Liquid immersion cooling also lowers noise levels and eases cooling energy requirements. For example, consider that a traditional air-based server cooling schemes uses 12 fans distributed throughout the server (sometimes more). Any IT professional knows how loud such a server can be when it's brought onto a bench for testing or configuration. An entire rack of servers running under load can produce enough noise to be uncomfortable for technicians nearby. This noise is produced by the fan blades cutting through the air. By removing all of the fans in those rack servers and replacing them with a single liquid pump, you can eliminate noise is almost completely -- the only noise is from the circulating pump.
Cooling energy needs are also lower. For example, an entire rack of traditional air-cooled servers can demand hundreds of watts to drive the assortment of cooling fans needed throughout each server, but systems like Iceotope's sealed blade configuration note that 20 kW of heat (the heat from an entire rack of systems) can be addressed using just 80 W of energy for a circulating pump.
Liquid immersion cooling offers thermal ride-through that would be impossible with traditional air-cooled servers. For example, if a power failure shuts down the data center's mechanical cooling system, temperatures inside the data center will start rising immediately. Similarly, if a fan within a server fails, the components cooled by the fan will start overheating right away. The large thermal mass provided by liquid immersion cooling allows the equipment to continue running for considerably longer before liquid temperatures become too high. This provides a great deal of tolerance for short power disruptions or maintenance windows.
Although immersion cooling should not pose a health risk to personnel or threats to electronic equipment, any deployment should include safety considerations like coolant level monitoring and contingencies for spill containment and cleanup.
Immersion cooling has been the stuff of science fiction for many years, but strides in material science have provided systems developers with new mediums that can allow today's high-performance enterprise servers to run while submerged in actual liquid. This promises to simplify cooling, lower power requirements and provide thermal ride-through for short-term cooling power disruptions. Several companies are already marketing immersion cooling systems, and more cooling platforms will appear in the months and years ahead.
This was first published in April 2013