Effective substrate emissivity during dew water condensation

Dew water condensation is due to the radiative cooling of a surface and hence promoted on surfaces with high emissivity in IR spectrum. The search for enhanced properties usually carried out without considering contribution condensation. On condensing substrate, however, droplets can occupy more than 55 % surface. Given (∼ 0.98), condensed thus expected modify efficiency. present study aims investigate interplay between mean emissivity. Radiative experiments humid air environment are performed using two substrates contrasted emissivities (0.88 0.05). Although yield initially larger after transient rate appears essentially same both substrates. A simple geometrical model taking into account wetting reveals, addition effect droplet coverage, existence threshold drop thickness where effectively contribute process. results conceptual practical importance be generalized any process involving vapor induced by cooling.