Nexalus: The future of cooling the cloud with water

22 Mar 2021

Dr Tony Robinson. Image: Cathal Noonan

Trinity spin-out Nexalus has found a way for power-hungry data centres to keep cool and create energy, not just consume it.

The world’s appetite for data is not expected to abate any time soon, which is inevitably going to lead to increased energy demand from the data centre industry. Currently, data centres account for around 1pc of global energy consumption. But what if data centres didn’t just consume energy, but harnessed it for others to use? This is a circular economy concept proposed by Irish start-up Nexalus.

“Nexalus is the future of cooling the cloud,” said co-founder Dr Tony Robinson, who certainly knows a thing or two about keeping cool. An associate professor in Trinity College Dublin’s Department of Mechanical and Manufacturing Engineering, his particular area of expertise is experimental and computational thermal-fluid sciences. In fact, Robinson is a highly regarded thermal management consultant, with more than 25 years’ experience advising on heat transfer, fluid mechanics and applied energy research in industries such as automotive and aerospace. He’s even part of an elite team formed by the European Space Agency to design experiments for two-phase heat transfer.

Robinson brings this experience and expertise to his role as chief science officer at Nexalus, a high-potential spin-out coming out of Trinity College.

‘The economy and the world want to recover from Covid-19 in a green way … Nexalus is positioned with the right solution at the right time’

The cloud Robinson refers to involves many data centres producing a lot of heat that is counterproductive to performance. To keep the electronics from overheating, data servers are typically cooled using air. This means an immense amount of energy is lost to the atmosphere as impotent lukewarm air. Nexalus’ patented technology, however, is a cooling solution that can also capture and reuse this heat energy.

“The coolant of the future is water,” said Robinson, as water is a much better conduit for heat energy than air. And so, by using water to cool electronics, Nexalus can harness expelled heat and transfer the energy elsewhere. In the case of data centres, this could go to local residential areas to heat and power homes, or could even be reused by nearby industry.

On the one hand, Nexalus can cut costs and carbon emissions with more efficient cooling of electronics. On the other, it can support further decarbonisation in local economies as a source of recycled energy, reducing widespread reliance on fossil fuels.

As well as data centres, Nexalus is targeting this technology at high-performance computers, cryptocurrency mining and the gaming and automotive industries. “Many of these industries are being publicly exposed as among the biggest global contributors to CO2 emissions,” said Robinson. “Traditional air-cooling systems do not have the capability required to answer these carbon reduction demands.”

Seeing the inadequacies of traditional air-cooling, Robinson and his Nexalus team set out to find an answer to a difficult, two-pronged question: “How do we engineer a technology that provides the necessary cooling to solve the server heat problems, whilst at the same time acting as a heat recovery system that allows energy to be reused and recycled, tackling the energy problem?”

Their answer to solving both problems simultaneously is to integrate liquid cooling into what they call ‘sealed server’ technology.

“The strategy here is that if one seals the server and then deals with the heat and energy management problems right at the source (ie the individual server), then the larger energy problem not only becomes modular, and thus scalable, but it also becomes more to do with energy transport, which is comparatively quite straight-forward,” said Robinson.

And so, with data centre server technology from Nexalus, each server in a data centre is thermally isolated from its surroundings. Heat generated by high-powered processors can be recovered using the company’s patented water-cooled direct contact heat exchangers. Meanwhile, the lower-powered supporting components are air-cooled using an air-to-water heat exchanger. And all of the heat generated by the sealed server is thus recovered into a liquid stream, which can easily be transported for use elsewhere.

The modularity of the Nexalus system is highly important, not just for ease of installation and maintenance, but for scalability. “The solution is equally as viable for a single rack in a hotel as it is for a mobile cryptocurrency container or a hyperscale data centre,” said Robinson.

‘If it is not a win-win solution for industry, then we will go back to the drawing board, or the lab, until it is’

Adding to Robinson’s red hot thermodynamics credentials at Nexalus are co-founders Kenneth O’Mahony an Dr Cathal Wilson.

CEO O’Mahony is a seasoned board member and company director with experience commercialising applied research from academia. COO Wilson is a manufacturing engineer and adjunct professor of mechanical and manufacturing engineering in Trinity.

“Through our innovations, our goal is to facilitate industries to reach, and exceed, both their economic and environmental targets simultaneously. If it is not a win-win solution for industry, then we will go back to the drawing board, or the lab, until it is,” said Robinson of the company’s great ambition.

Nexalus is not looking for any quick wins, either, having taken a “crawl, walk, run” approach to starting out, according to Robinson. They crawled through two years of intense science and engineering R&D and began to walk with a concept design that was later tooled for mass manufacture.

Now, Robinson said, Nexalus is up and running. The branding and marketing is in place. Key partnerships in manufacturing and development have been secured. And independent verification will soon be underway at RISE, the research institute of Sweden.

“Along our journey from crawl to run we have expanded our core science and engineering foundation with people such as Dr Richard Jenkins [product development manager] and Dr Michel Lebon [research fellow at Connect], enabling us to be market-ready with offerings for data centres, edge computing, cryptography, gaming and automobiles,” he said.

But even taking it slow and steady, there was one disruptive force Nexalus simply could not avoid.

“Covid-19 has had an impact on market enthusiasm for innovation. Industries are in survival not change mode, so our new entrant status was more difficult,” said Robinson.

“That said, the economy and the world want to recover in a green way. Businesses wish to show more respect for the world we all call home, and this is leading to a very strong macro and micro view of the industry that our tech can influence,” he added.

“Nexalus is positioned with the right solution at the right time. Computing infrastructure, including data centres, can reduce their energy consumption and convert that energy consumed into a new green thermal source. So, what was worse than we could have possibly imagined ended up aligning with renewed market interest.”

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Elaine Burke is the host of For Tech’s Sake, a co-production from Silicon Republic and The HeadStuff Podcast Network. She was previously the editor of Silicon Republic.