22 May 2008

MINIMISING FROST GROWTH ON COLD SURFACES UNDER NATURAL CONVECTION CONDITIONS BY MEANS OF A HYDROPHILIC COATING


This paper reports our new achievements in the development of the new
hydrophilic anti-frosting paint. The coatings formed by the new paint have bigger surface
hardness, much thinner film thickness (~50µm) and longer life period. The performance in
restraining frost formation of the new paint was tested with wide air relative humidity (from
35.5% to 76.0%) cold surface temperature (from -7.1°C to -20.8°C) conditions. The frost
deposition on the hydrophilic surfaces formed by new paint coatings was delayed at least 3
hours compared with the plain copper surface under the conditions of a cold plate
temperature above -10°C and relative humidity below 55%. The new paint has better effects
to retard frost growth than the old paints under the conditions of plate temperature below –
15°C and relative humidity above 70% and under this condition frost deposition was delayed
for 90 min on the hydrophilic surface made by the new paint. Finally polarity of water
molecule, formation mechanism of frost crystals and the characteristics of substances used
in these paints were discussed to explain the effectiveness of the new hydrophilic paints in
anti-frosting.