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more efficient, which means, as with
the other solutions covered in this
article, that operating costs are
reduced. Approaches such as two-
stage power distribution also enable
high-density environments to achieve
the same levels of availability and
scalability as low-density
environments.
Single-stage distribution often is
unable to support the number of
devices in today’s data center, as
breaker space is used up long before
system capacity is reached. By
separating deliverable capacity and
physical distribution capability into
subsystems, two-stage distribution
overcomes this limitation.
The first stage receives high-voltage
power from the UPS and can be
configured with a mix of circuit and
branch level distribution breakers.
The second stage or load-level units
can be tailored to the requirements of
specific racks or rows.
Growing density can be supported by
adding breakers to the primary
distribution unit and adding more
load-level distribution units.
Additionally, higher amperage in-rack
PDUs can be deployed to manage
higher electrical requirements within
the rack. These systems can provide
60 amp capacity per strip, compared
with 15 amp for traditional rack
power strips, and they also feature a
modular design that makes it easy to
add receptacles or support high-
density equipment.
AUTOMATE ENERGY USAGE
DATA COLLECTION AND
ANALYSIS
Energy efficiency monitoring can track
total data center consumption,
automatically calculate and analyze
PUE, and optimize the use of
alternative energy sources.
Unfortunately, many facilities don’t
have energy monitoring capabilities.
Automating collection and analysis of
data from the UPS and PDU
monitoring systems can prevent
overloading, improve energy
efficiency and increase IT productivity.
Power should be monitored at the
UPS and the room PDU and within
the rack.
Using data from the UPS, the
monitoring system can track UPS
power output to determine when UPS
units are running at peak efficiency.
Monitoring at the room or row PDU
provides the ability to plan more
efficient loading of power supplies
and dynamically manage cooling;
panel board monitoring provides
visibility into power consumption by
non-IT systems, including lighting and
generators, to ensure efficient use of
those systems; and rack-level
monitoring provides the most
accurate picture of IT equipment
power consumption with continuous
monitoring of volts, kilowatts, amps
and kilowatts per hour. The ability to
automate data collection,
consolidation and analysis related to
efficiency is essential to data center
optimization and frees up data center
staff to focus on strategic IT issues.
MAKE SMART USE OF
INTELLIGENT DIGITAL
CONTROLS
Some UPS systems are equipped with
intelligent digital controls that enable
more efficient operation through
other options such as intelligent
paralleling in multi-module systems.
Intelligent paralleling manages the
load across multiple UPS modules
and can automatically deactivate
modules that are not required to
support the load, while still ensuring
that the system is providing adequate
redundancy. For example, a four-
module N+1 system sized to support
700kVA using four 250kVA UPS
modules can support loads below
400kVA with only three modules. This
capability boosts utilization rates and
can improve system efficiency by up
to 6 percent without sacrificing
protection.
IMPROVE UPS UTILIZATION
RATES BY DEPLOYING A
RESERVE ARCHITECTURE
A dual-bus (2N) architecture is often
chosen for the power system in
enterprise applications because it
provides the required level of fault
tolerance and concurrent
maintainability for Tier 4 data centers.
A properly designed dual-bus system
will eliminate every single point of
failure, and maintenance can be
performed on any component while
continuing to power the load.
But the downsides to failsafe uptime
are higher cost and low utilization
rates for power system components.
This is because to ensure safe
operating conditions when one bus is
carrying the full load, power system
components on each bus are typically
over-provisioned to about 110
percent of the data center load. With
more capacity than needed, the UPS
utilization rate falls below 45 percent
under normal operating conditions. In
periods of low demand—for example,
when the data center is first
deployed—utilization can be 20
percent or lower. Typically UPS
systems operate most efficiently at
utilization rates above 30 percent. At
The reserve architecture creates a fault tolerant
architecture with utilization rates of
approximately 75 percent.