Investigação experimental da formação de frost em placas planas de cobre com revestimento sinterizado

Abstract

This paper consists in an experimental analysis of the frost (porous ice) formation on cold copper surfaces with smooth, varnished and porous coating. Frost formation occurs when a moist airflow comes in contact with a cold surface below 0°C, transforming steam into a porous ice structure that acts as a thermal insulator. In equipment present in the refrigeration process, the frost accumulation in evaporators leads to a loss of efficiency and an increase in energy consumption, making this topic a subject of several researches that aim to obtain ways to reduce the formation of this phenomenon. In this context, an experimental apparatus with a 20 ºC cold surface was used, an experimental analysis was carried out on 3 samples manufactured from flat copper plates without surface coating, with a layer of varnish applied on the surface and with a porous coating made by sintering copper powder onto the sample surface. The experimental tests were carried out with stable ambient temperature and relative humidity parameters and lasted 120 minutes, aiming to obtain data on the thickness of the frost layer formed on the samples, the formation speed, and the surface temperature of the samples. The results obtained have a behavior similar to those found in the literature and showed that the samples with the sintered coating offer greater resistance to frost formation and present a higher surface temperature.