Google's Custom Built "Hot Huts" Keep Its Data Centers Cool [Gallery]

Very recently, Google started giving people tours of its highly secretive data centers. Not actual tours, mind you, you still need more clearance to get into a Google data center than to get into the White House and the vast majority of Googlers will never set foot in one.

But you can take a virtual tour of some of the data centers, as long as you don't mind the colorful and stylistic but not very revealing photos Google has put up.

If you're looking for realism, you can take the decidedly low-definition Street View tour of one data center.

Even with the photos hand-picked by Google, there's still some details to make out, if you know what to look for. For example, you may spot one of Google's custom cooling systems.

Cooling is the biggest energy drain of any data center, apart from the power needed by the servers themselves. Tech companies strive to bring down energy costs, but no one does better than Google.

It's opted for extreme solutions in some places, like sea water cooling in Sweden, or sewage water cooling in one data center in the US.

In most places, the cooling solutions are a bit more traditional, but still made to Google spec. One way of improving cooling efficiency is keeping the hot air isolated from the rest of the room.

Google does this via what it calls "hot huts," small rooms that sit behind the rows of servers and suck up all the hot air coming out of them.

These rooms are separated from the rest of the data center floor. Water pipes feed cooling pipes, sitting at the top of the room, which cools the air enough for it to be pushed back into the data center floor where it will begin a new cycle.