Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
CO2 TRANCRITICAL REFRIGERATION SYSTEMS USING EJECTOR: A-STATE-OF-THE-ART REVIEW.
Submission Author:
Frank Wiliam Adolfo Blanco Ojeda , MG , Colombia
Co-Authors:
Frank Wiliam Adolfo Blanco Ojeda, ENIO PEDONE BANDARRA FILHO
Presenter: Frank Wiliam Adolfo Blanco Ojeda
doi://10.26678/ABCM.COBEM2023.COB2023-0880
Abstract
The concern with the environment associated with the restrictions imposed by international agreements such as the Kyoto protocol and the Kigali Amendment, have driven the use of natural refrigerants as alternatives to synthetic fluids, mainly HCFCs and HFCs in refrigeration systems. Carbon dioxide (CO2) is a very promising natural fluid due to its properties: low viscosity, high heat transfer coefficient, non-flammable, non-toxic, and is widely used in cold climate countries. However, due to technological development, transcritical systems that operate with CO2 are being applied in temperate countries with the use of ejectors, which substantially increase the efficiency of these systems. Since this device can save a part of the energy consumption in the compressor by recovering the energy losses in the throttling process in a refrigeration system. In this review, the complex thermodynamic phenomena that occur within the two-phase ejector are described from a macro perspective, and the operating conditions are reported, thus geometric parameters that increase the efficiency of the ejector as a function of entrainment rate and pressure rise rate. Finally, the main results obtained from transcritical refrigeration systems using the ejector as an expansion device are compared. The results found in the literature indicate that the use of the ejector increases the performance of transcritical refrigeration systems due to the utilization of kinetic energy in the throttling process, raising the suction pressure of the compressor and consequently reducing energy consumption. However, it was observed that most of the works available in the literature are theoretical and numerical, demonstrating the need for experimental studies to substantiate the importance of ejectors in refrigeration systems.
Keywords
ejector, CO2, Transcritical cycle, Refrigeration
