Data centre cooling has become one of the most important aspects of the industry, largely because it is the hungriest power consumer.
Various studies purport cooling to represent 40-50 percent of the total energy bill for data centres, while a report from Climate Home News states that data centres will account for the usage of one fifth of all the electricity in the world by 2025.
Recently we were able to sit with an executive from one of the big data centre operators to get an idea of what’s under the hood at their facilities.
According to Aruba S.p.A head of engineering Lorenzo Giuntini, their data centres use a combination of groundwater and dynamic free-cooling systems to keep hardware temperature under control, while reducing energy waste and increasing efficiency.
“The dynamic free-cooling system is the result of an extremely efficient containment of the flows of incoming cold air and outgoing hot air. Special ducts ensure that the cold air is only used for the front area of the rack, which is isolated from the data room,” says Giuntini.
“With the low temperatures, dynamic free cooling allows us to save energy by using the outside air, filtered accordingly, to cool the server room. The hot air is expelled from the building via large fans, with electric shutters opening and closing as required. Heat exchangers are located on the roof of the building to reduce noise impact.”
Giuntini says there are many advantages to free cooling systems.
“Just as computers generate heat, the data centres that contain the servers that power our emails and data sharing culture also generate a lot of heat. As a result, finding the right cooling solution is important, not least because of the effect of overheating on performance and potential damage to hardware,” says Giuntini.
“The system is cost efficient, with cooling only provided where needed, and also environmentally-friendly. For example, with the groundwater system, the water is returned to the ground, on completion of the process, without any chemical alterations. The system is also flexible. The completely redundant system can be assisted or replaced by the air/water chillers in the emergency circuit, capable of ensuring the same cooling power as the primary system.”
In terms of what the future holds for the cooling, Giuntini believes currently not many people fully understand what free cooling actually is and how it works.
“However, with new regulation, mainly the ASHRAE 90.1, free cooling will soon be a requirement for all new data centres,” says Giuntini.
“This means data centres will not be able to use the old mission criticality argument – that free cooling will impact reliability – to avoid incorporating free cooling into their design. Put simply, free cooling will be more widely adopted as time goes on.”
Giuntini says regardless of how effective large industrial equipment like pumps, chillers, and cooling towers can be, they are simply unsustainable when it comes to efficiency.
“Also, with the rising cost, many data centre operators are now realising that this level of energy consumption cannot continue to rise indefinitely and are taking steps to make their facilities more energy-efficient,” says Giuntini.
“A study from The Green Grid of data centres (mostly in the US) shows that almost half are now using natural cooling to save energy and cost. Another quarter are considering doing the same in the near future.”