Greening Data Centers

How Building Teams in the U.S. and Europe Are Taming IT’s Energy Hogs
August 11, 2010

A 40-foot-high biowall helps cool the LEED Platinum Citi Data Centre near Frankfurt, Germany.


Tucked in a back corner of an office park on the outskirts of Iowa City, Iowa, stands a 10,000 sf-bunker-like structure that is mostly unremarkable to the eye. Aesthetics notwithstanding, this building is a first-of-its-kind in the U.S.—a LEED Platinum data center. Designed to withstand a direct hit from a tornado packing 250-mph winds, the relatively small, nondescript concrete structure contains critical infrastructure for the owner, ACT, the organization formerly known as American College Testing.




While many businesses house their data centers within a modified standard-issue office or warehouse building, some such as ACT (and, as we shall see, Citigroup) opt for single-purpose, secure, standalone structures. Regardless of the setting, if the data center goes down, operations at just about any organization grind to a halt, causing lost productivity, angry customers—and for some—massive revenue losses.

All data centers are power-hungry, with rows of computer server stacks emitting huge quantities of heat. The computer equipment requires large, robust environmental control systems to ensure uninterrupted 24/7 functioning. As mission-critical sites, data centers must have backup power and redundant HVAC systems and be able to survive natural calamities that would damage or destroy other buildings.

The innards of the ACT’s LEED Platinum data center in Iowa City


ACT located its new $3.5 million data center at a satellite location, retaining its original data center at its main campus for backup, thereby adding redundancy against power or telecom outages and natural disasters. If, say, a flood or tornado were to put one site out of commission, there is a good chance that the other site could remain operational.




The unique functional requirements of data centers make their design and construction a specialized AEC segment, one with robust growth prospects. AEC firms with the know-how to design and build data centers for maximum energy efficiency will have an even greater advantage over competitors in this sector.

Growing demand to go green

In today’s digital age, demand for bits and bytes seems insatiable. Having faster broadband networks means businesses and consumers can do more online, using larger graphics, audio, and video files for instruction, entertainment, and practical business uses—in other words, more computer gear, and lots of it. The total number of installed servers in the U.S. is expected to grow to around 15.8 million by 2010, which is nearly three times the number of installed servers in 2000, according to market research firm IDC.

Equipment at the Iowa City facility is cooled via a geothermal system. Cooling towers could not be used due to tornado risks. “We could not compromise functionality and resiliency,” said the ACT’s facility director.


As technology trends such as cloud computing (see page 38) and the explosion of multimedia use make servers work harder and run hotter, electricity demand to power and cool them increases. In 2007, the U.S. Environmental Protection Agency reported that energy consumption by data centers had doubled between 2000 and 2006, reaching some 60 billion kwh in 2006, roughly 1.5% of all U.S. energy use. The EPA said this is expected to double again by 2010.




The EPA also estimates that for every dollar spent on IT, companies spend 50 cents on related energy costs. Not surprisingly, companies that manage large data centers are increasingly seeking out the latest in efficiency technology and techniques to cut energy consumption. In the background are worries about possible enactment of cap-and-trade or carbon tax measures aimed at reducing greenhouse gases—measures that they fear could raise costs significantly for large consumers of energy.

Achieving LEED Platinum

Designing an energy-efficient data center, let alone a LEED Platinum one, is no small task. Rachel Atthis, Arup project architect who designed a LEED platinum data center for Citigroup near Frankfurt, Germany, says data centers are “a genre that could otherwise be an enormous oven, notoriously lacking in green credentials.”

The ACT building was designed to meet FEMA 361 standards for wind resistance and can withstand winds up to 250 mph from an Iowa tornado.


Despite Atthis’s characterization of data centers as energy-glomming ovens, innovative Building Teams are finding ways to build data centers with impressive sustainability credentials. While achieving LEED Platinum level may be the ultimate test of such design skills, applying well-proven systems, materials, and construction techniques on any data center project will go far in boosting sustainability at a reasonable cost.




“In the end, I don’t know that we paid a premium for LEED,” says Kevin Monson, president of Neumann Monson Architects, the local firm that designed the ACT data center. System and equipment choices reflected business criteria, and many of those carried strong green credentials. “It was more about creating the best project that we could, rather than building for LEED,” Monson says.

“When we were first talking to the client about the project, we never mentioned LEED,” says Monson. As the design process proceeded, the client talked about ACT’s aim to be a good corporate citizen, and LEED soon became a topic of discussion. “ACT’s board of directors requested that we aim for the highest LEED certification possible, though they didn’t specify Platinum,” says Monson.

The south elevation of the Citi Data Centre features external louvers of white oak to shade the glazed façade. The building also has a green roof and is landscaped with indigenous plants to provide a natural habitat for wildlife.


Structural requirements for the ACT data center focused first and foremost on tornado resistance and reliability, but those needs actually made highly sustainable features cost effective. The Building Team conceived a sturdy building with a structural steel frame supporting precast concrete wall panels and a concrete roof. The stout tornado resistance specs spawned partially from the fact that the Iowa City area had been victimized by a couple of damaging twisters in recent years. “We couldn’t have external cooling towers that could be destroyed by a tornado,” says Ryan Chapman, project manager for KJWW Engineering, Rock Island, Ill., the project’s mechanical/electrical design consultant.




