Immersion Cooling
What is immersion cooling
Immersion cooling is an IT cooling practice by which complete servers are immersed in a dielectric, electrically non-conductive fluid that has significantly higher thermal conductivity than air. Heat is removed from the system by circulating liquid in direct contact with hot components, then through water-cooled heat exchangers.
Immersion cooling is particularly effective in managing the heat generated by high-performance processors and GPUs, allowing for better thermal management in densely packed computing systems. Moreover, the ability of the liquid to capture all the IT energy combined with warm water cooling enables solutions ready for heat reuse.
Ultimately, immersion cooling offers energy saving, water saving and space saving.
Power Usage Effectiveness (PUE) has been adopted as a major KPI for datacentres. The formula is simple: total energy footprint of the facility / the energy consumed by IT.
Air cooling (the method traditionally used in datacentres) relies on fans and air circulation to dissipate heat from the IT components, while immersion cooling uses a fluid to directly cool the hardware, providing more efficient heat transfer. When the average global PUE is 1.55 and immersion cooling can reduce that to below 1.1, there’s no better efficiency approach than immersion cooling in today’s market.
Immersion cooling offers high thermal dissipation and can recover all of the heat created. It’s also clean and environmentally friendly. Removing the fans means that all the energy invested in the server is put to work, which adds value to the data, saving over 10% of IT power and essentially removes a failure point.
Decrease in datacentre CAPEX and OPEX. Air cooling requires large amounts of energy to continuously circulate and cool the air, not to mention run the compressors in refrigeration air chillers within the datacentre. Immersion cooling reduces energy consumption by leveraging the high heat capacity of the cooling liquid, resulting in significant energy savings.
Immersion cooling allows for a much higher computing density compared to traditional air-cooling methods. Since the dielectric liquid can dissipate heat more efficiently than air, tanks can be packed more closely together than racks in a smaller space, increasing the amount of compute housed in that area.
On an IT level, immersing the servers reduces the risk of overheating, thermal stress and oxidation on server components by displacing air from the server components, leading to fewer hardware failures and longer equipment lifetimes. It’s also worth noting that the Asperitas natural convection system is able to function very well on high operating temperatures, high utilisation while being self-managed at the same time. To tackle redundancy, continuous cooling and maintainability can happen concurrently – and this all happens alongside autonomous safety and comprehensive monitoring.
Asperitas makes use of Shell’s Immersion Cooling S5X hydrocarbon fluid, based on Shell’s Gas-to-Liquid (GTL) technology. The two companies have worked together to provide a safe, fit-for-purpose fluid in which the servers are fully immersed within the Asperitas solution. The fluid itself never leaves the tank - once it's in, it's in.
The single-phase fluid was co-developed with Asperitas and is designed to reduce energy costs and emissions through its high cooling efficiency, excellent flow behaviour as well as its thermodynamic properties. The system uses natural convection to transfer heat from the IT equipment via Shell’s immersion fluid to the water-cooled heat exchangers, making it much more energy efficient than using fans to transfer the heat.
We are very pleased with the technology from Asperitas using the Shell S5X immersion cooling fluid. The integrated cooling solution is helping us deliver very high-end Intel CPU and GPU processing power to our Research and Development departments whilst also reducing our energy consumption within the datacentre itself. Continued adoption of immersion cooling within the landscape is key for our partners and customers sustainability goals.””
Single-phase immersion cooling, as the name suggests, is where the coolant stays in a single (liquid) phase, and does not evaporate. The coolant captures the heat from the immersed components and is circulated through a heat exchanger that transfers the heat to a water loop, which in turn can be cooled with an evaporative/adiabatic cooling tower, dry-cooler (radiator), or an existing chiller plant (not required, but compatible).
Two-phase immersion cooling is where the coolant is designed to evaporate (change phase from liquid to gas) at lower temperatures, boiling off when it comes in contact with hot components. The evaporated coolant vapor is then condensed back to the liquid state through the use of condenser coils, typically located at the top of a sealed rack.
Asperitas is the only immersion cooling provider that has solutions for the full range of datacentre deployments and workloads to deliver cooling through Perpetual Natural Convection (no pumps) and Direct Forced Convection platforms.
