Technologies Behind NEC's High Temperature Ambient Server

White Paper
Technologies Behind
NEC’s High Temperature Ambient Server
Boosting the power efficiency
of data centers
http://www.nec.com/

Technologies Behind NEC’s High Temperature Ambient Server
1. What Are High Temperature Ambient (HTA)
Servers and Storage Devices?
1.1 Introduction
Cloud computing and other advanced information & communications technologies (ICT)
are changing business and society. But as cloud services expand, so do the data centers
housing the increasingly large numbers of servers and storages devices required to
deliver these services, leading to increased power consumption. Corporations looking to
make their data centers more power efficient and reduce their operating overhead are
therefore searching for new and effective power saving measures.
To address these issues, NEC is providing HTA servers and storage devices as well
as solutions to help improve the power efficiency of the cooling systems and facility
equipment used in data centers. This paper describes NEC’s technologies for
realizing HTA servers and storage devices, including the verification tests
performed on the HTA servers and storage devices.
1.2 Steps taken by NEC to realize power
saving servers and storage devices
Looking at a data center’s power consumption figures classified by usage, ICT
equipment such as servers and storage devices accounts for 53% of consumed
power, whereas the cooling systems, power distribution, lighting equipment, and
other facilities account for the rest (47%). (These are actual values measured in an
NEC data center.) In fact, the cooling systems accounts for as much as 31% of data
center power consumption. It is therefore important to reduce the power consumed
by the cooling system as well as by ICT equipment in order to achieve power savings
in data centers.
Power Consumption in Data Center Classified by Usage
Lighting and
other equipment
Power supply
equipment
7
9
1.3 NEC’s HTA servers and storage devices
To achieve further power reduction, NEC has released a platform that operates in
HTA servers and storage devices that operate up to 40 degrees Celsius (104
degrees Fahrenheit).
The maximum ambient operating temperature for conventional servers and
storage devices is generally 35°C. NEC has successfully increased this limit by
5°C to 40°C by selecting components that enable optimization of cooling design
and airflow. This makes it possible to set the cooling system in the data center to a
higher temperature, reducing the power consumption.
The figure below shows an example of a customer that is using ICT equipment
installed in 2007. If this customer replaces their existing devices with NEC’s HTA
power saving servers and storage devices, the ICT equipment will consume less
power and therefore generate less heat. This means that the cooling system will
need less power to cool the data center. Power consumption can also be reduced
by elevating the cooling system temperature setting by 5°C. These measures add
up to a reduction in cooling system power consumption of approximately 40% and
a decrease in data center power consumption of 34% (as estimated by NEC).
Breakdown of current power
consumption in data center* 1
Other facilities: 16%
Cooling: 31%
Networks: 11%
Storage devices: 9%
Servers: 33%
Before
Reduced by
40%
Reduced by
50%
Reduced by
53%
*1 Actual values measured in an NEC data center
Power consumption
reduced by
34%
After
Cooling system
31
ICT
equipment
53
2. NEC’s Technologies for
Realizing HTA Products
Power saving measures for cooling systems are as important
as improving the power efficiency of ICT equipment.
NEC has been addressing power saving for IT platforms since 2007. We have achieved
significant power savings in server and storage devices by implementing the internal
airflow designs and cooling technologies proven by us in supercomputer and
mainframe development.
With the rapid shift to cloud computing, ICT systems are being consolidated in data
centers, making it important to implement power saving measures for the whole data
center, including the cooling system, power supply equipment, and lighting equipment.
Determined to take a proactive approach to an issue that all corporations will have to
address, NEC launched a project in 2010 to save power in data centers as a whole.
NEC provides HTA servers in its Express5800 series x86 server lineup. The Express5800
series incorporates the Intel® Xeon® processor with excellent power efficiency. Power
consumption by these servers is also reduced by adopting the
80 PLUS® PL ATINUM power supply with high conversion
efficiency along with other power saving components.
