LIGHTING UP THE ARMY
The U.S. Army's new Green Building Strategy is illustrated in a recently completed Military Center that uses state-of-the-art technology to maximize daylighting while minimizing energy loss and running costs.
The new Greenlief Armed Forces Reserve Center (AFRC) in Hastings, Nebraska, has been designed and built to take advantage of all the latest developments in daylighting and energy-saving technology.
This not only provides the troops with the very best interior natural lighting but also helps reduce running costs. To do this as energy efficiently as possible and in accordance with the U.S. Army's new Green Building Strategy, a dramatic new way of improving the insulation has been achieved by introducing Nanogel® aerogel within the glazing.
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Completed in April 2009, the 59,000-square-foot center provides assembly halls, classrooms, and repair bays for the local National Guard and Army Reserve. Architects RDG Planning & Design were asked to draft a modern facility with as much natural daylight as possible. To achieve this, they designed the building to include extensive areas of glazing for the assembly, main corridors, and repair centers. However, although this would let in plenty of light, it would also let in unwanted glare and heat from solar gain. There was also the problem of insulation and energy saving in temperatures that ranged from -30°F in winter to over 100°F in summer. To help solve this problem, RDG turned to the daylighting experts at the Kalwall Corporation.
At the architects' request, the Kalwall engineering team generated a daylighting model of the proposed building. Taking into consideration façade orientation, and room height, size and use, several studies helped define the optimum positioning and size of the translucent windows and skylights to meet the Army's daylighting objectives. The main mission for this daylight study was to show compliance with the LEED®-required, minimum 25 foot-candles (fc) in 70% of regularly occupied spaces. Traditional methodology used daylight factor calculations, which assume an overcast sky. With dynamic daylight simulation (using Department of Energy weather tapes for the site location), Kalwall was able to show that the intended design had more than 25 fc in the space.
As a result, the architect could understand what light levels he would realize from internal daylight harvesting, borrowing light from top-lit corridors into adjacent room through clear glazing. “To me, it represents the 'living building' idea,” says RDG's Matthew Knutson. “It's alive!” Kalwall's translucent composite structure perfectly diffuses sunlight into museum-quality daylightTM so that shadows, glare, and hotspots are all eliminated.
Although the Kalwall system itself is highly insulating, the architects agreed that this could be dramatically improved by introducing Nanogel insulation within the system to help combat the extreme temperatures. Nanogel aerogel, a translucent form of silica aerogel made by Cabot Corporation, comprises 95% air and is the world's lightest and best insulating solid material which greatly improves the insulation of a variety of fenestration systems. When used in the Kalwall Translucent Wall and Skyroof systems, it increased the insulation value to R-20 (U=.05 Btu/hr/ft2/°F or 0.28 W/m2K ), which is better than many solid walls!
The National Guard has been very satisfied with the results. Gene Macapinlac, the project architect, explains, “We have had great feedback from both the soldiers and local community. They tell us the center is bright, open and welcoming, providing an excellent space in which to work and train. The Greenlief AFRC, we believe, represents a new standard in Training Center design and function. It supports the U.S. Army's commitment to reducing energy consumption and to provide sustainable facilities. The decision to use Kalwall+ Nanogel translucent windows has reduced their daily use of overhead lighting and promises to be a key component in reducing their year-round HVAC costs.”
The U.S. Army is well known for its innovations in defense technology but not usually for its innovations in architecture. Using the Kalwall+ Nanogel system in this facility means the troops get to enjoy all the benefits which natural daylight brings to their health, well-being and productivity. At the same time, the facility is saving money and energy and, importantly, using materials that are environmentally friendly and recyclable because Kalwall is 100% recyclable by weight and Nanogel aerogel is a Silver Cradle to CradleCM certified material by MBDC.
Greenlief Armed Forces Reserve Center
Hastings, NE
Architect: RDG Planning & Design
Photo courtesy of architect
Kalwall Specifications:
Walls: nearly 8,000 square feet (nearly 743 square meters)
U-value: 0.05 Btu/hr/ft²/°F (0.28 W/m²K)
Light Transmission: 15%
Interior face: .045 White Type 25
Exterior face: 0.70 Crystal SW
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