Effect of surface wettability of fins on dust removal by condensate water

•The dust removal performance on the fin samples with various surface wettability is experimentally studied.•The mechanism of dust removal by water condensation depends on the shape of the condensate water.•The remnant dust weight on the superhydrophobic surface is less than that on the other test samples in this study.•The calculation method of the dust removing rate via the two-degree polynomial is developed. Using the condensate water to remove the dust on fins is an economic way to maintain the heat transfer performance of a fin-and-tube evaporator, and the dust removal performance depends on the fin surface wettability. The purpose of this paper is to experimentally investigate the effect of surface wettability on dust removal by condensate water, covering the surfaces of hydrophilic coating, hydrophobic coating, superhydrophobic coating, and uncoated copper. The experimental conditions cover the inlet air temperature of 27 °C, the inlet air relative humidity of 50%, the inlet air velocity of 2 m s−1, the dust concentration of 10.8 g m−3, the dust deposition time of 30 min, and the sample surface temperature of 12 °C. The results show that, the superhydrophobic surface has the best dust removal performance, and the remnant dust weight on superhydrophobic surface is 69.9% lower than that on the uncoated copper surface, 61.1% lower than that on the hydrophilic surface and 3.59% lower than that on the hydrophobic surface.