Effects of Degree of Superheat on the Running Performance of an Organic Rankine Cycle (ORC) Waste Heat Recovery System for Diesel Engines under Various Operating Conditions

Energies

Kai Yang²  Hongguang Zhang²  Songsong Song²  Fubin Yang¹  Hao Liu²  Guangyao Zhao²  Jian Zhang² 

[1] School of Mechanical and Power Engineering, North University of China, Taiyuan 030051, Shanxi, China; E-Mail:;College of Environmental and Energy Engineering, Beijing University of Technology, Pingleyuan No.100, Beijing 100124, China; E-Mails:

关键词: diesel engine;    organic Rankine cycle (ORC);    waste heat recovery;    degree of superheat;    various operating conditions;   

DOI  :  10.3390/en7042123

来源: mdpi

【 摘 要 】

This study analyzed the variation law of engine exhaust energy under various operating conditions to improve the thermal efficiency and fuel economy of diesel engines. An organic Rankine cycle (ORC) waste heat recovery system with internal heat exchanger (IHE) was designed to recover waste heat from the diesel engine exhaust. The zeotropic mixture R416A was used as the working fluid for the ORC. Three evaluation indexes were presented as follows: waste heat recovery efficiency (WHRE), engine thermal efficiency increasing ratio (ETEIR), and output energy density of working fluid (OEDWF). In terms of various operating conditions of the diesel engine, this study investigated the variation tendencies of the running performances of the ORC waste heat recovery system and the effects of the degree of superheat on the running performance of the ORC waste heat recovery system through theoretical calculations. The research findings showed that the net power output, WHRE, and ETEIR of the ORC waste heat recovery system reach their maxima when the degree of superheat is 40 K, engine speed is 2200 r/min, and engine torque is 1200 N·m. OEDWF gradually increases with the increase in the degree of superheat, which indicates that the required mass flow rate of R416A decreases for a certain net power output, thereby significantly decreasing the risk of environmental pollution.

【 授权许可】

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