In the quest for sustainable and efficient power generation, geothermal energy stands out as a reliable and stable reservoir. Recent research led by Mojtaba Nedaei, from the Department of Management and Engineering at the University of Padova in Vicenza, Italy, has taken a significant step forward in optimizing geothermal power systems.
The study, published in the journal ‘Advances in Engineering and Intelligence Systems’, integrates a single-flash geothermal system with a dual-evaporation organic Rankine cycle (D-ORC). This innovative approach aims to enhance power generation efficiency and economic viability. The research focuses on using zeotropic mixtures as the working fluid in the D-ORC, evaluating five different mixtures to identify the most effective combination.
Nedaei explains, “The integration of single-flash geothermal with a dual-pressure organic Rankine cycle using zeotropic mixtures presents a promising avenue for improving the overall performance of geothermal power systems.”
The research reveals that perfluoropentane/butene mixture offers the best performance indexes among the tested mixtures. This finding is crucial as it directly impacts the system’s net power output and exergetic efficiency. The proposed system is estimated to generate 7992.29 kW of net power with an impressive 62.42% exergetic efficiency.
One of the most compelling aspects of this research is its economic analysis. The study reveals that the net present value (NPV) of the proposed system is approximately $10.85 million, with a payback period of about 3.47 years. This economic performance is particularly noteworthy given the variability in electricity sale and geofluid prices. The research underscores that the sale costs of the generated power significantly influence the system’s economic performance more than the purchase cost.
Nedaei elaborates, “The economic viability of geothermal power systems is not just about initial investments but also about the long-term benefits and operational costs. Our findings highlight the importance of optimizing both technical and economic aspects to make geothermal energy more competitive in the market.”
The exergy destruction distribution in the system components is another critical insight provided by the research. The Grassmann diagram, a visual representation of exergy destruction, shows that the steam turbine has the highest exergy destruction of about 996 kW, followed by the first expansion valve with 714 kW. Condensers also contain considerable exergy destruction, accounting for about 26.98% of the total exergy destruction.
This research not only advances the technical understanding of geothermal power systems but also provides a roadmap for future developments in the energy sector. As geothermal energy gains traction as a sustainable and reliable power source, optimizations like those proposed by Nedaei could pave the way for more efficient and economically viable geothermal power plants.
The findings published in ‘Advances in Engineering and Intelligence Systems’ (Advances in Engineering and Intelligence Systems) offer a comprehensive analysis that could reshape how geothermal power systems are designed and operated. By integrating advanced thermodynamic and thermoeconomic analyses, this research sets a new benchmark for the field, encouraging further innovation and investment in geothermal energy.
