Direct Liquid Cooling: The new gold standard for data centers

IT systems are placing increasing pressure on data centers as the demand for increased power and more cooling grows. New cooling technologies are needed that are not only efficient but also sustainable. One of the answers to these challenges is direct liquid cooling, which offers many advantages but also challenges in implementation that need to be overcome.

The increasing demand for cooling in data centers

With the rise of artificial intelligence (AI), machine learning (ML), and high-performance computing (HPC), data centers are facing unprecedented challenges. Cooling demands are soaring – sometimes up to 10x higher than traditional systems – while energy efficiency legislation pushes operators for integrated heat recovery solutions. Efficient, sustainable cooling isn’t optional, it’s essential!

Enter direct liquid cooling (DLC), particularly direct-to-chip cooling: a game-changing technology for today’s high-performance systems.

Modern and efficient cooling in the data center

For decades, air cooling dominated data centers, with 3.5 kW per rack considered standard in the late '90s. As virtualisation drove IT consolidation, solutions like hot/cold aisle enclosures and side coolers emerged, increasing rack cooling but even that is typically limited 10 to 35 kW per rack.

High-performance systems, such as HPC clusters, have long relied on DLC for IT chips/microchips, though demand was historically low. Today, with the rise of AI/ML, GPU-driven systems, and Large Language Models (LLMs), power density demands are skyrocketing. DLC, particularly direct-to-chip, offers a solution – enabling up to 10x the power density while supporting efficient heat recovery.

Meanwhile, immersion cooling remains niche, presenting practical challenges for daily operations.

So, what is direct liquid cooling?

DLC takes cooling to the next level by using, you guessed it, liquids – like deionised water or specialised coolants (like PG25) – directly on heat-generating components such as processors/CPUs, GPUs, and memory chips. Unlike traditional air cooling, which is hitting its limits, DLC delivers far superior heat dissipation. Why is that? Liquids have a much higher heat capacity than air, allowing them to absorb and remove heat faster and more efficiently.

Direct-to-chip cooling: the next level of cooling technology

Direct-to-chip cooling is a cutting-edge form of DLC where coolant flows directly over the chip's surface or close to it. By using cooling plates attached to the chips, this technology dissipates heat right at the source, creating an ultra-efficient cooling solution tailored for processors/CPUs, GPUs, and other high-performance components.

Advantages of direct-to-chip cooling

• Superior cooling power: liquids can dissipate heat up to 4,000 times more efficiently than air, dramatically boosting cooling performance.
• Space-saving design: direct-cooled systems are more compact, eliminating the need for bulky fans and air ducts.
• Smart Heat Recovery: by removing heat directly at the source, liquid cooling enables efficient heat reuse through district heating networks, helping meet energy efficiency regulations.

Challenges of introducing DLC systems into the data center

Although the advantages of DLC technology are clear, data center operators face major challenges when implementing it:

1. Outdated infrastructure: most data centers weren’t built for the intense cooling demands of modern high-performance systems. Upgrading to DLC often means costly renovations.
2. Compatibility challenges: standardisation is still evolving, with manufacturers offering incompatible solutions that complicate integration.
3. Regulatory demands: Energy efficiency laws require not just high cooling capacity but also effective heat recovery systems – adding complexity to design and operations.
4. Costs vs ROI: DLC comes with a hefty price tag. Servers with direct-to-chip cooling can cost 20 to 30% more, plus additional expenses for cooling distribution units (CDUs). While long-term efficiency gains are clear, the short-term ROI remains a concern.

Current solutions and approaches in practice

Cooling solution manufacturers are developing new models to make DLC more accessible, with three key approaches emerging:

• Single-phase direct liquid cooling: a liquid, typically water, absorbs heat without evaporating and is recirculated through heat exchangers. This method is currently the most common and enables efficient heat recovery.
• strong>Two-phase direct liquid cooling: in this system, the coolant evaporates on contact with the hot chip and is then liquefied again in a condenser. While more complex, it offers superior efficiency for power-intensive applications.
• strong>Immersion cooling: entire servers or components are submerged in non-conductive coolant. Though promising for certain systems, it faces issues with maintenance, compatibility, and the practical challenges among IT managers such as risk of leakage, space constraints and the investment in specialised equipment.

Future prospects: standardisation and further development

• As DLC technologies like direct-to-chip cooling gain traction, standardisation is key. Industry collaboration is needed to ensure system compatibility and simplify deployment. Organisations like the Open Compute Project (OCP) are leading the way, with the first IEEE* standards for manifold hoses and plug connections as well as liquid standardisation supported by all server manufacturers is expected this year.
• Meanwhile, ongoing research into advanced coolants and improved heat recovery systems aims to make DLC even more efficient, economical, and sustainable in the coming years.
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Practical steps for data center operators

For IT teams exploring DLC systems, these steps can help smooth implementation:

1. Assess feasibility: start with an inventory and analysis of your current data center campus/park/facility to evaluate DLC readiness.
2. Run pilot projects: test DLC on selected high-performance racks to gather insights and reduce risks.
3. Partner up: collaborate with manufacturers and DLC experts to develop tailored solutions and build internal expertise.Explore short-term options: since data center renovations can take 18 to 48 months, consider modular data center containers or colocation providers as interim solutions.
4. Invest in training: equip your team with the skills to maintain and manage DLC systems, which differ from traditional air-cooled setups.

 

Conclusion: direct liquid cooling – the new gold standard in data centers.

Direct liquid cooling, particularly direct-to-chip cooling, is emerging as the gold standard for modern data centers. By efficiently managing extreme heat loads and enabling heat recovery, DLC addresses both technical challenges and regulatory demands.

With standardisation on the horizon and ongoing innovation, DLC is set to transform data centers, meeting the growing needs for performance and sustainability.

Now is the time to invest in DLC and pave the way for a sustainable, future-oriented IT infrastructure.

 

If you are interested in hearing about how we can support you with this please contact your Computacenter Account Team.