United States
Environmental Protection
Agency
APPLICATION PROFILE
EPA 430^-96-055
October 1996
New Reserve Warehouse
Building
Freeport, Maine
PROJECT RESULTS
Energy Savings
Installed Cost
Rebate
Internal Rate Return
Simple Payback
Annual kWh Savings
Pollution Prevented
Photos courtesy of Wide-Lite
Enerffy Manager:
Ron Jacques
Confractor:
Lighting Solutions, Inc.
Ut/7/fy:
Central Maine Power
TYPICAL APPLICATIONS
| Warehouses
| Parking Lots
I Loading Docks
| Gymnasiums
I Security Lighting
| Arenas
Recycled/Recyclable Printed with
vegetable oil based ink on paper that
contains at least 50% recycled fiber
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MANUFACTURERS OF
BI-LEVEL HID SWITCHING
SYSTEMS
| Thomas Lighting
| Holophane
| Hubbell
| Lithonia
I Ruud Lighting
| Wide-Lite (Genlyte)
| Superior Electric
HID BI-LEVEL SWITCHING
Technology for Controlling HID Systems
with Occupancy Sensors
Call the Green Lights Hotline at
i-888-STAR-YES for addresses
and phone numbers of Green
Lights Allies.
When high-intensity discharge
(HID) lighting systems are turned off,
they require up to 20 minutes to cool
down before they can turn on again.
And an additional 2-5 minutes may be
needed for the lamps to return to full
brightness. Because of this inability to
hot restrike, HID lighting systems may
operate continuously, up to 12 to 24
hours per day, even if the space is
occupied only a fraction of that time.
HID bi-level switching controls can
be used to dim down — not turn off —
these HID lighting systems to save
energy during periods when the space
is unoccupied. Therefore, bi-level HID
switching systems are used to operate
the lamps in a reduced-wattage
"standby" condition until the sensors
detect occupancy, and the lights are
rapidly returned to full brightness.
Bi-level HID switching systems can
be installed as a retrofit to existing HID
luminaires or as a direct luminaire
replacement. Occupancy sensors
communicate with the bi-level control
located at each luminaire via low-
voltage wire, fiberoptic cable, or
powerline carrier signals. As a result,
specific luminaires may be controlled
independently of the power circuit.
Benefits
I Wattage reductions of up to 70%
can be achieved while operating in
the standby mode; reduced air
conditioning costs for removing
heat from the lighting system can
add to these savings.
I Bi-level systems can serve as a
theft-deterrent in parking lot
applications; the lights will
brighten when people approach
the lot.
I Multi-purpose facilities illumi-
nated with HID lighting can be
manually controlled with bi-level
(or even tri-level) systems to
provide a choice of light levels.
I When periods of vacancy coincide
with periods of peak demand, bi-
level HID switching will contribute
to savings in peak electricity
demand charges.
I Bi-level switching in warehouses
can help warehouse managers
track where activity occurs.
I In addition to occupancy sensor
and manual controls, bi-level
systems can be controlled by
inputs from photosensors or
scheduling systems.
Issues
I Standby light levels are typically
15-40 percent of full light output;
the standby wattage is 30-60
percent of full wattage. (See graph.)
I Although the lights appear to
instantaneously return to full
output when occupancy is de-
tected, they rapidly return to about
80 percent output and then take up
to a minute to reach full output.
I New HID luminaires are available
with dedicated occupancy sensors
and bi-level switching ballasts so
that no control wiring is needed.
I When metal halide lamps operate
in the standby light output setting,
the color rendering index will
decline, and their color tempera-
ture will increase (become bluer).
Use coated metal halide lamps to
minimize these effects.
I Alternative technologies to con-
sider for occupancy sensor control
of high-bay lighting systems
include instant-restrike high-
pressure sodium lamps and high-
bay compact fluorescent luminaires.
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CASE STUDY
L.L.Bean
Why use bi-level switching?
