They sit in nondescript office buildings or lie hidden in purpose-built mega warehouses on the outskirts of cities, yet data farms are an essential part of modern living.
Without them churning and storing data 24/7, we’d have no Amazon, no Facebook, no online banking, no bitcoin and no video streaming. The Internet – pictures of cute kittens and all – would simply cease to exist.
The trouble is, servicing the digital economy is a power-hungry task.
Concentrating large numbers of Internet transactions in one place, servers use a lot of energy. Vast amounts, in fact.
“Roughly 2 per cent of the world’s energy consumption is going into data centres in one form or another,” says Patrick Ruch, a scientist at IBM Research-Zurich. That’s the equivalent to the total annual energy consumption of France.
For years, this was data farms’ dirty little secret. Now, however, large investments are being made to eradicate the problem. As Ruch explains, the race is on to turn data centres green.
Solutions are beginning to spring up in several places, and come in several forms.
For example, less power hungry chips from British company ARM based on designs for mobile devices are being adapted to create microservers, the market for which is growing and set to be worth USD16 billion by 2019.
At the same time, chip giant Intel continues to improve the performance-per-dollar-per-watt of its servers.
However, super-efficient chips won’t solve the problem on their own. That’s because servers not only draw vast amounts of energy for information processing, they also require power to keep them cool enough to run smoothly.
“In many data centres, for every watt of power drawn by a server, roughly another watt is needed to cool it,” explains Professor Prashant Shenoy from the University of Massachusetts Amherst.
Some firms have taken to removing this server cooling problem quite literally, by shifting data centres wholesale to colder climates – Facebook’s Node Pole facility in Sweden is one example – to take advantage of natural cold air cooling. But it’s neither possible nor desireable to move them all to the Arctic. This is where energy efficiency can make a real difference.
A great example of energy efficiency in action is the 34-storey Westin Building in Seattle, home to 28,000 m2 of data centre facilities. Here, cool water flows into the building and through the heated data centres, collecting heat and increasing the water temperature.
Cool-water systems like the Westin Building’s are being developed because water is far better at removing heat than air.
Ruch and his team at IBM believe they can exploit this further with two innovative technologies: hot-water cooling and solid sorption heat pumps.
Hot-water cooling sounds counterintuitive until you zone in on the numbers.
A microprocessor might run at temperatures as high as 80°C while the air in a server room can be as low as 20 °C. The IBM – Zurich team developed a water cooling system based on specially-designed microchannel heat exchangers coupled directly onto the microprocessor chips.
“Instead of 20°C air we can run with 50-60°C water,” Ruch says, which in turn lowers the air temperature.
This eliminates the need for energy-hungry compression chillers and fans, and also means the heated water to be put to more productive use.
The hot water produced by the Westin Building, for example, no longer evaporates as steam from the roof but is instead used to heat buildings nearby. “The new system uses a heat exchanger to transfer 5 MW of heat to nearby Amazon office buildings,” explains property manager Sabrina Villanueva from Clise Properties.
However, because multi-megawatt data centres produce so much waste heat, nearby offices or homes would never be able to use it all.
That’s where Ruch’s other innovation – the sorption heat pump – comes in.
Traditional heat pumps move heat from a colder area to a hotter area, and usually require an electric compressor for the job. But the sorption pump – a technology being developed by the THRIVE project funded by the Swiss National Science Foundation – works in a more efficient way.
In place of electricity the sorption heat pump is powered by recycled heat – such as the ~60°C heat generated from the team’s data centre hot-water cooling system.
“A sorption heat pump does pretty much the same thing [as a normal pump], but instead of having a mechanical compressor do the work you actually use a porous material,” says Ruch.
Air conditioning derived from the sorption heat pump can be used to cool other parts of the data centre that cannot be water-cooled, meaning the combined system reuses as much waste heat as possible – a saving of 50-60 per cent of the electricity consumed by the supporting infrastructure.
But energy efficiency can only go so far in turning data centres green.
The source of electricity being consumed is another important consideration.
“Researchers and the data centre industry have focused on optimising cooling infrastructure to reduce total energy consumption. However, if the electricity drawn by the data centre comes from traditional [oil and coal] plants, it will still have a significant carbon footprint,” explains Prof. Shenoy
This is why he and his colleagues started the MassNZ project in Holyoke, Massachusetts. “We are studying the design of green data centres powered using renewable energy and energy storage.” The garage-sized MassNZ microcentre is designed for off-grid operation through on-site solar generation and energy storage batteries, and sits next to a hydroelectric turbine for grid electricity. “MassNZ has a near zero carbon footprint, since both grid and local renewable sources are clean,” he says.
With MassNZ sitting on the site of the Massachusetts Green High Performance Computing Center (MGHPPC) – a data centre owned by local universities that is itself designed to be green – any discoveries made by Prof. Shenoy will be immediately put to use. Such collaboration, in tandem with energy efficient technologies, will be key in consigning dirty data to history.
Four companies redefining data centres
Google – the search engine giant owns 15 data centres across the Americas, Europe and Asia. Not only does Google use the latest energy efficiency techniques, but it also recycles 100 per cent of the electronic equipment leaving the server farms, uses seawater cooling in its latest data centre in Finland, and even harnesses artificial intelligence (AI) built by Google’s DeepMind division to make its vast facilities more environmentally friendly.
Apple – in 2011, Apple was singled out by the environmental pressure group Greenpeace as being the amongst the worst climate offenders, with the most reliance on coal and the lowest score in clean energy. Now, Apple sits head and shoulders above other Internet giants, aggressively pursuing a 100 per cent renewable energy policy in all its data centre operations. Its facility in Maiden, NC boasts a 100-acre solar array, the largest non-utility biogas fuel cell installation in the US and free outside air cooling, meaning chillers can be shut off more than 75 per cent of the time.
Facebook – the world’s largest social network uses natural cold air in most of its facilities to provide cooling. In addition, the company launched the Open Compute Project to ‘create the same kind of creativity and collaboration we see in open source software’ in the data centre hardware space.
Microsoft – with over 100 data centres and 1 million servers globally, Microsoft’s infrastructure is vast. Alongside distributed on-site power generation, the company has piloted fuel cells inside server racks – shown to be twice as efficient as typical architectures – and is exploring the benefits of placing data centres underwater through Project Natick in their pilot submarine data centre off the coast of California.
