تجزیه و تحلیل اگزوژنتیک و بهینه سازی چند هدفه یک چرخه فلکی دوتایی ترکیبی جدید برای نیروگاه ژئوترمال سبلان در ایران

Employing high-efficiency thermodynamic cycles for power generation from available heat sources is an effective strategy for sustainable energy development. In this regard in the present work, a novel combined flash-binary cycle is proposed for power generation from Sabalan geothermal wells in Iran, considering the wellhead temperature and pressure differences of existing wells. Exergoeconomic approach is applied to investigate the proposed system performance from the viewpoints of both thermodynamics and economics. Using the real data and properties of brine exploited from Sabalan geothermal field, the cycle performance is assessed and a single-objective optimization is performed considering the specific cost of output power as the objective function for four candidate working fluids for binary unit. Then, a multi-objective optimization is conducted and the Pareto frontier as a set of optimal solutions is presented. The results showed that, when single-objective optimization is performed, the proposed cycle with R141b as the binary unit working fluid has the best performance for which the specific cost of output power is calculated to be 4.901 $/GJ with an exergy efficiency of 52.56%. However, the multi-objective optimization leads to an exergy efficiency of 54.87% and a power cost of 5.068 $/GJ at the selected optimal design point. Finally, a performance comparison is made between the proposed cycle in this work with the previously proposed systems for Sabalan geothermal reservoirs and it is concluded that the flash-binary system proposed here has significantly better performance than the previous systems.