Performance analysis of the coupled system of heat pump and double stage extraction rankine cycle

Abstract

This article presented a coupled system cycle (CSC) and the thermodynamic analysis of the CSC was employed, which was combined by the heat pump cycle and double stage extraction Rankine cycle. Taking CO2 and R1234yf as heat pump refrigerants, the influence of cycle parameters on the thermal efficiency of the CSC (ηcsc) was studied by contrast with that of the DSERC, and the performance analysis of the CSC was employed. The results show that increasing the evaporation temperature or decreasing the outlet temperature of gas cooler is beneficial to improve the ηcsc. The optimal compressor discharge pressure of the CSC with CO2 refrigerant is 8.5 MPa, and correspondingly, the maximum COP is about 4.21 and the maximum ηcsc is about 44.56%. Increasing the main steam parameters is beneficial to improve the ηcsc, and the ηcsc is increased and then decreased with the increasing of the steam extraction coefficient. The conclusion is that the CSC has higher thermal efficiency and better performance, which provides a theoretical basis for improving the performance of power plant. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 1856–1863, 2017