Artificial Intelligence, high-performance computing (HPC), and increasingly dense workloads are transforming how data centres operate. Across Australia and globally, data centre operators face the same question:

How do we cool increasingly powerful servers without sacrificing space, efficiency, or sustainability?

The answer that keeps coming up is Direct Liquid Cooling (DLC). But what is it, how does it work, and how does it really compare to traditional cooling methods?

What is Direct Liquid Cooling?

Traditionally, data centres have relied on air-based cooling systems:

• Chilled water systems cool air.
• Fans (CRAH, CRAC, fan walls) distribute cold air into the data hall.
• Hot air rises or is extracted through overhead ducts.

This works well for typical rack densities.

Direct Liquid Cooling changes the game:

• Instead of moving huge volumes of air, DLC uses liquid (usually water or a special coolant) to absorb heat directly at the server level.
• Coolant flows through cold plates attached to CPUs, GPUs, and sometimes memory or power components.
• Heated liquid is carried away to be cooled and recirculated.

Because liquid absorbs heat far more efficiently than air, DLC can handle far higher power densities, think more than 50 kW per rack or more.

Why Traditional Cooling Struggles with Modern Loads

Air has limitations:

• Low heat capacity. It can’t carry away as much heat as liquid.
• Space penalties. High-density racks require massive airflow, sometimes forcing empty rack spaces to act as “air gaps.”
• Energy penalties. Fans must work harder, consuming more power.
• Hotspots. Air-based cooling struggles with localised hotspots in dense deployments.
• Water usage. Many chilled water systems rely on evaporative cooling towers, which consume significant water.

In contrast, DLC solves these issues:

• Higher thermal capacity → absorbs more heat with less volume.
• Compact design → eliminates the need for large airflow corridors.
• Lower PUE → reduces energy costs.
• No air gaps → maximises rack density and revenue per square metre.
• Lower water usage → in liquid-to-liquid designs, water is recirculated rather than evaporated.

How Does DLC Stack Up Against Competitors?

Let’s compare DLC to other options on the market.

Key DLC Advantages:

• Handles extreme heat densities without sacrificing floor space.
• Retrofits into existing facilities (especially modular DLC systems).
• Hot-swappable components reduce downtime risks.
• Compatible with global standards like OCP Open Rack V3.
• Often integrates with existing chilled water infrastructure.

Key DLC Considerations:

• Requires specialised knowledge for design and operation.
• Initial costs higher than traditional air cooling.
• Not all data halls are immediately ready for liquid connections.

How Rittal Stands Out in DLC

While many vendors now offer DLC solutions, Rittal’s Direct Liquid Cooling system stands apart:

• Scalable from 250 kW to over 1 MW cooling capacity.
• Modular design → deploy as needed without full facility overhauls.
• Triple-pump redundancy for reliability.
• Hot-swappable modules → maintain service without downtime.
• Integrates with existing chilled water plants.
• Compatible with standards like OCP Open Rack V3.

Compared to niche immersion solutions or bespoke OEM systems, Rittal offers enterprise-grade support, global availability, and practical retrofitting options. That makes it an attractive option for hyperscale operators facing new thermal realities.

The Future is Liquid

Data centres in NSW, across Australia, and globally are increasingly designed not just for today’s workloads but for AI and HPC deployments still on the horizon. Direct Liquid Cooling is emerging as the enabling technology that bridges this gap.

For operators determined to:

• Keep PUE below 1.2.
• Maximise revenue per square metre.
• Achieve net-zero targets.
• Prepare for workloads drawing 50kW+ per rack 
• …it’s clear that traditional air cooling won’t be enough. Liquid is the new frontier.

Want to learn more about how Direct Liquid Cooling could transform your data centre? Click here