Tag Archives: LEED Platinum

Swimming Sustainably

A building that houses a swimming pool would seem to be a poor candidate for LEED Platinum status. But the East Portland Community Aquatic Center shows that isn’t the case. Swimming pools are “energy hogs,” says Eric Ridenour, architect at SERA Architects in Portland, which oversaw the project. But between the city’s mandate for LEED Gold certification in construction, and the Park Commission’s commitment to a building with green features, the Aquatic Center is a model for energy saving, water conservation, and daylighting.

It wasn’t easy. Swimming pools have special requirements for temperature, humidity and air quality. Ridenour says, “You have to heat the pool, keep the air comfortable, and people are wearing minimal clothes and are wet. Part of comfort is good air quality. You need fresh air from outside, which uses a lot of energy.” Another challenge was in using daylight.

Between SERA, Interface Engineering, WaterTech, and Brightworks, which advised on LEED certification, the challenges were met. Energy savings, according to Ridenour, came mainly from capturing heat from exhausted air. There’s also a heat recovery unit that heat the incoming water before it reaches the boiler.

But the biggest saving came in the form of water. Nicole Isle, project manager for Brightworks, which consulted on LEED certification for the project, says, “The savings in potable water were enormous—1.2 million gallons a year.” An innovative approach to filtering the pool water was in large part responsible. Conventional systems use “backward washing” to clean the filter. The water goes to a sanitary sewer—literally down the drain.

The Aquatic Center’s filtration system uses perlite. Ridenour says, “Because of the shape and physics of perlite, it doesn’t need to be backward washed. We saved capital cost and reduced water use.”

Daylighting was tricky, given the existing lights and the need to reduce glare. The design team relied on a modeling process. They built a physical model and took it to the University of Oregon’s Energy Studies in Buildings Lab, which had two tools to model daylight. One was the “heliodon,” which shines light to mimic sunlight at various times of the day. The other was an “artificial sky,” a big box with mirrored walls and a ceiling full of floodlights. To use it, the teams attached daylight sensors to the model, turned on the lights, and hooked it up to a computer. The sensor gave them the daylight factor for the project.

Testing the Model for Daylighting

The Design Team Tests the Model for Daylighting

The building’s window design and glazing were crucial in bringing in daylight. The building has clerestory windows that have been carefully positioned to admit daylight. Different glazing types also help. Ridenour says, “At the ground level, it’s transparent, and higher up it’s translucent.”

The building also relies on solar technology—a PV array on the roof, and a smaller thermal array that heat the water for showers. The financing was as innovative as the technology. Isle says, “Budget wise, we were fortunate. In Oregon there are incentives for solar and there’s a business energy tax credit available for non-taxable entities like the city.” The solar panels were the result of a third-party arrangement between the city and Commercial Solar Ventures (CSV) of Portland, in which they captured the incentives and the owners of the building got the electricity. The city will eventually own the system. Isle says, “After CSV collects the incentives, they’ll sell it to the Parks. You need creative financial knowhow to make the system work.”

Image courtesy of SERA Architects, Portland, Oregon.

Better Building through Green Chemistry

Visitors to Regents Hall, the new science building on the campus of St. Olaf College in Northfield, Minnesota, are impressed by the by the green roof, reliance on passive solar lighting, and the use of recycled building materials—features that have put the building on track for a LEED Platinum rating. They’re less likely to notice a feature that the chemistry department and facilities management are equally proud of: the labs use about two-thirds the number of fume hoods in an older building of equivalent size and complexity.

In a conventional chemistry lab, fume hoods capture toxic or hazardous fumes and use a fan to pull them through the hood and vent them out of the building. Chemical labs with fume hoods are heavy energy users. To vent the fumes, the fans need to run constantly, and to refresh the air in the lab, the HVAC system needs to bring in 100% of its air from outside, which puts an additional burden to dehumidify and heat or cool the air, depending on the outside temperature.

Regents Hall has only 55 fume hoods, down from 88 in the previous science building. They’re more energy-efficient, too. Pete Sandberg, Director of Facilities Management at St. Olaf, says, “The newest generation of fume hoods are low-flow. There are only a few fans pulling through all these hoods. Fewer fans are called on as needed, and only the amount of air needed at any one time is being pulled through.” According to Sandberg, the result so far has been greatly reduced energy use and lowered operating cost.

But the real innovation in the design of Regents’ Hall goes beyond fume hoods. It’s the result of new thinking in chemical practice and education: green chemistry. Paul Jackson, associate professor of chemistry at St. Olaf and a champion for green chemistry throughout the building’s design process, explains that “The goals of green chemistry are to design chemical products and processes that reduce or eliminate waste or hazardous materials. It’s predicated on the idea that there are two ways to reduce risk—through the hazard itself and through exposure. Green chemistry is about reducing hazardous materials or levels to the level where exposure becomes trivial.”

Using green chemistry techniques meant a big difference in the building’s design. Fewer fume hoods—and lowered energy demand—meant that the HVAC system could be sized and designed for the human load, not the fume hoods. Greatly reducing the amount of hazardous or corrosive substances in the labs meant that resistant materials, which cost more to install and maintain, could be used only where they were needed.

The interior space could be different too. Jackson says, “The counter space at the perimeter, or the counter room space, becomes much more flexible. You can have movable furniture, not fixed benches. There’s a daylighting opportunity around the perimeter—you can have windows, since you don’t have hoods.” Regents Hall labs move easily between functioning as labs and as classrooms.

Regents Hall didn’t have to look like a conventional science building, and that’s been an education for everyone—architects, students, and visitors. Jackson says, “The building re-engages other campus users, non-scientists, because it’s not a stereotypical ‘lab.’ The building interacts with users as much as users interact with the building. It’s a teaching tool for everyone who walks into it.”