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Fujitsu Helps Tohoku Electric Power Achieve Stable, Energy-Efficient Datacenter Operations with Optical Fiber Multipoint Temperature Sensing Technology

Cuts annual air conditioning power consumption by 20%, equivalent to roughly 350,000 kWh and 120 tons of CO2

Fujitsu Limited

Tokyo, June 11, 2012

Fujitsu today announced that it has implemented a fine-grained, real-time temperature distribution visualization system within Tohoku Electric Power Group's datacenter in collaboration with Tohoku Electric Power Co., Inc. and Tohoku Information Systems Co., Inc. ("TOiNX"). Using the results obtained from the generated visualizations, the companies have completed a trial to optimize the datacenter's air-conditioning power consumption.

Temperature distribution visualization, which employs optical fiber-based multipoint temperature sensing technology developed by Fujitsu Laboratories, is the first of its kind in the world to involve the large-scale deployment of such technology at a datacenter. The ability to visualize temperature distribution makes it possible to greatly improve the efficiency of the datacenter's air conditioning, thereby reducing annual power consumption by an anticipated 20%, equivalent to 350,000 kWh, or 120 tons of CO2 emissions.


Tohoku Electric Power has actively pursued energy conservation as part of its business activities, and the company has been working with TOiNX to help it balance maintaining stable operations of its internal information systems with energy saving.

ICT equipment is often densely arranged within a datacenter, thereby leading to increased power consumption and greater amounts of heat produced by the equipment. As a result, it can be a major challenge to deal with is the increasing amount of power required by cooling systems to maintain stable operations.

To adequately cool ICT equipment installed at a datacenter, an efficient supply of cool air is needed, as well as a system for properly circulating hot air vented from the equipment while ensuring that it does not mix with the cool air.

Although efforts have been taken in the past to implement improvements based on temperature data collected from a limited number of sensing points, confirming whether the cooled environment has been fully optimized throughout the entire datacenter has proved difficult.

By applying optical fiber-based multipoint temperature sensing technology from Fujitsu Laboratories as a way to visualize the temperature distribution within the datacenter—which is operated by TOiNX, part of the Tohoku Electric Power Group—Fujitsu completed a trial that leveraged the results of these visualizations to optimize the datacenter's air conditioning.

Trial Overview

A single optical fiber line, acting as a temperature sensor, was installed at the front and back of each server rack, as well as on the ceiling and floor, thereby enabling the temperature distribution in the datacenter to be measured in high resolution (in 10-cm intervals) and in real time (every 30 seconds). The results of these measurements revealed the following:

  • Heat accumulated at some locations near the ceiling, and portions of this warm air circulated around the server racks' air intake openings, heating up the upper part of the racks.
  • Warm air from adjacent server racks mixed with cool air, raising the temperature of cooling air being supplied to the air intake openings.

Based on these results, it was possible to observe changes in temperature distribution in real time while taking measures to optimize the air-conditioning system through repeated trial and error.

Trial Period

February 2012 to March 2012

Measured Targets

  • Server racks: front and back of roughly 120 server racks
  • Floor: double-layered floors beneath the server racks
  • Ceiling: roughly the entire server room (optical fiber arrayed in parallel every 50 cm)

Measures Taken

While the datacenter was in operation, a number of measures were taken which did not involve changes to the facilities or the repositioning of equipment.

  • Closed off parts of the ceiling intake port and floor grill using vinyl sheeting to improve the circulation paths of cool and warm air
  • Using rack airflow control plates, directed air vented from racks upward and isolated it from cool air near the floor
  • Using output airflow control plates, optimized the output direction of air conditioners
  • Using subfloor airflow control plates, modified and improved the subfloor airflow near racks
  • Idled five air conditioners


It was projected that power consumed by the datacenter's air conditioning would be reduced over one year by an anticipated 20%, equivalent to roughly 350,000 kWh and 120 tons of CO2.

Figure: Changes in temperature distribution near ceiling

Future Plans

Going forward, Fujitsu plans to continue employing this technology to optimize air conditioning utilization and enable stable system operations, while at the same flexibly adapting to different operating conditions.

Related Information

The optical fiber-based multipoint temperature sensing technology employed in this trial is available as a commercial product from Fujitsu Network Solutions.

This product will also be demonstrated at Interop Tokyo 2012, to be held from June 13–15 at Makuhari Messe in Chiba, Japan.

About Fujitsu

Fujitsu is the leading Japanese information and communication technology (ICT) company offering a full range of technology products, solutions and services. Over 170,000 Fujitsu people support customers in more than 100 countries. We use our experience and the power of ICT to shape the future of society with our customers. Fujitsu Limited (TSE:6702) reported consolidated revenues of 4.5 trillion yen (US$54 billion) for the fiscal year ended March 31, 2012. For more information, please see

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All other company or product names mentioned herein are trademarks or registered trademarks of their respective owners. Information provided in this press release is accurate at time of publication and is subject to change without advance notice.

Date: 11 June, 2012
City: Tokyo
Company: Fujitsu Limited, , , , , , , , , ,