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2.1.1.8 Power saving system control technology to maintain temperature and humidity of
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container‐type data centers
Power saving system control technology shall be included to maintain temperature and humidity of
container‐type data centers by closely coordinating the operation of servers and air‐conditioning
systems as elemental technology for ICT infrastructure of smart sustainable cities.

Data centers are used in smart sustainable cities in order to collect necessary data, process those
data and provide and manage application services using them.
With container‐type data centers rather than data centers in buildings, one can expand the scale of
data centers according to increases in demand. It facilitates the achievement of a balance between
investment and return for data centers providers as well as a reduction of environmental burden.
To reduce the environmental burden of the container‐type data centers themselves, the technology
is required to reduce the amount of electricity consumed to maintain proper temperature and
humidity levels.

There is technology that maintains temperature and humidity of container‐type data centers using
external ambient air and air‐conditioning equipment attached to the inside of the container, instead
of an internal fan equipped to each server. The use of external ambient air reduces the amount of
electricity used by the air conditioning.

By eliminating the use of internal fans of servers, the amount of electricity used by air conditioning
is also reduced. Generally speaking, when external ambient air is used to cool servers, the higher
the ambient temperature is, the larger the amount of electricity consumption of internal fans
becomes. However, this technology allows the use of internal fans by maintaining temperature and
humidity with air‐conditioning equipment attached to inside of the container.

The main composing elements of the air‐conditioning equipment attached to inside of the container
are the fans. They are controlled to achieve optimum temperature of CPUs using information of
location, temperature and electricity consumption of each CPU.

If the temperature of each CPU is too high, the performance of the CPU gets lower (Figure 14). The
technology controls the container air‐conditioning fan to ensure that the system never reaches an
operating temperature where CPU performance is compromised.
In addition, there is optimum temperature of CPU to minimize the total power consumption
(Figure 15). When a CPU's operating temperature becomes too high, the amount of electricity
consumed by a server increases as a result of the impact of the CPU's leakage current. Conversely,
by trying to lower the CPU temperature, greater power is consumed by the container air‐
conditioning fan. The technology controls the container air‐conditioning fan to achieve an optimal
CPU temperature that will enable the amount of power consumed by the entire container data
centers to be minimized.

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5 Corresponds to a contribution of FUJITSU (Japan) by document FG‐SSC‐0031.

232 ITU‐T's Technical Reports and Specifications