Hydrocarbon fluids used for single-phase immersion cooling are typically synthetic fluids, which should not be confused with mineral oil. Mineral oils can often have imperfections, impurities, and limit material compatibility. Synthetic fluids, on the other hand, are manufactured at a molecular level which results in an inherently stable product that offers superior performance and material compatibility.
They are clear, odorless, non-toxic fluids that are readily used in domestic products such as cosmetics and other household products, which have well-established material handling practices, minimal regulations, and no direct GWP (Global Warming Potential). The latter is known challenge with fluorocarbons.
Asperitas exclusively works with superior synthetic immersion fluids which are fully tested and optimized for immersion cooling.
The single-phase fluid used by Asperitas does not evaporate under normal operating conditions and does not need to be topped up. Regular lab tests are performed on the coolants to test for any variance in critical properties over time. To date, all commercial deployments have been running efficiently and reliably, with no degradation in the fluid’s performance.
The fluid used by Asperitas has a very low flammability rate and does not readily ignite. The US National Fire Prevention Association (NFPA) 704 diamond rates such coolants as 0-1-0 substances. This means that it poses no health hazard, has a high flash point, and is stable even under fire exposure conditions.
The fluid is pure, stable, non-toxic, non-volatile, bio-degradable and recyclable
To ensure access to compatible immersion cooling hardware, Asperitas has partnered with a wide range of industry leaders. Each of our partners is contributing to the success of Immersed Computing®.
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Yes, you can. Components can be easily replaced using the Asperitas Service Trolley. The horizontal, open rack design allows easy access to each immersed server individually.
While immersion cooling is commonly associated with servers, it can be extended to other components such as storage and networking equipment.
Yes, the cables can be immersed in accordance with material compatibility requirements.
Several OEMs offer standard warranty and Asperitas is working closely with system integrators and OEMs to offer suitable warranty models.
Standard hardware - hardware originally designed for air cooling, can indeed be optimized for immersion. However nowadays, many server providers are offering more than 70 different servers for immersion specifically that are ready to go. Asperitas is working closely with leading OEMs to provide immersion ready servers to ensure the best possible performance for your IT.
Immersion cooling solutions allows the datacentre to go to places potentially inaccessible before - whether it is an expansion of the existing datacentre space, inside an office building or closer to the edge of the network like a rural area. This opens up possibilities to integrate IT into other industrial processes to address the global need for energy efficiency.
A single water loop can be shared across multiple liquid cooling modules and the modules can be placed back-to-back and side-to-side. Since there is no air required for the system to operate, large rows of interconnected systems can be placed in relatively small spaces.
Each system requires only power, access to a water loop and data connectivity to operate. Combined with its silent workings, these limited requirements enable high flexibility in deployment sites and scenarios for immersion cooling, inside and outside the datacentre. The physical location of the datacentre becomes less challenging to work with.
Many colocation providers are ready for liquid cooling solutions including immersion, which makes sense because they can facilitate high density customers in a simple and cost efficient way. Asperitas is working with several colocation providers to ensure the immersion adoption process is smooth.
Immersion cooling eliminates the need for raised floors entirely, but if you already have a raised-floor infrastructure there is no need to remove it, and likely no need to reinforce or modify it in any way.
Immersion cooling produces significant space savings: no hot/cold aisles or high ceilings are required, neither is room for air circulation. Immersion Cooling does not need the height you will see in traditional datacenters, in fact in most cases the same data hall can be designed to have two levels with immersion cooling instead of just one traditional level. With immersion you will achieve a higher performance and more IT power per unit area.
Asperitas systems are compliant to the most common system certifications, but you can check your specific provider for details or for tailored certifications for your application.
For new users of immersion cooling, servicing and maintaining the system is simply different to air-cooled systems. It is not more complicated. The right approach is to train staff and Asperitas offesr this service.
It all starts with planning and road mapping. Setting sustainability objectives is one thing, but it’s important to also identify your performance requirements for the next few years. Also ask yourself, where do you see your workloads being facilitated? The next step is to share the project brief with us. Then it's a matter of gaining experience via remote testing and on-site experiences, starting with piloting and then building your scale-out plan.
Book your free consultation now. Let us guide you to a more sustainable and efficient datacentre.
