UA's Multilayered Sustainable Building Plan

The term “sustainable building” conjures up images of sleek shiny buildings made of masonry and steel with modern design and the latest in space-age technology. At the University of Arizona, however, sustainable building has many other dimensions, and it’s not all about the new.

Planners, designers, and managers of buildings on the university’s 380-acre main campus have been promoting sustainable building for the last two decades. While some projects have involved new technologies and modern designs, the university has also used the old, and learned from it.

“The most sustainable thing is to use what we have, and renovate buildings rather than demolishing them,” says Adriana Zuniga, senior lecturer in Sustainable Built Environments at the university’s College of Architecture.

Learning from the past

It turns out that the University’s iconic Old Main, built in 1891, is a great example of sustainable architecture in the desert climate.

“We traditionally used to know how to build sustainable buildings,” says Ladd Keith, Chair of Sustainable Built Environments at the University of Arizona.  “Old Main has the porch overhangs and high ceilings…that protect the windows from the sun and keep the inside cool. When air conditioning was invented buildings became closed off and we forgot those techniques. And now you see a re-emergence of those techniques combined with the technology that we have today.”

The porch runs around the entire perimeter of the building, creating a welcoming shady space from the searing sun. Old Main’s tiled, peaked roof has integral ventilation, which allows hot air to escape from the building. The building is sunk slightly below grade, taking advantage of the earth’s cooler temperatures to keep the ground floor cool. Thick masonry walls protect the inside of the building from the temperature extremes in the desert. During the day, they warm up slowly in the sun, and at night they radiate heat to warm the inside on cold desert nights.

Undulating metal decorates interior canyon of the ENR2 building on the University of Arizona campus. Dominika Heusinkveld photo

Mike Herman, senior architect and project manager at the university’s Planning, Design, and Construction (PDC) department, says Old Main’s design made it possible to make relatively small changes during its recent remodel and preserve the building’s historic integrity.

“We didn’t do anything to the walls and windows,” Herman says. “We found we didn’t need to.”

Today, Old Main is a LEED Silver-certified building. LEED is a certification process and building rating system led by the U.S. Green Building Council. As explained on their website, “LEED, or Leadership in Energy and Environmental Design…is a globally recognized symbol of sustainability achievement.” The certification levels are Silver, Gold, and Platinum. Last year the building received an additional award from the Green Building Council.

High tech in a new building

Sometimes it takes more effort and money to renovate that than build new. The PDC performs feasibility studies to figure out the economics and other needs—such as bringing buildings up to current building codes and educational standards.

“Whenever it’s possible to repurpose a building…that’s always the first avenue,” says Herman.  When a new building is needed, however, the newest technology is employed to ensure sustainability.

One of these new buildings at the university is the Environment and Natural Resources 2, or ENR2 building, which houses the Institute of the Environment, the School of Geography, the School of Natural Resources and the Environment, and Mathematics. The building is LEED Platinum certified.

It was designed with a huge internal courtyard which acts as an artificial canyon to provide sheltered and shaded outdoor space, an important component of green building design.

“Usable space on campus shouldn’t just be quantified as the space inside of buildings,” says Keith.  “The more we can build buildings that have open usable spaces outside that don’t require air conditioning—that is the most efficient building space you can have.”

The canyon inside ENR2 is more than just usable space. Upon entering, your eyes are drawn upward to the sky, past undulating rust-metal facades and a curving staircase. Vines hang from the canyon walls; plants grow on the floor. Even a huge group of students leaving class doesn’t disturb the quiet serenity of the cool, moist air. The building invites you to sit at one of the tables and contemplate it.

On the upper floors, the hallways of the building are located outside, in the central courtyard space, reducing the square footage that needs to be cooled or heated.

The building also supports alternative transportation, with bike racks and showers for people who arrive by bike—worth some points on the LEED certification according to Zuniga. It also provides a place to eat, so that people don’t have to drive to lunch.

