Yahoo has designed their data center for max power efficiency by using Chicken Coop design.
"A series of long, tall buildings aligned along the path of the prevailing winds, the Coop is able to harness those winds for free cooling for most of the year, much as chicken farmers use the wind to clear out the smells of hundreds or thousands of chickens."
"Based on its cooling-centric design, the YCC uses less than 1 percent of its total energy on cooling, and consumes at least 40 percent less energy than conventional data centers."