In addition, the Express5800 series lets you set a power cap
value to control power by using the bundled ESMPRO server management software.
In addition to the power saving features in the server itself, NEC has also thoroughly
reviewed the airflow design and cooling components in the housing to enable high
temperatures. The following sections describe NEC’s original designs for realizing power
saving.
© 2012 NEC Corporation The NEC logo is a registered trademark or a trademark of NEC Corporation in Japan and other countries.
2

2.1 Server cooling technologies
System design technology for optimizing the airflow
NEC has applied to the Express5800 series the advanced cooling technologies
acquired when developing mainframes, which require stability and robustness,
and fast and highly efficient supercomputers. Stable operation at 40°C has been
realized by thoroughly redesigning the airflow and cooling components in the
server.
One of these cooling technologies used for improving the cooling efficiency is
an airflow guide. The challenge of server cooling is how efficiently cool air taken
in from the front air inlet is transferred to the outlet on the rear. The
Express5800 series servers incorporate an airflow guide to adjust the airflow.
The shape and angle of the airflow guide is designed to generate the optimal
airflow so that the required amount of cool air is delivered to each component
without being heated.
As a result of this design, 2U rack mount servers can now incorporate hard disk
drives not only in the front of the main unit but also in the rear.
Express5800/R120d-2E can incorporate a total of twenty-six 2.5-inch hard disk
drives: 24 drives in the front and 2 drives in the rear. (Twelve 3.5-inch hard disk
drives can be incorporated in the front.) Increasing the number of hard disk
drives that can be incorporated eliminates the need to add servers to secure
hard disk capacity, resulting in an efficient use of rack space. A large hard disk
drive capacity is also beneficial for meeting big data needs.
Front HDD cage
Front
GT110d
Parts are placed parallel to
the airflow direction
Airflow
Power
supply fan
Heat sink
Heat
exhaust fan
GT110d-S
Cool down
CPU
Cool down PCI.
Offset fan placement
Fan for cooling down
2.5-inch SAS HDD
Airflow
Offset placement of fan for effective cooling
— Optimal placement of power supply unit in 2-way rack server —
NEC has enabled a maximum ambient operating temperature of 40°C in 2-way
rack servers which incorporate two CPUs in a single server chassis, by
conducting complex cooling simulations and operation tests.
The layout of the power supply unit leverages NEC’s expertise to improve the
cooling performance in 2-way rack servers. These servers require a high
cooling efficiency because parts that generate heat, such as the 24 DIMMs and
CPUs with a thermal design power of 135 W, are placed at a high density. By
placing the power supply units and CPUs as shown in the figure below, cool air
can be supplied to both the power supply unit and CPUs in such a way that air
heated by the CPUs does not flow into the power supply unit again. The cooling
performance of the two power supply units has also been improved by
separating them, and the airflow efficiency has been raised by laying out the
power supply units and CPUs symmetrically.
2.5-inch drives (24 units)
3.5-inch drives (12 units)
Rear
Rear HDD cage
Airflow
R120d-1M
Rear
2.5-inch drives (2 units)
Guide cool air to the HDDs in the rear
by fine-tuning the airflow
Front
Placing supply units away from
the hot air flowing from the CPUs
Layout technology to optimize airflow
NEC has devised a layout to optimize airflow by leveraging the strength of its
in-house design and development of motherboards. Cool air is designed to flow
in a straight line from the front intake to the rear of the housing in this design. In
tower-type servers, memory slots are placed horizontally so that the airflows in
a straight line, whereas these slots are generally placed vertically.
In addition, a larger heat sink and duct are employed to efficiently cool down
the CPUs which generate a large amount of heat. Offset placement, in which
the position of blower fan is intentionally shifted, is used to generate airflow that
allows a single fan to cool down both the CPUs and the PCI slots. On top of
that, this product is designed to allow airflow in a straight line from heat
sources by inclining the heat exhaust fan to directly and efficiently cool down
the PCI slot, which generates heat.
