Thermodynamic assessment of a biomass-driven integrated multigeneration system for power, hydrogen, and freshwater production

The efficient utilization of biomass for simultaneous energy and water production remains a key challenge in sustainable energy systems due to significant thermodynamic irreversibilities. In this study, a novel biomass-driven integrated multigeneration system is proposed and evaluated using detailed energy and exergy analyses. The system combines biomass gasification with a gas turbine cycle, a recuperative organic Rankine cycle (RORC), a proton exchange membrane electrolyzer, and an evaporative desalination unit to simultaneously produce electricity, hydrogen, heating, and freshwater. The system is modeled in Aspen HYSYS under steady-state conditions, and exergy analysis is employed to identify the main sources of irreversibility. Results show that the proposed configuration achieves an overall energy efficiency of 84% and an exergy efficiency of 44.68%. Exergy analysis reveals that the gasification and gas turbine subsystems dominate total irreversibilities, accounting for 82% of total exergy destruction, with the combustion chamber being the primary contributor. Parametric studies indicate that increasing the RORC operating pressure and the air temperature entering the combustion chamber enhances net power output and overall exergy efficiency, while reducing freshwater production due to lower availability of low-grade heat.