ANN-assisted Multi-Objective optimization and Techno-Economic analysis of a Geothermal-Based Partial evaporation ORC-Driven green hydrogen production system
Hall Ibrahim Topal
article (Uluslararası, Hakemli) | Yazar(lar): Hall Ibrahim Topal | Yıl: 2026 | Dergi/Kurum: ENERGY CONVERSION AND MANAGEMENT | İndeks: WOS.SCI | DOI: 10.1016/j.enconman.2026.122191 | Anahtar Kelimeler: Geothermal energy, Partial evaporation organic Rankine cycle, Green hydrogen production, Multi-objective optimization,
A geothermal-based partial evaporation organic Rankine cycle (PEORC)-driven proton exchange membrane electrolyzer (PEME)-integrated green hydrogen production system is proposed and investigated. Thermodynamic and techno-economic analyses are performed considering expander inlet temperature (EIT), vapor quality (x), pinch-point (PP) temperature difference, and wetness penalty parameter (k). The k parameter accounts for the reduction in expander isentropic efficiency during two-phase expansion, and three fixed values (0.05, 0.25, and 1.0) are considered. PEORC, conventional organic Rankine cycle (ORC), and trilateral cycle (TLC) cases are optimized separately under identical constraints. An artificial neural network (ANN)-assisted non-dominated sorting genetic algorithm II (NSGA-II)-based multi-objective optimization (MOO) combined with the technique for order preference by similarity to ideal solution (TOPSIS) is applied for hydrogen production-levelized cost of hydrogen (LCOH) and hydrogen production-geothermal outlet temperature objectives. For the first objective, the TOPSIS-selected PEORC with k = 0.05 produces 44.35 kg/h hydrogen at an LCOH of 3.127 $/kg and an exergy efficiency of 33.11%, whereas the conventional ORC gives the lowest LCOH of 2.819 $/kg with 35.10 kg/h hydrogen. As k increases, the hydrogen production advantage of PEORC decreases, and at k = 1 its performance becomes almost identical to that of ORC. For the second objective, PEORC with k = 0.05 achieves 41.80 kg/h hydrogen and 31.21% exergy efficiency while maintaining the geothermal outlet temperature at 61.88 degrees C. At a hydrogen selling price of 6 $/kg, its NPV reaches 11.69 M$, compared with 10.24 M$ for ORC. Overall, PEORC can provide thermodynamic and economic advantages when sufficiently high two-phase expander efficiency is maintained.