Benefits & Insights: Can Immersion Cooling Support Higher Data Center Density?

Cooling is a crucial aspect of data center design and operation. With higher computing demands and rack density increasing, data centers necessitate powerful cooling solutions, with immersion cooling becoming a promising option.

What is immersion cooling?

Immersion cooling is the process of submerging servers and other computing equipment into tanks filled with a dielectric fluid. 

This technology is best suited to powerful systems with intense cooling requirements. For example, crypto mining companies have embraced immersion cooling as a way to manage the tremendous amount of heat produced by crypto mining rigs. Some are even recapturing the heat and using it to increase productivity.

Overall, the immersion cooling market is expected to grow at a compound annual growth rate of more than 15 percent between 2021 and 2026.

What’s the difference between single-phase and two-phase immersion cooling?

There are two basic forms of immersion cooling: single-phase and two-phase:

1. Single-phase: In single-phase immersion cooling, fluid is circulated through the tank with the help of hydraulic pumps. After absorbing heat from the IT equipment, the fluid carries away this heat and is then cooled by a heat exchanger before returning to the tank to repeat the cycle.
   
   
2. Two-phase: A more recent development in immersion cooling is the two-phase approach. Rather than circulating liquid in and out of the tank, the fluid remains in the tank and boils as it heats up. This causes a liquid-to-gas phase change, and the resulting vapor condenses on a heat exchanger. 

Both options are popular for a reason, but two-phase immersion cooling’s simpler, self-contained design puts it at an advantage since it requires fewer components, and as a result, takes up less space and can cost less. For these reasons, some data centers prefer the two-phase approach to immersion cooling.

How does immersion cooling compare to other data center cooling options?

Immersion cooling is one option among many when it comes to data center cooling. Each cooling option offers its own advantages. 

Immersion Cooling vs. Liquid-to-Chip

Another system that uses liquid coolant is the liquid-to-chip method, also known as cold plate or direct-to-chip. In this system, coolant runs through tubing inside a metal plate. As the plate contacts the hot component, heat transfer takes place and the liquid moves to a chiller as it cycles back through the system. 

This system shares some similarities with immersion cooling, but in this case, the liquid never makes direct contact with the electronics. The most important distinction for data center operators is that direct-to-chip allows some heat to escape, which necessitates a hybrid cooling solution. Immersion cooling, on the other hand, is a more comprehensive cooling solution that does not require any extra cooling measures.

Immersion Cooling vs. Air Cooling

Most data center cooling systems use air rather than liquid. For example, some of the most traditional systems include computer room air conditioners and computer room air handlers. These legacy systems cannot match the power and efficiency of immersion cooling. 

A more efficient air cooling method is in-row cooling, where cooling units are positioned between server cabinets, keeping the source of cooling close to the IT equipment. These systems operate using a horizontal airflow pattern to prevent the hot and cold air from mixing, which enhances efficiency. However, they still can’t match the efficiency and power of liquid cooling solutions since liquid is a much better conductor of heat than air.

How does immersion cooling empower higher data center density?

Why is immersion cooling an attractive option for high-density data centers? There are three main reasons:

• Unmatched capacity: By surrounding IT equipment with liquid, immersion cooling can offer more heat removal capacity than you can achieve with other systems. The most advanced models on the market have a coolant distribution unit that can support up to 368 kW of capacity with chilled water! 
  
  
• Comprehensive solution: Immersion cooling doesn’t require additional measures to manage heat—it can effectively keep IT equipment cool within its self-contained system. This simplifies the cooling process.
  
  
• Higher efficiency: Immersion cooling is exceptionally efficient. It uses 5-20 percent less power than air cooling. Though immersion cooling solutions tend to be more expensive than other cooling equipment, this efficiency can lead to savings over time and can help data centers reduce their environmental footprint.

Small and medium data centers are unlikely to invest in immersion cooling since it’s overqualified for the job and comes with a higher price tag. For high-density data centers, however, it’s an option well worth considering.

What does immersion cooling look like in action?

As more data centers implement immersion cooling technology, we can see the advantages play out in real life. For instance, Microsoft found it was able to achieve higher performance with overclocked processors running in immersion cooling tanks. 

Intel has committed to a long-term partnership with Green Revolution Cooling to test and optimize immersion cooling tech. Intel also has a focus on the potential environmental benefits of more efficient cooling technology. 

As demands for high-density data centers increase, we’ll likely see more use of immersion cooling in the market. 

Keep up with data center trends.

PCX has been a trailblazer in the modular data center space and embraces innovations that help our customers—including hyperscalers, colos, and enterprises—meet their computing needs. 

Companies that have embraced the benefits of modular data center design will be happy to know that modular and immersion cooling are an excellent match. Equipped with the power of immersion cooling, modular data centers can truly maximize efficiency.

Want to learn more about recent developments and trends in the industry? Download our e-book, The State of the Data Center Industry Post-Pandemic.