How does a data centre stay nice and cool even when it’s 35°C outside?

Isabella Mysicka Aug 8, 2016

The cooling system is one of the most important components of a data centre. It’s what enables our data centres can keep their cool when temperatures outside are high - especially during the summer months.

It’s significant that not only a large proportion of the total energy consumption is defined by the type of cooling system used, but also the possible energy density and therefore the data centre’s level of utilisation. The more powerful the cooling system, the more heat that can be diverted per square metre. And the more efficient the cooling system, the larger the contribution it makes towards environmental protection in the form of Green IT.

In the last year, Greenpeace has updated its study about Green IT, Clicking Green, and come to the conclusion that energy consumption has grown considerably due to the digital transformation. One example makes it clear that online media now requires more energy than print media. Data centres across the globe cause approximately the same amount of CO2 emissions as global air travel.

Back to cooling data centres: with a classic cooling system, the whole room of a data centre is cooled, which can lead to large temperature differences within rack cabinets, especially between the bottom and top of the space. Modern data centres, on the other hand, are equipped with a cold & hot aisle containment principle - such as the data centres colozüri.ch and e-shelter of nine.ch.

In the cool aisle, cold air is guided across the raised floor to the front of the racks, which stand opposite one another. This aisle is sealed with doors and a ceiling. The server systems absorb the cold air and emit it, heated, back into the room outside the cold aisle. This space is called the hot aisle. With the release of heated air, the room temperature in the hot aisle increases considerably and, especially at the back of the racks, can rise to over 30° C. However, with the use of rack-optimised equipment and a constant regulated temperature in the cold aisle, the higher temperature does not cause any difficulties.

In the cold aisle itself, a constantly low air temperature is achieved, regardless of the location of the server system within a rack. The high contrast between cold and warm aisles enables more efficiency in the air conditioning, which in turn enables an extended use of free cooling without the use of cooling machines, even in the case of relatively high outdoor temperatures of up to 15 degrees.

The use of rack-optimised equipment is important for the whole cold and warm aisle containment principle. It must be possible for the cold air to be properly suctioned in on the front side. In addition, the racks have to be correctly sealed using blanking panels so that no warm air can make its way into the cold aisle. It’s important here that unused rack units are completely sealed. In order to be able to ensure this and therefore make an effective contribution to Green IT, nine.ch carries out weekly checks of the data centre.

As a further contribution to Green IT, nine.ch only uses electricity from renewable energy sources and also travels in a climate-neutral manner thanks to support from myclimate. Customers of nine.ch who would like to operate their server product in a green way can simply add the options CO2-neutral operations and/or Green energy to their product via email.