Liquid Cooling in Data Centres: Why It Is Replacing Traditional Air Cooling for AI and High-Performance Computing
- MTS DNC ENERGY CONSULTANTS LIMITED
- 6 days ago
- 5 min read
The Future of Data Centre Cooling Has Arrived
Every online search, streamed movie, cloud backup, AI prompt, financial transaction and connected device relies on a data centre somewhere in the world. Although these facilities are largely invisible to the public, they form the backbone of our digital economy.
The rapid adoption of Artificial Intelligence (AI), machine learning, cloud computing and High-Performance Computing (HPC) is transforming how modern data centres are designed. Today's servers consume significantly more power than those installed just a few years ago, generating unprecedented amounts of heat that conventional air-cooling systems are struggling to remove.
This shift has accelerated the adoption of liquid cooling, a technology that is rapidly becoming essential for next-generation data centres.
In this article, we explore why liquid cooling is gaining popularity, how it works, and why it is expected to become the industry standard for high-density computing.
The AI Revolution Is Driving Data Centre Growth
The global demand for computing power has never been greater.
Artificial Intelligence applications require enormous computational resources. Training a single large language model can require thousands of Graphics Processing Units (GPUs) operating continuously for weeks or even months.
At the same time, businesses continue migrating to cloud-based services, increasing demand for hyperscale data centres.
Industry analysts estimate there are now approximately 12,000 data centres worldwide, with the global market expected to more than double over the next decade.
Unlike traditional enterprise servers, AI servers place extreme demands on both electrical and mechanical infrastructure.
Modern hardware includes:
Central Processing Units (CPUs)
Graphics Processing Units (GPUs)
Tensor Processing Units (TPUs)
Field Programmable Gate Arrays (FPGAs)
Each new hardware generation consumes more electrical power while occupying roughly the same physical footprint.
For example:
Hardware | Typical Socket Power |
Traditional CPU | 100–200 W |
Modern High-End CPU | 300–400 W |
AI GPU | 600–700 W |
Next Generation AI GPU | 1,000 W+ |
Multiply this across eight GPUs inside a single server and dozens of servers inside one rack, and it becomes clear why thermal management has become one of the biggest engineering challenges facing the industry.
Why Cooling Is So Important
Every watt consumed by IT equipment eventually becomes heat.
If that heat is not removed efficiently:
processors throttle performance
equipment reliability decreases
hardware lifespan shortens
downtime risks increase
operational costs rise dramatically
Cooling therefore represents one of the largest energy consumers within any data centre.
In many facilities, cooling accounts for 20–50% of total electrical consumption, making it one of the biggest opportunities for improving energy efficiency.
This is why engineers closely monitor Power Usage Effectiveness (PUE).
PUE measures how efficiently a data centre uses electricity.
It is calculated as:
PUE = Total Facility Energy ÷ IT Equipment Energy
For example:
IT equipment = 1 MW
Total facility power = 1.4 MW
PUE = 1.40
A perfect data centre would achieve a PUE of 1.0, meaning every unit of electricity is used directly for computing.
Typical values include:
Facility Type | Typical PUE |
Older Data Centres | 1.8–2.2 |
Modern Air-Cooled Facilities | 1.4–1.6 |
Advanced Liquid-Cooled Facilities | 1.1–1.2 |
Reducing cooling energy has a direct impact on lowering operational costs and carbon emissions.
Why Air Cooling Is Reaching Its Limits
For decades, air cooling has been the standard approach for removing heat from IT equipment.
Cold air is supplied through Computer Room Air Conditioning (CRAC) or Computer Room Air Handling (CRAH) units before passing through servers and carrying heat away.
While this approach has worked well for traditional server rooms, it is approaching its practical limits.
Air Is a Poor Heat Transfer Medium
The fundamental problem is simple:
Air has a very low density and low heat capacity.
Compared with water, air carries very little heat.
Water can transport more than 3,000 times more heat per unit volume than air, making it vastly more effective as a cooling medium.
Removing increasing heat loads using only air requires:
larger fans
higher airflow rates
wider hot and cold aisles
larger cooling units
increased ductwork
higher electrical consumption
Eventually these systems become impractical.
Increasing Rack Densities
Traditional enterprise racks typically consumed:
5–10 kW per rack
Modern cloud facilities commonly operate at:
20–30 kW per rack
AI clusters now regularly exceed:
80–100 kW per rack
Some next-generation AI deployments are expected to surpass:
150–200 kW per rack
At these power densities, conventional air simply cannot remove heat quickly enough.
Hidden Costs of Air Cooling
Beyond the obvious increase in cooling energy, traditional air systems introduce several secondary penalties.
These include:
Higher Fan Energy
As airflow increases, fan power rises rapidly.
Dense AI servers may dedicate 10–20% of their electrical power solely to cooling fans, reducing overall computing efficiency.
Increased Building Size
Air requires space.
Large air-cooled facilities need:
raised floors
wider aisles
larger plantrooms
substantial ductwork
numerous CRAC or CRAH units
All of these increase construction costs.
More Noise
High airflow means high noise.
Modern AI halls can become extremely noisy because hundreds of high-speed server fans operate simultaneously.
Liquid cooling dramatically reduces fan speeds, creating a quieter and more comfortable environment for maintenance personnel.
Limited Waste Heat Recovery
Air is relatively difficult to use for heat recovery.
Although warm exhaust air contains useful energy, capturing and reusing it efficiently is challenging.
Liquid cooling changes this completely by producing a concentrated stream of warm water that can be reused elsewhere in the building or exported to district heating networks.
The Shift Towards Liquid Cooling
Rather than attempting to cool the surrounding air, liquid cooling removes heat directly from the source.
This allows engineers to cool processors much more efficiently while significantly reducing fan power and mechanical cooling requirements.
Liquid cooling is not a new concept.
Mainframes and supercomputers have used liquid cooling for decades.
However, today's AI revolution has transformed it from a specialist technology into a mainstream engineering solution.
Modern liquid cooling systems generally fall into three categories:
Direct-to-Chip Cooling
Immersion Cooling
Rear-Door Heat Exchangers
Each approach offers different advantages depending on the application, rack density, maintenance strategy and budget.
In the next section, we will explore each of these technologies in detail, explain how Coolant Distribution Units (CDUs) operate, and examine why hybrid cooling systems are becoming the preferred solution for many new and retrofit data centres.
How Our Consultants Can Help
At MTS DNC Energy Consultants, we provide:
Heat pump assessments
Part L compliance reports
Building energy modelling
Through NEXUS M&E Design, we also deliver:
Heat loss calculations
Heat pump sizing
Radiator and underfloor heating design
Mechanical ventilation design
We ensure every system is designed for maximum efficiency, compliance, and long-term performance.
Heat pumps work differently. Rather than generating heat through combustion, they transfer heat from the outside environment into a building. By exploiting the vapour compression refrigeration cycle, heat pumps can deliver three to five times more heat energy than the electrical energy they consume, making them one of the most energy-efficient heating technologies available.
Disclaimer
The content shared in these posts is intended for informational purposes only and should not be interpreted as design advice, specifications, or a calculation template. For professional guidance or design services, please contact us through our contact form.
