Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
REFRIGERATION CYCLE PERFORMANCE USING CO2 BLENDS TO OTHER NATURAL REFRIGERANTS
Submission Author:
Matheus Garros , SP
Co-Authors:
Matheus Garros, Robson Leal da Silva
Presenter: Matheus Garros
doi://10.26678/ABCM.COBEM2021.COB2021-1092
Abstract
Natural refrigerants are the best solution to reduce global warming, due to their low GWP. R744 has already been used in many applications, but for transcritical cycles, the performance is lower than the observed on other natural refrigerants cycles. This paper investigates the performance of R744 blends to other natural refrigerants, to evaluate performance enhancements. The research was carried out using the open-source software DWSIM, and the fluids used in the blends were R717, R600a, and R290. The reference synthetic fluid to analyze the results was R134a. The main findings are that all the blends are able to increase the COP, and with R717 it is possible to achieve almost the same levels as R134a. Also, a decrease on 2nd law efficiency is noticed, and it is worse for the hydrocarbons, mainly R600a, which had efficiencies near zero for evaporation temperatures close to 0°C. Mass flow rate and operational pressures are reduced, a great achievement, since the R744 cycle has high operational pressures. The present research shows improvements in R744 transcritical cycles, regarding COP, refrigerant charge, and operational pressures.
Keywords
GWP, COP, exergy, Transcritical
