Solar-driven thermochemical tri-generation of electricity, hydrogen, and green ammonia with AI-assisted triple-objective optimization

This study proposes and investigates a novel solar power tower-based tri-generation system producing electricity, hydrogen, and green ammonia through integrated thermodynamic cycles. The plant couples a Steam Rankine Cycle (SRC), a Vanadium-Chlorine Thermochemical Water Splitting Cycle (TWSC), and a Haber-Bosch reactor. Concentrated solar energy is stored in a heat transfer fluid and utilized to drive the SRC for power generation and supply high-temperature heat to the TWSC for hydrogen production, which, combined with nitrogen, is converted to ammonia. Comprehensive thermodynamic and economic models are developed, validated, and applied to assess system feasibility. Parametric analyses reveal that higher receiver temperatures and turbine inlet pressures increase power output but reduce hydrogen and ammonia yields, while hydrogen storage fraction significantly influences product distribution and cost. Dynamic simulations using real solar data demonstrate seasonal performance variations, with summer months offering peak outputs. A tri-objective optimization via the Grey Wolf algorithm balances ammonia production rate, exergy efficiency, and levelized cost of products, yielding optimal values of 0.154 kg/s, 61.7%, and 35.4 $/GJ, respectively. Results confirm that the proposed solar-driven system offers an efficient, low-carbon pathway for simultaneous renewable electricity generation, hydrogen production, and sustainable ammonia synthesis.