Analyzing the Performance of a Dual Loop Organic Rankine Cycle System for Waste Heat Recovery of a Heavy-Duty Compressed Natural Gas Engine

Energies

Baofeng Yao²  Fubin Yang²  Hongguang Zhang²  Enhua Wang¹  Kai Yang² 

[1] State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Qinghuayuan, Beijing 100084, China; E-Mail:;College of Environmental and Energy Engineering, Beijing University of Technology, Pingleyuan No.100, Beijing 100124, China; E-Mails:

关键词: compressed natural gas (CNG) engine;    waste heat recovery;    dual loop organic Rankine cycle;    various operating conditions;   

DOI  :  10.3390/en7117794

来源: mdpi

【 摘 要 】

A dual loop organic Rankine cycle (DORC) system is designed to recover waste heat from a heavy-duty compressed natural gas engine (CNGE), and the performance of the DORC–CNGE combined system is simulated and discussed. The DORC system includes high-temperature (HT) and low-temperature (LT) cycles. The HT cycle recovers energy from the exhaust gas emitted by the engine, whereas the LT cycle recovers energy from intake air, engine coolant, and the HT cycle working fluid in the preheater. The mathematical model of the system is established based on the first and second laws of thermodynamics. The characteristics of waste heat energy from the CNGE are calculated according to engine test data under various operating conditions. Moreover, the performance of the DORC–CNGE combined system is simulated and analyzed using R245fa as the working fluid. Results show that the maximum net power output and the maximum thermal efficiency of the DORC system are 29.37 kW and 10.81%, respectively, under the rated power output condition of the engine. Compared with the original CNG engine, the maximum power output increase ratio and the maximum brake specific fuel consumption improvement ratio are 33.73% and 25%, respectively, in the DORC–CNGE combined system.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.