Global Ecology - How to Get the Best of All Worlds in Sustainable Design

In January of 2007, we were honored to have our Department of Global Ecology project grace the cover of one of the first issues of GreenSource, a leading publication on green building in the U.S. Located on the Stanford University campus, Global Ecology – a department of The Carnegie Institution for Science – researches interactions among ecosystems, land, atmosphere and ocean which shape the earth system.

The editors at GreenSource, like us at EHDD, would like to get beyond all the hype and self-promotion surrounding green buildings, and look at real results. So they have begun a series called “Case Study Revisit” taking another look at how our project, and others, are actually performing. This feedback loop to architects and designers of real-world performance is essential, yet all too uncommon. Kudos to GreenSource for this initiative.

So, how is Global Ecology performing? First let’s take a look at the energy use, since reducing carbon emissions was a top priority for the scientists who are researching climate change. Working with our mechanical engineers, the Integral Group, we monitored energy use over the course of a year. The measured results show a total building energy use of 141 kBTU/sf/yr. This is plotted on the chart below relative to the 26 labs in our climate zone in the Labs21 database (as of 2009). Forty-four percent (44%) of this energy was for heating (mostly heating make-up air for lab ventilation). The remaining energy use is electricity – 44% of which runs the lab’s super-computer cluster where scientists run their climate models. If that were excluded, the building would use 106 kBTU/sf/yr.




Graphic illustrates measured energy use through 2009. (Click to enlarge)

 

The low energy use is due in part to the Night Sky cooling system, which at night sprays a thin film of water on the roof, which then radiates to the cold deep space sky.  This chilled water is stored in a tank and used the following day to cool the building, using 90% less energy than conventional compressor based cooling.  The client reports that the energy radiated to the night sky is remarkably close to what their climate modeling calculations predict.  It has been running since 2004 and has proven to be reliable and robust after the initial tuning and commissioning was completed.

The Cool Tower has generated a lot of interest, but is often misunderstood.  It serves the indoor/outdoor lobby, not the entire building.  It was intended to provide passive cooling to the lobby area when the bi-fold doors are open.  The client has tested out various configurations, and found it provides the most comfort when one door is open and two remain closed, channeling the cooling through the seating area rather than dispersing it.  The cool tower was originally generated in a workshop with our mechanical engineers; we were looking for a vertical element on the front façade to help people find the new department which was hidden behind other labs, with only a narrow slot to see through.  It has served  that purpose well, and become part of the identity of the Department.  There were initially some challenges with the mist not being fine enough and evaporating before it reached the bottom of the shaft.  The scientists worked to optimize the droplet size to maximize cooling and avoid water droplets spilling out on the floor at the base.

Not everything went exactly as planned. It took a while to get the daylight dimming controls to work properly, which we finally figured out was incorrect wiring, and easily fixed. The high velocity hand driers were louder than we expected, so the bathroom windows are usually kept closed to avoid sound transmission into other spaces through open windows. The waterless urinals have been a maintenance challenge, in this case for a highly motivated client with good maintenance practices.

But if you ask the people working in the building how they like it, they give it high marks. An online survey of the building’s occupants by the Center for the Built Environment (CBE) at University of California, Berkeley, scored in the 99th percentile of all the buildings in their survey, and the project was awarded the CBE’s first Livable Building Award in 2007. The full survey results are here, and summarized in the chart below. The air quality and thermal comfort ratings are exceptional, which we believe are due to the combination of radiant heating and cooling, along with operable windows in the offices and ample low velocity ventilation in the labs. The rating for acoustics was the lowest scoring category, reflecting a common challenge in open office environments, in spite of both carpet on the floors and a full acoustical perforated metal deck at the ceiling. (More information on the project can be found at AIA COTE Top Ten Case Study.)

We are often asked if people are willing to sacrifice to live and work in our sustainable or netzero energy buildings. Surprising to some people, but not to us, we are finding that our most energy efficient buildings are often the ones with the highest occupant satisfaction scores—a compelling case that integrated sustainable design can deliver the best of all worlds.

- Scott Shell, FAIA LEED® AP

  Principal and Director of Sustainability

Photo credit: Peter Aaron/ESTO