Assessment of organic working fluids feasibility for an ORC plant with waste heat recovery coupled to the gas turbine: Case study of the SGT-A65 intercooler unit

This study investigates the application of Organic Rankine Cycle (ORC) technology for recovering waste energy from the intercooler in the Siemens SGT-A65 gas turbine. ORC demonstrates high energy recovery potential for mid-grade waste heat within the 100–200°C range, which aligns with the temperature range available from the intercooler. Using EES software for thermodynamic modeling and analysis to evaluate various working fluids and operating conditions, comparing the performance of the standard gas turbine cycle with modified configurations. Findings indicate that ORC integration significantly enhances energy recovery efficiency, achieving an improvement of up to 7.51% in overall thermal performance while using R123 as the working fluid, along with a reduction of 9.65 $/MWh in LCOE compared to the baseline while using Ethanol as the working fluid. Furthermore, environmental analysis reveals a 14.85% reduction in carbon emissions (0.354 kg CO ₂ /kWh) while using R123 at 3.5 MPa HRVG pressure, enhancing the system’s environmental sustainability. Economic feasibility is also examined, emphasizing the potential for sustainable energy management. Recommendations focus on optimizing performance and minimizing environmental impact to encourage broader adoption.