An Empirical Study and Analysis of Daylight Penetration Through a Light Plenum

摘要

Lighting accounts for approximately 54% of theannual energy consumption of office buildings, andcan effectively be reduced through daylighting. Thesimplest way to provide day lighting into a typicaloffice space has been to use unilateral sidelighting. Discomfort and visibility glare from unilateral sidelighting cause the occupant to close drapesor blinds and turn on luminaries, resulting in aninefficient use of daylighting. One daylightingconcept that has been developed to alleviate thisproblem is the light plenum.A light plenum can be added economically to anoffice space by using a hung ceiling simultaneouslyas a return air and light plenum. The appropriateopaque ceiling panels could be replaced with transparent ones to get the light to the rear of thespace. The question is how much light can be expectedto be transferred to the rear of the room andhow different plenum opening configurations wouldaffect those light levels.The result simply that a hung ceiling lightplenum can provide adequate light to the rear of theroom to balance the high brightness ratios createdby unilateral sidelighting. Also, certain plenumopening configurations are more advantageous forcertain sky conditions and orientations, and thereare some which are of no benefit.