Data centers, which include all the buildings that contain data servers, telecommunication
equipment, cooling equipment and power equipment [2],
contribute a lot to this energy consumption raising. With the
development of information technology (IT), the amount of data
centers increase rapidly in recent years. Electricity used by data
centers worldwide increased by about 56% from 2005 to 2010. In
2010, it was of about 1.3% of all electricity use for the world and this
number continues to increase [3].