Experimental and theoretical study on effect of dust deposition on frosting characteristics of fin surface

Abstract

Since dust accumulates on the fin surface of the outdoor heat exchanger all year round, frost formation inevitably occurs on the fin surface with dust deposition when an air source heat pump is used for heating in winter. However, the effect of dust deposition on frosting characteristics of fin surface has not been clarified. Therefore, visualization experiments were carried out in this paper to study the frosting characteristics on bare and superhydrophobic fin surfaces under different dust deposition levels. Meanwhile, the influence mechanism of dust deposition on frost formation was analyzed theoretically based on phase transition dynamics. The experimental results showed that when the dust deposition on the superhydrophobic fin surface was less than 0.2 g, the dust deposition promoted crystal growth at the initial stage of frost formation, while the frost formation was inhibited when the dust deposition was more than 0.4 g. In the case of bare fin surface, dust deposition always inhibited the frost formation. As the dust deposition mass on the fin surface increased, the thickness and density of the frost layer decreased on both bare and superhydrophobic fin surfaces. In addition, it was worth noting that with the increase of dust deposition, the super hydrophobicity of the superhydrophobic surface was gradually lost. This is not conducive to the practical application of superhydrophobic anti-frosting technology.