Open AccessThermodynamic analysis and optimization of a vapor injection organic Rankine cycle system for low-grade heat recovery
Author(s) -
D T Li,
Zhonglu He,
LiPing Ji,
Ziwen Xing
Publication year - 2021
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/1180/1/012053
Subject(s) - organic rankine cycle , exergy , exergy efficiency , waste heat recovery unit , process engineering , rankine cycle , degree rankine , environmental science , waste heat , evaporation , waste management , thermodynamics , engineering , power (physics) , mechanical engineering , heat exchanger , physics
The organic Rankine cycle (ORC) system has been widely used in waste heat recovery and geothermal utilization, but the system efficiency is limited due to the large exergy loss in the evaporation process. To improve the performance of ORC systems, in this paper, a vapor injection organic Rankine cycle (VIORC) system using positive-displacement expanders was proposed. The thermodynamic model of the proposed system was developed in views of energy and exergy. The effects of system operation parameters on system performance were investigated, and the system was optimized under different waste heat temperatures. Furthermore, the optimized systems were compared with basic ORC (BORC) systems. Results showed that compared with the BORC system, the proposed system increased the net output power by 3-8% and the exergy efficiency by 0.8-3.2% under the heat source temperature of 90-150 °C. The exergy loss analysis further showed that the reduction of the exergy loss in the evaporation process was the main contribution to the efficiency improvement of the proposed system.