Performance optimization of a transcritical-subcritical parallel organic Rankine cycle for diesel engine waste heat recovery: Thermodynamic, economic, and environmental perspectives

IF 6.1 2区工程技术 Q2 ENERGY & FUELS

Applied Thermal Engineering Pub Date : 2025-04-16 DOI:10.1016/j.applthermaleng.2025.126512

Mahyar Avazpour , Rahim Khoshbakhti Saray , Samira Marami Milani

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引用次数: 0

Abstract

This research presents a comprehensive investigation of a parallel organic Rankine cycle configuration that combines transcritical and subcritical operations, aimed at recovering waste heat from off-road diesel engines. The study evaluates how different design parameters affect the cycle’s overall performance. The cycle’s efficiency is systematically examined by employing thermodynamic and economic models using R600 as the working medium. The results show that, under defined operating conditions, the cycle delivers a net power output of 11.99 kW, a thermal efficiency of 12.27 %, and an exergy efficiency of 34.72 %. Exergy-based evaluation highlights components such as valves, expanders, and the mixer are more effective in conserving exergy, whereas the condenser performs with comparatively lower efficiency. The high-pressure (HP) evaporator contributes the most to irreversibility, followed by the condenser and low-pressure (LP) evaporator. In terms of exergy destruction contribution, the HP evaporator holds the largest portion (42.6 %), followed by the condenser (21.8 %), LP evaporator (10.2 %), and turbine 2 (6.8 %). The optimization process incorporates a multi-objective strategy using a genetic algorithm, considering exergy efficiency and specific investment cost (SIC) as performance objectives. Based on the bi-objective optimization framework, the maximum exergy efficiency achieved is 45.92 %, with a corresponding SIC of 3350 $/kW.

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跨临界-亚临界平行有机朗肯循环柴油机废热回收的性能优化：热力学、经济和环境观点

本研究对一种结合跨临界和亚临界操作的平行有机朗肯循环配置进行了全面研究，旨在回收非公路柴油发动机的废热。该研究评估了不同的设计参数如何影响循环的整体性能。采用热力学和经济模型，以R600为工质，系统地考察了循环的效率。结果表明，在规定的运行条件下，该循环的净输出功率为11.99 kW，热效率为12.27%，火用效率为34.72%。基于火用的评估强调了诸如阀门、膨胀器和混合器等部件在节约火用方面更有效，而冷凝器的效率相对较低。高压（HP）蒸发器对不可逆性贡献最大，其次是冷凝器和低压（LP）蒸发器。在火能破坏贡献方面，高压蒸发器所占比例最大（42.6%），其次是冷凝器（21.8%），低压蒸发器（10.2%）和涡轮2（6.8%）。优化过程采用遗传算法的多目标策略，以能效和特定投资成本（SIC）为性能目标。基于双目标优化框架，实现的最大火用效率为45.92%，相应的SIC为3350美元/kW。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Applied Thermal Engineering 工程技术-工程：机械

CiteScore

11.30

自引率

15.60%

发文量

1474

审稿时长

57 days

期刊介绍： Applied Thermal Engineering disseminates novel research related to the design, development and demonstration of components, devices, equipment, technologies and systems involving thermal processes for the production, storage, utilization and conservation of energy, with a focus on engineering application. The journal publishes high-quality and high-impact Original Research Articles, Review Articles, Short Communications and Letters to the Editor on cutting-edge innovations in research, and recent advances or issues of interest to the thermal engineering community.