Smarter cooling: powering sustainable data centres

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As of 2024, the UK data centre capacity stood at an average of 1.6 GW, with preliminary analysis citing a rise between 3.3 to 6.3 GW by 2030. These figures highlight a core challenge arising for data centres: their cooling capacities and utilisation. Because these facilities require constant uptime, capacity expansion is driving an escalating energy demand. Data centres and data transmission networks currently consume around 1-2 per cent of global electricity, according to the International Energy Agency. The percentage might not be huge, but the trajectory is significant.

Data Centre Dynamics predicts that global data centre electricity use could double by 2026. Demand for cloud services, digital storage, and AI workloads is rising sharply. As Deloitte notes, much of this is associated with highly intensive machine learning and large language models that impose significantly higher heat loads on infrastructure than traditional enterprise tasks.

In many data centres, cooling is a significant issue. Depending on climate, design configurations, and workload density, cooling can utilise 30-40 per cent of all power in many facilities. As data centres become increasingly power-dependent, removing heat is no longer a straightforward background engineering task; it has evolved into a significant sustainability challenge.

Throughout the United Kingdom, data centres and colocation facilities are revolutionising cooling approaches, rules, and sources. Operators like Datum invest in cooling solutions that not only save energy but also support their clients’ Net Zero and operational resilience goals. This change is driven not by a single technology, but by an approach to cooling that is optimised for sustainability in the digital era.

Why cooling efficiency matters

The efficiency of cooling technology is directly related to environmental performance and operational costs. Inefficient cooling leads to a rapid increase in energy consumption; in today’s volatile energy market, it runs counter to economic rationale. Increasing energy demand generates higher electricity bills and higher carbon emissions, placing additional pressure on nearby power grids. As energy costs rise and environmental sustainability reporting becomes more rigorous, cooling performance is no longer a secondary consideration of IT operations.

The industry’s established efficiency metric remains Power Usage Effectiveness (PUE); however, even this sector-wide convention calls for greater ambition. While the global average PUE was 1.56 in 2024, market leaders are pushing toward the 1.1 range. Although a 0.46 reduction may appear modest, at scale it represents several megawatts of avoided power draw for large facilities.

Cooling is instrumental in this equation, as the International Energy Agency reports that it can account for 40 per cent of a data centre’s total energy consumption. In the United States, the Department of Energy emphasises that data centres consume 10 to 50 times more power per square metre than standard offices.

In the UK, it matters not only because of the utility bill. Net Zero commitments, investor expectations regarding ESG performance, and scrutiny from various pressure groups call for robust evidence that efficiency improves outcomes beyond mere carbon offsetting. Enhancing cooling is a practical step that enables data centre operators to reduce carbon emissions without compromising potential uptime or future capacity.

Smarter cooling technologies

Data centres are increasingly moving away from a standardised approach to cooling. Instead, operators deploy a mix of technologies and strategies to suit local climate, workload density, and sustainability targets. The following are some of the most innovative.

a) Free cooling

Free cooling uses ambient air or water to reject heat, significantly reducing the need for power-intensive mechanical chillers. Depending on conditions, systems can operate with minimal or no input from refrigeration plants. In the most favourable environments, free cooling can reduce cooling energy use by up to 80%.

For example, data centres in Northern Europe and the Nordic region can draw in external air for much of the year. While the relatively unpredictable UK climate complicates matters, free cooling remains increasingly attractive; dependable, high-efficiency units can now guarantee long-term hours. However, as refrigeration experts such as STULZ note, the reality of most environments is far more nuanced.

Depending on climate, seasons, and design, free cooling is unlikely to be a year-round solution everywhere. Nevertheless, it introduces the concept of passive efficiency: by working with ambient conditions rather than fighting them, data centres could significantly reduce their reliance on mechanical cooling. For example, UK colocation operators, including Datum, have sought to leverage free cooling, reducing both energy use and mechanical complexity.

b) Liquid and immersion cooling

As compute densities skyrocket, simple air cooling reaches its limits, necessitating a more efficient heat transfer solution. From a physics perspective, liquid is significantly more effective at heat removal than air. At nearly 1,000 times the density of air, liquid cooling excels at carrying heat away thanks to its superior heat capacitance and thermal conductivity. Liquid cooling, or even the total immersion of a server blade in a non-conductive dielectric fluid, is now a feasible solution for these environments.

