Thermodynamic and thermoeconomic evaluation of integrated hybrid solar and geothermal power generation cycle

Abstract

The present investigation examines geothermal and solar energy for electricity generation. The proposed cycle can generate electricity independently or jointly using geothermal and solar sources. Organic Rankine Cycles (ORCs) have been employed due to their positive effects, including improved efficiency, comprehensive performance and economic analysis, adaptability, and the benefits of using ORCs with refrigerants in the hybrid power generation system. The proposed system is designed to include two evaporators, each working at distinct temperature levels, with one running at a high temperature and the other at a low temperature. Consequently, the system is outfitted with a pair of turbines functioning at elevated and moderate pressures. The analysis of the performance of the suggested cycle was conducted considering both energy and exergy perspectives; this leads to the determination of the efficiency of the first and second laws of thermodynamics. As a result, the exergy loss amount was calculated, and the exergy utilization efficiency for each component was determined. To assess the financial implications of the end product, a comprehensive study including electricity and exergy economic factors was conducted. A sensitivity analysis for many different aspects of the design factors and a parametric study, such as the difference in temperature at the pinch point and the temperature of the evaporator and their effects on energy and exergy performance, as well as the cost, are done. Findings revealed that the high-pressure turbine is directly related to the highest second-law efficiency. In contrast, the low-pressure turbine had the highest value for the exergy economic component. The average cost of energy production, obtained by evaluating power generation through low-pressure and high-pressure turbines, was calculated as 27.23 $S/Gj$. The system presented in this article can expand and adapt to diverse case analyses and can be effectively applied under various climatic conditions.