Monthly Energy, Exergy, Environmental, and Economic Performance and Green Hydrogen Production Analysis of a Flat‐Plate Solar Collector‐Driven Organic Rankine Cycle System Under Variable Mass Flow and Irradiance

This article comprehensively evaluates the energy, exergy, environmental, and economic performance of a hybrid system integrating a proton exchange membrane (PEM) electrolyzer with an organic Rankine cycle (ORC) driven by flat‐plate solar collectors (FPSCs) (224.64 m 2 ) under varying flow rates. Five flow rates were simulated in engineering equation solver (EES), yielding daily electricity outputs between 86.33 MJ and 91.52 MJ, equivalent to 2.676–2.837 GJ throughout July. Hydrogen production ranged from 414.35 to 439.30 g per day, resulting in 12.85–13.62 kg over the month. The highest hourly energy efficiencies varied from 23.82% to 21.71%, while the maximum exergetic efficiencies remained nearly constant at 6.70%–6.72%, indicating stable system behavior. The hybrid setup reduced CO 2 emissions by 39.39–42.56 kg per day, totaling 1221.09–1984.31 kg in July. While the financial gain declined marginally as the flow rate increased from 10.90 USD to 10.15 USD per day, corresponding to 337.91–314.57 USD monthly, the system nevertheless indicated considerable operational and ecological advantages. The average monthly electricity generation across the evaluated flow rates was calculated as 1.974 GJ, corresponding to an average monthly revenue of 235.12 USD and an estimated annual revenue of 2,821 USD, with a simple payback period of 9.73 years.