The finite-difference equation method is used to derive expressions for the directional-hemispherical transmittance as measured in the integrating sphere; and for the correction factor necessary with a one-port sphere to account for changes in the enclosure caused by substituting the open port (the standard device) for the sample. Expressions are also derived for the hemispherical reflectance, since this quantity is necessary to compute the correction factor. It is also shown that no correction factor is necessary with a two-port (comparative) sphere.

%B Applied Optics %V 25 %P 2752-2756 %8 08/1986 %G eng %1Windows and Daylighting Group

%2 LBL-18234 %0 Conference Paper %B Illuminating Engineering Society Annual Technical Conference %D 1984 %T Integrating Sphere Measurements of Directional-Hemispherical Transmittances of Window Systems %A Jeffrey Kessel %A Stephen E. Selkowitz %XEquations are presented that express the directional-hemisphericalstransmittance of window systems in terms of the experimental parameterssof an integrating sphere. The construction and operation of a 2-meter diameterssphere is described. Experimental results are given for bothsconventional and novel window systems.

%B Illuminating Engineering Society Annual Technical Conference %C St. Louis, MO %8 08/1984 %G eng %L LBL-17284 %1Windows and Daylighting Group

%2 LBL-17284