Perhaps they could consider using something like the "propane refrigerator" (http://www.warehouseappliance.com/HowLPfridgeWorks.html) concept to increase the efficiency of their AC units.

I'm not sure just how efficient they try to make these facilities and where the point of diminishing returns is reached.

As for making servers last 10 years, I think you can depreciate them over 5 years, and technology has made them obsolete at 3, so I don't see the value in keeping them that long. I think the cost in lost efficiency would make it not cost effective.