The building collects rainwater and air-conditioning condensate water from its roof, storing it in a cistern and using it to irrigate the landscaping. Native and drought-tolerant plants are planted in the internal courtyard. As in Old Main, energy-efficient electrical fixtures with occupancy sensors are used to conserve energy and low-flow plumbing fixtures are used.

The high tech doesn’t stop at the design aspects. Most buildings on campus are monitored with multiple utility meters, checking to see how the various systems are working, and whether they are performing as expected. ENR2 alone has seven meters, monitoring its water use, electrical use, heating, cooling, and sewer output.

Vines hang down on the north side of the ENR2 building. Dominika Heusinkveld photo

It’s not just the buildings

There are other important components to sustainability. Mark Novak, landscape architect with PDC, says landscape design “plays a big role in creating a sustainable campus.”

The landscape and the buildings need to work together, says Novak. Water conservation and comfortable outdoor spaces are priorities, but the campus landscape also acts as a research laboratory and educational space for researchers and students. The goal is to change out water-thirsty landscapes to more drought-tolerant plants, and to work on different ways of harvesting and reusing water. Drip irrigation is now almost exclusively used on campus, with the exception of lawn irrigation and annual flower beds.

To achieve these goals, Novak focuses on plant choices, water use, and stormwater management. The urban environment is a challenge, he says. Shaded areas between buildings and narrow spaces mean there are limitations on plant selection. In ENR2’s internal canyon, plants are still being monitored, and changed out if they aren’t doing well. Many native plants do well in full sun, not shade, and non-native drought-tolerant plants need to be brought in to fill in the spaces where natives aren’t thriving.

Novak says the university’s high building density also provides challenges. “Our open space really needs to be multifunctional.  We look at it to be attractive. We look at it to help cool down the environment and adjacent buildings. We look at it to provide gathering spaces for the campus community, and now we’re looking at it to help address our stormwater.”

Keith points out that the university campus is one of the cooler places in the city due to the incorporation of green landscaping on campus (see map link below). Compared with roads, parking lots and malls, vegetation creates cool spots in the urban heat island. White roofs also help reflect the sun’s energy.

A major difficulty of urban environments is managing stormwater runoff. Paving and other impermeable materials mean that water can’t percolate into the ground, and runs off into streets, eventually to rivers, streams, or to Tucson’s water treatment plants. The water picks up pollutants as it runs on roads and highways. It also creates hazards for cars and pedestrians and causes flooding. Tucson’s monsoon rains can bring as much as a couple of inches in an hour during intense rainstorms; this water needs to be managed.

“The old civil engineering approach was to get water off your site as quick as possible,” says Novak. “That adds up downstream. [Now we] try to slow down that water, absorb it, try to make beneficial use of it.”

A stormwater catchment area near the Tree Ring Laboratory building on the University of Arizona campus. Dominika Heusinkveld photo

Christopher Kopach, assistant vice president of Facilities Management, co-chairs  the university’s stormwater committee. He says the university has been building retention basins which hold water until it can percolate down and eventually recharge the aquifer. One such basin is on the east side of the Tree Ring Laboratory building; another is next to the Optical Sciences building.

Facilities Management has worked with students to create another catchment area near the Mechanical Engineering building. Prior to the project, Kopach says, all of the stormwater was coming off the building into the streets. After students and Facilities Management collaborated to install catchment areas and harvesting basins, ““We’ve been able to capture 99% of the water coming off that building.”

Waste management is another major issue on a campus trying to be sustainable. According to Kopach, the university has its own recycling yard. The campus recycles metal, building waste, and organic debris from landscaping. In addition, there is a yearly campaign to recycle cardboard boxes after move-in day.

“You can imagine with 40,000 students-plus the amount of cardboard with move-in,” Kopach says. “We try to capture all of it.” He says nearly 40% of waste material on campus is diverted from the landfill.

Overseeing sustainability

Facilities Management is tasked with the long-term job of maintaining all of these improvements, and ensuring they are performing as expected.

One of the people in charge of this daunting task is Energy Manager Michael Hoffman. “All the buildings that have any substantive utility impact are fully metered,” says Hoffman, referring to sensors installed in the buildings.

