October 01, 2008
Appeared in Engineered Systems
It’s typical for a chiller to contribute to occupant comfort. It’s less typical for a chiller to ensure occupant survival, but such is the mix of occupants at The Wild Center in the Adirondacks. In this year’s Engineering Award-winning project, the array of HVAC challenges and circumstances is as wide as the variety of environments recreated “in nature” for two-legged visitors to experience. All in all, New York’s first LEED® certified museum brings the outside in with nimble but powerful design.
Nestled in the center of Adirondack Park in Tupper Lake, NY, The Wild Center is a bastion for native habitat. Even the building’s plumbing and mechanical systems simulate those of Mother Earth in order to support the indigenous otters and trout living inside year round.
Designed by Syska Hennessy Group, the MEP systems of the 35,000 sq-ft Natural History Museum of the Adirondacks were precisely calculated to illuminate the wild world outside it.
In order to design a living museum in which native otters and trout could exist in their natural environments, a variety of plumbing systems were employed. Life support systems and strategically placed pumps create a river stream with flow rates that cause the animals to feel as if they’re swimming, when in fact they stand stationary. Fresh water supply and return piping, filtration, holding tanks, heat exchanger cooling systems, and drainage and automatic pump controls were also specified, while makeup water is primarily filtered from the ground. A duct-mounted reheat system controls the exhibit’s humidity level to maintain comfort for the visitors as well.
The otters themselves posed an additional challenge to systems design. Due to the animal’s bathing and refuse habits, combined with their strong body odor, dedicated exhaust systems were needed to eliminate odor buildup in the confined space. Additionally, in the Adirondack Mountains, otter falls begin from on high, emptying into natural pools of water. The same landscape was mirrored here. Housed under one roof, these displays demand that water enter the Exhibit Hall at varying temperature points, specific to the requirements of each animal. Air cooled chillers located outside the building serve as lifesupport systems and provide temperature control for the animals, via a chilled water loop which also supports the building’s main AHUs.
The Museum’s live exterior exhibit, a manmade pond that lies flush up against the Museum’s building, is complete with a stormwater runoff system, native Adirondack fish, and ground water. Plumbing mechanisms are employed to drain a portion of the pond in the winter, lowering its height to prevent freezing water from expanding and damaging the Museum’s exterior.
In addition to the live animal displays, the Exhibit Hall also presents the Adirondacks through the seasons, clad with fog and wind generation.
Simulating an Adirondack Fall morning, fog moves out toward the visitors, covering the bottom portion of Museum’s replica mountains at the Hall’s entrance. In order to limit the extent of the fog to this specific display, Syska employed floor-mounted linear registers at the foot of the exhibit, pulling the fog to the mountain’s edge and confining it within the space.
Wind generation in the Exhibit Hall furthers the exploration of the Adirondack seasons for its visitors. Here, museum curators wanted strong winds to blow through a visitor’s hair. Supply air jets were placed within columns to disperse air among the mountains at eye level.
Mastering the mechanical systems
Architecturally designed as one large mixed-use space, The Wild Center is made up of three smaller, interconnected buildings. From the Exhibit Hall to the Museum’s theater/administrative offices and the entrance rotunda, each building demands function-specific mechanical systems support. Because of the building’s diverging needs, project design engineers specified both constant air volume (CAV) and VAV systems where appropriate, furthering energy efficiency and enhancing visitor comfort throughout the Museum.
Clad with 42 ft.-tall, high-efficiency glass windows, the 7,50 sq-ft conical Great Hall, or museum entrance, posed a mechanical challenge to HVAC systems design. With outdoor temperatures ranging from -40°F in the winter to 95° in the summer, the Museum’s heating and cooling systems demand a tremendous amount of flexibility.
The solution: Syska specified a number of smaller, modular boilers that enable the HVAC system to respond quickly to the varying outside air temperature demands, creating more precise indoor environmental controls. More energy efficient, this design ensures that only the exact amount of heating equipment needed is utilized at each moment. By contrast, large boilers would not have been able to meet the Museum’s seasonal temperature swings within the Museum’s tight time constraints.
Because glass doesn’t have the same insulating properties as an exterior wall and inside heat naturally wants to rise, a large mass of air was needed to push heat down the glass walls; so conditioning the space was possible only with a CAV system. Condensation was avoided by blowing air down from the ceiling, running parallel to the glass.
The Exhibit Hall also employs a CAV system, but in this case, it was specified to manage humidity and pressurization issues. Duct-mounted reheat coils equipped with thermostat and humidity sensors constantly moderate the Exhibit Hall, including its aqueous exhibits. As visitors leave the space and the temperature in the room decreases, the valve on the coils is triggered to give off heat. The reverse principal also apply: as visitors enter the room and the temperature increases, the valve conversely disables the coils.
The Museum theater, café, and administrative office area, on the other hand, employ a VAV system to manage fluctuating loads. Specifying a traditional HVAC system gave this area the flexibility it needed, as the theater’s projection equipment require more temperature and humidity control and the administrative spaces demand less.
The acoustics of both the theater and Exhibit Hall also require air and noise from the fans be kept to a minimum. In the Exhibit Hall, it was crucial to the fostering of the Museum’s natural environment that the noise of live crickets and bugs emerging from the simulated forest floor be heard over any HVAC clatter. In the theater, of course, any noise would disrupt the feature presentation.
Syska’s team was able to reduce mechanical equipment clatter with soundlined ductwork and a series of duct elbows that inhibit the transfer of sound from the fan though the ductwork to the theater space itself. A similar scheme was employed in the Exhibit Hall.
Additionally, in order to keep energy consumption to a minimum, CO2 monitoring systems were installed throughout the building. As the population of each room and therefore the CO2 levels increase, fresh air dampers are triggered, opening up to release more air into the room through the air handling systems. As CO2 levels drop, the dampers close down, conserving energy while each area is not in use.
Powering The Wild Center
As in many rural mountain regions, electric power supply in the Adirondacks fluctuates with local weather conditions.
Similar to its neighbors, the Museum receives most of its electricity from hydroelectric power, generated at Niagara Falls and supplied to the Adirondack region. A 40 kW photovoltaic array on the roof of the building supplies the Museum with 10% of its daily power as well.
During a regional blackout, however, the Museum needs 24/7/365 back-up power to maintain its living animal exhibits. So when electrical power to the building and its array are not available, the Museum’s expandable, standalone emergency back-up power system, which consists of a 1,000-kW generator, keeps all Museum operations online.
Residents of the Adirondacks use electric power to heat their homes as well, as the area is void of natural gas lines. Due to the size and energy demand of the Museum, though, using electric power as heat was not an option. Instead, the Museum employs propane tanks. Five interconnected, manifold 1,000-gal tanks combine to meet the Museum’s winter heating demand. During extreme conditions, the gas can be exhausted in as little as five days. Propane was chosen, for its availability and supplier proximity to the Museum. ES