Tucked away inside a modest-looking building at the Australian National University is the most powerful supercomputer in the Southern Hemisphere.

Since 2013 the National Computational Infrastructure (NCI) has been supporting research projects across the country.

Its high-performance computer, Raijin, is able to cope with enormous amounts of data.

"We have over 50 petabytes of research data stored at NCI and a high-performance cloud," NCI spokesperson Lucy Guest said.

"It's for science that's too big or too small, too fast or too slow, too expensive or too dangerous to happen anywhere else in the world."

In digital storage terms, one petabyte is 1,000,000,000,000,000 bytes (one quadrillion bytes or 1,000 terabytes).

Raijin is housed inside a dedicated facility at the Australian National University. ( Supplied: NCI )

The supercomputer is made up of thousands of computers simultaneously sharing the tasks of a project.

"You might want to look at the human genomes, for example," Ms Guest said.

"So you have petabytes of data that you need to sift through to sequence human genomes and it needs to be done quickly.

"Or if you want to map the entire Southern Ocean and look at variables like wind and salt and temperature, you need something really big with a lot of guts behind it."

Raijin supports the work of more than 4,000 researchers including those at the CSIRO, Geoscience Australia and the Bureau of Meteorology.

"Most of the scientists who use the supercomputer will never actually see it," Ms Guest said.

"You submit your job through online code and it bubbles away in the supercomputer and then spits out your results."

Running hot 24 hours a day

Visitors to the ANU can identify the NCI building by the steam billowing from the roof. ( Supplied: NCI )

Steam billowing from the NCI building is generated by Raijin, which is running at about 95 degrees Celsius.

"Running over 80,000 computer cores 24 hours a day produces a lot of heat," Ms Guest said.

"Raijin runs at 95C and needs constant cooling.

"We use a system called free cooling."

Free cooling uses fans to dissipate the heat produced by the computer through a series of radiators.

NCI uses a free cooling system to deal with the heat produced by the supercomputer. ( Supplied: NCI )

"There's a hot aisle where all of the heat from the supercomputer is trapped," Ms Guest said.

"Fans suck out the heat and water collects that heat which is directed to the roof where it escapes as steam."

Ironically, given the amount of climate research processed by Raijin, the NCI uses about the same amount of electricity as a small suburb in Canberra.

"We have banks of batteries that kick in if the power goes down," Ms Guest said.

"And we have two giant diesel generators that then kick in to keep the data alive, so data is never lost."