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How Data Centers Use Water to Cool

It’s no secret that data centers consume a lot of energy. In the US, they consume about 50 billion kWh a year, about as much as 4.7 million homes. Although modern, efficient data centers change almost all this energy into computation, they also transform it into heat.

To keep the computer chips working efficiently (and not melting), data centers must cool their servers.

Water plays an important role in data center cooling. Water is used to cool with:


Each strategy has its own part to play in the future of efficient cooling data centers.

Evaporative Cooling

Evaporative cooling is the most common and effective use of water to cool data centers. In evaporative cooling, water takes energy from hot surfaces or air to evaporate. This cools the air or surface.

The most effective evaporative cooling strategy uses an evaporative medium. The evaporative medium soaks up water, allowing a high degree of contact between water and hot air. As air passes through the medium, the water evaporates, cooling the air. This is essentially the same as a residential evaporative cooler, but it’s generally used on a much larger scale.

Other times, misters apply water directly to flowing air or spray it on a surface. In both cases, the water evaporates, cooling the air or surface, but the process is less efficient in terms of water use and heat exchange.

Learn more about water distribution best practices in our Kuul video library here.

Air Chillers

Woman holding an ipad in a data centerAir chillers work by cooling water to a low temperature, then passing it through a heat exchanger with a flow of warm air over it.

The cold water takes heat from the air, cooling it off. The water is then re-cooled to be used again for chilling. Although this process uses less water, it uses much more energy.

Rack Cooling

Another strategy is to install the air chillers directly on the server racks. In this design, the air intakes for a server rack draw air directly over the heat exchangers full of chilled water.


This system uses many more heat exchangers, but it increases the cooling on the server racks.

Direct-to-Chip Cooling

In this design, the water cooling bypasses the air entirely. Instead of passing cooled air over the processing chips, this system uses heat exchangers built atop the chips. Water flows through the heat exchangers and takes heat directly from the chips themselves.

This system can handle the highest heat, but it’s also the most resource-intensive because it requires heat exchangers atop each chip and constantly flowing water to maintain cooling.

Direct-to-chip cooling also has the disadvantage that if there’s a break in the cooling system, water can spray directly onto the chips, causing severe damage.

Explore data center cooling best practices.

Efficient Evaporative Cooling with Kuul 

The most widespread use of water for cooling data centers is by using evaporative cooling. Kuul evaporative media is a highly effective choice for data centers.

Kuul Evolution FirePro™ evaporative cooling media meets strict UL 900 standards, which helps reduce the spread of fires. Plus, Kuul evaporative media is more than 98% efficient at low airflow, and even at the highest airspeeds, it remains 90% efficient.

Even when saturated, Kuul evaporative media provides 20% less air resistance than competing brands, which means less power consumption by your evaporative coolers.

We offer a powerful option for customizing your data center design. We offer evaporative cooler pads ranging in thickness from 4” to 12”, with custom sizing to your application. We also offer Kuul Evolution FirePro DE™ for drift elimination. This lets you use even thinner evaporative cooler pads and higher air velocities so you can achieve cooling under the tightest of space demands.

Want to learn more about the benefits of Kuul evaporative media for your data center? Please contact us today with questions or schedule a free video consultation.