Next-Generation: Gen-2 Dual-Phase Liquid Immersive Cooling Systems

Modern high-computing loads will soon be beyond the capabilities of traditional air cooling, and this trend is only going to accelerate. Direct-to-chip (DTC), one of the alternatives to air conditioning your data center, also known as cold plate cooling or direct liquid cooling, is a single-phase cooling technology. The DTC cold plate contains channels or tubes through which a coolant flows, typically water. As the coolant passes through the chamber, it absorbs heat from hot components connected to this cooling circuit, cooling them down. The heated coolant exits the chamber and is either cooled in an external heat exchanger or expelled from the system. Although DTC targets the majority of the heat-generating components in a data center, it does not eliminate the need to air-cool the heat generated by the rest of the components such as memory chips and power supplies.

While the benefits of air cooling vs. direct-to-chip are clear, immersion cooling is even more efficient and captures 100% of the heat generated from hot components. Plus, immersion cooling has a major safety advantage over DTC: Operational DTC water-cooled fluid accidents can result in a catastrophic health hazard and damage to your equipment. DTC cooling systems do not eliminate the need for air cooling; fans are still required to remove heat from warm circuits not attached to DTC cooling tubes.

Space limiting: Adding DCT cooling to a server limits rack density by adding manifolds and cooling tubes to both sides of a chip (board), and creates an additional 600 failure points per rack.

What is immersive cooling?

Immersive cooling systems are much more effective in that they can remove 100% of the heat from submerged liquid-cooled systems from the data center. This directly translates into cost savings and lower overall power consumption – in nearly all cases, 40% less energy consumption (e.g., chassis cooling fans use 15-20% of the total server’s power and can be a major source of failures; removing fans = fewer moving parts =  less maintenance – all attribute to additional TCO saving).

What are the major differences between immersive cooling solutions?

There are two methods of immersion cooling: single-phase and dual-phase (a/k/a 2-phase, Two-Phase and 2-PIC). A phase is a state of matter: solid, liquid, or gas. In the application of liquid immersion cooling, the chemically engineered fluids used in immersion cooling tanks are specifically designed for electrical component immersion – 100% submerged in a bath of liquid coolant.

This immersion cooling method establishes direct contact between the electronic components and the coolant, leading to superior heat dissipation. Immersion cooling has a range of benefits, including improved cooling efficiency, a smaller physical data center footprint, and minimized thermal stress on the components, which leads to increased overall performance and an extended lifespan (longer EOL) for equipment. In Alibaba’s 2018 immersion cooling project, they found their components are more reliable when submerged and not exposed to air.

At operational temperatures, hot components transfer their heat directly into the specially designed engineered fluid. The coolant used for immersion cooling referred to as a dielectric liquid; the liquid must be electrically non-conductive to prevent short circuits when it is in contact with electronics. Note: Pure ionized water (H2O) is a great dielectric; the engineered fluid used for immersive cooling looks like and acts like water. Once pure H2O is contaminated with metals and minerals, it becomes dangerous around electronics.

Immersion cooling shows a higher heat transfer coefficient than conventional cooling (<37 W/cm2).

Both single-phase and dual-phase systems share the same method for expelling heat from the tank to the outside (waste heat) or recirculated (reused heat) for facility warming. Immersion cooling systems facilitate higher-density deployments and contribute to a reduction in noise pollution within computing environments. 

Single-phase systems: In this method of immersive cooling, the engineered fluid or coolant is temperature designed to remain in a liquid state/phase in the tank/bath at component operating temperatures.  To remove heat from the submerged computer system components, the liquid is continuously circulating through the tank using pumps and an exterior heat exchanger. In our competitor's video https://www.youtube.com/watch?v=M1Sd9phNIWk they demonstrate this technology.  Note: The coolant/Cooling Distribution Unit (CDU) circulation pumps are diagrammed outside the cooling tank; the leading single-phase manufacturer installs one or more CDUs inside their cooling tank.  This is an important distinction because anything you add to the tank effectively takes up workload-producing/server space.

Gen-2 Dual-phase systems: In this method of immersive cooling, the coolant is engineered to change phase - a physical process in which a substance changes from one phase to another (liquid to gas, gas to liquid). A phase change occurs when adding or removing heat at a specific temperature, referred to as the melting point or the boiling point of a substance (coolant). Coolant boils or phase shifts into gas vapor at a chemically engineered temperature to phase shift heated liquid to carry away heat.  Dual-phase coolant is specifically designed by professional chemical engineers to “boil off” heat from hot components (CPU/GPU chips). This heat is boiled out (encapsulated in a bubble) and raised up and away from other components to the top of the tank where the gas encounters cooling (condenser) coils that are kept at a temperature below the melting/boiling point.  The cooling coil removes enough heat from the gas to force a phase change; the gas turns back into a liquid and rains down into the tank. Gen-2 Dual-phase immersion tanks are sealed when operating to contain vapor.

A phase change (liquid <-> gas) does not alter the chemical composition of the substance, only its appearance. Dual-phase tanks are a simpler design than Single-phase tanks eliminating the need for CDUs/pumps for circulation.

