Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
DESIGN OF AN FINNED TUBE EVAPORATOR WITH CROSS-FLOW FOR A REFRIGERATION MACHINE OPERATING WITH CO2 IN SUBCRYTIC CYCLE
Submission Author:
Hélio Augusto Goulart Diniz , MG , Brazil
Co-Authors:
Carlos Henrique Neto da silva, Hélio Augusto Goulart Diniz, Ivo Zatti Lima Meyer, Grack Rodrigues Gama, Leandro Pinto
Presenter: Hélio Augusto Goulart Diniz
doi://10.26678/ABCM.COBEM2017.COB17-2583
Abstract
The emission of some gases used in the refrigeration has caused a worrisome environmental impact, as they cause the disintegration of the ozone layer. CO2 - Carbon Dioxide (R744) has been the subject of research in recent years because it is a refrigerant fluid that is not aggressive to the environment and presents good thermodynamic properties. In the design of an air-water refrigeration machine using components that operate in a subcritical cycle, the specific design of one of the heat exchangers was abalyzed, the crossed-flow finned tube type evaporator. The mathematical modeling of the project was programmed in the MATLAB® software (MATrix LABoratory), aided by the EES® software (Engineering Equation Solver). A complete approach to the evaporator design was performed by analyzing the convective coefficients (monophasic and biphasic) of heat exchange of the refrigerant and secondary fluid (air), through correlations in the literature. The cooling capacity of the evaporator was 3.47 kW, working at a pressure of 19.7 bar and the evaporation temperature of - 20 °C, its dimensions was obtained in which the total length of the tube was 14 m. The idealized machine has a cycle with a COP (Performance Coefficient) of 3.47, being designed for a research laboratory and will allow the production of cold air at 8.1 °C that can be used to aid a room air conditioning system of laboratories and can also be applied in laboratory tests of domestic refrigeration machines.
Keywords
Refrigeration machine, CO2, R-744, finned tube evaporator
