Innovative Hybrid Energy System Integrating MCFC and ORC for Efficient Waste Heat Utilization and Near-Zero Carbon Emissions

Abstract

This research introduces a novel hybrid energy system that combines a heating system, an Organic Rankine Cycle (ORC), and a Molten Carbonate Fuel Cell (MCFC) to produce almost no carbon emissions while efficiently utilizing waste heat. The system utilizes biomass gasification to produce syngas, which fuels the MCFC, while waste heat from the MCFC is recovered by the ORC to generate additional power and provide heating. Advanced thermodynamic modeling and parametric analysis were conducted to evaluate system performance. Key results reveal that the system reaches a maximum total efficiency of 47.46%, generating a net power output of 670.7 kW when operating at a fuel utilization factor (Uf) of 0.88. The MCFC contributes significantly to power generation, with efficiencies highly sensitive to current density and stack temperature. Parametric analysis indicates that raising the current density from 630 to 900 A/m2 enhances power generation at the expense of efficiency, primarily because of increased ohmic losses. Increasing Ufinitially boosts efficiency, but it drops beyond 0.88. CO2 emissions are minimized at Uf = 0.9, with a product unit cost of 7.534 $/GJ at Uf = 0.95. The system demonstrates superior performance compared to conventional biomass- based plants, with a levelized cost of energy (LCOE) of 0.044 $/kWh, underscoring its economic and environmental viability for sustainable energy generation.