Modares Mechanical Engineering

Modares Mechanical Engineering

Exergy and exergoeconomic analysis of complete waste heat utilization using a supercritical sCO2–Rankine combined cycle for hydrogen production

Document Type : Original Article

Authors
shoayb khanmohamai
Mohammad Dabiri
Department of Mechanical Engineering, Kermanshah University of Technology, Kermanshah, Iran
10.48311/mme.2026.119141.82972
Abstract
This study introduces a novel and integrated configuration aimed at the complete and maximum utilization of waste heat in order to enhance exergy efficiency. In the proposed system, which is capable of simultaneous power and hydrogen production, a high-temperature supercritical carbon dioxide (sCO2) cycle is directly integrated with a lower-temperature Rankine cycle. The primary innovation of this system lies in its advanced internal heat management structure, whereby the heat rejection process of the sCO2 cycle is replaced by the evaporation process in the Rankine cycle. This approach enables effective recovery of internal heat and its conversion into additional power output. A portion of the net power generated by this high-efficiency thermodynamic system is fully allocated to a proton exchange membrane (PEM) electrolyzer for green hydrogen production. To comprehensively evaluate the thermodynamic performance and economic potential of the system, detailed exergy and exergoeconomic analyses are conducted. The results demonstrate that the proposed integrated configuration significantly reduces total exergy destruction while achieving a substantial increase in power output and elevating the hydrogen production rate to optimal levels. Overall, this cogeneration system is presented as an efficient and effective solution for clean energy production from low-grade thermal resources.
Keywords
Supercritical carbon dioxide cycle (sCO_2)
electrolyzer
hydrogen production
exergy analysis
waste heat recovery
Subjects
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Modares Mechanical Engineering
Volume 27, Issue 2
February 2027
Pages 93-102