“We’re reading electricity, chilled water, steam, potable water, and tracking them on a digital system that is able to read them--in some cases on a per minute basis,” he says. The sensors are also used for maintenance and as a troubleshooting and as a diagnostic tool.

“The analytic value is tremendous,” says Hoffman. The sensors are also useful for determining where improvements are most needed. Each building’s energy usage is available on a website for the university community to see (see link below).

The university has a unique advantage regarding their energy consumption. It has its own powerplants—a total of three—and also can generate about a third of its own electricity. Many of the buildings are connected to the power plants via underground tunnels, which pipe chilled water for cooling or steam for heating. The chillers and boilers allow for a huge economy of scale.

“We’re enjoying the benefits of some very forward-thinking planners early on in the university’s history,” says Hoffman.

The set-up also allows the university to use a sort of cold battery. “To offset our demand at the utilities’ peaks, we have one of the largest thermal energy storage systems in the country,“ says Hoffman. In summer, ice is frozen in tanks at night by specialized chilling machines, and the cold they store is used during the day.

“At the peak of the day when [Tucson Electric Power] is most sorely taxed, and also when our consumption is at its highest premium, we can turn off some of our chillers and use our ice tanks to provide cooling,” says Hoffman.

One of his goals is to get students more involved in energy management of the buildings they use. As part of this goal, two residence halls, Likins Hall and Arbol de la Vida, each have energy use dashboards in the buildings to allow students to track their energy usage.

“It’s very hard to manage something that everyone else is responsible for using,” says Hoffman, referring to energy use. “End-user behavior is really the primary driver of how efficient or inefficient a building can be.” Giving students feedback on their energy usage “gives them a chance to peek behind the curtain…The transparency and the visibility enables us to be better stewards for the community.”

What is sustainable building?

To drill down to the elements of sustainable building is complicated. To some extent, it depends whom you ask.

“The aesthetics are always important, because part of sustainability is having buildings that increase the happiness and wellbeing of the inhabitants and occupants,” Keith says. “If you have a building that’s unattractive and no one wants to be in, it’s not going to help if it’s the most efficient building on campus.”

As an architect, Zuniga says, “What we use as a definition is that it has to have the three E’s. It has to be environmentally friendly, it has to be economical…and the last one is equity: to be inclusive to all segments of a population.” Zuniga says it’s also important to keep in mind that a building can change uses, and thus needs to be adaptable and easily converted to other uses.

Hoffman agrees that adaptability and flexibility are key to sustainable building design. Allowing for future infrastructure systems—for example, leaving room in the ceilings and floor--minimizes disruption in remodeling. The ENR2 building, for instance, has raised floors which provide space for cables, electrical connections and other utilities.

Joseph Iuliano, a graduate student who teaches sustainable environments in the School of Architecture, says “It’s more than just the building, it’s how it integrates into the community,” and how it interacts with people and the natural environment around it. “Does it attract people…is there patio space and seating and areas for meetings? Internally is it designed in a way that is easy for people to move through the space…can you be productive in it?”

Hoffman has a somewhat different viewpoint. “As an energy manager, I look at sustainability as the ability to operate at as maximum efficiency as possible for as long over the lifetime of the building as possible…It’s not enough to build a green building if you don’t leave it in a condition where the operators can maintain it.”

The future of sustainable buildings

Universities are a great place for innovation in sustainable building, according to Keith. “Government institutions and universities have a leg up on building for the future compared to the private market. The reason is that it may cost a little bit more money to make a building more sustainable and save money in the long run. So when…you’re going to own the building and it’s going to exist for the next 50-100 years, you have a really big incentive and you have the longer view.”

Iuliano, like others, says there is a lot we can learn from older buildings.

“I don’t think sustainable design has to be complicated. I think it really can be rather simple, in looking at what has worked before and how can we improve it.”

If designers combine older techniques with current technology, such as solar technology, better insulation, and electrochromatic glass (which darkens in the sun), Iuliano says buildings can be even more sustainable.

“If you look at what has been done in the area in the past and update it, it works.”