Frost growth behavior according to the cold surface inclination angle

•Frost growth behavior according to the cold surface inclination angle was observed.•Frost thickness increased and the density decreased as the angle increased.•Scattering of the frost particles and initial shape of the frost crystals were observed.•Frost layer was strongly bound as the cold surface temperature increased. Frosting experiments were performed to analyze the frost growth behavior according to the inclination angle of a cold surface. The thickness and density of frost on an inclined cold surface were analyzed with respect to a horizontal cold surface. The scattering of the frost particles and the initial shape of the frost crystals were observed. The frost thickness increased and the frost density decreased as the cold surface inclination angle increased, even with variable operating conditions (humidity and cold surface temperature). In the case of varying humidity, the initial frost crystals exhibited feather shapes under relatively high humidity conditions, and needle and pole shapes under relatively low humidity conditions. The decrease in frost density owing to frost particle scattering was significant when feather-shaped crystals were observed. As the cold surface temperature increased, the frost layer was strongly bound, and frost particle scattering occurred less frequently.