High Performing Buildings - Winter 2008 - (Page 42)

Curved, translucent lightshelves enhance daylighting in Reedy Fork’s science room. The new daylighting design needed to produce glare-free, uniform daylighting that was superior to the ﬂuorescent backup system two-thirds of the time. It also had to cost less than previous strategies. In comparing the cost of the various optional daylit classroom wing designs, the design team broke down the construction cost of every component in a typical wing design. Using detailed component costs, each daylighting strategy option was compared to the conventional, non-daylit designs (Figure 1). Innovative Classroom Design building section. In Innovative Design’s previous daylit schools, south- and north-facing roof monitors were used. Although the energy performance is good, it was important to reduce ﬁrst cost even more. Coupled with the daylighting, two other main drivers impacted the design. To improve air quality, an underﬂoor air-distribution system in combination with a variable air volume (VAV) mechanical system approach was considered. To implement an underﬂoor system, a holistic approach was needed since most buildings incorporating this strategy were adding at least $15/ft2 to the cost. Additionally, because of dissatisfaction with the compatibility between daylighting and lay-in ﬂuorescent ﬁxtures, indirect lighting strategies that more closely mimic daylighting were considered. The goal was to capture the energy, health, productivity and quality beneﬁts of these strategies without the high cost. The preferred daylighting design from the evaluation process features two south-facing clerestories that use curved, interior, translucent lightshelves that ﬁlter sunlight down and bounce the remaining light deep into the classroom. Indirect lighting complements the approach, and an underﬂoor air-distribution system provides superior indoor air quality and further reduces energy consumption. Highly reﬂective ceiling tiles enhance the light being reﬂected deep into the space. This new approach to daylighting was ﬁrst at Northern Guilford Middle and also is now at Reedy Fork Elementary. The strategy requires 40% less glass than typical side-lit solutions. Additionally, because of the 20% visible light transmittance of the translucent panel used in the lightshelf, glare is reduced and a soft light is well distributed within the space. The curved translucent lightshelf provides light immediately under the lightshelf, bounces light back into the space, and diffuses the light. This allowed for glazing at the wall clerestory aperture with maximum SECTION THROUGH CLASSROOM WING 42 HIGH PERFORMING BUILDINGS Winter 2008

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High Performance Buildings - Winter 2008 Passing On the Gift: Heifer International Headquarters Head of the Class: University of Florida’s Rinker Hall How Far Can You Go? Pearl River Tower The Proof Is Performance: How Does 4 Times Square Measure Up? Lighting the Way: Two Guilford County Schools Montreal’s Retail Example: Mountain Equipment Co-op® (MEC)

High Performing Buildings - Winter 2008

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