Operation guaranteed at an ambient temperature of 40°C
to help reduce the power consumption of cooling units
A cooling design that enables operation at an ambient temperature of 40°C was
realized in an innovative 2-way rack server by conducting complex cooling simulations
and operation tests. (The guaranteed ambient operating temperature is generally 35°C.)
Power
supply unit
Express5800/
R120d-1M
Airflow
The cooling performance of the
power supply unit was improved by
placing the power supply units at
positions so that the airflow heated
by the CPUs could not reach them
and also separating them (i.e., they
could be supplied with fresh air).
An efficient airflow was realized
by a symmetric layout.
Large CPU heat sink
(supporting 135W CPU)
Power
supply unit
Airflow
Express5800/
R120d-2M
© 2012 NEC Corporation The NEC logo is a registered trademark or a trademark of NEC Corporation in Japan and other countries.
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Technologies Behind NEC’s High Temperature Ambient Server
2.2Storage device cooling technologies
NEC provides the NEC Storage M series SAN disk array as an HTA storage
device. NEC Storage M series is a storage device that saves power by
approximately 50% compared with the conventional model with the same
capacity by adopting the common architecture of the Express5800 server
series. The MAID (Massive Array of Inactive Disks) automatically switches less
frequently accessed volumes to power saving mode to reduce power
consumption.
2.3 Cooling assessments
The server mother boards have been designed with an optimal component
layout through measurements and simulative analysis of temperature and its
distribution. For measurement, temperature sensors were placed in more than
100 positions, NEC also verified the cabling at the design and development
phase so as to not affect maintenance work after installation. NEC’s HTA
servers and storage devices have all passed these strict cooling assessments.
System design technology for optimizing the airflow
The adopted airflow design allows cool air to flow in a straight line from the
front to the rear of the unit to improve the cooling efficiency. The structure of
unit is designed considering the airflow going from the hard disks to the air
holes to the control board and out through the fan.
There are also air holes on the back plane to optimize airflow in order to
increase the cooling efficiency between HDDs.
HDD
Back-Plane
Power
supply
Blower fan
3. Verification Tests
Front side
Rear side
Control board
Layout technology to optimize airflow
The cooling efficiency has been improved by adopting Intel low-power
processors as the CPUs and also by using a large heat sink. In addition, the
airflow and component placement have been optimized to allow for the worst
case scenario of fan failure.
To facilitate understanding of the cooling effects of the Express5800 series and
NEC Storage series, this section describes two verification tests – a fresh air
cooling verification test in which the device was operated in an environment in
which only the direct free air cooling method was used, and a long duration
verification test.
In addition to these verification tests, NEC also supplied HTA servers to Intel for
assessment and verification of heat and power consumption reduction mainly
from the viewpoint of the CPU.
Optimal placement of power supply unit in NEC Storage M series
Winner at Green IT Awards 2011
The use of power supply unit with high conversion efficiency improves the
cooling efficiency of the power supply unit and thus allows more cool air to flow
to the control board.
Optimized amount of airflow
for power supply and control
board
Optimization of HDD airflow
(Back plane air holes)
Layout design
considering airflow
Low-power CPUs
Large heat sink
The Express5800 series and NEC Storage M series, which can operate at a maximum
ambient temperature of 40°C, received the Green IT Promotion Council Chairman’s
Award* 2 in the energy saving of IT equipment (“of IT”) category at the Green IT Awards
2011. The award was received in recognition of the power saving performance of these
products and the originality and innovation required to increase the ambient operating
temperature to 40°C. The award in this category is given to IT devices, services, systems,
and other products that deliver an excellent power saving performance.
Product name/model number
1-way tower: Express5800/GT110d
1-way slim: Express5800/GT110d-S
1-way water-cooled slim: Express5800/GT110d-S (water-cooled)
1-way rack: Express5800/R110d-1E and Express5800/E110d-1
SAN storage: NEC Storage M10e and NEC Storage M100
*2 The Green IT Promotion Council is a Japanese industry-academic-government organization
found in 2008 to address the global warming issue. The council promotes power saving through IT.
