Liquid Cooling For Data Centres
Billions of us are gaming, using Facebook, Instagram, Amazon, Alibaba, and Netflix. Our use plus company and government computing added up to IP traffic of 4.7 billion zettabytes in 2015 according to Cisco. With the rise of cloud computing, big data, artificial intelligence and exascale super-computers for science, global data traffic could zoom to 15.3 zettabytes per year by 2020. A zettabyte equals 1000 gigabytes x 1000 x 1000 x 1000.
Data centres (DCs) full of computer servers use a huge amount of power for data functions and an equal amount for cooling the servers. In the US alone DCs use 70 billion kilowatt/hours of electricity per year. Big players like Google and Facebook successfully slowed down energy use increases to 4% from 2010-2015, but it’s still increasing, because our thirst for data will roughly triple from 2015-2020.
At first they sought clean energy and efficiency, adding solar panels to data centre roofs, buying electricity from wind farms, re-using heat in condos and offices. Later they moved some data processing to cooler northern places like Scandinavia and Canada, for what they called ‘free-cooling.’ This works for big sophisticates, but doesn’t really apply to thousands of smaller corporate DCs.
Some success came from reducing oversizing, cold aisle containment, software games and so on; but they needed a big idea. Google tried sea-water cooling in Finland using heat exchangers. Apple added LED lighting and geothermal. Microsoft enclosed some servers in a watertight tank and dropped it to the ocean floor.
Recently an old-new counter-intuitive game-changer has emerged: Yes: Cooling servers directly with liquid. “Our liquid has about 1200 times the heat absorbing capacity of air cooling,” says Brandon Moore of Green Revolution Cooling in Austin. GRC completely submerses the electronic components in a dielectric, non-conductive synthetic mineral oil blend. The tanks are just a bit bigger than the servers -very efficient. There is a 90% reduction in cooling energy, 20% less data crunching power and 60% less DC construction cost. The company has completed installations around the US and in Japan, Australia, Canada, the UK, Spain, Austria, and Costa Rica.
The longer engineering journal version of this story can be found here.