Condensation frosting detection and characterization using a capacitance sensing approach

Frost growth is detected using capacitance sensing approach. A capacitive sensor with interdigital electrodes (IDEs) is designed and fabricated based on the fringing effect. Frost growth experiments under different surface temperatures, air temperatures, and air velocities are conducted with simultaneous frost imaging. The results show that the capacitance sensing approach can accurately reflect not only the characteristics of different frost growth stages but also the differences of frost growth under different conditions. The rate at which the capacitance increases changes for different frost growth stages and fluctuations decrease during the mature growth stage. Changes in the rate at which the capacitance increases are relatively small under a high surface temperatures or high air velocities, and the time it takes to reach to the mature growth stage is shorter at lower cold-surface temperatures, higher air temperatures or higher air velocities. This work has potential for advancing the understanding of frost growth mechanisms and for better defrost control.