Performance Analysis of the Vehicle Diesel Engine-ORC Combined System Based on a Screw Expander

Energies

Kai Yang¹  Hongguang Zhang¹  Songsong Song¹  Jian Zhang¹  Yuting Wu¹  Yeqiang Zhang¹  Hongjin Wang¹  Ying Chang¹ 

[1] College of Environmental and Energy Engineering, Beijing University of Technology, Pingleyuan No.100, Beijing 100124, China; E-Mails:

关键词: waste heat recovery;    vehicle diesel engine;    organic Rankine cycle;    screw expander;    various operating conditions;   

DOI  :  10.3390/en7053400

来源: mdpi

【 摘 要 】

To achieve energy saving and emission reduction for vehicle diesel engines, the organic Rankine cycle (ORC) was employed to recover waste heat from vehicle diesel engines, R245fa was used as ORC working fluid, and the resulting vehicle diesel engine-ORC combined system was presented. The variation law of engine exhaust energy rate under various operating conditions was obtained, and the running performances of the screw expander were introduced. Based on thermodynamic models and theoretical calculations, the running performance of the vehicle diesel engine-ORC combined system was analyzed under various engine operating condition scenarios. Four evaluation indexes were defined: engine thermal efficiency increasing ratio (ETEIR), waste heat recovery efficiency (WHRE), brake specific fuel consumption (BSFC) of the combined system, and improvement ratio of BSFC (IRBSFC). Results showed that when the diesel engine speed is 2200 r/min and diesel engine torque is 1200 N·m, the power output of the combined system reaches its maximum of approximately 308.6 kW, which is 28.6 kW higher than that of the diesel engine. ETEIR, WHRE, and IRBSFC all reach their maxima at 10.25%, 9.90%, and 9.30%, respectively. Compared with that of the diesel engine, the BSFC of the combined system is obviously improved under various engine operating conditions.

【 授权许可】

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