Immersion Cooling Technology Will Be Widely Used in the Server Field in the Future

Server immersion cooling is achieved by immersing computer components (such as CPUs, graphics processors, SSDs, and DDR memory) and other electronic components (including entire servers) in a fully thermally conductive dielectric liquid or coolant, which is then cooled through a circulation system using liquid pumps, pipes, liquid-to-liquid heat exchangers, and/or dry cooler (radiator) style coolers to remove heat from the coolant.

Common dielectric coolants used for electronic liquid immersion cooling are mineral oil-based or fully synthetic chemistries. These chemistries can be divided into two major categories: single-phase, liquid immersion coolant (SLIC) or two-phase liquid immersion coolant (2PIC). Server immersion cooling has the potential to become a popular server cooling solution, especially for green data centers, because it does not require expensive air cooling infrastructure (including onboard server fans) and can provide significant energy savings.

Immersion-cooled servers and other IT hardware do not require fans to circulate the dielectric coolant, so it is removed from the system before immersion. Hydrocarbon-based thermal pastes are commonly used with heat sinks on CPUs and other chips, and they need to be replaced with different compounds to prevent them from dissolving in the coolant. Indium foil and thermally conductive epoxy are commonly used alternative materials. The temperature used for liquid immersion cooling depends on the maximum temperature at which the immersion equipment can operate reliably.

For servers, this temperature range is typically between 15 and 65°C (59 and 149°F), but can extend to 75°C in ASIC-based crypto mining equipment. The increase in the high end of the temperature range enables data center operators to use fully passive dry coolers, or more efficient evaporative or adiabatic cooling towers, rather than chiller-based air cooling. The increase in temperature range also allows operators to use single-phase liquid immersion coolants to more effectively take advantage of changes in outdoor temperature and obtain more efficient cooling from their systems, since the effectiveness of single-phase systems is not limited by boiling point, rather than two-phase coolants.

Some related brands, such as Intel, have demonstrated the advantages of immersion servers. Currently, commercial applications of immersion cooling include commodity server cooling solutions for data centers, server clusters, and mainstream cloud-based web hosting architectures. Electric vehicle and battery manufacturers also use liquids in batteries, powertrains, kinetic energy recovery systems, and motors, motor controllers, and other on-board electronic subsystems for immersion and cooling. Liquid immersion cooling is also used for thermal management of LEDs, lasers, X-ray machines, and magnetic resonance imaging equipment.