Energy and exergy optimization of a combined solar/geothermal organic Rankine cycle power plant太阳能/地热联合有机朗肯循环电厂的能量和火用优化

Energy and exergy analysis of an organic Rankine cycle (ORC) power plant driven by solar and geothermal energy in southern Tunisia was conducted. The effects of main operating parameters on the combined solar/geothermal ORC system on two days in winter and summer were studied, where the mass, energy, and exergy balances were determined. Results showed that the main source of irreversibility was the parabolic through collector. Aiming to reduce the exergy destruction and to optimize the system’s performance, a polynomial regression analysis was applied. Hence, a relationship between both the mass flow rate and the inlet temperature of the heat transfer fluid and solar radiation was established. The proposed optimization can improve the system’s exergy efficiency by 2.06% to 5.44% in winter and 1.00% to 4.10% in summer. Also, the analysis revealed an increase in both the overall exergy efficiency and the net power by 26.6% and 21.0%, respectively, in winter.