Immersion Cooling: What Is It?
The next chapter in liquid cooling
Immersion cooling, also known as liquid submersion cooling, is the process of immersing entire servers or computer components in a liquid that conducts heat but not electricity.
This creative method of cooling servers or IT gear eliminates the need for fans, and the heat exchange between the cool water circuit and warm coolant typically takes place via a heat exchanger, such as a radiator or heater core.
Several Cray-2 and Cray T90 extreme-density supercomputers remove heat using sizable liquid-to-chilled heat exchangers. In this instance, the fluid used needs to have a low enough electrical conductivity to prevent interference with the computer’s regular operation. It might be essential to insulate specific areas of components that are vulnerable to electromagnetic interference, like the CPU, if the fluid has some electrical conductivity. It is preferred to use dielectric fluid for these reasons.
What are the Different Types of Immersion Cooling?
The use of immersion cooling in one phase
Single-phase coolant is a liquid that never boils or freezes and never changes its state. Heat is transferred from a cooler water circuit to a heat exchanger via the pumping of coolant.
Since there is little to no chance of the coolant evaporating, this method makes use of open baths.
Immersion Cooling in Two Phases Also known as flow boiling or evaporative cooling
The working fluid in two-phase cooling can be in either a liquid or gaseous state. This technique makes use of the idea of latent heat, which states that heat energy is needed to alter a fluid’s state. Once the working fluid reaches its boiling point, it is cooled and stays at this saturation temperature. The working fluid receives energy from the heat source, which causes some of it to boil off into a gas. After that, the gas rises above the fluid pool and condenses back to the temperature of saturation. The fluid returns to the fluid pool as a result of this.
Semi-open baths are necessary for this cooling technique, which means that the system must be sealed to prevent coolant evaporation while in use.
Additionally, two-phase coolants are very costly, and it’s still unclear how the vapor will affect the bath operators.
Evaporation can cause issues with immersion cooling fluids that are two-phase or even single-phase. The fluid inside the bath enclosure might need to be sealed or replenished regularly.
Together, Intel and Dell Technologies are still paving the way for breakthroughs that enhance people’s lives, boost output, and inspire creativity. Energy efficiency is rising with each generation of processors, meaning that more calculations can be done for every watt of power required by the servers. But because there is an unquenchable need for computing power, processors are being made to operate at higher power levels to keep up with demand.
It becomes difficult to cool these processors with higher thermal design power (TDP) from an energy consumption and technological perspective. Conventional cooling systems were not intended to remove the increased heat generated, which accounts for up to 40% of an energy-intensive data center. By using immersion technology to cool the data center, it is possible to cool components with higher TDP while using less electricity and water, making the process more environmentally friendly.
Immersion cooling is one of the cooling technologies that could reduce the energy consumption of data centers. With this technology, the servers are immersed in a liquid that is safe for the computer’s internal parts and won’t conduct electricity. The server doesn’t have fans, which alone conserves data center electricity. Since immersion tanks normally capture almost all of the heat from the computer directly into the liquid, there is usually no need to move large volumes of air within the data center facility.
Additional facility savings result from the removal of facility fans, which in an air-cooled data center would have supplied air to the cold aisle in front of the racks since the heat is retained by the fluid in the immersion tanks. In certain situations, the cooling system’s compressors may be removed, which would increase energy savings. In certain compute configurations, the hot coolant that exits the computer could even be beneficial for other uses, such as industrial processes or district heating.
A primary obstacle confronting the technology is that certain processors and servers may find the thermal performance of existing immersion systems to be prohibitive. But together, Dell and Intel have made the most of the chances to implement sustainable computing in immersion. Users can benefit from the newest Intel compute architecture, integrated accelerators, and security features with Intel Xeon processors, like the Xeon Platinum 8480+ or 8470N, for increased performance.
Additionally, these processors are more energy-efficient than their predecessors, offering 2.9 times more performance per watt on average across a range of workloads. The 5th generation of Intel Xeon Scalable processors, which have more integrated accelerators than any other CPU on the market, offer exceptional performance and low total cost of ownership for workloads related to AI, databases, networking, and HPC.
With specific workloads, you can observe up to 10x greater performance per watt when utilizing built-in accelerators. Additionally, these processors have higher TDPs, but Dell has countered this with new immersion cooling features for Dell PowerEdge servers. Systems can be cooled more efficiently with Dell’s PowerEdge Smart Cooling features, which include a symmetrical layout and simplified flow paths for immersion liquid. According to internal Dell modeling, energy savings of up to 30% can be achieved over traditional perimeter air cooling for comparable servers and configurations when coolant flows efficiently around the hottest components.
