ベネシャンブラインドの分光透過指向特性の算出方法 CALCULATION METHOD FOR SPECTRAL TRANSMITTANCE DIRECTIVITY OF VENETIAN BLINDS
Venetian blinds are usual devices for controlling daylight admittance. The spectral transmittance of venetian blinds is affected by shapes, reflective properties of the slats, and the direction of incident light. We incorporate these factors into a method for calculating the spectral transmittance directivity of the blind. The slats are assumed to be arcs on a two-dimensional cross section, which constitutes a Lambertian surface of negligible thickness. The spectral irradiance distributions on the slats and virtual elements in optical directions are calculated by two-dimensional spectral interreflection. The spectral irradiance distributions are then transformed into a three-dimensional spectral BTDF<sub>λ</sub>. The BTDF<sub>λ</sub> and transmittance are determined from the incident direction of the direct radiation and the blind geometry. Using the proposed method, we can calculate the spectral irradiance distributions of rooms shaded by venetian blinds. The result shows quantitatively that the spectral reflective properties and angles of the slats affect the spectral transmittance directivity of the blinds and spectral irradiance distributions of the room.
日本建築学会環境系論文集 79(705), 937-945, 2014