Performance Analysis of a New ORC-VCC System With Mechanical Overheating and Correlation Fitting of Most Important System Parameter

Abstract

This paper proposes a new organic Rankine cycle + vapor compression cycle (ORC-VCC) system (with mechanical overheating refrigeration cycle), and this system can not only reduce the heat absorption of the ORC evaporator, but also increase the refrigeration capacity of the system. Simulations were conducted to analyze the thermal efficiency and performance of the new system, and compare it with the system of ORC-VCC (with regenerator). The results show that the ηth, ηsys, and coefficient of performance (COPsys) of the new system are higher than the system of ORC-VCC (with regenerator), ηth, ηsys, and COPsys of new system increased by up to 31.6%, 6.48%, 10.63% respectively. The influence of superheat on both systems is stronger than other factors, the influence of superheat on the new system is obviously stronger than those of the system of ORC-VCC (with regenerator), and the influence of superheat on R245fa and butane is stronger than those of other working fluids. In addition, ηth, ηsys, COPsys, and ηex of system increase with the increase of Te-mech and decrease with the increase of Tg-mech. Finally, the correlation of ΔTmax with the change of ηexp and Te-ORC is fitted, the results will provide some reference for the development of the ORC-VCC system in the future.