Efficient DC power supply in data center
Data centers consume about 100 times more power than an office building of
the same size. Valuable electrical energy is lost in the individual components
when alternating current is converted into direct current and vice-versa. In a
project for the ITC service provider Green, ABB shows how a DC power supply
can help a data center cut energy consumption by 10 to 20 percent.
Data centers consume vast amounts of energy every year. Size for size they consume
around 100 times the power used to run the average office building. In total that is a
staggering 80 million megawatt hours of electricity a year, representing nearly 2 % of the
global CO2 emissions.
Rows of servers storing trillions of megabytes of information operate around the clock to
enable organizations to run applications, process information and automate their operations.
At home they allow you to upload a video, play a game, share a photo, e-mail a friend, tweet
your location or check your bank balance.
With the addition of more than 5,75 million new servers every year, worldwide carbon
emissions from data centers will quadruple by 2020. On average, one data center uses the
equivalent power of 25’000 homes in the western world and together they produce CO2
emissions that are fast approaching the levels generated by countries such as Argentina or
the Netherlands.
Significant amounts of energy can be saved through improvements to data center
equipment, facility design and management, and ABB provides a wealth of expertise,
engineering, products and support to not only help today’s data centers operate more
efficiently but also to operate safely and more reliably.
With reported data center outages costing 1 million USD or more per hour, uptime is critical,
particularly for banking and financial institutions. Therefore unplanned outages have to be
reduced, service quality improved and energy saved.
Reduced energy consumption thanks to DC power supply
Computer systems and associated components such as telecommunications and storage
systems operate on direct current (DC), yet the grid-supplied power coming into data centers
is alternative current (AC). That is why each device needs its own power supply unit to be
connected to the AC power grid. This arrangement results in cumulative conversion losses
and waste heat, which must be offset with cooling. An obvious alternative for a data center
operating a multitude of servers would be to have a separate DC feed to power this
equipment directly.
DC power technology saves a considerable amount of energy in electrical power distribution
compared to conventional AC power technology. A DC solution can also deliver better
energy efficiency in data centers than AC power systems because it reduces energy
conversion losses by at least 10 percent. Less cooling is also required in the IT room, which
further cuts energy needs.
The costs of power engineering equipment, installation, operation and maintenance are
likewise reduced. Moreover, DC power systems are less complex and need less space and
equipment, thus cutting real estate and other investments substantially. The total facility
costs can be decreased by up to 30 percent as a result.
The advantages of DC power systems in data centers at a glance:
- 10 percent better energy efficiency (not counting the reduced need for cooling in the
IT room)
- 15 percent lower investment costs
- 25 percent less space required
- 20 percent lower installation costs
- Improved reliability
- Reduced operating and maintenance expenses
Pilot plant at Green in Switzerland
ABB fitted the data center in Lupfig in the Swiss canton of Aargau with a DC power
distribution system throughout, making it the first data center in the world to be so equipped.
In a showcase project, about 1100 square meters of Green’s new data center was furnished
with an innovative DC power supply featuring a completely redundant design and an output
of about one megawatt. Low Voltage Systems, a local business unit of ABB Switzerland,
implemented, supplied and installed this groundbreaking solution in collaboration with
Validus DC Systems, a leading supplier of equipment for DC power infrastructure for data
centers in the ABB Group. The solution meets the specifications of the International
Electrotechnical Commission (IEC) that apply in most countries of the world.
GREEN.CH
is a leading ITC service provider for Internet-based data communication and
security in Switzerland. The company has four data centers, the most modern of which is in
Lupfig. Known for stringent ecological standards, Green agreed immediately to be part of
this pilot project of ABB as a way of operating its data center with greater efficiency and less
energy.
Figure comparing AC and DC:
Reduced direct current architecture
Prior to this project, servers were supplied with electrical energy in an alternating current
system via medium-voltage transformers, AC switchgear, a battery-supported uninterruptible
power supply (UPS), AC power distribution units and AC power supply units. The following
simplified architecture is now planned for the new direct current power supply:
The local power utility feeds power in at a level of 16 kV to gas-insulated medium-voltage
switchgear of the type ABB ZX0. In case of a grid outage, an emergency power system also
feeds power to this switchgear following an automatic changeover by the control system.
The rectifier unit consists of a medium-voltage switch, a highly efficient transformer and the
actual rectifier. It transforms the 16 kV alternating voltage immediately thereafter into 400 V
direct current and ultimately sends it to the servers without any further transformation
(simplified DC power supply units supply the servers with the power they need). The rectifier
employs highly efficient power electronics with semiconductors that have proven themselves
in industrial practice, like the ones produced at the ABB factory in Lenzburg . Batteries with
an autonomous operation time of 10 minutes are used for bridging the time from the grid
failure to power being supplied by the emergency power system. They too are connected to
the rectifier unit merely via diodes and without any further conversion.
ABB as a pioneer in direct current technology
This approach of feeding the data center directly from a DC power supply is a revolutionary
step for ABB into a more energy efficient future. Michael Gabriel, head of the local business
unit for low-voltage products in Lenzburg that implemented the project, is optimistic about
the pilot project: “We hope the findings from this pilot project will persuade as many top
server producers as possible of the advantages of DC power technology.”
Tarak Mehta, head of ABB’s global Low Voltage Products division, also sees promising
market opportunities in direct current power supplies: “With this approach, we present a top
technical solution that has a number of advantages. But it will be the customers who decide
whether it becomes established.”
For further information, please contact:
André Schärer
Vice President Global Data Center Segment Manager
ABB Switzerland Ltd.
Lenzburg, Switzerland
Phone: +41 79 592 96 10
andre.schaerer@ch.abb.com
The low voltage DC main distribution board at the DC datacenter of Lupfig.
The Emergency diesel generator set with generator breaker type ABB Emax
Generator breaker type ABB Emax with control system type ABB Tanomat (backgorund)