Imagine a computer processing chip that could run at any speed, without any cooling. Imagine that this processor could be mass produced using existing technologies, and using off-the-shelf substrate materials. Well, this is not fantasy and I was reminded the other day about the work NASA has been doing for a few years...
It is true! Nasa has been demonstrating a set of chip technologies that have been able to operate at over 1000-degrees F for extended periods of time. While this is remarkable for NASA, now adjust your focal point to the usage of this technology for standard IT purposes. Cooling as we know it today would be a thing of the past. We might have cooling just for the human occupied areas, and perhaps some filtering still required, but here we'd see data centers running happily at over 100 degrees F.
http://arstechnica.com/hardware/news/2007/09/nasa-designs-new-ultra-high-temperature-chips.ars
Finally PUE of 1.00! Curious reading to be sure...