The Benefits of Liquid Cooling, Sustainability, Retrofit Challenges and the Future of Data Centres
- MTS DNC ENERGY CONSULTANTS LIMITED
- 6 days ago
- 6 min read
The transition from traditional air cooling to liquid cooling represents one of the biggest changes in modern data centre design.
As artificial intelligence, cloud computing and high-performance computing continue to increase server power densities, liquid cooling is becoming essential for achieving acceptable energy efficiency, reliability and sustainability.
However, the decision to implement liquid cooling is not only a technology choice. It affects the entire building design, including mechanical systems, electrical infrastructure, controls, operation and maintenance strategies.
Key Benefits of Liquid Cooling in Data Centres
1. Higher Rack Density and Improved Space Utilisation
One of the biggest advantages of liquid cooling is the ability to support significantly higher rack densities.
Traditional air-cooled systems are typically limited to approximately:
20–30 kW per rack
Modern liquid-cooled systems can support:
80–100+ kW per rack
Future AI workloads are expected to require even higher densities.
This allows data centre operators to install more computing power within the same building footprint.
The consequences include:
Smaller data halls
Reduced floor area requirements
Lower building construction costs
Improved utilisation of existing facilities
For operators facing limited site availability, liquid cooling can provide a major strategic advantage.
2. Reduced Cooling Energy Consumption
Cooling represents one of the largest energy consumers in a data centre.
Liquid cooling improves efficiency because heat is removed directly from the source rather than relying on large volumes of air movement.
Benefits include:
Reduced fan power
Lower airflow requirements
Reduced dependency on mechanical cooling
Higher chilled water temperatures
Increased use of free cooling
In many cases, liquid cooling allows cooling systems to operate using warmer water temperatures, reducing or eliminating the need for energy-intensive chillers.
3. Improved Power Usage Effectiveness (PUE)
Power Usage Effectiveness (PUE) is one of the most widely used indicators of data centre efficiency.
It is calculated as:
PUE = Total Facility Energy / IT Equipment Energy
Example:
A data centre consumes:
IT load: 1 MW
Cooling, lighting, power losses and other systems: 0.3 MW
Total facility energy:
1.3 MW
PUE:
1.3 ÷ 1.0 = 1.30
Typical values:
Data Centre Type | Typical PUE |
Older facilities | 1.8–2.2 |
Modern air-cooled facilities | 1.4–1.6 |
Advanced liquid-cooled facilities | 1.05–1.15 |
Lower PUE means less wasted energy and lower operating costs.
4. Reduced Water Consumption
Water consumption has become an increasingly important consideration in data centre design.
This is measured using:
Water Usage Effectiveness (WUE)
WUE is calculated as:
Annual Water Consumption ÷ Annual IT Energy Consumption
Traditional evaporative cooling systems can consume significant quantities of water.
Liquid cooling can reduce water consumption by:
Operating with closed-loop systems
Increasing dry cooling opportunities
Reducing reliance on cooling towers
Improving heat recovery opportunities
Modern liquid-cooled facilities can achieve significantly lower WUE values compared with older designs.
5. Waste Heat Recovery Opportunities
One of the most exciting benefits of liquid cooling is the opportunity to reuse waste heat.
Traditional data centres reject large quantities of low-temperature heat into the atmosphere.
Liquid cooling produces a concentrated warm water stream that can be recovered.
Potential applications include:
District heating networks
Nearby residential developments
Industrial processes
Office heating
Swimming pools
Absorption cooling systems
For example:
A liquid cooling system may produce water leaving the IT equipment at approximately:
30–40°C
A heat pump can increase this temperature to a useful heating level.
This creates an opportunity to transform data centres from energy consumers into energy contributors.
6. Reduced Noise Levels
Air cooling requires large quantities of airflow.
This means:
High-speed server fans
Large AHUs
High ventilation rates
Liquid cooling reduces airflow requirements, resulting in:
Lower noise levels
Improved working conditions
Reduced acoustic challenges
This becomes particularly important where data centres are located near residential or mixed-use developments.
