Interxion Uses Sea Water to Cool Stockholm Data Centers
European data center provider Interxion has dropped the Power usage Effectiveness (PUE) for its Stockholm facility 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.
But Interxion doesn’t use air economization. It uses chilled water, because it does not have to be cooled over time.
By pumping seawater through a data center’s HVAC system, the air circulating within a facility is cooled, which lowers the inside temperature. Although similar to chiller systems, seawater cooling eliminates the need to cool the water, which requires a lot of energy.
What is notable about Interxion’s seawater cooling system is that it runs water through multiple data centers multiple times, instead of running water through just one facility. This 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 many ways to tap external sources of cold water, but some work better than others. There is a lot of pushback in regards to using deep lake and aquifers because of concerns over legionella. You could drill into the ground for water, but that’s not allowed often. Because Interxion is based in Europe, they don’t have to focus on smart grid pipes, because those are automatically connected to the national and international grid.
Seawater cooling could become a trend in the United States. It’s just a matter of finding cool water, like in California. Google uses seawater in their cooling system for its data center in Hamina, Finland. A data center in Helsinki uses both seawater cooling and district heating. Helsinki Energy and IT service provider Academica built a data center for IT outsources Atos that utilizes a design the two companies created in a cavern underneath Helsinki’s historic Uspenski Cathedral.