This paper describes the use of light redirecting panels to improve the daylighting inside highly obstructed rooms at the lower levels of high-density residential developments in dense cities such as Hong Kong. Light redirecting panels are described and a simple design rule for the application of panels to highly obstructed windows, panel tilt angle-one half the obstruction angle, is derived. Scale model measurements demonstrate redirecting panels improve daylight factors by up to three times before discomfort glare becomes a limitation. Average ratio of daylight factors is a more useful measure of improved daylighting than the conventionally used average daylight factor.
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