Enhancing Sustainability Through a Hybrid Organic Rankine Cycle and Hydrogen Production Systems: A Thermo-Economic Analysis

This study investigates the integration of Organic Rankine Cycle systems with hydrogen production and use to enhance energy efficiency and economic viability in waste heat recovery applications. A comprehensive thermodynamic, exergoeconomic, and environmental assessment evaluates multiple ORC configurations and six working fluids across hospital and hotel facilities. The analysis quantifies component-level exergy costs, system-level economics, and operational CO2 emission reductions, focusing on optimal sizing strategies and threshold conditions under which hydrogen storage enhances energy autonomy without compromising economic viability. Results reveal fundamental design trade-offs: Basic ORC achieved the lowest LCOE at 0.033 $/kWh through operational simplicity, while complex configurations extract up to 70% more power at 14–32% higher cost. N-pentane exhibits superior thermodynamic–economic performance in the Parallel Dual ORC configuration, achieving 20% thermal efficiency and 40% exergy efficiency. R1233zd emerges as the preferred alternative from a safety perspective, exhibiting comparable performance with minimal penalties in both power generation and efficiency metrics. System-level analysis shows that properly sized ORC–hydrogen integration reduces Hospital 1 user LCOEtot from 0.23 $/kWh to 0.069 $/kWh—a 70% reduction achieved by minimizing grid dependence. Environmental benefits strongly correlate with grid carbon intensity, with operational CO2 emission reductions ranging from 181 tons annually in Spain to 752 tons in Poland.