THERMO-ECONOMIC OPTIMIZATION OF SOLAR-DRIVEN ORGANIC RANKINE CYCLE

According to the heat collection characteristics of parabolic trough solar collector，R600 and R245fa are selected as circulating working fluids. The thermo-economic models of basic organic Rankine cycle（BORC）and the ORC system with internal heat exchanger（IHE-ORC）are established with the exergy efficiency and levelized energy cost（LEC）as objectives，respectively. Bi-objective optimization is conducted using the non-dominated sorting genetic algorithm. The optimal thermo-economic performance of two systems with two working fluids are obtained using TOPSIS with entropy weight method integrated. The variations of thermo-economic performance of the systems with evaporation pressure，superheat degree and condensation temperature are analyzed. The results show that，under optimization and decision making，when R245fa is used，IHE-ORC system has clear advantage in thermodynamic performance with the optimal exergy efficiency and LEC of 54.11% and 0.1548 $/kWh，respectively. When R600 is used，BORC system exhibits better economic performance with the optimal exergy efficiency and LEC of 49.89% and 0.1318 $/kWh，respectively. Within the variation range of operating parameters，the exergy efficiency and LEC of IHE-ORC system are always higher than those of BORC，and much higher exergy efficiency is obtained when using R245fa，while much lower LEC is achieved when using R600. © 2024 Science Press. All rights reserved.