Data cooling centre goes green

Reliable and economical.

Google's data centre in Hamina, Finland.
Google's data centre in Hamina, Finland.

Google's data centre in Hamina, Finland.

When Greenpeace said: “Google retains its leading position in building a green Internet”, it may not have realised that one of the big contributory factors to this was the pumps installed by German manufacturer, Wilo. The pumps are from the CronoLine-IL series, which are not only green in colour, but also energy efficient and reliable.

In its latest Clicking Clean report, Greenpeace examines the environmental footprint of 300 of the largest data centres worldwide. Unlike many well-known internet companies who look only at the lowest electricity prices when making decisions, Google chose to set up its data centre in an eco-friendly way. The company has set the long-term goal of using only renewable energies for its data centres. It is also making efforts to increase energy efficiency in those centres, especially for the energy-intensive cooling of the servers.

When it came to choosing where to locate its newest data centre for Europe in Hamina, Finland, the decisive factor was not the electricity price, but rather the low average temperature of 2°C and the location's proximity to the Finnish sea. There, server cooling is done using cold seawater, saving energy in the process. In addition, the Wilo CronoLine-IL pumps play a crucial role in making a main node on the global data highway economical and eco-friendly.

A lot of water, little electricity

In 2011, the electricity requirement for data centres worldwide stood at 684 billion kWh. For comparison, the whole of Germany consumed around 607 billion kWh in the same year. According to forecasts, energy consumption is expected to increase by 63% by 2020, driven by cloud computing. Today, 22% of energy consumption in data centres is attributed to cooling. Water cooling through the use of natural resources, as in Hamina, is therefore a vital strategy for improving efficiency. In addition, efficiency criteria are also set high for the pumps used to convey cooling water in the data centre, which is clear from the specifications of the Wilo CronoLine-IL pumps used there.

Wilo's CronoLine-IL pump.

To be able to supply the required amount of cooling water, the glanded pumps are installed horizontally as in-line pumps in the piping systems. The pipe sizes of the cooling circuits range from DN 150 to DN 200. The impellers of the pumps have been designed to suit this: they have a nominal diameter of 320 or 270 mm. The specific impeller geometry and a flow-optimized coating play a part in the high overall efficiency. The hydraulic efficiency of the Wilo-CronoLine-IL pumps with connection nominal diameter DN 150 is over 80% and the hydraulic efficiency of that with DN 200 is more than 70%. The motor efficiency is at 94%. As a result, a motor nominal power of between 30 and 37 kW is sufficient to pump the volumes required for meeting the cooling loads. Additional energy savings are achieved by the consumption-based pump speed control through a frequency converter.

Wilo's CronoLine-IL pumps in action at Google's data centre.

Reliable and economical

The internet never sleeps. Google answers around 64,000 search queries per second; this number alone shows the high demands that the company has to place on the availability of its data centres. Further, important cloud services for other companies with locations worldwide also require data to be available around the clock. Therefore, besides computing technology, cooling is also a crucial factor for operational reliability. Modern server systems are allowed to operate at temperatures of up to around 35°C. Without cooling, however, this limit would be exceeded very quickly, bringing everything to a standstill.

In order that the pumps convey cooling water reliably for keeping temperature as constant as possible, Wilo manufactures its pump housing and individual components from highly durable materials. The housing and impeller of the CronoLine-IL series of pumps used in the Google data centre are made of, for example, wear-resistant cast iron with flake or spheroidal graphite. To further reduce the pumps' life cycle costs, the pump lantern is made using a patented design. The design ensures specific removal of the relatively large amounts of condensate formed on the pump housing when a pump is conveying a cold medium at high ambient temperatures. This protects the pumps from typical corrosion damage. In addition, highly wear-resistant mechanical seals made of graphite, silicon carbide, EPDM and stainless steel allow for long maintenance intervals.


Digitalization in companies is progressing at a rapid rate and, at the same time, energy resources are becoming increasingly scarce. This makes green IT ever more important, according to Wilo SE's senior vice president of its Group Information Management, Sven Prochowski. The IT company, Cisco, shares this opinion and forecasts a massive growth in internet usage by 2020: In 2015, “only” 40% of the world population had access to internet; this figure will certainly increase to 52% by 2020. At the same time, technological advancement will enable ever larger amounts of data to be transported. In 2015, a user transferred on average 9.9 GB of data per month, but this figure is set to exceed 25 GB by 2020 – a 150% increase.

Dr.-Ing. Markus Beukenberg, chief technology officer of Wilo SE, says: “Computer technology is making great leaps and this is evident to most people in their daily lives. Behind the scenes, however, pump technology, which is perceived as a conventional technology, is playing a very important role as well in terms of combining energy efficiency and global networking and Wilo is contributing to this through its research and development work. 

The servers at Google's data centre.