Glare Analysis of Daylit Spaces
Alstan Jakubiec and Christoph Reinhart (supported by the NSF)
Glare, physical discomfort caused by contrast or luminous intensity, is an underutilized parameter in contemporary architectural design.
This project consists of a series of related activities that are concerned with experimental and computer-based design analysis techniques
to asses the appearance of glare in daylit spaces.
Adaptive Visual Comfort
In this study we compared simulation results for five glare metrics under 144 clear sky conditions in three spaces in order to investigate the ability
of these metrics to predict the occurrence of discomfort glare and to hence support the design of comfortable spaces. The metrics analyzed are Daylight
Glare Index, CIE Glare Index, Visual Comfort Probability, Unified Glare Rating, and Daylight Glare Probability. It is found that Daylight Glare Probability
yields the most plausible results. In an attempt to deal with multiple positions and view directions simultaneously, the concept of an 'adaptive zone' is
introduced within which building occupants may freely adjust their position and view in order to minimize the effect of glare. The spatial and directional
extents of the adaptive zone depend on furniture layout and the freedom of occupants' tasks. It is found that applying the adaptive zone concept to a sidelit
office with manually operated venetian blinds reduces the predicted hours of intolerable discomfort glare from 735 to 18 occupied hours per year and increases
the annual mean daylight availability from 40 to 72 percent. paper
The animated image above shows a cylindrical 360o
view of a work space in a studio sapce. The color coded lines at the bottom show the predictions of different
glare indices (DGP, DGI, UGI, CGI and VCP) whether discomfort glare will be experienced in a particular direction at at different times of the day (Green=Imperceptible
Glare; Yellow=Perceptible Glare; Orange=Disturbing Glare; Red=Intolerable Glare).