Total energy transmission of transparent insulation material

Abstract

Transparent insulation materials for solar energy applications are classified and described in this paper. An experimental set-up with an integration sphere for the whole global spectrum range having a large entrance port is capable of measuring angle-dependent directional-hemispherical transmittances for planar samples and non-planar structures with acceptable accuracy up to about 70 degrees. Especially for structures such as honeycombs or sun-protecting glasses, which may absorb in the solar range, the total energy transmission is markedly higher than the solar transmission because of additional heat flux towards the absorber. A measuring device, currently in development, is presented