Open Access

ARTICLE

Optimal Working Fluid Selection and Performance Enhancement of ORC Systems for Diesel Engine Waste Heat Recovery

Zujun Ding, Shuaichao Wu, Chenliang Ji, Xinyu Feng, Yuanyuan Shi, Baolian Liu, Wan Chen, Qiuchan Bai, Hengrui Zhou, Hui Huang, Jie Ji^*
Department of Electrical Engineering, Faculty of Automation, Huaiyin Institute of Technology, Huaiyin, 223002, China
* Corresponding Author: Jie Ji. Email:
(This article belongs to the Special Issue: Advanced Analytics on Energy Systems)

Energy Engineering https://doi.org/10.32604/ee.2025.068106

Received 21 May 2025; Accepted 09 July 2025; Published online 18 December 2025

Abstract

In the quest to enhance energy efficiency and reduce environmental impact in the transportation sector, the recovery of waste heat from diesel engines has become a critical area of focus. This study provided an exhaustive thermodynamic analysis optimizing Organic Rankine Cycle (ORC) systems for waste heat recovery from diesel engines. The study assessed the performance of five candidate working fluids—R11, R123, R113, R245fa, and R141b—under a range of operating conditions, specifically varying overheat temperatures and evaporation pressures. The results indicated that the choice of working fluid substantially influences the system’s exergetic efficiency, net output power, and thermal efficiency. R245fa showed an outstanding net output power of 30.39 kW at high overheat conditions, outperforming R11, which is significant for high-temperature waste heat recovery. At lower temperatures, R11 and R113 demonstrated higher exergetic efficiencies, with R11 reaching a peak exergetic efficiency of 7.4% at an evaporation pressure of 10 bar and an overheat of 10°C. The study also revealed that controlling the overheat and optimizing the evaporation pressure are crucial for enhancing the net output power of the ORC system. Specifically, at an evaporation pressure of 30 bar and an overheat of 0°C, R113 exhibited the lowest exergetic destruction of 544.5 kJ/kg, making it a suitable choice for minimizing irreversible losses. These findings are instrumental for understanding the performance of ORC systems in waste heat recovery applications and offer valuable insights for the design and operation of more efficient and environmentally friendly diesel engine systems.

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Keywords

Organic rankine cycle (ORC); waste heat recovery; working fluid selection; exergetic efficiency; net output power

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