NTT Data Corp. has announced the details of its "Green Data Center," – a data center with a dc power system, which will be available for use in October 2008. NTT Data has offered the Green Data Center service since January 2008. The company will additionally provide various types of power saving technologies such as the dc power system, starting in October 2008.
According to the company, "approximately 10% of power is lost" every time ac-dc conversion or another process is conducted. It is claimed that the use of a dc power system could reduce the power consumption by about 20%, although it depends on other factors (such as the conversion efficiency and the number of times of dc-dc conversion conducted to control the voltage). Because a data center consumes an enormous amount of electricity, it is claimed that the power that can be saved is considerable, even though the reduction rate is only 20%.
For the first phase of the new Green Data Center service, NTT Data will only provide a low voltage (48V) dc power system. In many servers, a 380V direct current is output from an ac-dc converter of a power supply module installed on a rack or the server machine chassis. The resultant current is immediately converted into a direct current of 12V or lower with the use of a dc-dc converter. Therefore, if a dc power system is capable of providing a voltage of 380V, it is more effectively used with a server. The company claims that it will probably take some time, however, before the commercialization of a 380V system.
NTT Data stated that, in Japan, power systems of 300V or higher is generally prohibited by law because they are considered hazardous. The company states that it will thus take time to commercialize a high voltage dc power system because it needs to tackle some issues including the improvement of relevant laws. Nonetheless, the company said it is planning to start test services of the 380V system.
