Electrostatic Defrosting

Abstract

Electrification of ice has been studied for over half a century, mostly in the context of atmospheric science. Here, the polarizability and natural thermovoltage of a substrate-bound frost sheet are exploited for frost removal by placing an actively charged electrode overhead. This new technique, which we term electrostatic defrosting (EDF), can remove up to 75% of the frost’s mass from its substrate over a time scale of only minutes. A one-dimensional numerical model is developed to rationalize the effective electrostatic force exerted by the electrode on the warm end of the frost sheet. Experimentally, the effectiveness of EDF is shown to depend on the applied voltage, relative humidity of the ambient air, the gap height between the frosted substrate and the electrode plate, and the type of substrate. Although EDF primarily removes the dendritic frost structures rather than the underlying frozen condensate, this selective removal can still offer significant advantages for applications requiring improved visibility or reduced surface roughness. EDF can effectively remove frost without the application of heat, chemicals, or mechanical forces, rendering it a promising new construct for defrosting.