Tahoe Center Sets an Example

The Tahoe Center for Environmental Sciences is a role model for other buildings. It’s good-looking, and smart, too; it’s frugal, but not cheap, generous but not showy. It was carefully designed to complement the other buildings on Sierra Nevada College’s Incline Village campus and the sensitive environment surrounding it.

Maybe it’s no surprise, given the innovative sponsors of the Tahoe Center. Sierra Nevada College and the University of California at Davis are the two primary owners of the 45,000-square-foot research facility, which also provides facilities for scientists and students from the University of Nevada at Reno, Carnegie Mellon University, the RAND Corporation, and other institutions. The unique public-private partnership behind the building’s design and funding is expected to be a model for future projects, as is the multilateral approach to solving thorny environmental challenges.

The shared focus is on understanding and protecting lake ecosystems, though the audiences and methods vary: 3D exhibits let schoolkids “fly” over the Tahoe basin and “swim” through the lake’s underwater canyons. Exhibits on sustainable design and construction help families and businesses reduce their environmental impact at home and work. State-of-the-art research labs and classrooms let biologists, physicists, planners, and policy makers collaborate and teach tomorrow’s leaders.

Designing for Green—and LEED Silver

The structure that houses these diverse communities is remarkable inside and out. Its beauty, comfort, usability, and environmental performance are all a testament to the design team’s talent and the power of an integrated design process—cooperation in action. “It was a confluence of the right design team,” says Peter Rumsey, president of Rumsey Engineers, who handled HVAC and plumbing. “The architects, Lundahl & Associates, were new to sustainability, but very motivated, and wanted this building to stand out. The rest of the team—Integrated Design Associates for electrical engineering and David Nelson & Associates for lighting—were all very focused on integrated design, and we had a client that was very motivated,” Rumsey continues. “It all came together. If even one team member is not on board, you’re lucky to get a LEED silver rating. If the client is not on board, you won’t go anywhere with LEED or sustainable design.”

And the two clients were very much on board, setting the goal for a LEED silver rating, considered challenging in most circles. But as the team progressed, the clients pushed to add new energy-related features and pursue a platinum rating. The only obstacle became battling to bring the project back under budget.

Which brings us back to the integrated design. A good low-energy design requires a lot of integration, Rumsey says, and David Kaneda of Integrated Design Associates agrees. “The traditional way is for an architect to design without sitting down with the engineers and the rest of the team and asking ‘if I do this, how does it affect you?’” Kaneda says. “In this case, the architects really listened to what the engineers wanted, and asked ‘what do we need to do to make this work?’"

Using Sunlight and Snow

The team’s first smart move was to take advantage of things that are free, such as sunlight and snow. Extensive daylighting lets the sun reach deeply into the building and reduces the need for daytime lighting. “Daylighting is an intricate dance between a building’s architecture and thermal mass, the HVAC and lighting systems, and direct sunlight gain—they all affect each other,” Kaneda explains. “Harvesting daylight is a huge piece of the energy picture. Lighting accounts for about 25 percent of the energy use in a building,” he says, with HVAC systems and electrical outlet use (plug loads) each responsible for another 25 percent. Using fewer lights and highly efficient bulbs such as compact fluorescents saves energy and generates less heat. Less heat means a smaller cooling system is needed, saving money on initial costs as well as ongoing utility bills.

Local snowmelt is used to flush toilets, after being run through both particle and ultraviolet filters. The extra cost was modest (between $20,000 and $40,000 to install separate water lines to the fixtures), but the payoffs are big–reducing overall water use in an ecologically sensitive area and saving the owners a bundle on the water rights they needed to purchase before construction began.

Finding a Better Way to Cool the Labs

The team embraced another innovative principle: Use the best method available, even if you haven’t done it before. The Tahoe Center includes several laboratories, which are generally notorious energy hogs. One reason? Typically, all ventilated air is chilled to 55 degrees, and then reheated to whatever temperature is needed, usually between 65 and 68 degrees. You can imagine the enormous energy wasted on a hot day to cool and then reheat the air.

In energy-frugal Europe, a different approach is used, decoupling the ventilation and HVAC systems. Ventilated air enters the lab at a more neutral 70 degrees, and a long diffuser with integrated heating/cooling coil in the ceiling adjusts the temperature as needed. Rumsey researched this “active chilled beam” technique and applied it to the Tahoe Center as part of the overall low-energy design. By using much less outside air for ventilation, a smaller air handler and smaller ducts could be used, and the standard-issue chiller was eliminated. As with the other elements of an integrated design, an investment in one area can end up saving money elsewhere, both on initial costs as well as in the more obvious ongoing savings.

Collaborating with AutoCAD

The design team used AutoCAD® software as a common platform for collaboration, as well as custom and commercially available software to perform engineering calculations and link to sophisticated energy-modeling programs. Rumsey sees the value in good collaboration tools and the importance of having design tools that make it easier to design sustainably. And good tools—especially 3D tools—make it easier for contractors to build features they’ve never seen before, such as the chilled beam ceiling.

The exemplary traits seen in the Tahoe Center building and its team—creativity, collaboration, and making the most of what you’ve got at hand—have had a big impact on the research community in a small ecological footprint. The center uses 60 percent less energy and 30 percent less water than a comparable building, setting a good example for us all.