Consulting-Specifying Engineer - December 2008 - (Page 28)

\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ the middle of the lake. The coils were then slowly filled with water to submerge the bundle. Each bundle has its own isolation valve so if a leak occurs, air can be blown into the tube to surface the raft and make repairs. Chilled water is generated using the core water with water-towater heat pumps that is then distributed throughout the 180,000sq-ft building to air handling units. Photovoltaic panels were installed on part of the roof, and a 166-fttall wind turbine was installed on the property to generate 15% of the building’s energy. Interior fixtures are controlled by photocells that sense the available daylight and automatically dim the fluorescent lighting to maintain a minimum of 30 foot candles in offices and conference rooms. Machine room-less elevator systems were used because they require less space, do not contain any hydraulic fluid, and consume 40% less electricity than conventional elevators. Low-flow plumbing fixtures, along with dual-flush toilets and a 20,000-gal cistern that captures rainwater from the roof, were also installed. Native plantings that use very little irrigation, including northern climate apple trees, were planted. The biggest challenge Perkins+Will had already participated in a prototype “healthy building” study for the American Lung Assn. in 2000 that tested how to optimize indoor environmental quality. “The concepts from that study and other energy studies demonstrated that daylight harvesting would be a huge step in saving energy,” Olson said. East-west orientation allows plenty of daylight. To do so meant orienting the building in an east-west fashion to capture the maximum amount of sun. To allow the daylight to penetrate, there had to be narrow floor plans to optimize the daylight harvesting. This meant creating a set of four- and three-story buildings that connected with center atriums. The vast amount of glass created unique HVAC challenges, especially during the afternoon hours when the sunlight penetrated so deep into the building that some interior zones had to be treated like exterior zones because the temperatures would dramatically fluctuate. As a result, five extra temperature control zones had to be added. While most floor diffusers, 964 to be exact, were adjustable, 113 were motorized in areas that experienced extreme temperature changes. The end result Great River Energy is one of less than 100 buildings in the world—and the first in Minnesota—to achieve U.S. Green Building Council LEED Platinum status. The building, which earned 56 LEED points, four more than the Platinum requirement, uses 45% less energy than a comparable facility built to state code requirements and 89% less water than a similarly sized corporate campus. It features an in-lake geothermal HVAC system, in-floor displacement ventilation, daylight harvesting, 72 kW of on-site solar panels, and a 200-kW wind turbine. Often, the building produces an excess of power that is then put back on the grid. It officially opened in April 2008, less than two years after construction began. “We did things that were never done before,” Olson said. “Not anywhere in the world.” The building form was established to enhance natural light and views to the outside. East-to-west building orientation and narrow floor plates provide effective daylighting. Photo: Lucie Marusin Distributed break areas provide an opportunity for either a quick break or an informal meeting. The largely open floor plate enhances displacement ventilation. Photo: Don F. Wong 28 Consulting-Specifying Engineer • DECEMBER 2008

Table of Contents Feed for the Digital Edition of Consulting-Specifying Engineer - December 2008

Consulting-Specifying Engineer - December 2008 Contents Viewpoint News M/E Roundtable ARC Awards New Construction Gold New Construction Silver New Construction Bronze Renovation Gold Renovation Silver A Green Approach to Air Conditioning Systems Turning Down the Lights Case Study New Products Equipment Lifecycles Advertiser Index Green Space Gas Technology Pure Power Supplement

Consulting-Specifying Engineer - December 2008

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