The data centre market is already vast and its growth keeps accelerating. The question for building services engineers is how to keep up with the industry’s voracious appetite for cooling, ventilation and power without doing further harm to the environment. Daikin Applied’s Amin Dadgari has some answers.
Other parts of the economy might be on a go-slow at the moment, but there has been no let-up in the rapid growth of data centres – a market that is predicted to keep expanding at around 7% a year between now and 2025.
The Internet of Things, Artificial Intelligence (AI) and the proliferation of smart technologies that connect the digital with the real-world; has turbocharged demand for seamless connectivity. As a result, network providers are under significant pressure to expand and improve their bandwidth. Cloud computing and Big Data means the continued expansion of multi-tenant hyper-scale data centres is inevitable.
The focus until now has been on the security of power supplies and buying up land so these power-hungry data centres are in the right places to achieve the best connectivity. However, the conversation has moved on to environmental impact and whether they can make use of renewable energy and greener technologies to lower their carbon footprint.
This presents some big challenges for our industry, but also some real opportunities. In an ideal world, we would also use 100% renewable energy to power these facilities, but we can also go further. How about capturing the waste heat the centres produce for use in district heating, for example?
Also, as many data halls are situated in highly polluted urban settings could their ventilation systems, which operate 24/7, be adapted to help clean the surrounding air by removing harmful gases likes VOCs, SOx, NOx and ozone?
As well as capturing energy and using it more efficiently, we also have to look at how we reduce power consumption. The advances in the fabrication of semiconductor devices, forming smaller and more powerful microprocessors have huge potential. By reducing the size of components, the capacity of data halls can be expanded to house hundreds and even thousands of servers without increasing their physical footprint.
The conversion of electrical energy into heat in combination with manufacturing advancement means each data rack is now capable of processing double and triple the amount of data it could previously. Of course, this also translates into more heat generated by each rack that has to be removed by mechanical ventilation.
The rapid development in server technology is a direct consequence of this global trend towards the downscaling of electronics and semiconductors. However, going smaller also has significant cost and energy-saving implications for manufacturing.
The evolution of electronics is so fast it is also forcing a faster pace of innovation in our cooling and ventilation technologies. Air, our traditional cooling method of choice, has been pushed to its thermal conductivity limits and the use of liquid cooling for high demand applications like these greater density data halls is taking over.
In short, consumer demand, driving the miniaturisation/downscaling and consequently mechanical design challenges, along with the need for improving the effectiveness of materials are all coming together to put pressure on our industry to come up with new solutions. This is like all the pieces of a puzzle falling into place: For the first time, everything now connects and it all makes sense. This is a fast-paced, high-intensity environment with no boundaries and one that is still unexplored in terms of regulation (but that will not be far behind).
In the short term, with most big players moving towards a standard design for data centres, we can focus on easy wins like improving individual components for efficiency and custom design of impellers for a specific range of static pressures. The use of coatings on heat exchangers is now a widely used technique, but there is room to go further with this by using chemical compositions that can deliver even better efficiencies while enabling air purification and the capture of harmful gases.
Taking advantage of low ambient air to provide free cooling is also a no-brainer. Free cooling can only be achieved when the ambient temperature is lower than the temperature of the return chilled water stream. It is fairly simple for chiller management systems to compare the two temperatures to decide whether compressors should be on or off.
Some data centre operators are already using elevated temperatures to increase the return water temperature and take advantage of more hours of free cooling. Also, there is a growing appetite for building these facilities in colder parts of the world where the ambient is always lower than the supply water temperature. However, other technology advances like AI is driving the demand for data processing to be closer to the source to ensure stable and seamless connectivity. This has created a market demand for versatile and powerful edge computing solutions.
It does look like we are all heading in the right direction at the front end because these innovations have a financial benefit for the operators, but at the back end, we are still rejecting significant heat into the atmosphere that should be recovered and repurposed using large heat recovery systems.
This requires more far-sighted designs, but the difficulty faced by engineers is that data centres are getting larger while construction lead times are getting shorter. This is forcing the use of immature design, and putting pressure on the supply chain and natural resources. Demand is so high and the pressure to deliver these facilities so pressing that consultants and contractors are given too little time to design, develop and construct data centres that tick all the boxes of improved operation efficiency and, more importantly, smaller carbon footprint.
With a competitive market and shorter time to market, there is a significant interest in a turnkey solution for modular construction while demand for high resilience and sophisticated controls to operate these facilities remotely also continues to grow.
We have to keep pressing clients to recognise that these centres have huge environmental potential and demonstrate the wider value in looking at the bigger picture – but greater financial incentives would also help encourage more investment in greener design and research into innovative approaches.
*Dr Amin Dadgari is Data Centre Technical Manager at Daikin Applied UK.
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