Page 61 - Zero Net Energy Case Study Buildings-Volume 3

LA ESCUELITA EDUCATION CENTER
CASE STUDY NO. 13
Daylighting and Electric Lighting
Daylighting has traditionally been a design feature of classroom facilities because of the perceived health and learning productivity benefits. Modern daylighting design adds sophisticated daylight controls and computer modeling to the design methodology. The design team utilized this approach through daylight modeling and technical specification, particularly in the classrooms and large multi-purpose room (the “Great Room”).
The daylighting design in the classroom spaces is strongly integrated with the cooling system design (displacement ventilation in the classrooms and the “Cool Towers” in the Great Room— see the discussion below under Heating, Ventilating and Cooling Systems) as well as the building envelope design (glazing specifications, as discussed in the previous section).
But first the designers attended to good light levels and glare control by utilizing tall windows and fixed shading devices in the classrooms. The fixed sun shades are structural overhangs and were designed also to act as a “Light Shelf”, reflecting sunlight to the interior of the room. Secondary light from the large daylit common space adjacent to the classrooms was provided via additional windows on the opposite side of the classroom, also creating light balance in the space and visual comfort conditions. Daylight models confirmed these space characteristics and that good classroom light levels would be provided under most daily conditions. (See images from the daylighting studies on facing page.)
For the large Great Room, daylight modeling was used to evaluate several architectural approaches to daylighting the large space, including skylights and a north-facing clerestory. The clerestory scheme resulted in a tilted roof, slightly sloping to the south, which had a slight advantage in PV performance. The skylight scheme produced more uniform daylight across the space. (Daylight modeling images rendering the appearance of these two schemes at top of facing page.) The clerestory scheme was selected and ultimately integrated with relief louvers for the operation of the Cool Tower. (See discussion below.)
For electric lighting when daylight is not ample, T-8 lamps are used in the overhead light fixtures because LED sources were not cost effective at the time of design and construction.
(Below) North clerestory of the Great Room as built, with one of the Cool Towers. (Photo courtesy of SVA Architects)
Zero Net Energy Case Study Buildings, Volume 3
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PHOTO: DALE LANG