A solar thermal system integrated with biomass gasification for clean hydrogen production

This study presents the development and thermodynamic assessment of an integrated solar-biomass multigeneration system for the simultaneous production of electricity, heat, cooling, freshwater and clean fuels, such as hydrogen and methane. The proposed system integrates a two-stage Brayton cycle driven by solar thermal energy during daytime and combustion chamber during non-solar periods, combined with an organic Rankine cycle, an ammonia-water absorption cooling system, and a multistage flash desalination unit. In addition, municipal sewage sludge is processed through drying, pyrolysis and gasification to produce hydrogen- and methane-rich fuels, enabling waste-to-energy conversion and reducing environmental impact. The system achieves an overall energy efficiency of 47.03% and an exergy efficiency of 42.43%, respectively. The current integrated system delivers 3391 kW of net electricity, 939 kW of heat, 343 kW of cooling, and 1500 m 3 /day of freshwater production, while simultaneously generating 140.74 kg/h of hydrogen and 80.7 kg/h of methane as valuable fuels and energy carriers.