Choosing the right dielectric fluid for your application is critical in liquid cooling systems. The climate/ecosystem in which the cooling tank will be operational must be taken into consideration when selecting your coolant. The selection of a fluid that best suits your operational environmental parameters must be considered to ensure chemical stability and a long lifespan. Also, the design of the immersion enclosure is crucial for effective heat dissipation. The enclosure must allow for optimal contact between the fluid and the IT components while ensuring a secure and controlled environment.

Maintaining a lower operating temperature through liquid immersion cooling contributes to better overall performance and reliability of IT equipment and under controlled environments can allow for additional server throughput via over-clocking your CPUs and GPUs.

Liquid immersion cooling solutions are highly scalable, allowing data center operators to expand their infrastructure without the limitations imposed by traditional air cooling methods. This scalability is particularly advantageous in dynamic environments where rapid expansion may be required.

Advantages of Liquid Immersion Cooling

•Waste heat can be reused

•Improves IT hardware’s lifespan by 20%, reducing replacement costs

•Quiet operation, reduced data center noise

•39% reduction in carbon emissions

•91% reduction in water consumption

Gen-2 Dual-Phase

The second generation of Dual-phase was born out of the rebirth of the 3M™ Novec™ era. After the 3M Novec division was disbanded, a core group of chemical engineers continued reformulating their engineered fluids; there have been over 50+ reengineered improvements in dual-phase fluids to address:

• Safety - safer to handle, safer for the environment

• Hardware Reliability – More stable and longer life than HC oils (single-phase) due to the presence of fluorine.

• Sustainability – designed to be a new ultra-low Global Warming Potential (GWP) coolant - the most sustainable cooling solution for IT cooling.

• Power Density & Heat Removal Performance – Three (3) times more heat removal capacity than single-phase - enables significantly higher power densities required for Generative-AI workloads.

• Enable Overclocking – improved sustainability, increased ROI, and reduced total cost of ownership.

• System Complexity & Reliability – Superior reliability, the elimination of complex fluid pumps and Coolant Distribution Units (CDUs) - less complexity equates to higher availability and lower OpEX.

• Operating Expenses and Upfront Costs – Flipped the initial coolant/fluid cost equation; Dual-Phase is still more expensive per gallon than single-phase fluid, but it now takes fewer gallons of fluid to cool the equivalent number of IT servers - 12:1 coolant ratio. This 12:1 ratio becomes even more apparent when you scale up your operation above 100kW. It takes five (5) Single-phase tanks to do the work of a "single" similar-sized dual-phase tank = lower cooling infrastructure and energy costs.

• Electromagnetic pulse (EMP) safe! When grounded, a sealed Dual-phase tank enclosure forms a natural double-layer Faraday cage or Faraday shield around your immersed components; the first layer from the tank, and the second layer from the non-conductive fluid (dielectric)/coolant.

• Fireproof - the tank coolant used for cooling components is the same non-conducive fluid data centers use in their fire suppression systems which makes it mathematically impossible to have a fire in the tank.

• Queit - When you remove the fans from power supplies and eliminate the A/C systems from the data center, no longer are you plagued by the constant hum of machinery.

• Optimal Data Center Temperatures - Go lights out and keep it hot, or create a more comfortable and consistent environment for your staff - no more sweaters and jackets, or shivering when entering the data center.

• Healthier - Protect your investment and your employees. Our immersion cooling solution eliminates the risk of server damage from airborne contaminants while providing a healthier workspace.
  

E3 leads the industry charge in the Gen-2 Dual-Phase industry with over 70% of the market share of operational dual-phase tanks worldwide.

Advantages of Gen-2 Dual-Phase Liquid Immersion Cooling

• Less space requirement (compared to single-phase)

• Lower CAPEX and OPEX (per kW)

• Yields a higher heat transfer coefficient (HTC) than single-phase cooling

• Around 2x more heat rejection capacity (compared to single-phase)

• Better TCO (per kW) - 30% savings

• Best efficiency in any form of cooling

Don't be fooled; a Gen-2 Dual-phase immersion tank design, at first glance, may seem rather simple. Nearly half a billion dollars has been spent by F500 companies to design and build their dual-phase tanks - every one of them failed.

The next generation of Dual-Phase cooling, (Gen-2 Dual-Phase), included seven years of advancements from E3 NV, LLC's tank engineering team. With a graveyard of over 1,000 failed parts, E3, the only dual-phase tank manufacturer to receive a certification from 3M, has finally cracked the code for building a sustainable Gen-2 Dual-phase liquid immersion cooling system.

It is extremely important to work closely with your liquid immersion tank provider and utilize their expertise to select the right coolant for your tank. It is critical that you purchase your immersion tank and coolant together as a single cooling solution. Otherwise, you risk warranty issues, and the wrong fluid selection could be dangerous and susceptible to explosions and implosions upon initial start-up. A certified cooling technician should always be onsite for your cooling solution's initialization to ensure the coolant levels are set properly and the filters have removed all initial tank, cable, and circuit board contaminates before going into live production.

Contact@E3nv.com