Data Centre Cooling in the Age of AI and High-Density Computing

WWith the UK Government’s latest initiative to expand the nation’s data centre capacity, aiming to compete with superpowers like the US and Germany, the number of facilities is set to grow significantly in the coming years. At the same time, the rapid adoption of generative AI and cloud computing is driving an urgent need for data centres that are not only efficient but also resilient and future-proof. 

But with this growth comes a major challenge: heat. High-density computing generates enormous amounts of it, demanding sophisticated cooling strategies. These solutions must balance technical performance with sustainability, cost, and long-term planning, making cooling one of the most critical aspects of modern data centre design.

With the rise of AI and high-performance computing, data centres are facing much higher heat densities than ever before. Traditional air cooling alone can no longer cope, which is why we’re seeing a growing shift towards liquid cooling. This trend is also reflected in the market, with more manufacturers introducing Cooling Distribution Units (CDUs) as standard solutions. 

The choice of cooling system ultimately depends on the technology within each data centre. The AI boom, in particular, has accelerated the move towards liquid cooling and immersion cooling. Whilst immersion cooling has its benefits and is anticipated to see an upscale in its use going forward, concerns around cost, familiarity and limited manufacturer support have restricted its use. 

Direct-to-chip liquid cooling on the other hand has seen a significant uplift in its use, particularly due to the capability of retrofitting into existing facilities, and this shift is already changing how we approach data centre design, ensuring that infrastructure is both resilient and future-ready. You can read more about the wider influence of AI on data centre design in our article The Influence of AI on Data Centre Design 

Sustainability is a justified concern in data centre design, particularly given the significant energy required to operate and cool these facilities. Cooling systems alone account for a large proportion of overall consumption, which makes selecting the most efficient approach, and identifying opportunities to minimise energy use, critical for both performance and environmental impact. 

Globally, there is a growing shift toward waste heat recovery. While the UK currently has no legislative requirements, the EU’s Energy Efficiency Directive (EED) already mandates that data centres over 1MW must either reuse waste heat or prove that it is not technically or economically feasible. It seems likely that similar measures will eventually be introduced in the UK. Implementing such systems will typically require additional plant to uplift temperatures to usable levels and, crucially, local heat demand, meaning not every site will be suitable. 

Powering data centres is another challenge. While renewable integration is possible, a single renewable solution alone cannot realistically meet the demand of high-density facilities, particularly AI-focused ones. More promising are direct links to multiple sources of renewable generation, such as connections between data centres and nearby wind farms, helping to ensure energy use is closely matched with green generation. In Scotland, this presents a major opportunity given the country’s extensive renewable energy resources.

Scotland also offers a natural advantage in cooling. Its consistently low ambient temperatures, and designing to higher facility water temperatures available via liquid cooling, allow for extensive use of ‘free cooling’, using outside air to significantly offset or replace mechanical cooling. This can be applied directly, by filtering and circulating outdoor air into the data hall, or indirectly, by transferring heat through an exchanger. In either case, it significantly reduces energy consumption while maintaining optimal operating conditions. 

Practical Considerations 

Designing or upgrading data centres to ensure adequate cooling brings a number of complex challenges. One of the most significant is striking the right balance between minimising plant provision, and the associated capital costs, while still satisfying both client requirements and the accreditation standards often sought in the industry, such as Uptime Institute Tier Certification, or the CEEDA Award for energy efficiency. 

Acoustics can also be a major issue, particularly when sites are close to residential or commercial properties. Cooling plant and supporting infrastructure such as generators and cooling plant can generate substantial noise, often requiring careful screening, attenuation, or alternative design solutions to comply with planning constraints. 

Another critical factor is heat load testing. As data centres move towards higher capacities, the industry is shifting from small-scale load banks and towards larger-scale solutions, such as boilers, to more accurately simulate operational conditions. 

Where clients plan for future growth and modular expansion this must be carefully planned from the outset. For example, integrating additional cooling plant into a live environment requires careful sequencing and, where possible, planning for downtime during system modifications, commissioning, or top-ups. This becomes especially challenging in facilities that operate 24/7 and cannot afford service interruptions, making forward planning and resilient design strategies essential. 

Future Considerations 

Looking ahead, cooling strategies are set to evolve rapidly alongside the growth of high-density and AI-driven data centres. Liquid cooling and CDU solutions, which are already becoming widely available from multiple manufacturers, are expected to become commonplace over the next few years, particularly as demand for AI-ready facilities continues to grow. 

The pace of technological development presents a unique challenge. IT hardware is advancing so quickly that by the time a data centre project completes design, planning, and construction, the equipment it houses may already be on the verge of being outdated. This underscores the importance of designing flexible and adaptable cooling strategies that can accommodate future innovations without requiring extensive retrofits. 

For data centre designers, like ourselves, and even operators, this means planning not only for current requirements but also for scalability and future technological advancements, ensuring that these facilities remain efficient, resilient, and future-proof. 

If you’re looking to design or upgrade a data centre with efficient, sustainable, and future-proof cooling solutions, get in touch with our team today, or contact John Moore at [email protected]

At Wallace Whittle, we combine MEP and sustainability expertise to deliver innovative designs tailored to your specific needs.