© 2012 NEC Corporation The NEC logo is a registered trademark or a trademark of NEC Corporation in Japan and other countries.
4

3.1 Direct free air cooling verification
test in data center
3.1.1 Outline of verification test
Purpose
• To verify the operating status of servers and storage devices throughout the
year in an outdoor air intake environment.
Verification environment
• Data center in Tokyo with no cooling system used
Equipment used for verification
Server : Express5800 series
Storage : NEC Storage series
3.1.2 Details and results of assessment
Details of assessment
• The server CPU and storage IO were operated constantly in a high load
state (almost 100%).
• The intake air temperature, internal temperature, and power consumption
were measured.
Assessment period
Verification has been ongoing from December 2010 until now (Septmber 2012).
Assessment results
Although the intake temperature of the server exceeded 35°C in summer when
the outdoor air temperature exceeded 35°C, the server, whose maximum
ambient operating temperature is 40°C, operated stably.
Even when the external humidity suddenly increased due to evening showers or
other weather conditions, the proper humidity was maintained at an optimum
level inside the ICT equipment by keeping the temperature of the intake air
several degrees higher than the outdoor air, using exhaust air from the server.
3.2 Long duration verification test
3.2.1 Outline of verification test
Purpose
• To confirm long-term stable operation in a high temperature environment of
40°C or higher
Verification environment
• The server was installed in a constant temperature chamber (constant
temperature oven) and exhaust air from the server was circulated, with the
temperature maintained at 40°C or higher.
Equipment used for verification
Server : Express5800 series
Storage : NEC Storage series
3.2.2 Details and results of assessment
Details of assessment
• The server CPU was operated constantly at a high load state (almost 100%).
• The server was operated in a constant temperature chamber with the
temperature on the front panel of server maintained between 40°C and 42°C,
with the error status of the server being checked.
• The intake temperature, internal temperature, and power consumption were
measured.
Assessment period
Verification has been ongoing from April 2011 until now (July 2012).
Assessment results
The server has continued to operate stably even in a high load state without
generating errors for over one year. This verification test is ongoing.
Constant temperature chamber Temperature of the front panel of server: 41.7°C
41
Highest outdoor air temperature and highest server
intake temperature in August in Tokyo
40
35
100
90
80
Highest and lowest outdoor humidity in August
70
30
60
Highest outdoor air temperature
25
Highest intake temperature
20
Aug.1 Aug.15 Aug.31
50
40
Highest outdoor humidity
Lowest outdoor humidity
30
Aug.1 Aug.15 Aug.31
Exhaust air from the server is circulated and partly emitted
to maintain a front panel temperature of 40°C.
(The server is being operated at between 40°C and 42°C).
The door on the right is opened briefly to measure the temperature
with a thermo camera.
27
Advantages of HTA servers and storage devices
in terms of relative humidity
A humidity of 80% or less is recommended for IT devices to prevent dew condensation.
With an outdoor cooling method, if the humidity of the outside air is as high as 100%, the
temperature inside the data center must be kept higher than the outdoor air in order to
maintain a lower humidity. In general, the relative humidity drops to approximately 80% if
the air temperature when the humidity is Humidity
100% rises by several degrees.
100
80
HTA servers and storage devices are very
effective in environments in which the
temperature must be kept higher than the
0
outside air.
35 39
Temperature
4. Applications of HTA Servers and
Storage Devices
4.1 Higher temperature setting of cooling system
The temperature of the cooling system can be set higher by implementing HTA
servers and storage devices. This will reduce the power consumption of the
cooling system. This section introduces an example of reducing cooling system
power consumption by 37% at an NEC testing center.
© 2012 NEC Corporation The NEC logo is a registered trademark or a trademark of NEC Corporation in Japan and other countries.
5

Technologies Behind NEC’s High Temperature Ambient Server
Environment
• NEC IT platform Testing Center with 200 to 300 servers, storage devices, and
network devices installed.
