Optimizing power, cooling, and hydrogen generation: A thermodynamic and exergoeconomic study of an advanced sCO2 trigeneration system

Abstract

This paper presents an innovative trigeneration system designed for efficient power, cooling, and hydrogen production. It combines a supercritical carbon dioxide (sCO2) power cycle with a Kalina cycle (KC) and an ammonia-water-based absorption refrigeration cycle (ARC), all integrated with a PEM electrolyzer (PEME) unit. The system optimally utilizes waste heat from the sCO2 power cycle to enhance power generation through the KC and provide cooling via the ARC. Additionally, it leverages the PEME system and KC-generated power for eco-friendly hydrogen production. Mathematical models, thermodynamic, and exergoeconomic analyses were performed, including parametric studies, optimization, and comparative analyses. The results indicate that the reactor experiences the highest exergy destruction rate, while components in the bottoming cycles exhibit lower exergy destruction. From an exergoeconomic perspective, the reactor and sCO2 turbine are ranked as the first and second most significant components. Under the optimal conditions, the system achieved a 9.76 % increase in exergy efficiency and a 6.63 % reduction in total product unit cost. The system also provides substantial net power output, cooling capacity, and hydrogen production rates of 261.74 MW, 123.95 MW, and 176.328 kg/h, respectively. These findings highlight the system's significant thermodynamic and economic advantages, making it a promising choice for diverse user needs.