Case Study: Planetary Perspectives
Global Ecology Center
Stanford, California
Design for labs and offices for a team of climate researchers mimics natural systems to drive down energy use and carbon emissions
02/2007
This article appeared in the January 2007 print issue of GreenSource Magazine.
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KEY PARAMETERS
GLOBAL ECOLOGY RESEARCH CENTER TEAM SOURCES |
This was the first program I’ve seen in which you can tell that someone approached the building with sustainability in mind,” says Scott Shell, of EHDD Architecture, in reference to the client’s concept document for the Department of Global Ecology, a new arm of the Washington, D.C. –based Carnegie Institution. Located alongside the venerable Department of Plant Biology on a 7.4-acre site leased from Stanford University, Global Ecology has 50 researchers and staff who study planetary systems, especially the changes, including those affecting climate and biodiversity. “We’re concerned about humanity’s effect on the planet,” says director Chris Field, “particularly regarding energy use.” That concern came through loud and clear in their priorities for the facility.
Rather than clearing a mature oak forest from the site to create a one-story structure, the designers chose to tuck the building into a previously paved utility area at the back of the property, creating a new core for the campus. A two-story building better accommodated the area’s smaller size, and the narrow, 40-foot-wide plan facilitated daylighting.
The program called for roughly equivalent amounts of lab and office space. Instead of adopting a typical approach, giving each research team offices adjacent to its labs, designers put all the labs on the first floor and the offices above, a decision that enhanced both interaction and flexibility. This separation also saves energy because it lets large amounts of outside air into the lab zone without overventilating the offices.
The department has many climate researchers on staff, so the designers felt it natural to develop energy systems related to their client’s work. An evaporative downdraft chilling tower cools the lobby, working in a similar way to the katabatic winds that form as the temperature drops and moves air down the faces of glaciers. And in lieu of a large chiller, water is cooled by spraying it onto the roof at night, where it releases its heat through night-sky radiation; the cooled water is then stored in an insulated tank until it is needed. This system, originally developed by Richard Bourne of Davis Energy Group, has been so successful that the building uses a small backup chiller for additional cooling only rarely, and then only under peak conditions.
Radiant heating and cooling is delivered throughout the building via water pipes in the slab floors; air distribution is used exclusively for ventilation. Labs are typically ventilated by a mechanical system that can supply 100 percent outdoor air. When the air supply is also the delivery mechanism for heating and cooling, poor outside air temperatures can mean huge expenditures of energy to cool or heat air to comfortable levels. The department’s water-based system saves energy by separating heating and cooling from ventilation requirements.
Placing several heavy-duty freezers for the labs in a semi-conditioned warehouse next door instead of in the labs themselves is another example of how the building program was developed with sustainability in mind. These deep-freezers produce a large amount of heat as they maintain temperatures as low as –80° Celsius, so keeping them out of the occupied building reduced the cooling load significantly.
Although the designers were sold on open offices as a way to optimize daylighting and natural ventilation, they questioned how to manage acoustics, a particular concern because much of the staff moved from private offices. Ultimately, Shell credits the occupants with making the building work. “They meet and frequently discuss its performance,” Shell reports. On an occupant survey concluded by the Center for the Built Environment (CBE) of the University of California, Berkley, the facility received the second highest rating of the 158 buildings in the CBE database. And it was “the [only] green building that scored positively for acoustics,” says Shell.
The natural ventilation also took some teamwork to figure out. “When they first moved in, they were trying to figure out when to open the windows,” Shell says. Eventually they learned to keep the windows closed on really hot days, because the radiant cooling in the slab couldn’t keep the space comfortable with the windows open.
Atmospheric impact was a serious consideration in material selection. The designers, looking to reduce the carbon emissions associated with certain materials, specified high levels of fly ash in the concrete, which reduced the amount of cement used by more than half. Slabs for three adjacent greenhouses poured before the main building was constructed were used to test whether moist-curing was needed for the mix; results showed that applying a standard curing compound would be sufficient. In the main building, the high-volume fly-ash concrete posed a problem only when thin topping slabs were poured in cold weather. (These mixes don’t produce as much heat as standard concrete, so it takes longer than usual before they are ready for finishing.)
Much of the building’s equipment and materials, including siding, casework, workstation tabletops, sinks, and faucets, were salvaged, including both used and new items from off-spec orders found on the California Materials Exchange. “I was a skeptic before this project,” admits Shell, about using salvaged materials, but “it was a lot easier than I expected. I’m now convinced that it is possible to do this even on larger projects.”
In addition to its aggressive sustainability goals, Carnegie was interested in publicity for the project in hopes that it would inspire others to pursue similarly low-impact design. Nevertheless, it chose not to pursue LEED certification, for two reasons. The first was cost, which Field estimated to be in the tens of thousands of dollars. “We wanted to invest those funds in additional green features rather than in certification,” he says. The second was that Carnegie had a specific set of environmental priorities for the project that didn’t align precisely with those in LEED.
Unlike some owners, for whom a decision not to pursue LEED might have resulted in an unraveling of green strategies as the project unfolded, this project’s environmental performance remained a top priority. Without the LEED framework, however, there was no commissioning requirement, and the designers were unable to convince Carnegie to engage in a formal commissioning process. “I refused to accept the idea that the sign-off meant that they hadn’t checked out this stuff,” says Field. With or without commissioning, neither Carnegie nor the designers were satisfied until everything was working properly, which, for certain problematic systems, took a long time. “We did our commissioning on an item-by-item basis, rather than comprehensively,” notes Field.
Although Field feels formal commissioning is unnecessary, the design team has no doubts. “I’m not going to do another green building unless it’s commissioned, since the onus falls on the designers to prove the design wasn’t at fault,” says mechanical engineer Peter Rumsey. “When you do a green building and something goes wrong, people blame it on what’s different and new. Our company paid for the commissioning ourselves, three times over,” he concluded.
“I’m thrilled with how the technology works, now that we’ve worked out the kinks,” says Field. Rumsey is also proud of the results, although he has learned that using a rooftop spray system for night-sky radiant cooling is easier on a flat roof, where the spray nozzles are readily accessible, than on a sloped roof. The main lesson, according to Rumsey: “It’s possible to design a building that uses significantly less energy but is also very comfortable. People love being in there.”
- by Nadav Malin
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