42 / 80
42
• 15-25 percent reduction in
operating expenses
• 75 percent or higher asset
utilization
Even seemingly small power
infrastructure efficiency improvements
can add up to big savings. For
instance, with energy costs at
$0.10/kW, a 1 percent efficiency
improvement for a single 1 MW UPS
translates into approximately $10,000
in annual savings. For instance,
updating a legacy power system with
a new power distribution system can
improve its efficiency by about 2
percent for an annual energy savings
of $20,000, with a five year ROI.
Upgrading to a modern UPS system
will reduce losses at the UPS itself by
4-5 percent, yielding a $40,000-
$50,000 annual savings and also a
five year ROI.
In addition to cutting operating
expenses, modern power
infrastructures can improve
application availability, and they can
reduce the complexity and increase
the cost-effectiveness of future
growth. The strategies outlined below
will enable you to gain a more
efficient, productive and available
data center while managing capital
costs.
DEPLOY NEW TRANSFORMER-
FREE, DOUBLE CONVERSION
UPS TECHNOLOGIES
Legacy uninterruptible power supply
(UPS) systems for enterprise data
centers typically operated at a peak
efficiency of 91-92 percent at 100
percent load (85 percent efficiency at
40-60 percent load). The other 8-9
percentage points are lost as a
byproduct of the conversion process,
and this has traditionally been
accepted as a reasonable price to pay
for protection from unplanned
downtime. But with new high-
efficiency options, many modern UPS
technologies offer higher efficiency in
all modes of operation.
Today, transformer-free UPS systems
operated in double conversion mode
are 96-97 percent efficient at 100
percent load and 94-95 percent
efficient at 40-60 percent load.
Considering that only a 1 percent
efficiency improvement at $0.10/kWh
for a single 800kVA UPS translates
into approximately $10,000 in annual
savings, the reduction in operating
expenses can be significant when you
multiply this savings by the number of
UPS units in use.
Some UPS systems also offer an eco-
mode operation option that allows
the conversion process to be
bypassed, and operating efficiency
increased even further. This mode can
be enabled when data center
criticality is not as great or when
utility power is known to be of the
highest quality. This is accomplished
by utilizing the automatic static
bypass switch of the UPS during eco-
mode.
This bypass normally operates at very
high speeds to provide a break-free
load transfer to a utility or backup
system during maintenance and to
ensure uninterrupted power in the
event of severe overload or
instantaneous loss of bus voltage.
The transfer takes less than 4
milliseconds to prevent any
interruption that could shut down IT
equipment. With eco-mode and using
intelligent controls, the UPS can stay
on utility power as an efficiency mode
of operation, circumventing the
normal AC-DC-AC conversion
process while the UPS monitors
bypass power quality. If utility power
is out of specification, the UPS will
transfer back to double conversion
mode.
INVEST IN NEWER POWER
DISTRIBUTION UNIT (PDU)
TECHNOLOGY
The UPS system and PDUs are key
components in the data center power
infrastructure; the UPS feeds power
through the PDUs to IT equipment
throughout the facility. The three
functions of the PDU system have not
changed over the past decade:
1. Transform the voltage from 480V
or 600V to 208/120V so it can be
used by the IT equipment. Most
servers run on 208V line-to-line
today.
2. Distribute and control the power.
There is a circuit panel on the
secondary side of the PDU feeding
various servers located on the data
center floor. Many businesses
meter their circuits to measure the
amount of energy provided to
each server or set of servers.
Metering is especially helpful to
colocation providers to measure
customer energy use and,
depending on the rate structure,
bill for it.
3. Monitor energy consumption to
manage planning. Data center
managers can view and
understand energy consumption
from a central location via the PDU
system, allowing them to take
holistic actions to improve
efficiency.
At the PDU level, the efficiency of the
transformer technology has improved
and meets certain mandated
efficiency standards that are in place
today. The National Electrical
Manufacturers Association mandates
standard TP 1-2007 (NEMA TP 1-
2007), which specifies minimum
efficiency levels based on transformer
size. Generally, the specified
efficiencies are greater than 98.5
percent for the most common PDU
sizes used today. Before the TP 1-
2007 standard, PDU efficiency was
96-97 percent, so deploying newer
PDUs can add another two or more
efficiency points at the PDU itself.
ENABLE A HIGH-DENSITY
ENVIRONMENT
Dense environments are inherently
7X24 MAGAZINE SPRING 2015