At last week's Data Center World conference, 3M demonstrated a data center cooling concept called “open bath immersion cooling,” which it says is simpler and less expensive to implement than other pumped liquid cooling techniques. The system is an example of passive two-phase cooling, which uses a boiling liquid to remove heat from a surface and then condenses the liquid for reuse, all without a pump. The servers are immersed in 3M's Novec, a non-conductive chemical with a very low boiling point, which easily condenses from gas back to liquid. Each processor is capped with a copper plate coated with a material that enhances boiling, improving the efficiency of the heat transfer. The vapor generated by the boiling Novec rises to a condenser integrated into the tank and cooled by waters, and then condenses back to liquid for reuse. In this video, 3M Appplication Specialist Phil Tuma provides an overview of the system and its capabilities, which will be of particular interest to users contemplating extreme power densities.
The 3M system is known as "open bath" immersion because the chamber can be opened so that components can be replaced. This differentiates it from two-phase cooling systems used in other industrial systems, in which the liquid chamber is often sealed.
The 3M technology offers an additional approach to immersion cooling, which has gained interest along with the growth of high performance computing and supercomputing, which entail density that can exceed the capacity of traditional air cooling. For more coverage of this trend, see our stories about technologies from Intel, Green Revolution, Iceotope and LiquidCool.
3M has a lengthy history in liquid cooling, including immersion systems for industrial equipment cooling dating to the 1940s, Tuma notes. Computer enthusiasts may be familiar with the use of 3M's Flourinert liquid coolant in the early Cray supercomputers.
For more information, check out the project's YouTube channel.