Employing thermodynamic-exergoeconomic approach and multi-objective optimization of an efficient SOFC-based multi-integrated system, generating liquefied hydrogen

The liquefaction of hydrogen (H2) is essential for its large-scale adoption in energy applications. This study proposes a high-efficiency H2 liquefaction system integrating a solid oxide fuel cell (SOFC), a generator–absorber heat exchange (GAX) refrigeration cycle, and a Claude cryogenic liquefaction unit. The integrated configuration aims to enhance energy recovery, reduce irreversibilities, and minimize H2-to-liquid conversion costs. The proposed system enables the production of clean fuel and large-scale H2 storage. Comprehensive thermodynamic and exergoeconomic models are developed, incorporating both parametric and multi-objective optimization techniques. Key design parameters include SOFC operating temperature (700–1100 K), current density (5000–7000 A/m2), degassing range (0.25–0.30), and compressor pressure (5000–6000 kPa). Sensitivity analyses reveal that the SOFC temperature and degassing range have a significant influence on the liquefaction rate, economic performance, and environmental impact. Using NSGA-II and TOPSIS for optimization, the best-performing configuration achieves an exergy efficiency of 46.73%, CO2 emissions of 34.19 kg/MWh, and a H2 production cost of 1.412 $/kg. Compared to the base case, this design yields improvements in efficiency and emissions while maintaining economic feasibility. These results demonstrate the technical and commercial viability of system, positioning it as a promising candidate for next-generation H2 liquefaction infrastructure.