Reducing cost and climate risk for data centres with ambient air cooling

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The current pandemic has focussed attention on the digital age that we are living in. Digitisation means data, and lots of it that needs processing and storing, which is good news for data centre operators. It is also a boost for manufacturers of data centre cooling. Market analysts signal an increased awareness of data centre cooling technologies with some projections predicting that the market will grow to $2 billion in revenue by 2023.

But those cooling systems are traditionally power and water hungry, which is bad news for the industry’s drive to a sustainable future. “The heat removal systems of data centres have a big, ugly, carbon footprint,” David Binger, CTO, Forced Physics DCT, explains. “A rapid shift to a different cooling technology could reduce annual CO2 equivalent emissions by 500 million metric tons by 2030. A reduction of that size could significantly reduce the pain of climate change.”

Forced Physics DCT offers an innovative data centre cooling solution utilising patented JouleForce Technology. This scientific breakthrough provides simple and efficient cooling without the use of liquid or need to cool inlet rack air. Customers save over 40 per cent in both CapEx and OpEX by eliminating water/liquid, air conditioners, server fans, and cooling towers.

Current solutions rely on compressors to boost the delta T (temperature difference) that drives the

transfer of heat to the outside environment,” Binger adds. “Compression-based systems lock up a big slice of costly data centre electrical capacity, consume a substantial amount of electrical energy, use refrigerants, and they tend to break. Where possible, compression is often supplemented with evaporative cooling to reduce energy consumption, but these more complex systems cost more and are harder to keep working.

“The usage of water for cooling at the data centre is an obstacle and a continuing risk for data centre operators. The bigger water cost, though, comes from power generation, where water is evaporated to cool steam. Most people are surprised to learn that power plants are responsible for about 40 per cent of freshwater usage. So, data centres are ultimately responsible for a great deal of water consumption, whether or not they use any on-site evaporative cooling. All these challenges just get worse as more data centres are needed in warmer climates.”

Utilising a scientific discovery

JouleForce Technology is an innovation in solid-to-gas heat transfer based on a new scientific discovery. “Our patented fin geometry transfers more heat to the air stream and produces hotter exhaust than conventional heatsinks of comparable size,” Binger explains. “We are applying JouleForce Technology to the data centre problem first, but it will have applications in many other markets where efficiency is currently limited by excess heat.”

Forced Physics’ racks utilise air more efficiently than conventional racks: they produce hotter exhaust. Because they produce such hot exhaust, it means that the rack inlet air does not need to be so cool. This makes it possible to support even high-density IT equipment without any cooling of rack inlet air. The rack inlets are supplied with filtered air drawn from the outdoor environment.

“We have developed a new kind of CPU heatsink called a JouleForce MicroConductor,” Binger adds. “The rack-mounted server enclosures provide an isolated path for the hot exhaust to flow to a row-level exhaust duct. Exhaust ducts deliver hot exhaust to downstream industrial blowers that expel the air directly to the outdoor environment. In our racks, there are no fans of any kind. We also eliminate the need for all cooling water. The crucial feature of the Forced Physics solution is that it eliminates the need to cool rack inlet air.”

JouleForce Technology was first implemented in MEMS devices over a decade ago. The scientific results were outstanding, but Force Physics soon realised that they needed to focus on larger applications using less expensive manufacturing methods. This effort led to the JouleForce Conductor, a large format heatsink that was introduced in 2019 at many data centre conferences, including the first Digital Infra Network conference in Montreal. “In that year we talked to potential customers and learned that the market really needed our technology to work as a direct replacement for standard heatsinks, without requiring any change in motherboard designs,” Binger continues. “In response, the MicroConductor was developed in 2020 and it turns out to be not only more flexible, but also even more energy efficient than our previous product.”

Ready to deploy

Binger expects the Forced Physics system can have a big impact on all data centres. In hyperscale data centres, it reduces both total construction and total operating costs by 40 per cent while providing the world’s greenest data centre. “Our benefits really shine with edge applications,” he adds. “In the edge market, the value of eliminating air conditioners is high because it is so expensive to provide power capacity and service calls for air conditioners at remote locations. Eliminating the need for chilled air and water allows us to operate in any location, in any climate.”

The blowers in the Forced Physics solution do require some energy, but the average power is only two per cent of the heat load. This number, calculated from lab measurements and from hourly weather data, has been checked by professional mechanical engineers at multiple firms.

“Our system also eliminates server fans, which according to high level design engineers at HPE, typically use about eight per cent of server power, adding not only to the direct energy usage of the server, but also to the load imposed on air conditioning systems,” Binger explains. “The combined magnitude of these energy savings in comparison to a typical conventional data centre is around 40 per cent, so every system that uses Forced Physics cooling uses 40 per cent less total energy than it would with conventional cooling, and the carbon footprint of operations is reduced by 40 per cent.

Similarly, the indirect water impact due to power generation is reduced by 40 per cent. Because we do not use any on-site water, the direct water impact is reduced to zero.”

The system is now tried and tested and ready for commercial use. Binger reports that three micro data centres (NanoDCs) are soon to be deployed. The first will be placed outside in Phoenix where summer temperatures can exceed 115℉. The only cooling required for this system is JouleForce MicroConductors and a blower (the only moving part). The plan is to build and deploy more NanoDCs later this year that will be offered as a commercial service.

“I think there will always be a range of available solutions, but they will not have the same market share,” Binger concludes. “Although we can wish for buying decisions to be determined by sustainability objectives or shocking power densities, the cold truth is that the broad market is driven primarily by failure risk and total costs.

“Right now, conventional air-based cooling dominates and is clearly thought to be the safest and cheapest option. If Forced Physics can convince businesses that an alternative approach beats conventional air cooling on both failure risk and total costs, there could be rapid change and a timely impact on global climate. I like our chances.”

The Forced Physics JouleForce Technology was selected for the 2020 OCP Future Technologies Symposium. The OCP Future Technologies Symposium effort has been successfully led by Chairs Allan Smith, currently the Lab Manager for Area 404, Facebook’s hardware prototyping laboratory, and Lesya Dymyd, a strategic innovation engineer at 2CRSi, serving as the Symposium Program Chair.

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