Facebook gave a keynote presentation on its Data Center Design
Facebook's Latest Innovations in Data Center Design
Senior Electrical Engineer, Facebook Paul Hsu
Datacenter Mechanical Engineer, Facebook Dan Lee
Below is a side by side slide Paul presented on the difference between a typical data center power conversion vs. the Facebook design.
Dan has a slide with side-by-side comparison of a typical mechanical system vs. the Facebook design.
A couple of other slides share are on the Reactor Power Panel and Battery cabinet.
The results Facebook shared.
For more details you can find information at Facebook's Open Compute Project web site.
If you want to see pictures of inside the Facebook data center check out http://scobleizer.com/2011/04/16/photo-tour-of-facebooks-new-datacenter/ and http://www.datacenterknowledge.com/archives/2011/04/19/video-facebooks-penthouse-cooling-system/