@Article{ee.2024.056195,
AUTHOR = {Guowei Li, Shujuan Bu, Xinle Yang, Kaijie Liang, Zhengri Shao, Xiaobei Song, Yitian Tang, Dejing Zong},
TITLE = {Thermodynamic, Economic, and Environmental Analyses and Multi-Objective Optimization of Dual-Pressure Organic Rankine Cycle System with Dual-Stage Ejector},
JOURNAL = {Energy Engineering},
VOLUME = {121},
YEAR = {2024},
NUMBER = {12},
PAGES = {3843--3874},
URL = {http://www.techscience.com/energy/v121n12/58713},
ISSN = {1546-0118},
ABSTRACT = {A novel dual-pressure organic Rankine cycle system (DPORC) with a dual-stage ejector (DE-DPORC) is proposed. The system incorporates a dual-stage ejector that utilizes a small amount of extraction steam from the high-pressure expander to pressurize a large quantity of exhaust gas to perform work for the low-pressure expander. This innovative approach addresses condensing pressure limitations, reduces power consumption during pressurization, minimizes heat loss, and enhances the utilization efficiency of waste heat steam. A thermodynamic model is developed with net output work, thermal efficiency, and exergy efficiency (<i>W</i><sub>net</sub>, <i>η</i><sub>t</sub>, <i>η</i><sub>ex</sub>) as evaluation criteria, an economic model is established with levelized energy cost (<i>LEC</i>) as evaluation index, an environmental model is created with annual equivalent carbon dioxide emission reduction (<i>AER</i>) as evaluation parameter. A comprehensive analysis is conducted on the impact of heat source temperature (<i>T</i><sub>S,in</sub>), evaporation temperature(<i>T</i><sub>2</sub>), entrainment ratio (<i>E</i><sub>r1</sub>, <i>E</i><sub>r2</sub>), and working fluid pressure (<i>P</i><sub>5</sub>, <i>P</i><sub>6</sub>) on system performance. It compares the comprehensive performance of the DE-DPORC system with that of the DPORC system at <i>T</i><sub>S,in</sub> of 433.15 K and <i>T</i><sub>2</sub> of 378.15 K. Furthermore, multi-objective optimization using the dragonfly algorithm is performed to determine optimal working conditions for the DE-DPORC system through the TOPSIS method. The findings indicate that the DE-DPORC system exhibits a 5.34% increase in <i>W</i><sub>net</sub> and <i>η</i><sub>ex</sub>, a 58.06% increase in <i>η</i><sub>t</sub>, a 5.61% increase in <i>AER</i>, and a reduction of 47.67% and 13.51% in the heat dissipation of the condenser and <i>LEC</i>, compared to the DPORC system, highlighting the advantages of this enhanced system. The optimal operating conditions are <i>T</i><sub>S,in</sub> = 426.74 K, <i>T</i><sub>2</sub> = 389.37 K, <i>E</i><sub>r1</sub> = 1.33, <i>E</i><sub>r2</sub> = 3.17, <i>P</i><sub>5</sub> = 0.39 MPa, <i>P</i><sub>6</sub> = 1.32 MPa, which offer valuable technical support for engineering applications; however, they are approaching the peak thermodynamic and environmental performance while falling short of the highest economic performance.},
DOI = {10.32604/ee.2024.056195}
}