With cooling towers out as an option, the team went geothermal to provide a reliable cooling mechanism that also met FEMA 361 standards for wind resistance. The geothermal system was cheaper than another tornado-resistant option that would have required burying a fluid cooling system underground. External dry coolers provide a redundant cooling system that can draw in cool air from the outside—another green, money-saving feature.

Bunker-like design requirements were essential to ensure reliability for ACT’s critical functions, such as online course offerings and registrations for the ACT exam. “We could not compromise functionality and resiliency,” says Tom Struve, ACT assistant vice president in charge of facilities. The facility was built to the Uptime Institute’s Tier 3 uptime standards for 99.982% availability.

Although the ACT building houses only a small staff, the Building Team made sure their workspace had plenty of sunlight.


Struve says perhaps the chief reason that ACT chose KJWW for the project team was its extensive experience on mission-critical data centers. Neumann-Monson, while lacking prior data center experience, brought an extensive track record on LEED projects to the Building Team, which was rounded out by local GC McComas-Lacina Construction.




With ACT in sight of maxing out its original data center capacity, the project team, working under a design/build delivery plan, was asked to get the job done as fast as possible while adhering to Tier 3 and LEED standards. “We didn’t have a specific date for completion in mind, but we knew we needed a streamlined process,” Struve says. Design/build helped to deliver the project in about 18 months from the initiation of the design to construction completion. McComas-Lacina Construction and its subcontractors moved the design process along by offering materials suggestions for sustainability.

Though the building’s primary purpose is to house and safeguard electronic gear, the needs of its human crew were given due consideration. The ACT Building Team racked up LEED points in the small office area, located on the perimeter of one wall outside the hardened data center core, which accommodates up to seven technical specialists. Large south-facing windows provide abundant daylighting and allow workers who spend a lot of time gazing at computer monitors to relax their eyes by looking into the distance. The area also has enhanced indoor air quality from robust air quality control systems and ventilation rates 30% greater than code requirements. Each workstation is equipped with individual HVAC controls for maximum comfort.

The emergency generator for ACT Data Center sits in a protective building envelope to provide maximum security for backup in a power outage.


“Those are highly paid, critical employees, and their indoor environment is very important,” notes Bill Hoefer, project architect for Neumann Monson. “Keeping them happy and retaining them is key for the client.”




A number of green material choices helped boost the LEED score and were cost-neutral or even provided a savings, Monson says. These included recycled raised flooring in the data center core and wood fiber ceiling panels made from rapid-growth aspen trees. “All are readily available, off-the-shelf materials,” Monson points out.

So, how does the ACT data center actually perform? “We are thrilled with the performance of the entire project,” Struve says. To earn LEED status, the design has to promise more than 30% greater efficiency than a standard design for a comparable facility. Operational since the first quarter of this year, HVAC and electrical efficiency has met or exceeded expectations, Struve says.

Updating LEED for data centers

There are many other ways to boost a data center’s LEED rating. Citigroup’s new 100,000 net sf Citi Data Centre in Am Martinszehnten, Germany, the world’s first LEED Platinum data center, includes a biodiverse green wall on the east face that was designed to subtly camouflage and aesthetically reduce the mass of the main data center. The biowall extends across the façade for 180 feet and stands nearly 40 feet high. The wall and an extensive green roof enhance insulation and make use of recycled rainwater for irrigation.

The facility will save a projected 9.5 million gallons of water a year with a reverse osmosis water treatment feature in the cooling plant. Power systems, central plant, building services, and environmental management systems were designed for optimal energy efficiency. Arup says the facility will use 30% of the power of a conventional data center and only 40% of the heating energy.

In some respects, the LEED rating system does not adequately weigh the environmental impact of data centers, especially their energy consumption and production of greenhouse gas emissions. Compared to office buildings—the “base building” for LEED—data centers are disproportionate users of electricity (and also water, for facilities that use chilled water for cooling), so most other LEED point categories pale in comparison to energy efficiency when gauging environmental impact.

Plans are in the works, however, for a new LEED data center category. “USGBC intends to develop credits for data centers, and we are currently in the process of developing a working group that’s envisioned to develop alternative compliance paths for data centers,” says Ashley Katz, USGBC’s communications manager.

Future-proofing for expansion

Data centers are huge capital investments. Thus, it’s extremely important that they are sized to accommodate future capacity expansion. “If you have to expand the facility structure afterwards, it gets outrageously expensive,” Struve says. In that light, building the ACT data center with plenty of extra space for potential future server capacity was a cost-effective choice, he says.

The same principle applies to backup generating capacity. “We put in a generator that could handle a full build-out in square footage at the outset,” Struve says, even though its full capacity may not be needed for many years. The design also located the geothermal well field in a position that would allow it to be cost-effectively expanded, if needed.

With the technology world changing quickly, divining future IT needs is nearly impossible. As silicon chip technology advances, servers become denser—able to do more in the same package, but drawing more power at a higher temperature. “We designed mechanical and electrical systems on a modular basis so that we can gradually upgrade capacity as our IT needs increase,” Struve says.

No data center project can succeed by planning strictly for the short term—in square footage, systems capacity, or sustainability. This adds complexity to planning and design, but addressing the need for flexibility will pay off for AEC professional services firms and their clients.

Data centers, already key pieces of infrastructure, are destined to become even more critical. Many clients are going to expect new facility designs and construction to display innovations along the lines of their own IT applications. Building Teams that produce scalable, sustainable, and secure facilities and deliver operational cost efficiencies will have a much better chance of attracting new clients in this crucial section of design and construction.