Solar transmission of transparent insulation material

Abstract Transparent insulation materials for solar energy applications are classified and described in this paper. An experimental setup with an integrating 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 nonplanar structures with acceptable accuracy up to ∼ 70°. The theoretical description of such structures allows to calculate directional transmittances even for combinations of different kinds of layers, for instance to determine seasonal variations of monthly-averaged transmittances for the whole cover system.