• Eight air conditioners under operation
• Total power of approximately 150 kW
Issues
• It is difficult to separate cool and warm air because there is no underfloor
cooling system.
The environment used for verification is a space designed to assess ICT
equipment before shipment and therefore does not have any underfloor cooling
system. It was therefore difficult to control the cool and warm air.
• Frequent unit displacement and fluctuation of operating rate
Multiple ICT devices are tested at the same time in the testing center and the
device configuration is frequently changed according to the type of test. It is
therefore difficult to keep the temperature constant, leaving no choice but to set
the cooling system to a low temperature to avoid the generation of hot spots.
Investigation
After performing measurement across the whole floor, it was found that there were
many low temperature areas where the indoor temperature was 23°C or less.
Analysis
As a result of performing heat analysis using an analysis tool, it was determined that
five air conditioners could cover the current amount of heat generation. Three of the
eight operating air conditioners were therefore stopped and the optimal temperature
(25°C to 30°C) was successfully achieved at the air inlets of the ICT equipment.* 3
Measures
We determined the positions of the three operating air conditioners that had to be
stopped by using heat analysis.
We also implemented measures to optimize the airflow of exhaust heat by using a
capping method and adjusted the airflow direction of the cooling system for some
racks to realize airflow control in which hot spots would not be generated even if
those three air conditioners were stopped.
Results
We succeeded in reducing the cooling system power consumption from the
current 24 kW to 15 kW (a reduction of 37%) without generating hot spots. This
will lead to savings of approximately 1.1 million yen in annual power charges* 4 .
As described above, it was demonstrated that the power consumption can be
significantly reduced by raising the cooling system temperature. It is
particularly difficult to maintain the supply of power to the cooling system when
Development of NEC proprietary cooling technology using thermosiphon cooling
Reduction in the amount of airflow required to cool down ICT equipment
Because the layout of the ICT equipment in a data center is often very complicated, it is
difficult to evenly feed in cool air. In general, this problem has been solved by installing fans
in the ICT equipment itself to cool it directly by generating a large amount of airflow. If the
CPUs and other components of the ICT equipment are more efficiently cooled down, it will
require less fan airflow, and thus result in less power consumption.
Based on this concept, NEC has developed a technology to cool down ICT equipment using a
“thermosiphon cooling” method. With thermosiphon cooling, the heat is absorbed when the
refrigerant changes from a liquid to a gas (evaporates). Applying this thermosiphon cooling
technology to cool down the server reduces the fan airflow in the ICT equipment, cutting
power consumption by 60% or more. This is estimated to result in a reduction in total cooling
power, including that of the cooling system, of 20% or more.
The amount of airflow from the cooling system
can be reduced by cooling down
the ICT equipment with a small amount of airflow.
Amount of airflow in
the ICT equipment100
Elimination of hot spots Measures to reduce
the amount of airflow
Amount of airflow in
the ICT equipment70
Reducing the large amount of
airflow for this rack eliminates
hot spots. (It is not necessary to
reduce the amount of airflow for
all the racks.)
It was verified that the power for the fan for a 1U server was
reduced by 60% or more by adopting the thermosiphon cooling
Thermosiphon
cooling
Features of thermosiphon cooling technology
In the thermosiphon cooling method, refrigerant liquid is heated by the CPU or other heat
generator and evaporates, generating a gas-liquid two-phase flow, which consists of liquid
and gas. When vapor is generated in the heat receiving section, the liquid level drops in the
heat receiving section, generating a level difference from the liquid in the heat emitting
section. The gas-liquid two-phase flow, consisting of liquid and gas, is efficiently transferred
to the heat emitting section due to gas-liquid equilibrium. Gas-liquid equilibrium is a
characteristic in which the vaporization speed becomes equal to the devolatilization speed.
This method is applicable even to 1U servers with a design optimized for the best airflow
because a pump or other external driving force is not required to circulate the refrigerant.
