Why liquid-to-liquid cooling tests are essential for AI Data Centre Upgrades and Commissioning

Discover why liquid-to-liquid cooling tests are crucial for commissioning and upgrading data centre systems. Optimise performance and prevent downtime with Aggreko's expertise.

Introduction
How Liquid-to-Liquid Cooling Tests Work?
Real-World Applications
The Growing Importance of Liquid Cooling in AI Data Centres
Aggreko’s Investment in Liquid-Cooled Load Banks
Why Liquid-Cooled Load Banks?
Conclusion

Introduction

As data centres face growing demands for speed, efficiency, and reliability, liquid cooling systems have become the industry standard for high-density environments. At Aggreko, we understand that reliable cooling systems are essential for optimal performance, and liquid-to-liquid cooling tests are an integral part of ensuring that your system operates as expected, especially during commissioning and upgrades.

Importance of Testing in Commissioning and Upgrades

Data centres are increasingly adopting liquid cooling solutions to handle the heat generated by high-density server setups. However, commissioning a new system or upgrading an existing one without proper testing can expose you to significant risks. Aborted tests can add to commissioning delays and lead to downtime, equipment failure, and disrupted service. Testing ensures your cooling system can efficiently manage heat and reduce the chances of costly operational disruptions.

Before a data centre can be fully operational, thorough testing and commissioning of both the electrical and cooling systems is crucial. Any interruption in these systems, especially the cooling, can lead to overheating and costly downtime.

During the commissioning of liquid cooling systems, we simulate the load of the AI servers before they are installed. This is to make sure that the system operates effectively under load conditions. These tests not only confirm the mechanical robustness of the system, but also verify the coolant flow, temperature regulation, and pressure levels as per the system design.

Aggreko’s expertise in this testing ensures that the cooling system can handle the full operational load of the data centre, minimising risk and guaranteeing long-term efficiency. Our liquid-to-liquid cooling tests are designed to verify your system's performance, ensuring it meets operational requirements before it goes live.

How Liquid-to-Liquid Cooling Tests Work

When commissioning or upgrading a data centre cooling system, conducting liquid heatload tests is essential. These tests simulate real-world conditions to ensure your cooling loops function correctly, and that the heat exchange processes within the CDU’s are operating efficiently.

Here’s how the process typically works:

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Liquid-to-liquid cooling tests involve replicating the exact thermal load conditions your data centre will experience in live operations. Using specialised liquid cooled load banks, we simulate the heat generated by servers, ensuring the liquid cooling system is tested under realistic stress levels.

During the test, sensors are placed throughout the cooling system to monitor coolant flow rates, pressure levels, and temperature regulation. This helps identify potential imbalances in pressure or issues with flowrates that could hinder the system’s ability to maintain safe operating temperatures.

The test evaluates how effectively the cooling system transfers heat from the secondary (technical) loop where heat is collected from direct-to-chip servers to the building’s primary loop, which dissipates it. Efficient thermal exchange between these circuits is critical to maintain optimal server temperatures and minimise energy consumption.

By gradually increasing the simulated load, engineers can observe how the cooling system performs under various levels of demand. This stress testing highlights any weak points, such as leaks, insufficient pump performance, or overheating risks in critical areas.

Part of the test also ensures that alarms, sensors, and backup safety mechanisms (such as automatic shutoff valves) are functioning correctly. This ensures the system can respond quickly to anomalies in live operation.

Aggreko’s team uses advanced equipment and a data-driven approach to perform these tests with precision. This ensures that any issues, such as pressure imbalances or coolant flow deficiencies, are identified early, preventing costly delays or system failures once the system is live.

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Real-World Applications

Aggreko’s expertise in liquid cooling testing has been instrumental in helping data centres validate their systems during commissioning and upgrades. Recently, we worked with a leading operator in Paris to conduct rigorous heat load testing on their liquid-cooled infrastructure. By replicating real-world conditions, we ensured the system could handle high workloads reliably and efficiently.

