TY - JOUR
T1 - Study on mixed working fluids with different compositions in organic Rankine cycle (ORC) systems for vehicle diesel engines
AU - Yang, Kai
AU - Zhang, Hongguang
AU - Wang, Enhua
AU - Song, Songsong
AU - Bei, Chen
AU - Chang, Ying
AU - Wang, Hongjin
AU - Yao, Baofeng
N1 - Publisher Copyright:
© 2014 by the authors; licensee MDPI, Basel, Switzerland.
PY - 2014
Y1 - 2014
N2 - One way to increase the thermal efficiency of vehicle diesel engines is to recover waste heat by using an organic Rankine cycle (ORC) system. Tests were conducted to study the running performances of diesel engines in the whole operating range. The law of variation of the exhaust energy rate under various engine operating conditions was also analyzed. A diesel engine-ORC combined system was designed, and relevant evaluation indexes proposed. The variation of the running performances of the combined system under various engine operating conditions was investigated. R245fa and R152a were selected as the components of the mixed working fluid. Thereafter, six kinds of mixed working fluids with different compositions were presented. The effects of mixed working fluids with different compositions on the running performances of the combined system were revealed. Results show that the running performances of the combined system can be improved effectively when mass fraction R152a in the mixed working fluid is high and the engine operates with high power. For the mixed working fluid M1 (R245fa/R152a, 0.1/0.9, by mass fraction), the net power output of the combined system reaches the maximum of 34.61 kW. Output energy density of working fluid (OEDWF), waste heat recovery efficiency (WHRE), and engine thermal efficiency increasing ratio (ETEIR) all reach their maximum values at 42.7 kJ/kg, 10.90%, and 11.29%, respectively.
AB - One way to increase the thermal efficiency of vehicle diesel engines is to recover waste heat by using an organic Rankine cycle (ORC) system. Tests were conducted to study the running performances of diesel engines in the whole operating range. The law of variation of the exhaust energy rate under various engine operating conditions was also analyzed. A diesel engine-ORC combined system was designed, and relevant evaluation indexes proposed. The variation of the running performances of the combined system under various engine operating conditions was investigated. R245fa and R152a were selected as the components of the mixed working fluid. Thereafter, six kinds of mixed working fluids with different compositions were presented. The effects of mixed working fluids with different compositions on the running performances of the combined system were revealed. Results show that the running performances of the combined system can be improved effectively when mass fraction R152a in the mixed working fluid is high and the engine operates with high power. For the mixed working fluid M1 (R245fa/R152a, 0.1/0.9, by mass fraction), the net power output of the combined system reaches the maximum of 34.61 kW. Output energy density of working fluid (OEDWF), waste heat recovery efficiency (WHRE), and engine thermal efficiency increasing ratio (ETEIR) all reach their maximum values at 42.7 kJ/kg, 10.90%, and 11.29%, respectively.
KW - Mixed working fluids
KW - Organic Rankine cycle
KW - Various operating conditions
KW - Vehicle diesel engine
KW - Waste heat recovery
UR - http://www.scopus.com/inward/record.url?scp=84907231917&partnerID=8YFLogxK
U2 - 10.3390/e16094769
DO - 10.3390/e16094769
M3 - Article
AN - SCOPUS:84907231917
SN - 1099-4300
VL - 16
SP - 4769
EP - 4787
JO - Entropy
JF - Entropy
IS - 9
ER -