Thermodynamic, economic and environmental assessment of solid oxide fuel cell-based hybrid cogeneration system for power generation and water heating

Efficient recovery of high-grade waste heat from solid oxide fuel cells (SOFCs) is crucial for enhancing energy utilization and environmental performance. This study addresses this challenge by proposing an advanced SOFC-based cogeneration system that integrates a gas turbine (GT), a recuperated regenerative organic Rankine cycle (RRORC), and a water heater for simultaneous power and hot water production. A comprehensive thermodynamic, economic, and environmental assessment was conducted using a detailed computational model to evaluate system performance and feasibility. The results indicate that incorporating the RRORC with the SOFC-GT system enhances exergy efficiency by 9.56%, while the inclusion of a water heater further raises the improvement to 11.14%. The overall energy efficiency increased by 30.76% with only an 11.16% rise in total cost, and CO₂ emissions were reduced by 23.49% compared to the conventional SOFC-GT system. These findings demonstrate that the proposed configuration effectively harnesses SOFC waste heat for improved energy recovery and sustainability. The novelty of this work lies in the integration of a RRORC and a water heating subsystem with the SOFC-GT cycle, extending the efficiency and environmental advantages beyond previously reported hybrid configurations.