The White Oak Independent School District (ISD) in
northeast Texas was burdened by high energy costs and outdated,
inefficient air conditioning and heating equipment.
"We simply did not have a method to control
our energy costs," said District Superintendent Dr. Tim Sonnenberg.
"They were much too high for a school district our size."
The district serves approximately 1,350 students,
kindergarten through grade 12. It has an elementary school, a
middle school, a high school, and an administration building,
all part of one large complex.
By the time the 1993 school year began, costs became
unrealistic. Electricity alone averaged $17,000 per month between
April and September. Most of the equipment was 20 to 30 years
old, efficiency ratings were dismal and, other than a few mechanical
timers on some of the units, there was virtually no way of monitoring
the system's use.
Carrier's Total Retrofit Solutions (TRS) program
helped the school district bring costs back into line. Implemented
for the 1994 school year, TRS saved the district a total of $156,000
in cost-avoidance and reduced energy consumption during its first
year, according to Dr. Sonnenberg.
In the eyes of the school district's administration,
the program also resulted in a more efficient and environmentally
sound air conditioning system - all at no additional expense to
taxpayers.
PROGRAM OVERVIEW
White Oak's decision to participate in the TRS program
was made possible through the performance contracting legislation,
which Texas recently adopted, along with many other states. This
legislation enables schools to contract with a private company
if the company guarantees that the cost of the equipment will
be offset by the direct and indirect savings it generates.
In other words, the system must be "self-funding."
In accordance with the law, Dr. Sonnenberg invited
interested companies to propose a retrofit plan and energy management
program. His past experience with a similar program as superintendent
in Denton, TX, led him to believe that this idea might work in
White Oak.
Ultimately, four companies responded to the district's
request. After an extensive review of their proposals, White
Oak ISD selected carrier. In making its decision, the school
board, according to Dr. Sonnenberg, considered costs, 10-year
energy savings, impact on the district, qualifications of the
company, name recognition, and proximity to the Tyler, TX-based
carrier plant.
The board found Carrier's "System Analysis Modeling"
software useful in the decision-making process, too. The software
analyzed data on the existing equipment, contrasted it with the
recommended new equipment, and calculating the expected energy
savings.
Under the terms of the TRS program, the customer
faces no up-front costs - the calculated energy savings pay the
cost of the new equipment. Carrier guarantees the savings. If
the new system does not generate the calculated energy savings,
the manufacturer says it will make up the difference.
DOLLARS, SENSE
Although carrier arranges financing as part of the
TRS program, White Oak chose to finance for 10 years through the
Texas Association of School Boards.
According to Dr. Sonnenberg, the fist-year savings
for electricity during the 1994 school year were $52,274, exceeding
the guaranteed savings by $23,565. White Oak's cost-avoidance
savings, including repairs and other miscellaneous costs related
to the old system, were $104,000, said Dr. Sonnenberg. So, the
total first-year savings for White Oak ISD surpassed $156,000.
ACTION PLAN
Beginning in May, 1994, White Oak replaced 49 old
rooftop units with more-efficient Carrier Model 50SS
units, ranging from 3 to 30 tons. Then. The district replaced
old chillers with Carrier 23XL
screw chillers. The two new chillers have a capacity of 160 tons
each, and a life expectancy of 20 to 25 years, the manufacturer
said.
The elementary school retained its two original chillers,
which use HFC-refrigerant R11, no longer produced in the U.S.
As part of its refrigerant management service, carrier equipped
each chiller with a "PreVent" High Efficiency Purge
System refrigerant containment device. According to the manufacturer,
these devices are designed to help retain refrigerant vapor and
return it to the chiller, curbing refrigerant leakage and, in
turn, protecting the environment.
Later, White Oak installed a new cooling tower at
the elementary school. The school district also retrofitted all
district lighting. Using high-efficiency fluorescents and reflectors,
Dr. Sonnenberg said the district maintained the quality of the
light at a significantly reduced wattage and electricity usage.
FINAL PHASE
Before the project was done, White Oak tied the retrofit
together with the Carrier
Comfort Network (CCN), a communicating
controls system for managing and monitoring hvac equipment.
According to Dr. Sonnenberg, with CCN, the maintenance
staff manages system operations and constantly monitors the system's
performance, observing such measurements as the current temperature
in each section of every building, energy consumption in kilowatt
meters, actual run-time of equipment, and even filter status.
Through instant analytical reports comparing actual and estimated
energy consumption, Dr. Sonnenberg said the district can always
track its energy consumption and savings.
White Oak has programmed CCN to activate or de-active
the hvac system at desired times in order to achieve better efficiency.
The district has also found CCN to be extremely convenient for
altering schedules on nights when the school is holding a meeting
or extracurricular activity. In addition to pre-setting the hvac
system, district personnel can also access, monitor, and manage
hvac operations remotely, via a laptop computer.
Dr. Sonnenberg said the district has used CCN to
examine valuable data on its energy costs. For example, White
Oak officials now know exactly which parts of the building are
best-suited for holding after-school functions, based on the amount
of energy the rooms require to heat or cool. Prior to installing
the system, Sonnenberg said, an individual building might have
run a system at half capacity in order to cool one room.
"We've been able to control our energy costs
much more effectively than ever before, and the system is user-friendly,"
said Dr. Sonnenberg.
As part of the TRS program, White Oak ISD has a service
agreement under which Carrier solves any major maintenance problems,
added Dr. Sonnenberg.
According to school officials, Carrier technicians
and representatives are also frequent visitors to White Oak, just
to make sure things are running smoothly and to answer any questions
on system operation and performance.