Data center cooling and heat reuse

Data Centre Cooling - Frequently Asked Questions

Why do data centres use so much water?

Data centres use water primarily for cooling - removing the enormous heat generated by servers, networking equipment, and power infrastructure. Traditional cooling systems, particularly those using evaporative cooling towers, consume significant volumes of water as part of the heat rejection process. A large hyperscale data centre can use millions of litres of water per day under this model.

As data centre heat densities increase - driven particularly by AI and high-performance computing workloads - water consumption has become a major sustainability concern for operators, regulators, and local communities alike. Alfa Laval’s liquid cooling solutions are designed to address this directly, using highly efficient closed-loop heat exchanger systems that dramatically reduce water consumption compared to evaporative approaches, while simultaneously enabling waste heat to be recovered and reused rather than rejected to atmosphere.

Can the water used to cool data centres be recycled or reused?

Yes - and increasingly, it should be. In well-designed liquid cooling systems, cooling water circulates in a closed loop, meaning it is continuously recirculated rather than consumed and discharged. This approach dramatically reduces overall water consumption compared to open evaporative cooling systems.

Beyond recycling, Alfa Laval’s heat recovery solutions go a step further - capturing the heat absorbed by the cooling water and transferring it to a secondary use, such as district heating networks, domestic hot water systems, or industrial processes. This transforms water from a cooling consumable into a carrier of recoverable energy, turning a sustainability liability into a genuine asset for data centre operators working toward net zero targets.

How are data centres - and AI data centres in particular - cooled?

Data centres are cooled using a combination of methods depending on their age, design, and heat density. Traditional facilities rely on air cooling - using computer room air conditioning (CRAC) units and raised floor systems to circulate cold air around server racks. However, as rack densities have increased - particularly with the rollout of AI infrastructure where a single rack can exceed 50–100 kW - air cooling alone is no longer sufficient.

Modern and AI-optimised data centres increasingly use liquid cooling, where chilled water or coolant is brought directly to the heat source via cooling distribution units (CDUs), rear-door heat exchangers, or direct-to-chip cooling systems. For the most extreme AI workloads, immersion cooling - where servers are submerged in dielectric fluid - is also gaining traction. Alfa Laval’s plate heat exchangers sit at the heart of these liquid cooling architectures, providing the efficient heat transfer interface between server-level cooling loops and the facility’s wider cooling or heat recovery infrastructure.

How can data centres reduce their energy consumption?

Cooling infrastructure accounts for a significant proportion of a data centre’s total energy consumption - in many facilities, 30–40% of all electricity used goes toward cooling rather than IT equipment itself. Reducing this overhead is therefore one of the most impactful levers available to data centre operators looking to cut energy costs and carbon emissions.

Key strategies include switching from air cooling to liquid cooling (which transfers heat far more efficiently), maximising the use of free cooling - using naturally cool ambient air or water to meet cooling demand without mechanical refrigeration - and implementing heat recovery to make productive use of waste heat rather than simply rejecting it. Alfa Laval’s heat exchangers are central to all three of these approaches. Their high thermal efficiency means free cooling can be exploited for more hours per year, mechanical chiller operation is reduced, and PUE - the standard measure of data centre energy efficiency - improves measurably as a result.

Who makes cooling systems for data centres?

Several manufacturers supply cooling equipment to the data centre sector, but few bring the depth of heat transfer engineering expertise that Alfa Laval does. As a global leader in heat transfer technology with over 130 years of experience across industrial, marine, food, energy, and process applications, Alfa Laval applies proven, field-tested engineering to the specific demands of data centre cooling - rather than adapting general HVAC products for a specialist environment.

Alfa Laval’s data centre cooling portfolio includes gasketed and brazed plate heat exchangers, welded heat exchangers for high-pressure applications, and complete cooling distribution solutions - all designed to maximise thermal efficiency, minimise energy consumption, and support heat recovery. For data centre operators, developers, and M&E engineers specifying cooling infrastructure, Alfa Laval offers both the product range and the application engineering support to design and deliver the right solution for facilities of any scale.