Engineering studies performed by industry leaders show the significant impact of this transition. In a fully optimised facility study, the move to liquid cooling delivered a 10.2% reduction in total power draw. This makes the approach particularly attractive for AI, HPC, and dense racks that would otherwise necessitate high-velocity, high-decibel fans to cool their hardware. In fact, server fan power, which is a major source of parasitic energy loss, can be reduced by up to 80% compared to traditional air-cooling.

Most major hyperscalers and specialised computing businesses are already investing heavily in this technology. Analysis from Uptime Institute confirms this shift is becoming essential as rack densities climb. While liquid cooling requires a new infrastructure design, it enables customers to acquire significantly more computing power within a smaller physical footprint, allowing racks to exceed the limits of traditional air-cooled rows.

c) Closed-loop and waterless cooling

Water use has gained broader attention as a sustainability issue. Conventional evaporative cooling units require significant amounts of water to operate. According to the Environmental and Energy Study Institute (EESI), some large data centres can consume up to 5 million gallons of water per day. This is an amount equivalent to the daily water use of a town with 50,000 residents.

This order of magnitude is one of the justifications for the adoption of closed-loop and water-efficient designs in the UK and EU. By recirculating refrigerant and using closed-loop systems, operators can reduce environmental risk while significantly lowering their reliance on regional water supplies. This approach promotes resilience in locations where water supplies are under more pressure due to scarcity or changing local policies.

Importantly, water efficiency is now part of an institution’s environmental posture, particularly for data centre operators serving corporate consumers with strict ESG mandates.

d) AI-driven cooling optimisation

Both software and hardware are becoming more critical. AI-driven cooling optimisation employs distributed point sensors and ML algorithms to adjust temperature, flow rates, or even humidity levels within some tolerance band in real time.

One example from the Wired report that has been popular in such discussions is Google DeepMind’s achievement of a 40% reduction in cooling-related energy consumption through continuous parameter tuning. The true value lies in the concept: AI-driven assistance enables responsive controls that adapt to real-time operating modes and external environmental factors.

These systems are already accessible beyond hyperscale installations. For UK data hubs and colocation firms, smart controls enable greater margin from existing facilities with minimal physical intervention.

Industry-wide progress and future outlook

This drive for more innovative cooling is part of a wider reimagining of how data centres are created and operated. The International Energy Agency estimates that global data centre electricity consumption was about 460 TWh in 2022, representing almost 2 per cent of global total electricity consumption. The agency further warns that demand could double by 2026, outpacing the ability of efficiency gains to contain it.

Investment is closely following this trajectory. According to a report by MarketsandMarkets, the global data centre cooling market is projected to skyrocket from $11.46 billion in 2025 to over $32.48 billion by 2032. Some commentators cite artificial intelligence and machine learning as major trend drivers, along with increasing rack densities and more stringent sustainability demands.

The United Kingdom is a central part of this massive worldwide shift. As a leading hub for cloud services and colocation, the UK is expected to be a major driver of this global growth. To meet these rising demands, continued development in high-efficiency cooling will be essential for local providers.

A range of national and voluntary bodies reinforces this. Most operators follow the Climate Neutral Data Centre Pact and the United Kingdom’s Net Zero 2050 standards. Adherence to audited standards like ISO 50001 for energy management and the EU Code of Conduct for Data Centres is now fundamental. These frameworks, alongside 100% renewable energy sources, ensure that modern cooling installations deliver both performance and transparency.

Looking ahead: smarter cooling for a greener digital future

Cooling is a critical element of the digital ecosystem’s sustainability. Using innovative cooling systems can reduce energy and water consumption and lower emissions while maintaining reliability.

As workloads change and expectations increase, successful data centres will be those that regard cooling as an essential element of their overall sustainability initiatives. The present and future actions of colocation providers like Datum demonstrate how modern UK-based data centres can maximise reliability, performance, and environmental sensitivity.

Improvements in cooling technology will be driven by a blend of climatic considerations, legislation, and evolving computational methods. However, it will always be necessary to adopt effective green solutions.

Discover how Datum can future-proof your colocation strategy or get in touch with our expert team to discuss your specific infrastructure requirements.

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