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Efforts to Reduce Greenhouse Gas Emissions

Supercomputers at the Human Genome Center are working to reduce greenhouse gas emissions. In a typical computer, it is possible to reduce the number of servers by consolidating servers through virtualization, for example. In contrast, supercomputers have many jobs running 24 hours a day, 365 days a year, and many computers are always running at full capacity.
In the operation of a supercomputer, it is difficult to save energy without reducing the processing efficiency of the computer, but we analyze the operation in detail and make daily efforts to drastically reduce the resources that can be reduced.

Efforts to reduce greenhouse gas emissions at the Human Genome Center
空調消費電力量の 2009 年度比約 10% 削減

Reduce air conditioning power consumption by approximately 10% compared to fiscal 2009

  • Power consumption for air conditioning was reduced by approximately 10 percent compared to fiscal 2009. (July 2010).

  • Due to the record cold summer in August and September 2009 and the extremely hot weather in August and September 2010, we were unable to reduce the amount of electricity we use compared to fiscal 2009.

Temperature in the supercomputer room

Supercomputers, which are made up of many computers, consume a lot of power and generate a lot of heat. When the operating temperature of a computer rises, malfunctions due to errors in the processor's internal electrical signal processing and hardware failures due to thermal wear and tear can occur. However, in light of the global warming problem, it is very important to reduce greenhouse gas emissions through energy conservation in the operation of supercomputers, which require a lot of electricity. Therefore, the Center for Human Genome Analysis is currently implementing the following initiatives.


  • Monitoring of air conditioner power consumption, computer power consumption, and temperature inside the computer chassis

  • Analysis of heat pools and optimization of air conditioner setting temperatures

  • Partial shutdown of air conditioning units in the winter (those units that are shut down should be rotated to minimize the impact of long shutdowns).


Temperature distribution in the server room


Server Enclosure Temperature Monitoring Chart

Setting up a capping

The high heat exhaust from a supercomputer creates a "heat pool" where only one part of the space is hot. In the above diagram of the temperature distribution in the server room, a heat pool with an intake temperature of 25°C is generated in the area marked with a black circle. This heat pool can also adversely affect the stable operation of blade servers in proximity racks. To deal with such a heat pool, the method of using air conditioners to cool the entire server room will result in excessive cooling of the non-hot areas, which will not only reduce cooling efficiency but also cost excessive electricity.
To solve this problem, we set up a cover as shown in the left figure and let cold air blow up from under the floor of the enclosure, making the temperature of the intake part in the front of the server housing the same as the temperature of the air conditioner outlet, and solved the heat accumulation problem.

Server rack enclosures

Other Initiatives

  • The fluorescent lights in the supercomputer room are turned off except when necessary.

  • The effect of changing the operating frequency according to the CPU load on the computer was verified. The operating frequency when the CPU load is high cannot be changed because the processing speed will be reduced. Therefore, we verified the setting to lower the CPU operating frequency when the job is not running and the CPU load is low, but when the CPU load is low, the power consumption has already decreased and the reduction effect could not be confirmed.

  • Hitachi Appliances, Inc.'s high-efficiency inverter-controlled air conditioners make air conditioning more energy-efficient. Please click here for more information.

  • The server room temperature distribution diagram simulates the air-conditioning environment of a supercomputer room using AirAssist®, an air-conditioning environment consulting service that uses a three-dimensional thermal fluid simulator. For more information, please click here.

Power consumption monitor in the Medical Research Institute (IMSUT use only)

New discoveries and learning

If you are a member of the Institute of Medical Science and have obtained permission, you can view the power consumption monitor page of the Institute of Medical Science from this page. You will need a password to view it. If you would like permission to view the site, or if you have forgotten your password, please send an email to the following address

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