Modeling and analysis of solid oxide fuel cell-based multigeneration system with supercritical and transcritical carbon dioxide power cycles, humidification-dehumidification system and hydrogen generation

Abstract

This study explores the development and performance evaluation of an innovative solid oxide fuel cell-based multigeneration system designed to enhance energy efficiency and facilitate hydrogen production. The system integrates advanced thermodynamic cycles, including a recompression supercritical carbon dioxide Brayton cycle, a reheat transcritical carbon dioxide Rankine cycle, a humidification and dehumidification unit, and a hydrogen production subsystem. The supercritical carbon dioxide Brayton cycle improves energy recovery by utilizing waste heat, while the reheat transcritical carbon dioxide Rankine cycle enhances thermal efficiency. Additionally, the humidification and dehumidification unit provide a novel approach to sustainable water production. Energy and exergy analyses indicate that the solid oxide fuel cell generates a net power output of 420.8 kW with an exergy efficiency of 53.88 %. Waste heat recovery from the supercritical carbon dioxide Brayton cycle and reheat transcritical carbon dioxide Rankine cycle contributes 32.74 kW and 7.636 kW, respectively. The humidification and dehumidification unit achieves a distilled water production rate of 23.62 kg/h, while the proton exchange membrane electrolyzer produces hydrogen at 0.7935 kg/h with an energetic efficiency of 61.96 %. Parametric studies assess the influence of solid oxide fuel cell inlet temperature, current density, and fuel utilization factor on system performance, revealing that efficiency and hydrogen production peak under moderate operating conditions. However, extreme conditions lead to increased irreversibilities and performance degradation. Exergy destruction analysis identifies the solid oxide fuel cell as the dominant source of system inefficiencies, contributing 531.8 kW (83.4 % of total irreversibilities), emphasizing the need for targeted design optimizations. The findings highlight the potential of the proposed multigeneration system to efficiently integrate power, hydrogen, and water production while optimizing energy utilization and sustainability.