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Wal-Mart's
new lighting design strategy is intended to increase
sales and decrease operating costs, while at the
same time reinforcing the image of the store as
a place that cuts overhead in order to offer more
competitive pricing.
The
City of Industry Wal-Mart is one of their Environmental
Demonstration stores. In addition to the usual
merchandise, it also has an "Eco-Room",
an interactive environmental display area to teach
about sustainable design. The building's lighting
is an important part of that demonstration.'
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The
low-mercury T8 lamps also dramatically reduce
pollution, lowering both the total volume and
the toxicity of the waste.
"[People
considering lighting design] definitely
need to continue in this particular mode.
It can really be a win-win situation,
and I think that the more we use these
ideas, the more the price comes down.
That's been a big concern - that you pay
more for recycled or ecology-minded items.
We're finding that the tide is shifting,
and it's because more designers are taking
advantage of it and more building owners
are willing to take a chance on it."
|
Cherie
Dubrow,
Green Coordinator at Wal-Mart
Duration : 8 minutes 43 seconds |
|
Daylight
Penetration
Daylight
penetration is a vital component of this facility.
To see more details of how daylighting was incorporated,
click on the graphics below.
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Design
Goals
The
main goal for this building was to demonstrate
an integrated building design that was both environmentally
responsible and that exceeded the current building
energy standard by at least 25%. Wal-Mart wanted
this Environmental Demonstration Store to educate
the public by example on the benefits of energy
efficient technologies and environmental issues.
Lighting
designer
Innovative and cost-effective design solutions.
Using the Fresnel lens skylights gave a significant
improvement over typical skylights. Using continuous
dimming controls was a critical factor in the
lighting design. Another goal was to show that
lower nighttime light levels are more comfortable
than the standard level.
Owners
Energy savings should exceed current building
energy standards, and the building should be an
effective educational tool, demonstrating sustainable
design.
Project
Manager
In addition to all of the other goals mentioned,
this is an opportunity to perform long-term monitoring
and verification of the system's performance.
What
were the constraints?
Initial costs were the greatest constraint. Wal-Mart
was receptive to the idea of using controlled
electric lighting, but we had to prove it's cost-effective
and would work for that kind of space.
What
were the greatest challenges?
There were some initial tuning problems with the
sensors and controls. They had to be adjusted
for unexpected differences in light levels in
different areas of the store. Figuring the correct
lighting distribution and calculating the cooling
load savings from the electric lighting reduction
was not simple and required computer simulation.
What
prompted the decision to use controls?
We wanted to minimize operating costs, and at
the same time demonstrate that this can be done
with no loss of lighting quality.
Was
there a 'champion' for the use of controls?
Southern California Edison was a champion of using
controlled lighting from the beginning.
Solutions
To achieve
the design goals, the design team demonstrated
creativity and excellent technical competence.
How
did you meet the challenges and constraints?
We had a strong collaborative effort among all
the team members. This meant we had an integrated
design approach from the start. We used detailed
energy simulations and scale modeling during schematic
development.
What
did you learn from doing this project?
We did some full-scale testing of night lighting
levels, and found that substantially less lighting
was needed at night than was normally used.
What
were the successful moments or unexpected consequences?
What was the worst problem you faced?
We were surprised at how good it looks. There's
no hard data yet, but people seem to stay in the
store longer. It feels open and airy, not confined
or gloomy. After the initial tuning, the controlled
lighting is automatic and virtually maintenance-free.
What
components did you select, and why?
The equipment was chosen in response to several
factors: the desire to run the luminaires parallel
to the front of the store, the requirement that
the luminaire provide a good amount of indirect
lighting, lamp shielding and cost.
The
lighting installed has a 2-lamp cross section,
with 90% downlight and 10% uplight. In addition
to pendant mounted luminaires, luminaires with
an asymmetric parabolic reflector on the perimeter
walls are used to give visual cues to the boundaries
of the space. The dimming system responds automatically
to daylight levels.
Benefits
These
were some of the benefits incurred in this project:
Reduced
energy use - Lighting energy was reduced 47% and
total energy reduction was 49% compared to California
energy standards (Title-24) for 24-hour operation.
Payback is estimated at less than three and a
half years (excluding the photovoltaic panels).
Reduced
toxic waste - The low-mercury T8 lamps dramatically
reduce pollution, lowering both the total volume
and the toxicity of the waste. And, since they
pass the EPA test, Wal-Mart estimates the savings
in hazardous waste transportation and disposal
costs will exceed $5,000 every three to four years,
with no reduction in lighting quality. Nearly
two million pounds of pollutants are avoided each
year as a result of this project.
Reduced
construction or retrofit costs from integrated
design - Removal of a drop ceiling from the design
saved about $68,000. Having the entire design
team excited and actively involved from the beginning
probably minimized some of the usual design problems
and delays.
Besides
the cost-saving lighting, the store also used
non-ozone-depleting refrigerant, and incorporated
sustainable and renewable materials wherever possible.
Specifications
& Credits
Owners
:
Wal-Mart Stores, Inc
Daylighting Consultant : ENSAR Group,
Inc. (Gregory Franta, FAIA), Boulder, CO
Electrical Engineer : Consulting
Engineers (Jack Vest, III, P.E.), Tulsa, OK
Controls Mfg. : Novar Controls Corp.
Ballast Mfg. : Lutron Electronics
Co.
Luminaire Mfg. : Thomas Industries
Inc. / Day-Brite
Size : 131,000 sq. ft.
Photography : Michael Mutmansky
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