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TRW
Inc., one of the nation’s
largest aerospace companies,
occupies more than 27 buildings
in Redondo Beach, California.
The Space and Defense Park
includes more than three million
square feet of office space.
Most of the Space Park buildings
were built in the 1960’s,
when energy costs were low
and conservation was not a
major consideration in building
design. Lighting control was
accomplished via central panels
in building hallways. Lights
were turned on by building
staff before office workers
arrived and off when a work
area was no longer occupied.
TRW was spending millions
of dollars on inefficient
lighting of its facilities.
Jerry Andis, a Certified Energy
Manager and the Director of
the TRW Space and Defense
energy management program
in 1988, began searching for
a way to reduce TRW’s energy
bill.
Design
Goals
TRW’s
aim was to cut the multi-million
dollar cost of lighting its
Space Park facility through
lighting renovations. The
exact method had not been
decided and many types of
energy-saving devices were
evaluated. "We wanted
a system that would be flexible
to our changing needs, that
would be reliable in turning
the lights on and off, and
that would be convenient for
our employees," said
Andis. The requirement for
convenience and adaptability
to individual employee needs
eliminated computerized central
control systems from consideration.
Occupancy sensors seemed the
more logical choice, Andis
said.
Solutions
The
decision to install Novitas®
Ultrasonic Occupancy Sensors
was the result of a painstaking
18-month evaluation of three
major brands and two different
technologies. Occupancy sensors
use either ultrasonic or passive
infrared technology to detect
the presence of workers in
an office or other area. TRW’s
energy management team reviewed
both technologies in the initial
stages of their evaluation.
Ultrasonic
sensors have the superior
ability to detect the normal,
minor motions of employees
working at their desks. The
sensor produces a low, inaudible
sound. It detects changes
in the acoustic waves caused
by motion, such as reaching
for the telephone or turning
the pages in a book. The lights
will turn on automatically
when someone enters a room
and will stay on as long as
the room is occupied. If no
motion is detected for a predetermined
period, typically six to eight
minutes, the lights are turned
off and energy is saved.
As
a pilot study, both ultrasonic
and passive infrared occupancy
sensors were installed in
six offices, after baseline
data was gathered about energy
costs for them. Recording
devices then tracked energy
usage in the offices.
Engineers
in TRW’s electronics lab were
also asked to evaluate the
units’ electronic components,
the circuit board design and
the quality of manufacturing.
According to Andis, the engineers
considered Novitas Controls
to be extremely well made.
The
six-month initial test showed
the potential for dramatic
savings. Even in peak demand
periods, energy usage was
lower in the sensor-equipped
offices. This was because
some offices were unoccupied
due to flextime schedules,
trips to other offices and
lunch breaks. After the normal
workday, demand for lighting
dropped much more sharply,
as expected.
Based
on a 17-criteria scoring system
used in the initial tests,
the energy management team
at TRW selected the Novitas
ceiling-mounted occupancy
sensor for larger-scale testing.
The next step in the evaluation
was the installation of 550
Novitas sensors in two TRW
buildings. This phase of the
test included an evaluation
of employee satisfaction with
the occupancy sensors. "Senior
management was very concerned
about what employees felt
about the system," noted
Andis.
The
results of the 550-unit test
confirmed the forecasts by
the company’s energy management
team for cost and energy savings.
Employees adapted readily
to the automated lighting
control system, Andis reported,
and maintenance costs for
the installed devices were
negligible.
As
a result of that study, TRW
retrofitted more than 8,000
offices, labs, conference
rooms and work areas in Space
Park and other TRW facilities
with Novitas sensors and continues
to install them in all new
construction.
Benefits
TRW
Inc. is saving more than $1.3
million per year after the
installation of Novitas Controls.
Each sensor saves TRW about
$169 per year.
TRW
used two methods to evaluate
a capital investment: payback
period and return on investment.
The company required that
an investment pay back its
cost (in this case through
lower energy bills) within
1.5 years. Using the sophisticated,
more complex criterion of
return on investment, TRW’s
goal was 15 percent or greater.
Jerry
Andis reported that Novitas
sensors paid for themselves
in only 1.1 years. The saving
translated into a 61 percent
return on investment.
The
sensors have reduced by 50
percent the total number of
kilowatt-hours used by TRW
to light the offices where
they are installed, said Andis.
Equally important to TRW’s
management, the cost savings
and energy conservation were
accomplished without inconveniencing
TRW’s employees.
Specifications
& Credits
Controls
Manufacturer :
Novitas, Inc.
Size : In excess
of 1.5 million sq. ft.
Completed : Ongoing |