Our tailored approach provided the operator with peace of mind that their cooling system would perform as expected from day one. With modular equipment and expert engineers, Aggreko delivers cost-effective, flexible solutions that reduce risks, optimise performance, and support data centre growth.

To see how we helped this client succeed, read the full case study here.

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Data centres

Essential liquid cooling test for data centre

Data centres

Perfecting water heat-load tests for colocation data centre performance

Experience top-tier water heat-load testing for colocation data centres in Europe. Our bespoke solutions ensure precision and reliability, optimising cooling infrastructure with real-time monitoring. Trust us to elevate your data centre's performance efficiently and effectively.

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The Growing Importance of Liquid Cooling in AI Data Centres

The rise of AI workloads is driving a fundamental shift in data centre design:

Traditional cloud or colocation data centres typically have rack power densities between 6 kW and 20 kW .
AI data centres demand much higher densities, ranging from 30 kW up to 300 kW per rack.

AI workloads are split into two main types:

Model training: resource-intensive processes to build AI models using large datasets, often requiring GPUs and high power. Requires very high rack power densities (100 kW to 300 kW per rack) with clusters of machines running in parallel.
Model inference: deploying trained models for real-time predictions, less compute-heavy but scalable for applications like chatbots or image recognition. Uses lower rack densities (50 kW to 80 kW) but requires many racks to handle real-time AI predictions.

Conventional air cooling methods are insufficient for these elevated power and heat densities. Liquid cooling is essential because it is approximately 35 times more effective at removing heat than air and consumes roughly seven times less power.

This shift requires new testing solutions that can accurately simulate liquid-cooled environments.

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Aggreko’s Investment in Liquid-Cooled Load Banks

To meet the growing demand for advanced data centre testing solutions, Aggreko has expanded its European fleet by adding liquid-cooled load banks specifically engineered for AI data centre commissioning.

These units simulate the electrical load and heat output of IT equipment, testing the capacity and reliability of power and cooling infrastructure.
The primary markets include the UK & Ireland, Germany, Netherlands, France, Italy, and Spain — Europe’s largest and fastest-growing data centre regions.

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Liquid cooled loadbank data centre website asset

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Why Liquid-Cooled Load Banks?

Liquid-cooled load banks are easier to integrate into data centres because they do not require extensive exhaust or ventilation systems. They offer fast response times in modulating heat output, which is particularly valuable when testing high-density systems with varied thermal demands.

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Types of Testing

Technical Aspects of Liquid Cooling Testing

Primary Loop Testing: This test verifies the loop prior to the Cooling Distribution Unit (CDU)’s being installed. What we are testing is the functionality of the building chilled water system, ensuring reliable circulation and heat rejection under operational conditions.
Secondary (Technical) Loop Testing: This involves validating the CDU’s performance by ensuring the correct rejection of heat from IT equipment, including tests with rack-connected setups to simulate real rack environments.
Heat Load Simulation: Liquid-cooled load banks simulate heat loads expected of the AI systems.
Electrical Distribution Testing: Simulates electrical loads during Integrated Systems Testing (IST) to validate electrical distribution capacity and reliability.

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Key Parameters and Considerations

Total capacity required (MW) and number of load banks.
Load increments or steps (e.g., 20 kW steps).
Hydraulic and cooling system details: chilled water connection points, flow rates, liquid medium, temperature requirements, and delta T.
Electrical supply details and connection types.
Equipment footprint, weight restrictions, and site constraints.
Data collection and monitoring needs, including pressure monitoring.
Cleanliness and compliance standards (e.g., WRAS certification).

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Conclusion

Liquid-to-liquid cooling system testing is an essential part of ensuring the efficiency and reliability of your data centre infrastructure. By partnering with Aggreko, you gain access to expert testing services that help you avoid unnecessary risks, improve system performance, and safeguard your operations from costly downtime.

Aggreko’s investment in products tailored to the application, combined with our deep commissioning expertise, positions us as a trusted partner for AI data centre operators across Europe.

Contact Aggreko today to learn how our liquid cooling tests can optimise your data centre’s efficiency and performance.

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