fall 2008
illinois association of school business officials
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ASBO INTERNATIONAL ANNUAL EVENT IN THE MILE HIGH CITY
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iasbo.org
Walking through the hall of schools today both new and old, you pass doors
that are locked and signed "Electrical." Most know behind these locked doors
reside the breaker panels for the electrical lighting and plug circuits in the
school, but in many also resides a transformer, which step down the incominq
voltage to that which can be used by electrical devices in the classrooms and
other areas of the schools. Though you may be aware of their presence, you
don't know how much energy is wasted behind closed doors.
Schools built or renovated since the late 1960's normally
contain several dry transformers, which transform the
480/277 Volts entering the building to the 120/208 volts
used in outlets throughout the building. These transformers
range in size from 15KVA to 500 KVA and are placed in
either mechanical rooms or electrical closets throughout
the building and behind closed doors. The U.S. DOE
estimates approximately 40 million dry transformers exist in
all commercial building types in the nation, which includes
schools. An existing 75 KVA transformer, typically installed
in schools, consumes over 850 watts/hr/day of electrical
energy to energize it for the life of the building. This
consumption is 24/7 whether in use or not.
When the price of a barrel of oil was around $25, at the turn
of the 21st Century, U.S. DOE realized dry transformers in
buildings were wasting significant energy and their efficiency
should be improved. At that time they began evaluating
standards for energy efficient transformers. The standards
were first published in 2004 with five designs recommended
from C-1 to C-5. An economic and performance evaluation
determined the C-3 transformer design had the lowest Life
Cycle Cost. A C-3 75 kVa energy efficient transformer will
reduce the wattage need to energize the transformer to 180
watts, saving 700 watts per hour. This means one 75 kVA
C-3 energy saving transformer would save over 300,000
kWh in 50 years. The U.S. DOE estimates if all existing dry
transformers were replaced with energy saving transformers,
the energy saved would be between 60-80 Billion kWhs or
a cost savings of more than $6 Billion annually. This wasted
energy amounts to about nine days of electrical generation in
the country annually. This means if all could be replaced, our
power generation capacity could be reduced an equivalent
amount or new requirements could be absorbed. In schools
today, a typical elementary school with dry transformers is
wasting between $5,000 and $8,000 annually; a middle
school between $7,000 and $12,000; and a high school
between $10,000 and $25,000.
Electrical loads in our schools have changed in the past
40 plus years from linear loads - incandescent lighting,
electric typewriters, standard motors, and resistive heating
-- to non-linear loads - fluorescent lighting with electronic
ballasts, variable speed motors, computers and its related
The U.S. DOE estimates
approximately 40 million
dry transformers exist in all
commercial building types
in the nation, which includes
schools. An existing 75 KVA
transformer, typically installed
in schools, consumes over
850 wattslhrlday of electrical
energy to energize it for
the life of the building. This
consumption is 24/7
whether in use or not.
See ENERGY page 30
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ENERGY from page 19
equipment, and anything electronic.
These changes have resulted in
changes in electrical power needs
from continuous flow to pulse. This
change impacts the efficiency of the
transformers and demands of the
transformers and resulted in the need
for an energy efficient transformer
today which matches the demands of
the facility and its components.
A typical high school has between
12-25 dry transformers dependent
on design. This means about 96,000
to 250,000 kWh is wasted annually.
You should ask yourself the following
question: Should one operate for 50
years 24 hours a day everyday of the
year, eight 100 watt bulbs or one 100
watt bulb? The answer is a no brainier.
With the passage of Energy Bill in
2005 (EPACT 2005), the first step in
the adoption of the U.S. Department
of Energy's new dry transformer
standards was made. The legislation
required the C-1 or TP-1 transformer
as the minimum efficient transformer,
which could be installed in buildings
after July 1 of 2007. The legislation
removed the designation of an
Energy Star Transformer. The C-3
transformer, being the Lowest Life
Cycle design, has an efficiency of
98.6 percent and has energy losses
30 percent less than the legislated
minimum TP-1. Though the C-3 has
the lowest life cycle cost it does have
a higher initial cost of between 30 35 percent.
9 - 23 percent of the rated capacity.
Other testing of existing transformer
loading found the loading from 2 - 20
percent. These loading percentages
are below the point where maximum
efficiency is reached in existing
transformers, 35 - 50 percent. This
adds to the energy wasted every
hour of every day. How can one
benefit from this low loading? When
replacing existing transformers with
new C-3 Energy Efficient transformers
this means the new transformer can
be sized from Y2 to 1/3 the current
size, which will add to the energy
annual energy and overall energy
cost savings. With new construction,
the specifying of energy efficient
transformers in a typical high school
could reduce energy costs over its
life by over $1 million and a middle
school by over $600,000 and an
elementary school by over $400,000.
This means an ROI of between 33
and 50 percent. In renovation, the
savings is comparable but with an
ROI between 12 and 17 percent
based on energy unit costs.
What should Illinois Schools
do now and in the future?
The US Dept of Energy surveyed
different building types in 1999
Schools should require their
designers to include the
performance specification for
C-3 transformers in all their future
new or major renovation projects
with electrical upgrades;
School Districts should randomly
test existing transformers to
determine typical loading;
Schools should replace existing
units with appropriate sized units
based on testing either through
a performance contract or lease
purchased of the units with the
determined
energy savings as the collateral
existing dry transformers
in schools were only loaded between
30 iasbo.org
•
•
for the purchase.
What will be benefits for
requiring installation of energy
efficient C-3 Transformers?
•
•
Reduced electricity usage in
schools - continuous -- no
action required by personnel
either in behavior
or maintenance;
Reduced energy costs (no
control on unit costs);
More funding available for
educational program and
positions;
Funding available for facility
needs.
Unlike a lot of energy efficiency
improvement made today, which
rely upon individual actions to
insure savings are achieved, energy
efficient transformers energy
savings occur without anyone's
actions. Set it and forget it. The ROI
will not change but will remain the
same throughout the life of the unit
and school. What a benefit to the
school district and the citizens of
the school community.
This savings and its benefits begin
by looking behind the Door marked
electrical and finding out how much
energy is being wasted behind
closed doors.
.....00 you know how much energy is
wasted behind closed doors ... ?"
For more information, contact Lorenz
V. Schoff, Energy Consultant, Energy
Efficient Solutions, at 540.961.2184
or [email protected] . Larry is a Service
Associate member, and is a member
of the Sustainability Professional
Development Committee.