Immersion Cooling: Development & Implementation Guide

A data center server room

Last Updated on April 6, 2022 by Josh Mahan

Data has become the lifeblood of commerce. There’s a problem, though—the heat generated by technology is starting to push legacy cooling systems past their limits. As a result, companies are seeing the necessity of digital transformation to accomplish their goals.

With next-gen applications like AI, IoT, AR, and ML becoming critical tools that require complex, dense CPUs, data centers are becoming the heart of organizations worldwide. But they’ve also become an area of concern as the trend toward high-density technologies pushes hardware to the limit and generates unprecedented amounts of heat with no signs of slowing down.

IT leaders are continuously searching for answers—immersion cooling is an effective solution in a world where legacy systems can’t keep up.

Related: Cooling Capacity Guide

The Need for Immersion Cooling: Legacy Systems Won’t Cut It Anymore

It’s clearer than ever that relying on conventional infrastructure for data centers is getting in the way of IT professionals meeting today’s challenges with an adequate degree of energy efficiency. Capacity planning is challenging with the current data center trends; conventional construction times are long, and augmenting with similar infrastructure makes operational costs soar.

Many operators realize that they’ll run out of space and power before achieving their required density. And meanwhile, data centers continue to produce more and more heat. With conventional infrastructure, IT leaders and data center operators will struggle to meet today’s data center capacity and cooling challenges.

While you could stretch legacy systems to meet some of the heat and density-related challenges that data centers face today, there comes a point where using old tech to solve new problems doesn’t make sense. Infrastructure and operations professionals need a solution, and legacy systems aren’t cutting it anymore.

We’ve used mechanical air conditioning as the preferred cooling method since the 1920s. And for a long time, conventional wisdom stated that it was also the best way to cool data centers. However, times have changed—as data centers get hotter, the limitations of legacy systems become clearer.

Air is not the best transfer agent of heat. While data center handlers and chillers worked well enough when hardware densities were lower and efficiency was less of an issue, as densities rise, their efficacy wanes. It didn’t take long for data centers to implement fluid coolants, which have a much higher heat capacity by volume. Now, we’ve arrived at immersion cooling, and it tops the PUE charts.

Two Methods for Implementing Immersion Cooling: Single-Phase & Two-Phase

With immersion cooling, servers and hardware in data center racks get submerged in a dielectric fluid or liquid that’s thermally conductive. Data centers that implement immersion cooling can eliminate their need for air cooling, including the fans within servers. It’s a solution that maximizes liquid’s thermal transfer properties and is the most energy-efficient type of liquid cooling.

Mac Minis in a data center rack

Similar to direct-to-chip cooling methods, immersion cooling systems are available in single- and two-phase. 

Related: How to Cool a Server Room

With single-phase immersion cooling, data centers install their servers vertically in a thermally conductive dielectric fluid. It works by transferring heat to the coolant through the direct contact of server components, which is then removed by heat exchangers in a cooling distribution unit (CDU). For data center applications, CDUs are typically separate components located close to the immersion tank or at the data center’s perimeter. 

However, there are also “micro” immersion tanks that data centers can integrate with their CDU to provide a self-contained and complete cooling solution for their high-density applications.

With two-phase immersion cooling, data center servers get immersed in a dielectric fluid with a boiling point that’s low enough to produce the proper IT case temperature but high enough to lower energy consumption while transferring the heat. The heat from the servers boils the dielectric fluid, changing its phase. Then, the rising vapor gets condensed back into a liquid by coils at the top of the tank before falling back into the liquid tank.

Immersion Cooling: Single-Phase vs. Two-Phase

Two-phase immersion cooling boasts impressive performance metrics; however, for most of today’s data centers, it’s quite complex and expensive to implement. Single-phase immersion cooling, on the other hand, is much simpler while remaining reliable and cost-effective.

In addition to being costly, the fluids used in two-phase systems have health, safety, and environmental concerns due to vapor loss. For data centers that need the absolute maximum cooling per rack, two-phase is the best solution. But for all others, single-phase is typically cheaper, safer, and effective. And unlike two-phase immersion cooling, most fluids used in single-phase applications are non-toxic, non-volatile, and last much longer.

Benefits of Developing & Implementing an Immersion Cooling System

Immersion cooling can help data centers solve a wide range of challenges related to their build and operating costs, space and power, and deployment time. Some of the most significant benefits of developing and implementing an immersion cooling system include:

Lower pPUE

With single-phase immersion cooling, data centers can see a pPUE of 1.03 or less, which is much better than free-air cooling. It works efficiently with water temperatures less than 89 °F and in extreme heat conditions where temperatures approach 122 °F. In addition, the return water can get used for heat recapture, supplementing hot water and space heating needs.

Related: Server Room Temperatures Guide

Reduce Server Energy Draw

Immersion cooling solutions can also reduce server power draw by 10% or more. The removal of server fans and lower equipment operating temperatures lessen the power draw from data center servers.

Simplify Capacity Forecasting & Planning

A man taking photographs in a server room

Forecasting demand isn’t easy with traditional data center layouts, and misjudgments are expensive. Infrastructure and operations leaders must use their capital efficiently and not create bottlenecks for future growth.

Immersion cooling systems give those leaders the flexibility they need to build out infrastructure and computing power in an almost linear fashion. These systems make it easier to ramp up computing power in small increments, unlike legacy cooling options.

Increase Reliability

With immersion cooling systems, your servers are sealed off from the environment and lose their moving parts (like vibrating fans). When servers are optimized for immersion cooling, they become exceptionally reliable and easy to service. And by eliminating CRAC and CRAH units, there are fewer overall points of failure in an immersion cooling system.

How are you cooling your data center? Book a call with our data center cooling experts and see how we can boost your energy efficiency with the right cooling systems.

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