2009
GREEN MECHANICAL
AWARDS
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SCHOOL GETS A GREEN MAKEOVER
Mount Vernon Middle School, Mount Vernon, Ohio, had
been struggling with comfort issues since its construction in
1997. Issues of high humidity and inconsistent temperatures
were common complaints. ;e school district had experienced extremely high operational costs due to running the
building 24/7 trying to combat these issues.
After seeking an energy audit from CCG Energy Solutions, Inc., Rich;eld, Ohio, the district approved an energy
conservation project entailing a complete redesign of the
school’s heating and cooling systems, a lighting upgrade, and
a new building automation system (BAS). The previously
dysfunctional building is now so energy-efficient that the
project team has applied for ENERGY STAR recognition.
“Not only were the mechanical systems poorly designed
and installed, but the BAS, which should have been coordinating all of the mechanical systems to provide proper
comfort at optimum energy consumption, performed so
poorly it was virtually controlled manually since its installation,” says Brian Wagner, president, CCG Energy Solutions.
The building was
cooled by two 155-
ton air-cooled chillers
with ice storage tanks
and a water-to-water
heat exchanger. The
ice storage system
never worked properly and had been
bypassed for nearly
its entire life. The
school district averaged approximately
$45,000 per year in
compressor replacements alone in the last three years prior
to the energy audit. ;e two, constant-;ow, 6,000,000 Btu
boilers were so grossly oversized, and mismatched with their
pumps, that the relief valves o;en opened and drained water
and chemicals due to system overheating.
New lighting technologies were
part of the package.
;e CCG Energy Solutions approach was as follows:
★ Replace the existing boilers with a variable-primary
system with two 2,000,000 Btu Aerco Benchmark high-e;ciency condensing boilers.
★ Install variable frequency drives on the existing hot
water pumps and replace three-way heating valves with
two-way valves.
★ Redesign the chilled water system by replacing the
existing primary/secondary system with a variable-primary system.
★ Upgrade the BAS to an Automated Logic WebCTRL
system.
★ Upgrade the lighting throughout, using cutting-edge
technologies to provide multi-level lighting and dimming. Rooms with low or high footcandle readings were
brought to current standards.
Many other miscellaneous items relating to the mechanical system also were addressed. Piping to coils in air handlers
was corrected (hot water had been piped to some chilled
water coils and vice versa), and the ability to control all of the
exhaust fans was added to the BAS.
According to Wagner, the building systems are now working together, the humidity issues have been resolved, and the
temperature is being controlled to within +/- 1/10th of 1 deg
from setpoint.
;e project was completed in June 2008. One year later,
the project had exceeded its projected savings by $175,885,
realizing nearly 85% in energy savings. “There is also less
employee time needed for troubleshooting and equipment
repairs,” Wagner notes.
The system, which was originally calculated to pay for
itself in 10.92 years, will have a 4.01 year payback based on
the first year reconciliation. “We’ve also reduced carbon
dioxide emissions equivalent to removing 255 cars from the
road,” Wagner says.
;is project is an outstanding example of the impact that
properly designed and installed mechanical, lighting, and
building automation systems can have on energy consumption,
operation costs, equipment life, and occupant comfort.
