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A few kilometres from the centre of Perth sits the Pawsey Supercomputing Centre. This futuristic building contains several supercomputers, including the fastest computer in the southern hemisphere, Magnus. Pawsey is dedicated to supporting science, but it takes a lot of science to keep the building running.

Fast and hot

Pawsey’s supercomputers are very fast, nearly 40 000 times faster than a new laptop computer. Just as a laptop can get hot, supercomputers get very, very hot. The Pawsey Centre can use 1000 kilowatts of electricity, and most of that energy eventually turns into heat. “The best way to take away all that heat is with water,” says Neil Stringfellow, from the Pawsey Supercomputing Centre. “But we don’t spray that on the machines.”

Instead, CSIRO developed an innovative and sustainable solution to Pawsey’s cooling needs. The first step is common to most computers – fans blow air over the chips to cool them. However, this makes a lot of hot air, which then needs to be cooled. So the air blows through radiators, which are filled with cold water.

Cool from the deep

How do you cool that water? As Neil says, “the heat has to go somewhere.” And in the Pawsey Centre, the eventual destination is underground. “One hundred metres below us there is an underground lake, an aquifer,” says Neil. “And the water there is only ever 21 degrees Celsius.”

Cool water is pumped up from the aquifer, used to cool the system, and is then pumped back underground about one kilometre away. That way, the aquifer will never run out of water.

There are plenty of benefits to pumping heat underground. It uses much less electricity than a standard air conditioning system, and less water than the cooling towers found at power plants. It’s also not dependent on the weather. “It could be 46 degrees outside, and the system doesn’t care,” says Neil. Deep underground, it’s still 21 degrees.

Australia does some super science. From hypersonic scramjets to the brand new ASKAP radio telescope, we’re leading the world. But next time you read about a super scientific discovery, think about the infrastructure that made it possible. It’s clever, and very, very cool.

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