Carbon-neutral Tri- and Multi-Generation Plants with CO2 Capture Unit Integrated Modified Gas Turbine, Recuperative Steam Rankine, Absorption Chiller, and MED: Life Cycle Assessment and Multi-Scenario Chameleon Swarm Optimization with XGBoost Modeling

The decarbonization of fossil fuel-powered systems remains a critical challenge due to the energy penalties and economic burdens associated with conventional COQ capture technologies. This issue is particularly pronounced in tri- and multi-generation systems, where integrating carbon capture without compromising efficiency and profitability requires advanced system-level solutions. Addressing this challenge is essential to enable reliable low-carbon energy supply while meeting increasing demands for electricity, heating, cooling, and freshwater. This study proposes and systematically examines advanced carbon-neutral tri- and multi-generation energy systems featuring deep thermal integration and alternative heat supply strategies for COQ capture. Two integration scenarios are investigated: a methane-fueled tri-generation system incorporating a MEA-based COQ capture unit (System I), and an extended multi-generation configuration supported by geothermal energy to drive COQ capture and desalination (System II). Comprehensive thermo-enviro-economic assessments, gate-togate life cycle assessment, and data-driven multi-objective optimization using XGBoost surrogate modeling and advanced metaheuristic algorithms are employed. System I achieves 54.00% exergy efficiency and 98.78% COQ removal, reducing emissions to 21.47 kg/h, while System II further enhances performance, attaining 54.51% exergy efficiency, reducing specific GWP to 0.0179 kg/kWh, and increasing NPV to 14.07 M$. Optimized operation yields exergy efficiency up to 55.28% with minimal economic and environmental impact. The proposed systems provide a scalable and economically viable pathway for deploying carbon-neutral multi-generation plants in industrial and urban energy hubs, supporting long-term decarbonization and sustainable energy transition strategies.