Consulting-Specifying Engineer - May 2008 - (Page 64) Case Study Academic Center schools in electrical distribution AT A GLANCE W Components that make up the photovoltaic system at the Harm A. Weber Academic Center on the campus of Judson University turn sunlight harvested from photovoltaic panels into dc power, which is subsequently changed to 208 V AC power via an inverter. Photo: Robb Davidson The Harm A. Weber Academic Center at Judson University, Elgin, Ill., is one of the most sustainable schools in the United States—due to a natural ventilation, daylighting controls, and a photovoltaic system that reduces grid power usage. Square D, a division of Schneider Electric North American Operating Division, Palatine, Ill., is instrumental in the electrical distribution process of solar power. The building uses photovoltaicsourced ac power. A Square D 30 kVA step-up transformer increases the voltage to 480 V so it is distributed throughout the building via the Square D QED Power-Style switchboard. hat if the intent of a green building on a university campus is to be a model for more sustainable design, meaning the physical structure itself becomes a means of learning for both students and scholars alike? That was the challenge facing KJWW Engineering Consultants’ branch in Rock Island, Ill., when designing the electrical distribution system of the Harm A. Weber Academic Center on the campus of Judson University in Elgin, Ill. The building opened in time for the fall 2007 semester, with green features that include natural ventilation design, extensive daylighting, and a photovoltaic system that reduces grid power usage. As of early 2008, the university was striving toward USGBC LEED NC Gold certification, which is expected to be achieved by fall 2008. Additionally, KJWW was honored for its work on the project with this magazine’s ARC Silver award in New Construction (see Consulting-Specifying Engineer, December 2007, page 25). Unique building design At 88,000 sq. ft, the Weber Academic Center is the biggest building on the Judson University campus. It houses the School of Art, Design, and Architecture; the university library; 20 faculty offices; an administrative suite; and a host of studios and classrooms. It is roughly divided into three separate areas: • The block element, including the library and studios • The bowtie element, a four-story area made up of classrooms • The bar element, made up of studios and offices. A sustainable design can encompass many things. In the Weber Academic Center’s case, that included substantial window glazing and a 4-ft-thick wall cavity that simultaneously reduces solar heat gain and allows in abundant natural light. Photosensors strategically placed throughout the facility turn artificial lights off when there is enough natural light. Project manager Wade Ross, senior engineer at KJWW, knew that designing an appropriate electrical distribution system to adequately support the Weber Academic Center’s sustainability goals would take a fair amount of research. The premise of a natural ventilation system at the Academic Center is simple. Cool air is drawn in at separate points in the lowest level of all three areas of the complex, which then rises naturally due to warming, traveling a path throughout the building before being exhausted on the roof in a stack effect. However, seasonal extremes play a role in the design. For example, in the middle of winter or summer, warm and cool air, respectively, is recycled rather than exhausted. That means fans at the lower levels that draw in air from the outside don’t have to run as often. KJWW specified 15 and 20 hp Square D Class 8839 Econo-Flex variable frequency drives for this purpose, which create energy savings by varying the speed of the motors powering the fans, based on the season. A key component of many sustainable buildings is the use of solar power, and the Weber Academic Center is no exception. Photovoltaic panels located on the south exterior of the building draw in sunlight, which initially becomes dc power but is then changed to 208 V ac power via an inverter. From there, a Square D 30 kVA step-up transformer increases the voltage from 208 to 480 V so it can be distributed throughout the building via the Square D QED Power-Style switchboard. Other distribution tools include the Square D PowerPact 1,200 A main circuit breaker, Square D 64 Consulting-Specifying Engineer • MAY 2008
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