As the thermosiphon cooling method transfers heat using latent heat* 5 , there is almost no
difference in temperature between the liquid and the gas. The gas-liquid two-phase flow
technology. T he total power
required for cooling, including
that of the cooling system, could
be reduced by 20% or more.
Server fan
Power consumed by fan airflow
Power consumed by refrigerator
55
54
30 Reduction by
60%
15
21
5
Current Cooling using less air
Features of technology – 1
Heat receiving section Heat emitting section Heat receiving section Heat emitting section
Vapor
Vapor + liquid Liquid
Heat generator
Liquid
Radiation fin
Because there is a fin flow channel, generated air bubbles
include surrounding liquid and become a gas-liquid
two-phase flow when rising due to buoyancy.
When vapor starts to occur, the liquid in the heat receiving section
drops, generating a level difference and refrigerant circulates to achieve
a gas-liquid equilibrium. (The vaporization speed is equal to the
condensation speed.)
goes from the heat receiving section to the heat emitting section and simply condenses the refrigerant
vapor. Therefore, the power consumed by the fan in the heat emitting section can be reduced compared
with the air-cooling method, in which a large amount of airflow is supplied to the radiator for cooling,
and the water-cooling method, in which the rise in the refrigerant temperature is large.
Assuming that this thermosiphon cooling technology will be applied to 1U servers, NEC has adopted a
structure whereby the heat receiving section can be connected to a radiator through the tube for heat
transfer. Separate installation of the heat generator and radiator in this way enables a high
implementation density and flexible component layout.
The thermosiphon cooling module is the outcome of the “The Research and Development Project for
Green Network/System Technology,” a Japanese government project in which NEC is involved* 6 . This
module is currently being researched with the goal of practical application.
Features of technology - 2
An air duct structure is used to cool down all
the ICT equipment by using airflow
management technology.
Heat emitting section
(flow line graph)
Condensation
part
Condensation part equipped with
a guide vane that concentrates
airflow onto the memory.
Vapor
Chipset
Heat receiving section
(flow line graph)
Chipset
Heat receiving
section
Cylinder-type vaporization part,
which sends airflow to the chipset
Operating
temperature
Temperature rise
CPU
Rated
temperature
Fan powerW
Temperature rise
Thermosiphon
Air cooling (21W)
6
Without air duct
Parts other than
CPU
Liquid level
Reduction of 60% or more
Thermosiphon
6
With air duct
Air cooling (21W)
*5 Latent heat indicates that the temperature remains the same even if the state changes.
For example, water evaporates and becomes vapor at 100°C and ice melts and becomes water at 0°C.
*6 This project is being run by the New Energy and Industrial Technology Development Organization (NEDO),
an Incorporated Administrative Agency of Japan.
OFF
ON
© 2012 NEC Corporation The NEC logo is a registered trademark or a trademark of NEC Corporation in Japan and other countries.
6

using a UPS or other device in the case of a power outage, in which the indoor
temperature rises as time passes. The adoption of HTA servers and storage
devices allows operation under such an environment.
Before
4.2 Free cooling
After
*3 The optimal temperature at the air inlet is set to be between 25°C and 30°C, taking into account the cases
in which the cooling system stops due to a power outage or other factor, causing the temperature to rise.
*4 Calculated based on an electricity fee of 14 Japanese yen/kWh.
What is free cooling?* 7
The free cooling method uses outdoor air rather than a chiller in cold seasons when
the outdoor air temperature is sufficiently low.
In summer when the outdoor air temperature is high, cool air is constantly supplied
because the refrigerating machine operates like a normal cooling system. The cooling
environment can be stably maintained and the power consumption kept low by
controlling the operation of the refrigerating machine.
Usually, the cooling system compresses and devolatilizes refrigerant by using a
refrigerating machine and volatilizes it by using a heat exchanger to absorb the
surrounding heat and cool down the air. This kind of cooling system consumes a large
amount of power, because it operates a refrigerating machine throughout the year.
