Almost everywhere in Finland the conditions are good for maintaining large machine rooms. Ten percent of Finland’s land area is water. The annual average temperature varies in Southern and Central Finland between five and eight degrees, which guarantees that the waterways remain cool almost throughout the year.

“Depending on the method of implementation, when the temperature of water or air outside falls to around 15 ºC, machine room cooling can be established by utilizing the cooling energy provided by nature, free of charge. In Finland, most of the hours in the year are below this temperature limit, which gives Finland a significant competitive advantage concerning machine rooms supporting sustainable development”, says Tero Tuononen, the manager responsible for machine room planning at CSC’s Information Management Services.

According to Tero Tuononen, climate will be an important criterion for choosing the location for future machine rooms. A major computer system consumes as much as hundreds of kilowatts of electricity over an area of just a few square meters, and almost 100 percent of this is turned to heat. With the heating power of dozens of sauna stoves it is typically on 24 hours a day, every day of the year.

“To secure the operation of computers, cooling is arranged by introducing cold air or liquid next to the computer equipment and by transferring the heated medium out of the machine room. If cold liquid is not available from natural sources, it has to be made by machines. Automatic cooling requires a considerable amount of additional energy. Traditional machine rooms in warm countries may have to consume additional 100–150 percent of energy to realize the cooling, in addition to the energy required by the computer”, says Tuononen.

The climate in Finland is sufficiently cool and energy is inexpensive. Placing service centers in the existing facilities is not only energy-efficient but it also diminishes the carbon cost. The cooling need is much greater in Central Europe, which makes machine room solutions expensive.

CSC uses green electricity

The energy consumption of CSC’s two server centers during the past year was 8.1 gigawatt hours. This corresponds to the annual consumption of more than 400 electrically heated private houses. Starting in 2009, both centers have used environmentally friendly energy. The Finnish Association for Nature Conservation has granted CSC the right to use their eco energy label. The label is granted only for energy meeting strict environmental criteria, produced by wind power, biofuels, solar panels, or the well-established hydroelectric power.

“Both CSC’s server centers have a free cooling system. To put it simply, free cooling means that the cooling effect of cold air or water outside is transferred from one space to another in a controlled manner, which makes automatic coolers redundant. This saves significant amounts of energy.”

Tuononen explains that alternating weather conditions have to be taken into account. Since weather conditions may vary from the heat of summer to extreme cold, we must have the necessary technology installed to secure that the ambient air temperature and humidity remain constant to meet the machine room requirements.

Energy efficiency is measured by the Power Usage Effectiveness (PUE) factor, which refers to the total power divided by the power consumed by the servers. Hence, the minimum is 1, if all energy is used by the servers. Normally server centers operate between 1.8 and 3.0. Google has reported that it has a few centers with a PUE factor 1.2 or below.

CSC’s newest machine room “Pohja” attained 1.48 during its first year of operation. This means that per each 100 watts, 67.5 watts was used by the server and 32.5 watts for cooling.

“We are making active efforts to increase energy efficiency. Every saved kilowatt saves a thousand euros at the annual level.”

Tero Tuononen emphasizes that having sustainable-energy machine rooms is not merely a question of minimizing the energy needed for cooling, but a larger entity.

“We should plan our future investments so that the life span of the entire facility is taken into consideration. The efficiencies within a facility must be planned for various loading conditions enabling even recycling use for the created thermal energy – at least for some of it. But then, heating is not always needed, even in Finland.”

Ari Turunen