A model of the test facilities introduced into the "Tachikawa ICT Ecology Center"
A power supply system that supports DC power supply
The "FATSCL," a partial air conditioning system, is the black device seen in the center.
NTT DoCoMo unveiled its Tachikawa ICT Ecology Center, which was established in the NTT DoCoMo Tachikawa Building (in Tachikawa City, Tokyo), to the press Feb 19, 2009.
The building has communication facilities for commercial services on the first to fourth floors. The center was built in a free space on the top floor of the building with test facilities to reduce CO2 emissions.
"We aim to reduce CO2 emissions by 50% compared with existing facilities," the company said.
NTT DoCoMo started proving tests in February 2009. It plans to sum up the results of the tests by the end of March and to use the new facilities for its i-mode communication service from mid-2009 at the earliest.
The center is equipped with 14 racks of servers, four racks of network devices, two racks of air conditioners and some power supply devices. The company runs the programs for proxy data that are used in its commercial services by using those facilities and check the effect of CO2 reduction.
NTT DoCoMo adopted three measures to cut CO2 emissions. They are the introductions of (1) servers that consume less power, (2) DC power supply technologies and (3) new air conditioning technologies.
The company intends to reduce CO2 emissions by 40% through the introduction of the servers with power-saving features. But it has to wait until a server manufacturer develops an appropriate product.
Therefore, this time, NTT DoCoMo conducts proving tests of the DC power supply technologies and the air conditioning technologies.
It aims to reduce CO2 emissions by 10% through the introduction of the former and 30% through the introduction of the latter, compared with the amount of CO2 emissions from the facilities equipped with only low-power-consumption servers.
The voltage value for the DC supply technologies is -48V, which is widely used for communication facilities of the NTT Group. The power supply devices for DC distribution were newly developed by NTT Facilities Inc and have a higher conversion efficiency than existing devices, according to NTT DoCoMo.
The power supply devices convert AC power to DC power, which is then supplied to servers that are operated by DC power. Of the 14 racks of servers, three racks hold DC-powered servers while the remaining 11 racks hold AC-powered servers.
The power inlet to each server is equipped with a sensor. And, by cumulating the supplied power, it is possible to know how much the efficiency is improved through the introduction of DC servers.
In respect to the air conditioning technologies, NTT DoCoMo used "partial air conditioning" and "aisle capping" for the first time.
In most of the existing data centers, the entire room equipped with servers and communication devices is cooled because heat release values of various devices were almost the same.
However, as processing density of servers increases, the heat release value per unit volume is increasing. Therefore, when a server is properly cooled, other devices can end up being cooled too much.
To prevent this problem, partial air conditioning systems were placed near the servers that need to be cooled. This air conditioning system, developed by NTT facilities, is named "FATSCL."
The aisle capping is a technology that prevents warm air exhausted out of the room from entering the area above air conditioning systems or servers. Specifically, a transparent panel is used to cover the ceiling of the room to prevent intrusion of warm air and improve the air conditioning efficiency.
The proving tests will be completed by the end of March 2009, but NTT DoCoMo will continue to introduce new technologies and test their CO2 reduction effects. One of those technologies is the high voltage direct current (HVDC) technology, which uses a voltage as high as 400V. But the schedule for its proving tests is yet to be decided.
"In respect to the HVDC technology, the voltage varies depending on region, and there are few types of servers that support the technology," the company said. "So, we will not start proving tests in the near future though we are still interested in them. Some companies in the NTT Group, like NTT Facilities and NTT Data are developing technologies related to the HVDC. In light of the results of them, we will conduct proving tests at an appropriate time."
Nikkei Electronics Asia magazine is available each month free of charge to engineers, managers and other qualified readers.
Nikkei Electronics |
Nikkei Monozukuri |
Nikkei Microdevices |
Nikkei Automotive Technology |
|---|---|---|---|
 |
 |
 |
 |
| The magazine for electronics designers and managers. | Design You Won't Regret - How to Reduce the Risk of Accidents | The most comprehensive technical journal for makers and users of LSIs and LCDs. | The comprehensive automotive technology magazine. |
Copyright © 1995-2009 Nikkei Business Publications, Inc. All rights reserved.
All editorial content and graphics on this Web site may not be reproduced in whole or in part without the express permission of the copyright owner.
November 2009
October 2009
September 2009