The cost of cooling a large scale data centres can run into the thousands of dollars per year. To combat this, one Swedish data storage company is simply using rocks. Joe Young reports.

To those readers of Electrical Connection who have spent their lives installing data centre infrastructure it will come as no surprise that approximately 3% of all the world’s electricity consumption is used to power and cool these facilities.

The fact is, a large scale data centre can draw the same amount of power as a medium sized city.

As a result, companies are going to extraordinary lengths to experiment with new ways of cooling data centres, to circumvent paying for air conditioning units operating on a 24/7 basis.

Microsoft, for one, recently created a prototype data centre housed inside a giant airtight tank that was lowered to the cold ocean floor, dramatically reducing the need for powered cooling systems.

Most recently, Swedish company Rockan opened a data centre that uses the cold Swedish air and natural rock cooling to lower operating costs. These efforts have almost eliminated the need for an electrically powered cooling system.

Built in a former military facility, the Rockan data centre is arguably the most secure data centre in the world.

Since the company started business in 2012 the demand from its clients for added security has grown exponentially, as has the need for more and more servers.

When an 8,000m² site in the rock caverns of the mountainous Swedish municipality of Atvidaberg became available Rockan saw the potential for huge power savings as well as greater data security.

The centre was constructed by drilling into the granite mountains – material so strong that it could survive a direct nuclear strike and still carry on data processing in a nuclear environment.

Rockan chief executive Frederik Vyncke says the company estimates of the cost for the military to build the facility initially would have been in the vicinity of EUR150 million ($A228.8 million); around 100 times more than Rockan’s purchase price.

After building the facility in the late 1960s, the military first used it as a radar control centre; then in the late ‘80s they started transforming the area into a data centre.

This meant Rockan just needed to upgrade the space to meet current standards. This dramatically cut the installation costs.

Rockan used Schneider Electric’s estimating model, which allows companies to gauge the cost of a project relative to similar jobs. Frederik says the estimating model calculated the installation costs to be approximately one 15th of the normal cost of an equivalent sized data centre.

Not having to install traditional expensive cooling systems greatly reduced the construction costs as well as the on-going running costs.

The bed rock encapsulating the centre is Nordic granite, one of the hardest materials on earth. Since the rock is a huge heat sink and has a high rate of thermal conductivity, it keeps a stable low temperature when heat is conducted into it from the warm operational data centre hardware. Given the facility is in such a cold climate, the rocks can hold a constant 10ºC. It is only if the server space is full that extra ventilation is required to supplement the natural cooling through the great rock heat sink.

Granite rock is an igneous rock, generally light in colour. This reduces the absorption of ambient heat, adding to the power saving thermal benefits of its natural form of cooling through conductivity of the rock. This gives the centre exceptional power usage effectiveness.

“We can hold up to 500 racks without additional cooling, which is a tremendous amount,” Frederik says. The total amount of racks which can be hosted is 1150 racks.

Rockan also plans to cleverly use the existing space to carry out the ventilation process if needed.

The facility was originally built with a 1km blast wave tunnel so the facility could withstand a 2.5MTdirect nuclear strike.

“We are going to use the tunnel to take heat out when temperatures reach a certain level and additional cooling is needed,” Frederik says.

“There is a liquid developed by MIT we can use; it brings hot air into water for highly efficient cooling.” The liquid is sprayed on the hot air and instantly turns it into purified water which is led into circulation again.

The company has further plans for energy efficiency by finding effective ways to use the heat created by the servers. Specifically, Frederik says the company has plans to construct a greenhouse on the site to repurpose excess heat, as opposed to allowing it to dissipate into the air.

The security measures that go into protecting the facility sound like something out of a James Bond movie. There is a 3m high barb wire fence all around the centre’s perimeter; each pole of the fence is equipped with 360º heat sensitive cameras.

While there are three entry points in the mountain, all of the points are blocked off by several class 13, security vault blast doors. The one that does allow access to the mountain has a guard monitoring everyone who comes in; there is a finger print sensor, a biometric scan and an access code. Phones, metal and magnetic objects are also taken off anyone entering the facility until they exit.

Clients need never visit the site because Rockan offers ‘intelligent hands’ support. So Rockan technicians can carry out IT tasks for clients without them ever stepping foot in Sweden.

Frederik says if requested, Rockan can take over a company’s entire IT department.

If clients do chose to visit the site, Rockan offers to take them via helicopter to the site from a nearby Swedish airport.

Although there are roads leading up to the centre it is a two-and-a-half hour drive from Stockholm, so the company built a heli-pad for faster and easier access to major cities, airports and suppliers.

Looking to the future Frederik says the company is looking more and more into automation and data centre information matrix systems to better track information.

On a larger scale, Frederik thinks Scandinavia as a whole will be a bigger player than ever before in data management due to electricity tax cuts, the development of major trans-Atlantic cabling, investment in renewable energy sources such as hydro and of course the cold climate. Sweden’s average temperature is just 5°C.

Since the oil crisis in the 1970s Sweden has invested heavily in the search for alternative energy sources. At that time oil accounted for more that 75% of Swedish energy supplies; today it accounts for around 20%.

Many large tech companies are already investing in data storage in the Nordic region and many are experimenting in alternative energy sources.

Google has a data centre in Finland which uses sea water from the Bay of Finland in a high-tech cooling system and Facebook has a data centre run primarily from renewable energy in Northern Sweden.

Rockan’s success in minimising energy consumption and improving data systems security reflects the engineering ingenuity that is likely to be a growing trend as the industry rapidly evolves to accommodate rising demands for data growth and security while minimising costs and minimising adverse impacts on the environment.