According to Ron )aques at L.L. Bean, it
makes perfect sense. "It's a reserve
warehouse. We use this facility to store
seasonal stock. Most of the warehouse
is in use only 30 percent of the time,
and some aisles won't see people for
days."
Ron had already upgraded the
lighting to more efficient high pressure
sodium lighting and adjusted the light
levels. He was seeing the energy
savings already. "Because this
building was unoccupied for most of
the time, it only made sense that
controls should be used. High pressure
sodium has a long restrike time, so bi-
level switching was the obvious
solution."
After researching different products
and performing metered trial installa-
tions, Ron found bi-level switching to
be a profitable upgrade that main-
tained the necessary light levels for
efficient operation. He chose a system
that uses fiberoptics to communicate
between the sensors and the ballasts
because "fiberoptics offered huge
benefits over hardwiring — especially
in the installation costs."
To improve energy savings, Ron
chose to control each aisle's lighting in
two zones. Each zone (or half aisle) is
controlled by two high-mount infrared
occupancy sensors, and only those
zones that are occupied receive full
illumination.
The project results are outlined on
the cover.
Facility Information:
I 180,000 square feet
I 44 aisles
I (7) 25O-watt high pressure sodium
lamps per aisle
I (4) infrared occupancy sensors per
aisle
I (2) controlled zones per aisle
I 6,936 hours per year
ii
Once the nuts and botts
are done, then you need to
start/ook/ng at controls—
that's where the b/g
ii
savings are.
-Ron Jacques
Energy Manager
Equipment Information:
I HID Fiber Optic Bi-Level Control by
Wide-Lite
Typical Bi-Level Performance in Reduced Output
50%-
High Pressure Sodium (HPS)
25oW ^ooW loooW
Metal Halide (MH)
loooW
0%
* Results will vary by manufacturer
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WILL IT WORK FOR YOU?
COST ANALYSIS FOR RETROFIT HID BI-LEVEL SYSTEMS
OH
oc.
s
•*->
c
o
4<>o-Watt Metal Halide or
High-Pressure Sodium
Systems
percentage of
time lights are on and
controlled space unoccupied
The Green Lights Program offers 2-
day Lighting Upgrade Workshops,
Application Profile brochures, and
other technical support services to
assist program participants in
applying cost-saving lighting
strategies. For more information,
call the Green Lights Hotline at
i-888-STAR-YES.
Graph
Assumptions
I Post-tax analysis: marginal income
tax rate of 30 percent. (Tax-exempt
entities will earn a higher internal
rate of return on their investment
than what is determined in the
graph.)
I 3 percent inflation for energy and
maintenance costs
I 6,000 hours per year of lighting
operation. (Fewer lighting operat-
ing hours per year may result in
reductions in the internal rate of
return.)
I No demand savings assumed.
Depending on when the lights are
dimmed, savings in peak demand
charges can be significant. Contact
your utility representative.
Use the graph to estimate the cost-effectiveness of an HID bi-level switching
system in your facility.
i. Determine your installed cost of the bi-level control system per watt con-
trolled, and mark this point on the graph. For example, $10,000 installed cost
for controlling a io,ooo-watt lighting load would be $i.oo/watt.
2. Draw a horizontal line from this point until it intersects the line that represents
the percentage of the time your lights are on when the space is unoccupied.
For our example, the space is unoccupied 60 percent of the time when the
lights are on.
3. Draw a vertical line from this point until it intersects the curve that represents
your average electricity rate. In our example, the electricity rate is 10 cents per
kilowatt-hour.
4. Draw a horizontal line from this point until it intersects the vertical axis that
measures the after-tax internal rate of return. Our sample upgrade earns an
after-tax internal rate of return of 20 percent.
IRR and cost savings will vary based on
system wattage, hours of operation,
inflation, corporate tax structure, and
utility rate structure.
FOR MORE INFORMATION
"Dimming Systems for High-Intensity
Discharge Lamps", Lighting Answers,
Vol. i, No. 4, September 1994.
The Green Lights Lighting Upgrade
Manual, Lighting Upgrade Technolo-
gies Chapter, 1995.
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