Green Data Centers

The widely adoption of the novel Internet services of the last decade, e.g., web 2.0 services, cloud services, and cloud computing, modified the structure of the whole Internet ecosystem. Contrary to the earlier disperse structure, where each service had its own server to be operated on, the infrastructures of the current cloud services are highly centralized; numerous services are run by a single infrastructure. These facilities are commonly known as data centers. The operators’ profit-awareness causes the recent golden age of the data centers. Due to the economics of scale principle, the expenditures (both capital and operational) can be reduced with these highly concentrated architectures. The energy consumption of the data centers is accounted for 15 percent of the total expenditures of a data center [1] while data centers have a non-negligible share of the total energy consumption of the society. Based on the study of J. Kroomey [2], the average power dissipated by data centers was 6.4, 4.7, and 1.8 GW in US, Western Europe, and Japan, respectively in 2005. The energy consumption of data centers was as high as 1.5% of the total energy consumption in the US in 2006. Moreover, these ratios are increasing resulting from the recent data center