Interxion Uses Sea Water to Cool Stockholm Data Centers
European data center provider Interxion is no stranger to innovation. Over the years, the company has been a pioneer in modular design and cold aisle containment, and is now using seawater to cool a Stockholm data center, generating some serious efficiency benefits. Energy costs have been reduced by 80 percent, the company said, slashing enough IT load to allow additional customers to colocate in the facility.
Interxion says the Power usage Effectiveness (PUE) for its Stockholm facility has dropped to 1.09, making it one of the most efficient data centers in Europe. The type of efficiency Interxion is experiencing in Stockholm is most commonly associated with facilities using air economization (free cooling) to leverage the cool environment in cool servers.
“We don’t use outside air. We use chilled water, and we achieve 1.2 from this,” said Lex Coors, VP data center technology for Interxion. “With the sea water we can achieve a PUE of 1.1 because we do not have to cool it over time. With sea water, you can take it in and push it out easily.”
Mother Nature as Your Chiller
Seawater cooling systems pump deep, cold seawater through a data center’s HVAC system. As a result, the air circulating within a facility is cooled, which has the effect of lowering the inside temperature. Although the mechanics of this process are similar to chiller systems, seawater cooling completely eliminates the need to cool water down, which requires high levels of energy.
Interxion’s seawater cooling system is particularly notable because it runs water through multiple data centers multiple times, instead of the conventional strategy to run water through just one facility. This method also reduces operational and environmental costs, as it requires half the amount of water to cool each of the data centers. Interxion also doubles the use of seawater by reusing the warm water to heat local offices and residential buildings before returning it to the sea.
There are a number of techniques to tap external sources of cold water, effectively using Mother Earth as your chiller. But some work better than others, Coors said. He noted the challenges of using deep lake cooling systems versus seawater and aquifers.
“With deep lake and aquifers there is basically a push back on using water,” said Coors. “People are so afraid of legionella that they don’t use water power. We have to look for alternatives. There’s drilling into the ground, but that’s not allowed often. We can use sea water and salt aquifers.”
Coors mentions there are advantages to working in Europe. “In Europe, we do not have to focus on the smart grid pipes, because basically if you are connected to a power grid in Europe, you’re connected to the national and international grid,” he said. “It’s a matter of paying a little bit more and telling them ‘I want this kind of green power.”
So will seawater cooling, and its benefits, become a trend in the US? “Depending on the area, it should be a design trend,” said Coors. “It really helps with the environment. If you have to run a pipe a mile, it’s still very beneficial. The Gulf is a bit hot, but in California there are enough opportunities.”
A Track Record of Innovation
Interxion has a history of innovating; in addition to seawater cooling, the company has been pioneers in phased design and cold aisle containment. The company has been practicing phased construction in its data centers since 1999, a time when most data centers were being built as “barns” with large open floor plans being built in their entirety.
“We had to build data centers in 11 countries and only had a limited amount of capital available,” said Coors. “I came from a ship company and took that idea of shipping containers back to the data centers. I didn’t want to build a bunch of data centers I’d have to upgrade in three to four ears. I did not install the whole infrastructure, nor did I build out the whole data center. Instead, we chopped the building into 4 phases of 10,000 square feet and installed infrastructure to support a limited capacity and over time, adding additional infrastructure to not interrupt operation.”