1. A smart cooling system for cooling racks in a data center, said system comprising: a cooling device for supplying cooling fluid to said racks, said cooling device including a variable output fan; a plenum having an inlet and a plurality of outlets, wherein said inlet of said plenum is in fluid communication with said fan; and a plurality of vents for delivering said cooling fluid to said racks, wherein said vents are operable to vary a characteristic of said cooling fluid delivered through each of said vents.