Multi-objective optimization and exergoeconomic analysis of geothermal-based electricity and cooling system using zeotropic mixtures as the working fluid

An innovative combined cooling and power generation system is designed employing the flash-binary geothermal system. In the proposed plant, an internal combination of dual-pressure organic Rankine cycle and ejector refrigeration cycle is employed as the binary subsystem in the flash-binary plant. Another positive aspect of the proposed system is the profiting of zeotropic mixtures advantages in the binary unit. The feasibility of the proposed system is analyzed from the energy, exergy, and exergoeconomic viewpoints. Then, the robust Non-Dominated Sorting Genetic Algorithm II optimizer and linear programming technique for multi-dimensional analysis of preference decision-making technique are employed to optimize the proposed plant's performance. The optimized values in the power-cost scenario are obtained for the mass fraction of 0.474 with the values of 1.745 MW, 232.92 kW, 18.23 %, 54.84 %, and 12.13 $.GJ(-1) for the total output power, total cooling capacity, energy efficiency, exergy efficiency, and sum unit cost of products, respectively. Finally, a parametric analysis is performed to show the effect of the main influential parameters on the system's performance. It is revealed that the increment of separator's pressure results in lower output power, lower exergetic efficiency, higher cooling load, and higher thermal efficiency. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

An innovative flash-binary geothermal system is designed, utilizing a combination of organic Rankine cycle and ejector refrigeration cycle, along with the advantages of zeotropic mixtures. The feasibility of the system is analyzed from energy, exergy, and exergoeconomic perspectives, with optimization using Non-Dominated Sorting Genetic Algorithm II and linear programming techniques. The parametric analysis reveals the impact of influential parameters on system performance.