Beryllium oxide: a frost-preventing insulator.

A method is suggested of achieving low outdoor radiative losses by low spectral emittance in the atmospheric window of 8-13 microm, which will reduce dew and frost formation on surfaces exposed to the clear sky. The use of this selectively low emittance makes it feasible to use electrically insulating materials. It is argued that lattice-based reststrahlen bands can be exploited for this purpose. The observation is made that hexagonal beryllium oxide has a strong reststrahlen band that covers most of the primary atmospheric window. Results from experiments with polycrystalline samples demonstrate that bulk beryllium oxide is equally effective for dew and frost prevention as glass coated with conducting tin oxide.