Efficient utilization of biomass through multigeneration energy systems provides a promising approach for converting biomass into multiple useful energy products while improving overall resource utilization. In this study, a multigeneration energy system is proposed for the simultaneous production of H2-rich biofuel, electricity, and hot water through CO2-assisted gasification of Chinar leaves. The proposed configuration integrates a gasifier, water-gas shift reactor, supercritical CO2 Brayton cycle, heat recovery unit, and auxiliary components. The system performance is assessed through energy, exergy, and exergoeconomic analyses. Multi-objective optimization is subsequently performed using response surface methodology coupled with a desirability function to maximize H2-rich biofuel production, net power generation, hot-water production, and exergy efficiency while minimizing the sum unit cost of products. At the optimal operating conditions, the proposed system produces 26.7 g/s of H2-rich biofuel, 119.6 kW of electricity, and 2.1 kg/s of hot water, while achieving an exergy efficiency of 41.1%. The resulting sum unit cost of products is 31.3 $/GJ based on a biomass cost of 2.0 $/GJ, with an overall desirability of 0.7. A direct confirmation simulation using the original thermodynamic model shows close agreement with the RSM predictions, with relative deviations of less than 1% for all five optimized responses.
