Focus COP 21 : the green revolution of datacenters

Data centers are often stigmatized because of their high energy consumption. However, alternatives exist: from its origins CELESTE offers innovative and greener solutions.

California, the land of technological innovations, is home to some 800 data centers. The problem is they need water, lots of water to refresh their servers. The equivalent of 158,000 Olympic swimming pools per year calculated the journalist Drew Fitzgerald in a Wall Street Journal article … But the region has such a drought since four years that mayors are asking residents to reduce their water consumption. A situation that questions the data centers on their medium-term operation.

In France, where the climate is more moderate, the problem of water consumption arises just as much. There are nearly 74 m3 of water per hour that are used for cooling the servers in a data center with a capacity of 1 megawatt. Part of this water is lost through evaporation or inefficient circuitry. An alternative exists: free cooling. This cooling technique uses air rather than water. However the heat of air quality are lower. In other words, we need a much larger volume of air than water to produce the same result: 240 000 cubic meters per hour for a data center with an electrical output of 1 megawatt. But « the advantage is that the air is renewable indefinitely, » says Nicolas Aubé, President of CELESTE. In addition, fans used for cooling air consume very little power, « 10 kWh per 1 megawatt server, or 1% of total consumption, so that close to 100% when should cool  » he continues. Besides the risk of loss, pump stops or other water-related risks are limited. In the end, a more reliable system, more robust and environmentally friendly.

The StarDC, datacenters « all-in-one » and Marilyn, the datacenter of CELESTE, operate in free cooling. Furthermore, Marilyn is the only high-density data center in France whose vertical construction allows the optimization of airflow. Saving about 6 GWh per year compared to a traditional data center, the equivalent of an office building of 150 000 m2, is realized. This innovation makes possible to reconcile advanced technological and environmental concerns.

Nicolas Aubé, President of MARILYN & CELESTE