Seawater cooling dramatically reduces data center energy costs
Interxion, a European data center operator, has reduced power bills for its Stockholm data centers by $1 million through a number of measures, but mainly through the use of remote seawater cooling. The Stockholm data center opened in January 2009 and at the time was one of the first data centers to use seawater cooling systems.
The Stockholm data center, Interxion claims, now operates at an exceptionally low and constant PUE, is not subject to PUE fluctuations caused by a surge in power to power the chillers during a hot summer, and uses 100% renewable energy. They also use continuous monitoring of their environments that helps improve efficiency, as well as employing a phased, modular architecture to optimize the effectiveness of energy use.
The company highlights its use of sustainable energy, such as free cooling, groundwater cooling, and waste heat reuse at its facilities, but says it never comes at the expense of reliability and availability. Many of its centers, such as Copenhagen, London and Amsterdam, use 100% renewable energy.
But it is the use of seawater for cooling that, according to Inerxion, has the greatest impact in reducing energy costs, giving them an 80 percent reduction.
In Stockholm, the water enters the first facility at six degrees Celsius and leaves at 12 degrees, according to an IDG report. The water is then pumped to a second site, which comes out at 18 degrees, and then to a third, which comes out at 24 degrees. And finally, the water is sent to a heat pump and used to heat the local homes and offices.
“Before Interxion started the project,” the IDG report continues, “its power bills were approximately $2.6 million a year to cool 1 megawatt of IT load. Today, its power bill is $1 million to cool 1 megawatt of IT load, which means the system has saved it about $1.6 million a year per megawatt.”
Seawater is an attractive option for cooling data centers. Among others, the Mauritius Eco-Park project has promoted this option with the aim of exploiting the position of the island in the path of a deep sea current. And Google has also used seawater to cool its data center in Finland.
However, there are other costs to consider when locating a data center near seawater. The costs can be high in obtaining land, and the required infrastructure can also be more expensive. More contingency plans are needed if the pumps that pump seawater fail.
Australia, as an island continent with a high percentage of its population on the coast, seems like a perfect candidate to employ this technology to boost efficiency.