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Appalachian Suncatcher The interior offers a welcoming, sheltered, treehouse-like atmosphere for exhibits about local culture and history. The center also orients visitors traveling the Blue Ridge Parkway, which winds for 469 miles (755 kilometers) through the Blue Ridge Mountains, part of the Appalachian Mountains. In addition to exhibit space, the building includes a gift shop, classroom, offices, and a 70-person high-definition theater. Undoubtedly, one of its most valuable lessons will be its demonstration of high-performance ecological design. Passive Solar Destination Proper site choice and orientation were key to optimizing passive solar strategies at the Blue Ridge Parkway Center. The building is built into a hillside on its north side. For maximum effectiveness, the Trombe walls had to be turned 30 degrees, in a sawtooth pattern, to face due south. Trombe walls use the sun to heat a small air space between a glass wall and a heavy-mass wall. The trapped heat is transferred into the building through vents or indirectly. The Trombe wall design updates the thermal-mass wall common to many traditional building types. With the center located at an altitude of 2,300 feet (700 meters), the Trombe walls work well with local conditions. They collect the heat during the day and radiate it into the building — with its 35-foot- (11-meter-) high ceilings — at night and into the next day. Summer temperatures in the Asheville area rarely exceed 90 degrees Fahrenheit (32 degrees Celsius), with nighttime temperatures in the 60s (16 to 21 degrees Celsius). The Trombe walls were particularly adapted to this type of setting and include vents that can be used not only to trap warm air and move it into the building, but also to trap cooler evening air and let it flow into the building on summer days. In the summer, an overhang shades the walls and prevents them from overheating. The building also includes an HVAC system for extreme weather conditions. Modeling Air Flow Lord, Aeck & Sargent called on Pennsylvania State University's Applied Research Laboratory to study the air movement and heat-transfer performance of the Trombe walls. The laboratory took historical data on local weather conditions and created a computational fluid dynamics (CFD) model to predict future performance. CFD has long been used in the aerospace and defense industries; it's now becoming more common in high-tech architectural applications. "We feel that its potential for modeling passive buildings is largely untapped," says Vikram Sami, energy analyst and daylighting specialist for Lord, Aeck & Sargent. The architects followed up with a study on the site to measure actual conditions in February. "We found a reasonably good agreement between what we simulated and what we measured," says Sami. "In winter conditions of 20 degrees Fahrenheit [-7 degrees Celsius] at night, the Trombe wall temperature was 60 degrees [16 degrees Celsius]," Sami says. "It maintains the building 40 degrees [22 degrees Celsius] warmer than outside." "The Trombe wall temperatures get up to 90 degrees [32 degrees Celsius] in the daytime," he adds. "You want it to heat up that much. In comparison, the typical HVAC system supplies heat at 85 to 90 degrees [29 to 32 degrees Celsius], depending on the design." Additional data collection will be done in the summer and winter. >>> Discuss this article in the Architecture Forum... Debra Moffitt writes about architecture, lifestyle, and design from Charlotte, North Carolina, and Lugano, Switzerland.
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