Green Computing : French providers initiatives #1

Be my guest in this series of articles about Green Computing, whose goal is to popularize the initiatives and challenges related to the cloud and its impact on the environment. Its role in global pollution is undeniably growing, but many players are working to improve this aspect of the global internet.

Scaleway DC5, a new-generation data center

Scaleway’s R&D division recently filed a patent on adiabatic cooling, allowing them to replace traditional air conditioning, which requires a huge amount of energy to cool the air.

The new DC5 data center was built in Saint-Ouen-l’Aumône in the Val d’Oise, north of Paris. Its goal is to meet the growing demand for physical resources in Europe while drastically improving the optimization of its facilities.

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Among the newly installed features, we find direct adiabatic cooling — an unbeatable cooling method if we look at its etymological meaning, which implies that heat does not pass through. The data center uses no air-conditioning system based on compression.

The media: honeycomb walls

First, filtration walls — called media — are installed to draw in outside air and bring it into the data center. This air is then expelled by extractors placed on the opposite side. Between the two, the servers are positioned directly in the airflow. Given the weather conditions of the region, this system, known as Free Cooling, is sufficient to cool all the servers.

Adiabatic cooling

Adiabatic cooling is only used during part of the year, when the outside temperature reaches 25 °C. At that moment, the media are sprayed with water so that the air loses about 10 °C as soon as it enters the server room. Indeed, the evaporation of water consumes a lot of energy, which drastically reduces the air temperature.

A “mixing” mode for winter

When outside temperatures drop below 10 °C, the equipment could deteriorate, which is why a “mixing” mode has been integrated into the data center. The media can be partially closed in order to mix the warm air coming from the servers with the very cold outside air.

Concrete results

This strategic choice may seem risky due to the humidity and pollution of the outside air. However, the data center is equipped with high-quality filtration systems, and IoT sensors have been installed to properly monitor the quality of the air entering the server room.

We can therefore measure the performance of such a data center:

• Power Usage Effectiveness — PUE : ~1.15 (traditional data centers are around 1.7). This is because almost all of the electricity consumed goes to the servers (and not to cooling).*
• Water Usage Effectiveness — WUE : ~0.15 liters per kWh (where a traditional data center would be around 1.9 liters per kWh). This result is achieved because the watering system is only used for a few hours per year.
• PUE represents the amount of energy consumed for every 1 kWh used by the server. Here, PUE = 1 kWh (server) + 0.15 kWh (fans).

It is mainly for this kind of initiative that at Caelus, we choose to work with French players in Cloud Computing. 🌎

For the Netflix of applications: Odin by Caelus 🌳🚀

Sources

• engie
• journeedudatacenter
• scaleway dc5
• Scaleway Environmental Impact Report 2024–2025