Retrofitting Liquid Cooling into Existing Data Centres
Although liquid cooling is often associated with new facilities, it can also be introduced into existing data centres.
However, retrofit projects require careful planning.
Older facilities were typically designed around one fundamental principle:
Keep water away from IT equipment.
Introducing liquid cooling therefore requires a significant change in design philosophy.
Key Retrofit Considerations
1. Space for New Infrastructure
Existing data halls may require additional space for:
Coolant Distribution Units
Pipework
Manifolds
Pumps
Heat exchangers
Although liquid cooling reduces the requirement for large air-handling equipment, new hydraulic infrastructure must be accommodated.
2. Reliability and Risk Management
Data centre operators have traditionally considered water near servers as a risk.
Modern liquid cooling systems address this through:
Closed-loop circuits
Leak detection
Double containment
Pressure monitoring
Automated isolation valves
The design objective is to provide liquid cooling benefits without compromising reliability.
3. Maintenance and Training
Liquid cooling introduces new operational requirements.
Maintenance teams require knowledge of:
Water chemistry
Pump systems
Heat exchangers
Coolant monitoring
Leak prevention
The transition requires new skills and operating procedures.
Cost Considerations: Air Cooling vs Liquid Cooling
Liquid cooling generally has a higher initial capital cost.
Additional equipment may include:
CDUs
Cold plates
Specialised pipework
Immersion tanks
Controls systems
However, the comparison should not only consider initial cost.
A lifecycle analysis should include:
Capital Cost Benefits
Reduced cooling plant size
Smaller buildings
Increased rack capacity
Improved space utilisation
Operational Cost Benefits
Lower electrical consumption
Reduced fan energy
Reduced maintenance
Longer hardware lifespan
Potential heat recovery income
For high-density AI facilities, liquid cooling can become more economical when considering the entire lifecycle.
Why Direct-to-Chip Cooling Is Currently Leading the Market
Although immersion cooling offers the highest theoretical efficiency, Direct-to-Chip cooling has become the preferred solution for many modern deployments.
The reasons include:
Easier Integration
Direct-to-chip systems can be introduced into existing facilities without completely redesigning the data hall.
Hardware Compatibility
Major server manufacturers now provide liquid-ready systems.
This reduces procurement and maintenance challenges.
Easier Servicing
Technicians can access servers using familiar methods because only selected components are liquid cooled.
Lower Operational Risk
The coolant remains inside controlled loops rather than surrounding the entire server.
The Future of Data Centre Cooling
The future of data centres will not involve a single cooling technology.
Instead, engineers will increasingly use a combination of solutions:
Air cooling for standard workloads
Direct-to-chip cooling for AI servers
Rear-door heat exchangers for upgrades
Immersion cooling for extreme computing environments
The correct solution will depend on:
Rack density
IT equipment type
Building constraints
Energy targets
Sustainability requirements
The Role of Building Services Engineers
The evolution of data centres highlights the increasing importance of mechanical engineering.
Modern data centres require expertise in:
HVAC design
Hydronic systems
Heat exchanger selection
Pump optimisation
Cooling controls
Energy modelling
Heat recovery
The traditional separation between IT infrastructure and building services is disappearing.
The data centre of the future will be an integrated energy system where electrical, mechanical and digital systems operate together.
Final Thoughts
The rapid growth of artificial intelligence is pushing traditional data centre cooling technologies beyond their practical limits.
While air cooling has served the industry successfully for decades, increasing rack densities and rising processor temperatures require a new approach.
Liquid cooling provides a pathway towards:
✔ Higher computing density
✔ Lower energy consumption
✔ Improved PUE performance
✔ Reduced water usage
✔ Greater sustainability
✔ Waste heat recovery opportunities
As AI continues to transform our digital world, liquid cooling will become a fundamental part of designing efficient, reliable and sustainable 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.
