A proposed discomfort glare evaluation method based on the concept of 'adaptive zone'

Abstract

Glare is position and view direction-dependent within a space, but most visual comfort analysis is taken place in a fixed position and view direction. Allowing occupant to rotate view direction or shift seat position to avoid glare will reduce the degree of discomfort perceptions. Such view direction rotation and position shifting range so-called ‘adaptive zone’. The aim of the paper is to acquire the extent of the reduction in predicting glare when considered the ‘adaptive zone’. The research objects are an office room with three façade types, and all the simulation data are generated from radiance-based visualization renderings, which is implemented by DIVA for Grasshopper plus rhino. The simulations are carried out on Summer and Winter solstices and autumnal equinox under Perez sky model. For the façade without shading, the mean glare reduction is 18.7%/28.4%/35.1% if the rotation freedom allowed within ±15°/±30°/±45° and permitting the seat position move about 0.5 m respectively; For the overhang variant, the result is 17.5%/26.2%/31.5%; For the lightshelf variant in this study, the result is 14.6%/22.7%/27.7%; The introduction of the concept of ‘adaptive zone’ in visual comfort predictions significantly reduces both the degree and the occurring time of discomfort glare. Continuous glare analysis based on a moveable view is a beneficial for studying the visual comfort issues rigorously which related to the occupant behavior in an interior space. The concept of ‘adaptive zone’ provides a reasonable idea to deal with the confusion of view direction in visual comfort detect cases.