TY - JOUR
T1 - Effects of critical and boiling temperatures on system performance and fluid selection indicator for low temperature organic Rankine cycles
AU - Yang, Lixiang
AU - Gong, Maoqiong
AU - Guo, Hao
AU - Dong, Xueqiang
AU - Shen, Jun
AU - Wu, Jianfeng
N1 - Publisher Copyright:
© 2016 Elsevier Ltd.
PY - 2016/8/15
Y1 - 2016/8/15
N2 - The critical temperature (Tc) and boiling temperature (Tb) of working fluids are important selection criteria for the organic Rankine cycle (ORC) system. In this study, the ratio of Tb and Tc (Tbr) and the vapor expansion ratio (VER) model based on Claussius-Claperyron equation are introduced to compare and explain their effects on the maximum net output power (Wnet,max) and VER of ORC. The investigation of 267 working fluids is done at four heat source temperatures (T5). Maximum vapor enthalpy method is proposed to determine the upper limit of the evaporation temperature, which is the optimization parameter for maximizing the net power output. At low T5 (423.15 and 473.15 K), the obvious relationships between Wnet,max and Tc are independent of Tbr. Therefore, Tc enables to select working fluids with high Wnet,max. However, at high T5 (523.15 and 573.15 K), Tbr is essential to exclude working fluids with optimum Tc (0.89 - 0.90T5) but low Wnet,max. Moreover, at a given Tc, high Tb or Tbr indicates high VER. Consequently, Tb or Tbr is suitable to be used as the second indicator. This paper proposes the optimal combinations of Tc and Tb and the developed composite indicator for selection of working fluids.
AB - The critical temperature (Tc) and boiling temperature (Tb) of working fluids are important selection criteria for the organic Rankine cycle (ORC) system. In this study, the ratio of Tb and Tc (Tbr) and the vapor expansion ratio (VER) model based on Claussius-Claperyron equation are introduced to compare and explain their effects on the maximum net output power (Wnet,max) and VER of ORC. The investigation of 267 working fluids is done at four heat source temperatures (T5). Maximum vapor enthalpy method is proposed to determine the upper limit of the evaporation temperature, which is the optimization parameter for maximizing the net power output. At low T5 (423.15 and 473.15 K), the obvious relationships between Wnet,max and Tc are independent of Tbr. Therefore, Tc enables to select working fluids with high Wnet,max. However, at high T5 (523.15 and 573.15 K), Tbr is essential to exclude working fluids with optimum Tc (0.89 - 0.90T5) but low Wnet,max. Moreover, at a given Tc, high Tb or Tbr indicates high VER. Consequently, Tb or Tbr is suitable to be used as the second indicator. This paper proposes the optimal combinations of Tc and Tb and the developed composite indicator for selection of working fluids.
KW - Boiling temperature
KW - Critical temperature
KW - Maximum net output power
KW - ORC
KW - Vapor expansion ratio
UR - http://www.scopus.com/inward/record.url?scp=84973449712&partnerID=8YFLogxK
U2 - 10.1016/j.energy.2016.05.021
DO - 10.1016/j.energy.2016.05.021
M3 - Article
AN - SCOPUS:84973449712
SN - 0360-5442
VL - 109
SP - 830
EP - 844
JO - Energy
JF - Energy
ER -