Computer data centers are large commercial buildings that house a very large number of computers, such as thousands or tens of thousands of rack-mounted computer servers and other computing equipment (e.g., storage devices, power supplies, and networking equipment). Generally, computer data centers provide computing services, such as web page hosting, search, e-mail, video, and other services, to a number of distributed remote users.
Because internet-connected users have grown enormously in numbers, and the types of services they demand have grown enormously in complexity, data centers must now provide a quickly increasing amount of computing resources. As a result, the size of data centers has increased, the number of data centers has increased, and because data centers require the use of electronic equipment, the electrical demands of data centers have increased. Because the electricity used by data centers is turned into heat, the cooling demands of data centers have increased significantly also.