Daylight prediction algorithms are developed for atriums under various sky conditions. In four-sided and linear atriums, empirically based algorithms are developed for the prediction of light levels on the horizontal surface of the atrium, and also on the vertical wall surfaces of the atrium (Saxon 1983, Kim and Boyer 1987). In addition, direct sun impacts are simulated for asymmetric toplighted atriums with closed sides. In three-sided atriums, previously studied, algorithms were developed for the prediction of light levels normal to the vertical wall surfaces of the middle foors (Kim and Boyer 1988).

Actual measurements were conducted at four existing Texas buildings in Dallas and College Station for the full-scale building tests. The case study buildings include one four-sided atrium and three linear atriums. Only two of the linear atriums are included in this paper. In the actual building measurements, horizontal illumination levels were measured. These horizontal light levels were measured on the atrium floor and at wall surfaces on the upper floors.

Units: Dual