As organizations seek to improve data center efficiency, data center managers can take advantage of several cooling system strategies to combat data center energy consumption while meeting varying business criteria. The use of economizers and supplemental cooling systems are two technologies that merit serious consideration. Fluid economizers bring free cooling or partial free cooling benefits to a wider range of geographic areas than commonly believed. Supplemental cooling, with or without a fluid economizer, provides substantial savings, depending on your business criteria. Beyond these technologies, additional energy savings can be gained by taking measures such as increasing supply chilled water temperature, using variable air flow and increasing the kW per rack in the servers.