If HTA servers or storage devices are implemented in a free cooling environment,
outdoor air can be used for a longer period of time, shortening the operating period of
the refrigerating machine. This results in a reduction in annual power consumption.
Structure of a normal air conditioner system
Cooling tower
Cooling tower
Heat exchanger
Heat exchanger
Measure to reduce exhaust heat
Semicylinder-type capping (rack image from oblique bird’s eye view)
Refrigerating machine
(compressor)
Stopped these
three air conditioners
Air conditioner
(indoor)
Structure of a free cooling system
(operating environment when outdoor air temperature is low)
The refrigerating machine operates
like a normal air conditioner systems
when the temperature of the outdoor air is high.
Cooling Used
TempertureC
Refrigerating machine
(compressor)
Air conditioner
(indoor)
The refrigerating
machine is bypassed.
4.3 Direct free air cooling
What is direct free air cooling?* 8
In conventional cooling methods, a cooling system is used to cool air in the whole
server room to indirectly cool down the ICT equipment. This leads to a large amount
of energy consumption. In contrast, the direct free air cooling method takes cold
outdoor air into the server room and blows it onto the ICT equipment to dissipate
internal heat and let the remaining exhaust heat escape directly outside. This
method directly cools down devices, dramatically improving the power efficiency.
This results in a significant reduction in facility costs associated with the cooling
system and other equipment.
Effects of direct free air cooling
1. Reduction in PUE* 9
The PUE (Power Usage Effectiveness) index indicates the energy efficiency of a data
center. This is the ratio of the power consumed by the ICT equipment to the power
consumed by the whole data center. When the power consumed by the whole data
center is close to power consumed by the ICT equipment (that is, the PUE is close to
1.0), the energy efficiency is high.
The PUE is approximately 1.9*10 when using a conventional cooling method in
which a cooling system is used. This means that the cooling system and other
equipment account for almost half of the total power consumption. With the direct
free air cooling method, power consumption by equipment is dramatically reduced
and the PUE drops to between 1.1 and 1.2*11 indicating improved efficiency.
Conventional cooling method : PUE of approx. 1.9
Direct free air cooling method : PUE of 1.1 to 1.2
2. Reduction in power consumption
The direct free air cooling method significantly reduces cooling system power
consumption. The total power consumed by the data center is reduced by 54%
(calculated assuming the use of 50 servers with a power consumption of 200 Wh).
3. Reduction in equipment-related costs
Average equipment-related costs in a data center are between four to six million yen
per rack when using a conventional cooling method. In contrast, when using the
direct free air cooling method, the cost of installing one rack is approximately two
million yen because a large cooling system and cooling system installation space
are not required. This means a cost reduction of 50% or more (if the building is
renovated).
Conventional method
Approx.
23,000 Wh
Reduction of
54%
Direct free air cooling
Approx.
10,500 Wh
Significant reduction in
cooling system
power consumption
—Cooling system using the free cooling method—
A hybrid-type cooling system for data centers equipped with a normal
refrigerating machine and a refrigerant pump is an example of this kind of cooling
system. This solution is useful even in environments in which it is difficult to
directly take in outdoor air.
Because the refrigerant pump circulates refrigerant and performs direct free air
cooling without using the refrigerating machine in cold seasons when the outdoor
air temperature is low, cooling system power consumption can be reduced
throughout the year.
Conventional method
Approx.
four to six
million yen/rack
Reduction of
50%
Direct free air cooling
Approx.
two million
yen/rack
Significant reduction in
cooling system costs
*7 Select the optimal air conditioning method for free cooling considering the regional climate and
geographical conditions.
*8 Select the optimal air conditioning method for direct free air cooling considering the regional climate
and geographical conditions.
*9 PUE = Total power consumption in the data center divided by power consumption by IT devices
*10 Quoted by “Consideration on New Data center Power Saving Indicator in Japan, DPPE, in International
Conferences” (Green IT Promotion Council, February 28, 2011).
