Multi-Objective optimization of a parabolic trough solar power plant integrated with an organic Rankine cycle: based on high pressure and working fluid mass flow rate

The optimization of a parabolic trough solar power plant is conducted using a multi-objective optimization algorithm in this study. Initially, the design of the plant, planned to be built in Afyonkarahisar province, is developed. Thermodynamic and thermo-economic analyses are performed based on this design. Key variables significantly affecting the system's outputs are identified as the fluid flow rate used in the Organic Rankine Cycle (ORC) and the turbine inlet pressure. A parametric study is carried out for these variables. However, optimizing the system requires more than just these parameters. The system is optimized multi-objectively, considering all relevant variables. A graphical multi-objective optimization algorithm is applied in this process. For the base case values of a 30 kg/s flow rate and 3500 kPa turbine inlet pressure, the net energy production, exergy efficiency, and unit energy cost are 0.8443 MW, 2.32%, and 0.2230 $/kWh, respectively. After optimization, the best results are achieved at a flow rate of 42 kg/s and a pressure of 4000 kPa. For the optimized case, the net energy production, exergy efficiency, and unit energy cost improve to 1.228 MW, 3.37%, and 0.1781 $/kWh, respectively.