According to GigaOM, Intel has just completed a year-long trial in which it kept servers cool by submerging them in oil. The trial used Green Revolution Cooling’s fluid submersion technology for cooling OEM servers.
It may sound odd, but there’s nothing new about fluid submersion for cooling electronics. Many high-voltage electrical transformers, circuit breakers, capacitors and power substations depend on liquid cooling for electrical insulation and heat dissipation.
Green Revolution has been around since 2009 and brought the technology to the data centre, using its GreenDEF coolant, a nonconductive (obviously!) white mineral oil that has 1,200 times more heat capacity by volume than air. Servers are placed vertically in coolant-filled tanks and the liquid dissipates heat as it circulates through the system.
Fluid submersion is cheaper than air cooling because the liquid can cool servers very efficiently at 40°C (104°F), while air generally needs to be around 24°C (75°F). It requires a lot less energy to maintain a coolant temperature at 40°C than it does to cool air to ~24°C, hence the savings. It also means that server power supply fans can be removed from servers saving another 10-25% of the power.
Intel gave the technology a ringing endorsement, reporting that servers were operating at a PUE (Power Usage Effectiveness) rating of between 1.02 and 1.03, compared with around 1.6 for air-cooled server racks. GigaOM quoted Mike Patterson, senior power and thermal architect at Intel, as saying that the technology appears perfectly safe for server components and might become the norm for anyone needing maximum computer power or building out data centre capacity.
Review: The data centre of the future looks like being a very different place from the typical fridge-filled-with-fan-heaters model we see now, although it’s still not clear exactly what it will look like.
Very much horses for courses I suspect, depending on whether a new build or refit, geographic location (so that outside air can be used for cooling), whether hot-running servers are used, and also whether companies will ever get over the innate fear of putting servers in liquid. Intel’s endorsement should certainly help with the last point.