Google's St. Ghislain, Belgium data center has made news before for running without the use of any chillers, the biggest energy-hogs in a data center. The data center uses fresh air cooling for its server areas and, up until recently, was allowing them to run at temperatures up to 80 degrees F, sending traffic to other facilities to be processed when it got too hot, but now the tech giant is pushing the boundaries of how efficient a chiller-free data center can be by running the servers at temperatures up to 95 degrees.
Most data centers are kept at temperatures between 68 and 72 degrees because it's believed that the equipment won't operate as well in higher temperatures, but it turns out that's a bit of a myth, and an energy-intensive one at that. Keeping server rooms cool with the equipment constantly cranking out heat requires a lot of electricity and it's been calculated that data center operators can save 4 percent in energy costs for every upward degree. Here's a video from Google explaining the benefits when they were running at 80 degrees.