*11 Calculated in a data center in Japan
© 2012 NEC Corporation The NEC logo is a registered trademark or a trademark of NEC Corporation in Japan and other countries.
7

Technologies Behind NEC’s High Temperature Ambient Server
5. Lineup
The Express5800 series of x86 servers supporting ambient operating
temperature of 40°C includes a wide variety of models such as a product
for data center providers that use a large number of servers and a tower
server ideal for offices, shops, and other smaller-scale applications.
DataCenter Line DataStation Line
8Way
A1080a
Eco-Friendly Data Center
NEC has launched an Eco-Friendly Data Center project to promote power efficiency in
data centers. The goal of this project is to implement power savings in facilities as a
whole by reducing the power consumption of not only ICT equipment but also the
cooling system and other equipment, as well as to promote eco-friendly data center
construction and facilities management.
The Eco-Friendly Data Center project supports data center power savings by providing
consulting services, ICT equipment, and facilities solutions. The consulting services
aim to visualize and highlight current problems in the data center from every viewpoint
and propose measures to achieve appropriate goals. The ICT equipment comes in the
form of the High Temperature Ambient Express5800 series, NEC Storage M series, and
power saving control software applications. The facilities solutions involve facility
monitoring and other solutions to improve cooling efficiency.
Consulting services
ICT equipment
2Way
E120d-M
E120d-1
R120d-2M
R120d-1M
R120d-2E
R120d-1E
T120d
Server consolidation assessment
IT environment assessment
Start,Basic,Advance
Construction assessment
Power saving hardware
Power saving control software
(such as virtualization technology)
1Way
R110e-1E
GT110e-S
GT110e-S
(Water-cooled)
GT110e
Facilities monitoring system
Cooling
system solution
Highly-efficient backup solution
Eco Cloth Jacket
Facilities solutions
HTA servers also useful for offices and shops
Power saving is required in many locations other than data centers. Even without the order
to limit the use of electricity issued by Japanese government in 2011, awareness has been
high concerning the need to save power in offices and shops. The Express5800 series of
x86 servers supporting ambient operating temperature of 40°C can be used to conserve
power in these places.
When servers whose maximum ambient operating temperature is 35°C are installed in an
office, there is no choice but to set the cooling system to a lower temperature.
Implementing a model supporting ambient operating temperature of 40°C allows you to
set the cooling system to a higher temperature, significantly reducing power consumption.
According to a document published by the Agency for Natural Resources and Energy of
Japan, increasing the office temperature by 2°C reduces cooling system power
consumption by approximately 8%.
6. Conclusion
This white paper describes a design concept developed by NEC to improve
the cooling ef ficiency of HTA ser vers and storage devices, and
demonstrates that cooling system power consumption, which accounts for
approximately 30% of the power consumed in data centers, can be
reduced by implementing these servers and storage devices. This white
paper also provides examples of verifications tests confirming that stability
can be maintained by only using a direct free air cooling method and that
the servers and storage devices can operate for a long period of time even
in a high temperature environment.
Before
35
Servers become
unstable unless the cooling
system temperature
setting is 20°C
or lower...
We need to
implement
power saving
measures...
After
40
Raising the cooling system
temperature setting
by 5°C saves power!
As we shift to cloud computing, data centers are becoming increasingly
important. The HTA servers and storage devices from NEC support
enterprises who want to promote environmental friendliness in their data
centers and IDC providers who want to provide high-quality, inexpensive
data center services.
Model that can operate
at an ambient
temperature of 40°C
The maximum ambient operating
temperature for servers is usually 35°C
The server’s maximum ambient
operating temperature is 40°C.
Increasing the ambient temperature in the office by 2°C reduces
cooling system power consumption by approximately 8%.
*Quoted from a document published by the Agency for Natural Resources and Energy of Japan.
(The average effect is calculated assuming maximum power usage on a day on which the temperature is 35°C or more.)
© 2012 NEC Corporation The NEC logo is a registered trademark or a trademark of NEC Corporation in Japan and other countries.
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