Aplicação de um modelo numérico para a estimativa da evaporação de água degelada em calhas de refrigeradores domésticos frost free

Abstract

This study had the objective of applying a numerical model for the estimation of the evaporation of defrosted water in Frost Free household refrigerators. The model was applied and validated through tests. The error between the numerical simulation and the experimental data was 1.4% for the water temperature in the defrost tray and 12% from the fifth hour of test. With the validated model, numerical simulations of improvement proposals were made. Three characteristics were simulated, each one adding a new proposal to previously simulated proposals, cumulatively. A proposal was made to change the material from the defrost tray, replacing polypropylene with aluminum. With this characteristic, the water temperature had a gain of 3.4% and the evaporated mass increased by 13.2% comparing to the refrigerator without any improvement. Then, in addition to the material changing, a 300 mm auxiliary tube was implanted, connecting the discharge from the compressor to the beginning of the condenser. With this characteristic, the water temperature had a gain of 12.1% and the evaporated mass increased by 52.3% comparing to the refrigerator without any improvement. Finally, the third simulated characteristic used, in addition to the aluminum tray and the auxiliary tube of 300 mm, thermal paste in the tray assembly on the top of the compressor. With this characteristic, the water temperature had a gain of 63.0% and the evaporated mass increased by 519.9% comparing to the refrigerator without any improvement. It was concluded that the use of thermal paste is the proposal that provides more relevant results, together with the auxiliary tube which, in addition to increasing the evaporation rate in the tray, helps condensation of the refrigerant gas, improving the refrigeration system as a whole.