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Getting the heat out: A look at evaporative cooling

When our data centers are answering your search queries and streaming YouTube videos, they’re generating heat. We wrote about our hot hut infrastructure which pulls heat from our servers in an earlier blog post, but how do we efficiently get that heat out of the building?

Cooling towers, like those pictured below, expose water heated by the data center floor to the outside air. In the same way that perspiration removes heat from the human body, we use water evaporation to cool the water that runs through our data centers. This allows us to use the ‘free cooling’ provided by the local climate.

Rooftop cooling towers 

We use two loops of water to remove heat from the data center floor and transfer it to our cooling towers. Red (hot) and blue (cold) pipes carry water to and from the data center floor. Yellow (hot) and green (cold) pipes carry water to and from the cooling towers on the roof. The photo below shows our heat exchangers, where these two loops of water meet. The colorful pipes aren’t just for decoration, they designate the hot and cold water traveling in each of the loops. It is a happy coincidence that our company colors worked so well for labeling our water pipes.

Heat exchanger room 

In some sites with hot summer climates, we have backup chillers on hand (the double-barreled green units on the left side of the photo)—just in case the temperature or humidity gets too hot to rely on our cooling towers. We only use these when absolutely necessary, since they’re not as efficient as using outside air for cooling.

We aim to use as little energy as possible to power our products, and our cooling towers are a critical part of this effort. Learn more about how we cool our data centers on our Data center site.

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