Experimental investigation of frost retardation for superhydrophobic surface using a luminance meter.

We experimentally investigated the phenomena of frost retardation in terms of the heat exchanger fins with various water contact angles under normal air-source heat-pump operating conditions. We first introduced a new experimental method using a luminance meter, which measured the light intensity from the surface, and determined the phase-change time, for quantitatively defining the frost stages. The phenomena of frost retardation was analyzed for 10 samples with different water contact angles (75°–160°) at different refrigerant temperatures. When the refrigerant temperature was −10 °C or −12 °C, the effect of frost retardation increased remarkably with superhydrophobic surfaces. However, when the refrigerant temperature was −8 °C, the effect of superhydrophobicity diminished at water contact angles greater than 150°. [ABSTRACT FROM AUTHOR]