Exergoeconomic and exergoenvironmental analysis and optimization of an integrated double-flash-binary geothermal system and dual-pressure ORC using zeotropic mixtures; multi-objective optimization

Abstract

The current study focuses on proposing a double-flash geothermal system with a dual-pressure organic Rankine cycle that utilizes zeotropic mixtures. This system aims to harness the geothermal energy efficiently and sustainably. The performance of the system is evaluated using the exergy, exergoeconomic, and exergoenvironmental approaches, taking into account the utilization of different mass fractions of the R123/R142b mixture. The results of the analysis indicate that the designed system is capable of producing a net power output of 6336.04 kW with an exergetic efficiency of 66.70%. The payback period of the system is estimated to be 3.48 years, indicating its economic viability. Moreover, the electricity sale price has a substantial impact on the system's payback period and revenue, surpassing the influence of the geofluid purchase cost. Through the application of triple-objective optimization scenarios, the best optimum state of the system is determined to achieve a 66.96% exergetic efficiency, 3017.82 mPts/h exergoenvironmental impacts, and a payback period of 3.38 years. Furthermore, this state yields a revenue of 11.1 M$. Overall, the study highlights the potential of the proposed double-flash geothermal system with a dual-pressure organic Rankine cycle utilizing zeotropic mixtures for sustainable power generation.