ASHBURN, Va. – Data center developer DuPont Fabros Technology has overhauled its facility design, seeking to bring the benefits of hyperscale server farms to companies leasing third-party data center space. The prototype for the new design is the massive ACC7 data center at the company’s campus in Ashburn, Virginia.
DuPont Fabros (DFT) has refined its approach to how it cools and powers its data centers, and has shifted from a raised-floor to a combination of a hard floor and a hot-aisle containment system to house customer cabinets. The end result is a data center that maintains DFT’s emphasis on reliability while delivering big improvements in energy efficiency and ease of maintenance. ACC7 will also allow customers to expand their capacity by housing server-filled containers on cement pads next to the data center.
“We recognize that in this industry, things change and evolve,” said Scott Davis, Senior Vice President of Operations for DuPont Fabros Technology (DFT). “We sat down with the design group and looked at the trends (n data center design). We took all those trends and came up with goals. The end result is (a data center that’s ) cheaper to build, requires lower maintenance, and has an industry leading PUE. We never save at the cost of reliability or resiliency.”
The company expects annualized Power Usage Efficiency (PUE) UE to be below 1.14 at 75 percent capacity, and below 1.13 at 100 percent utilization. That’s an improvement on DFT’s current design, which delivers a PUE of 1.28 at other facilities on the Ashburn campus.
With the new design, DuPont Fabros has gone bigger, taking advantages of economies of scale as well as a complete tech overhaul to bring efficiencies to new heights, without sacrifice of redundancy or resiliency. In approaching the design, Davis and the DFT team weighed three goals:
- Is it cheaper to build on a per megawatt basis?
- Does it have lower maintenance costs?
- Does it have industry leading PUE?
Building Bigger, But in Smaller Phases
The ACC7 data center is 446,000 square feet in size and has a total power capacity of a whopping 41.6 megawatts. The building includes 28 large computer rooms, with a standard critical load of 1.486 megawatts each, and the ability to increase density to offer up to 2.1 megawatts each. Each data hall can accomodate approximately 378 standard cabinets.
Dupont Fabros is building out the entire shell, finishing eight computer rooms in the first phase of construction, while the other rooms will be empty shell space. In the past, DuPont Fabros has built out as much as 18 megawatts of finished space at a time. With the new design, they’ll start out with 11.9 megawatts of customer capacity, and build out the building in smaller phases as it leases up.
In a base computing room there are a pair of a+b Power Distribution Unit (PDU) transformers capable of carrying a 1.5 megawatt load. The computer room air handling (CRAH) units are on the perimeter of both walls.
Dupont Fabros is not going to have a raised floor in this design, with all cabling running overhead. Each room has a ceiling height of 13 feet, leaving plenty of room for overhead cabling.
This approach allows Dupont to sell space in smaller chunks. There’s an option to deploy a still mesh fence in the computer rooms to break them up, or to isolate the air handlers from the server area for security reasons.. The PDUs and distribution panels are out of the room to increase the footprint for IT equipment.
Making Greater Use of Free Cooling
The new facility capitalizes on the greater opportunity for free cooling. The company calls its new approach “water side economization plant with chiller assist.” This means that outside air will cool water for the cooling system, using a plate and frame heat exchanger, which is expected to be the primary cooling source for 75 percent of the calendar year. Chillers will kick in on days with warmer temperatures. In the company’s previous design, the chiller plant did all the work. Less use of chillers and pumps leads to lower energy bills.