost rate of 1,168 $/h and a total exergy destruction of 3.872 MW, with thermal and exergy efficiencies of 24.80% and 63.11%, respectively. Through optimization using a genetic algorithm (GA), the total cost rate and total exergy destruction were reduced by 6.22% and 5.27%, respectively. The optimized configuration achieved a thermal efficiency of 25.94% and an exergy efficiency of 62.93%, while the net power output decreased from 5.234 MW to 5.163 MW. The exergoeconomic analysis revealed the cost structure of components and identified key factors for cost reduction and performance enhancement. The life cycle assessment demonstrated excellent environmental performance, with a global warming potential of 0.46 g CO2-eq/kWh for net electricity generation and 0.68 g CO2-eq/kWh for allocated delivered heat. Overall, the results confirm that the proposed system offers a promising pathway for low-carbon power generation with integrated carbon capture, combining thermodynamic efficiency improvements, economic viability, and substantial environmental benefits.