• CN: 11-2187/TH
  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2025, Vol. 61 ›› Issue (14): 285-296.doi: 10.3901/JME.2025.14.285

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Advanced Exergy and Advanced Exergy Economic Analysis of Double- stage Evaporation Double-regenerative Organic Rankine Cycle Based on Geothermal Energy

DAI Wenzhi, SHEN Xiongjian, LI Qingyang, YANG Xinle   

  1. School of Mechanical Engineering, Liaoning Technical University, Fuxin 123000
  • Received:2024-07-03 Revised:2024-12-11 Published:2025-08-25

Abstract: Two-stage evaporative organic Rankine cycle(ORC) can effectively improve the efficiency of heat source utilization, and regenerative-ORC can effectively utilize the waste heat discharged by the expander. Combining the advantages of the two, a two-stage evaporative double regenerative organic Rankine cycle system(DEDR-ORC) is proposed. The conventional method focuses on the exergy loss of independent components, and cannot identify the actual impact of the interaction between components on the system performance. The advanced exergy and advanced economic law are proposed to analyze the DEDR-ORC. The advancement of DEDR-ORC, the flow relationship between components and the actual improvement potential of components are discussed. The results show that the exergy efficiency and net output power of DEDR-ORC are 27.24% and 4 436.97 kW higher than those of two-stage evaporation-ORC and regenerative-ORC, and the leveling power cost is reduced by 0.006 . The maximum exergy loss of the expander and condenser obtained by the conventional exergy method is 755.15 kW and 567.20 kW, respectively. The total avoidable exergy loss of the expander, condenser and evaporator 1 obtained by the advanced exergy method is 553.28 kW, 223 kW and 103.20 kW, respectively. The potential for component improvement is sorted according to the total avoidable exergy loss. Therefore, the expander, condenser and evaporator are obtained. According to the advanced economic law, the total avoidable costs of expander, evaporator 1 and hybrid regenerator are 71.16 $/h, 1.14 $/h and 0.94 $/h, which are positive, and the remaining components are negative. The improvement potential of cost reduction is only expander, evaporator1 and hybrid regenerator, and the remaining components have no improvement potential. The research results can provide theoretical support and technical reference for ORC system design and optimization.

Key words: geothermal energy, organic Rankine cycle, double-stage evaporation and double recuperation, advanced exergy, advanced exergy economy

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