Underground well system AMS8

Seasonal cooling underground

Have you ever wondered how a data centre is kept cool? The most advanced data centres have long moved on from using enormous coolers buzzing 24 hours a day to cool the equipment. In fact, at Interxion’s new data centre, AMS8, the coolers have only been installed as a back-up. Cooling will primarily be provided by so-called dry coolers, which simply use the air outside, as long as it is cold enough. In addition, the AMS8 data centre also has an underground well system, meaning that seasonal effects can be reversed. Normally a cooling system has to work hard on a warm summer’s day (it has to use a lot of energy), but with the help of these wells, a summer’s day can actually become a very energy-efficient day. In this blog I will explain how the advanced, energy-efficient well system at the new AMS8 data centre works.

Approximately 10-15 years ago data centre cooling was much less efficient than it is nowadays. The equipment was set up haphazardly in a room and very cold air (sometimes less than 10 degrees) was blown around the area. Much has changed in recent years, both in terms of the servers – which are now resistant to much higher temperatures than previously – and also in terms of the generation and distribution of the cooling. This has been partly stimulated by the increasing concern about energy use in the IT industry and the sharply increased focus on low-energy design and build. The use of wells is a good example of this; the total energy needs of a data centre can be drastically reduced by using a well system.

Before the wells are dug, the soil structure needs to be examined. The area where the AMS8 data centre is being built has proven to be very suitable for constructing the well system. The wells are constructed by drilling to a depth of 160 metres and installing a system of pipes. At this depth there are various aquifers which can be tapped into. At AMS8 the so-called duo-wells are used. In total, there will be ten wells for AMS8, which will together form five duo-wells. Drilling a well is precise, specialist work. The pipes in the wells have filter units which will allow water in but keep sand out. The water in a well is brackish, a mixture of fresh water and salt water, and therefore the well system is made of corrosion-resistant materials.

‘It takes two to tango’
The operation of such a duo is as simple as it is ingenious. A duo consists of a combination of a cold well and a warm well, interconnected and positioned at a considerable distance from each other. At the start, the wells are all equally cold, the natural temperature of the water being around 11 degrees. In the summer, cold water is pumped up from the cold well and warmed once by the data centre and then fed back into the warm well. In the winter, this process is reversed. On cold winter days, the dry coolers easily provide more cooling than the data centre needs and the additional capacity is then used to cool the warm wells back to their original temperature. This means that the wells can be used sustainably, year after year, season after season.

Closed system
The well systems are closed systems so no ‘well water’ passes through the data centre. The cooling is extracted via a heat exchanger to which the data centre’s cooling system is also connected.

Renewable and efficient
Interxion wants to consciously manage its energy needs and so the use of these wells is a very good fit for fulfilling these energy requirements. It is a wonderful system that works together cleverly with the natural environment and the seasons to provide a reliable, energy-efficient cooling system which respects the environment and helps our clients further reduce their costs!