任意形態の開口部による直接昼光率の図式解法

Abstract

This paper reports some diagrams for computing the direct daylight factors which are attributable to those particular parts of the sky which are seen through the windows of different shapes. The luminance of the sky is so distributed that Lθ=(1+2sinθ) Lz/3,where Lθ is the luminance, Lz is the luminance at zenith, and θ is the altitude of that part of sky where the luminance equals Lθ. Daylight diagrams, which are two dimensional representation of the sky vault, take one of two basic shapes : (1) A circle, the radii of which represent an equally-spaced scale of azimuth and in which concentric circles represent a scale of angles of elevation whose spacing depends on whether the projection is orthographic, stereographic, or equidistant. (2) A rectangle, the abscissae of which represent a scale of azimuth, sometimes equally spaced and the ordinates of which represent a scale of angles of elevation.