Microsoft recently revealed a new datacentre cooling process that involves submerging its server racks into boiling liquid to improve power and energy efficiency.
This forms part of the company’s multi-purpose approach to make datacentres more sustainable and efficient to build, operate and manage.
Unlike water, the fluid used is harmless to electronic equipment and engineered to boil at 50 degrees Celsius.
The vapors rising from the boiling fluid condense and rain down on the servers, creating a controlled-loop cooling system.
This boiling effect is designed to reduce the demand on computer processors, and enable the servers to run at full power without the risk of failure or overheating.
Consequently, this two-phase immersion cooling is Microsoft’s long-term strategy to keep up with the demand for faster, more powerful datacentre computers.
“If done right, two-phase immersion cooling will attain all our cost, reliability and performance requirements simultaneously with essentially a fraction of the energy spend compared to air cooling,” said principal software engineer with Azure, Ioannis Manousakis.
Chip advances have been driven by the need to fit more transistors on the same chip size, doubling the speed of computer processors while increasing their energy usage.
To meet the need for increased performance, new chip architectures have increased maximum electricity usage on central processing units (CPUs) from 150 watts to more than 300 watts per chip, whereas graphics processing units (GPUs) have increased to more than 700 watts.
As more electric power gets pushed through the processor, the warmer the chip gets.
With these increased temperatures, better cooling measures are needed to prevent the chips from malfunctioning.
“Air cooling is not enough,” said engineer and vice president of Microsoft’s datacentre advanced development group in Redmond, Christian Belady.
“That’s what’s driving us to immersion cooling, where we can directly boil off the surfaces of the chip.”
Similar to this two-phase immersion cooling, Microsoft’s Project Natick is exploring the possibility of long-term underwater datacentres that do not need onsite maintenance.
These datacentres are designed to operate for years on the seabed, sealed inside submarine-like tubes.
Instead of engineered fluid, the datacentres are filled with nitrogen air, which is cooled with fans and a heat exchange plumbing system that pumps seawater through sealed tubes.
According to preliminary tests, the lack of humidity and corrosive effects of oxygen provided increased performance in the underwater servers.
Principal hardware engineer Husam Alissa anticipated that the servers in the immersion tanks would produce similar results.
“We brought the sea to the servers rather than put the datacentre under the sea,” he said.