Presented at MD Green Buildings
Conference 2009 March
25, 2009
To LED or not to LED? Is
that the question?
By Bob Gilbert
Efficient Lighting Specialist
Should we use LEDs? That seems to be
the current, most commonly asked question.
Whether it is nobler and wiser to be
on the ragged edge, or to be content with merely the cutting edge, that is our
dilemma today.
How do we implement the best
lighting project possible while taking into consideration maximum energy
savings, client comfort and well being (and hence productivity) while finding
the most cost effective solution?
Max Light / (Max Energy Savings +
Comfort & Productivity) to = Maximum Cost Benefit
The answer is…
It’s Application Specific. One
Technology fix does not fit all.
Hello. My name is Bob Gilbert, and I
have been working with Hunt Consulting & JCI and other preferred partners
since 1986 on approximately $100 million in installed energy efficient lighting
projects.
These include in this area, Prince
Georges and Baltimore County Schools, Architect of the Capitol, Andrew’s Air
Force Base, NIH, the State Dept, Dept of Agriculture and the White House
(during a previous Democratic administration), retail chains, casinos,
warehouses and just about anything else you can think of.
After all, lighting is everywhere.
I like to say we are the Marines of
Energy Efficiency. Getting it done in the trenches every day for over twenty
years.
Enough power saved to run a city of
50,000 or more.
So, everyone wants LED’s. News about
LED’s is everywhere.
LED’s seem to be the answer to
global warming, a balanced budget, world peace, receding hairlines, and just
about everything else under the sun.
Lets look at what’s great about
LED’s:
1) They are very cool. Actually they
operate very well in cool environments too, though they can also be very
sensitive to heat.
2) They are very bright, leaning
towards blue on the Kelvin scale (5000 K and above) and though they do not
quite yet meet fluorescent’s efficiency or color stability they are getting
closer all the time.
3) They are very tiny. Can be made
to fit in all sorts of great places you just can‘t stick a light bulb.
4) They use no mercury. Though the
semiconductor (LED’s are a semiconductor) manufacturing process is notoriously
littered with toxins and is volatile and dangerous. The dangers are limited to
their manufacturing and to the disposal of the LED boards. Yes, what are you
going to do with that circuit board when it burns out?
5) They can last from 50,000 hours
(White) to 100,000 hours (Red).
6) They are a UV free light source,
which can be very important in museum displays for fragile or precious
artifacts, as well as illumination of foods like fresh meats and fish in
grocery stores, which degrade quickly under fluorescent lighting.
7) Where as LED’s started out in
exit signs, graduated to stop lights, brake lights, and displays; they are now
everywhere from neon replacement to high hat cans to MR 16’s and track lights
to street and parking lot lights.
“Great sounds pretty good to me? So
what’s the problem?”
They are notoriously difficult in
other traditional lighting sources for general illumination like light bulbs. I
have a good LED light bulb. It’s $30.
You see…LED’s are a DIRECTIONAL
LIGHT SOURCE.
The light shoots out from the chip
and is difficult to disperse. It is difficult in the manufacturing (or binning process) to get consistent
color. Problems with color shift persist as different blended colors depreciate
at different lengths of time. They are very sensitive to heat degradation and
line voltage surges. This absolutely must be carefully designed for or they
will degrade or fail extremely quickly. Buyers beware and know what to ask.
They cannot be thought of as
something you just stick into a traditional lighting package. That was tried
for several years and the results were hokey at best, ludicrous at worst.
So where do LED’s work well?
Because they are UV FREE they do not
degrade items that are UV sensitive like cloth, paintings, fragile paper,
ancient artifacts, other perishable items like meats, fish etc.
Directional applications (brake
lights, exit lights, display lighting, etc.)
Very cold environments like freezers
in grocery stores.
Small localized sources of light
such as cell phone or display panel.
We are seeing excellent applications
for high hat cans and track lights.
We are also seeing them requested
for parking lot and street lighting.
.
A recent project in my home town of Raleigh NC, The city in partnership with
Cree LED, installed hundreds of LED Parking lot lights at the new convention
center. They are quite lovely; very modern. The fixtures are rated for 50,000
hours and cost $500. They will last 6 years. They saved 40% over the original
Metal Halide fixture spec
But, there are two problems with
these exterior applications – Cost and replace-ability.
They are very expensive. A 90-watt
LED street light Cobra head can run well over $1,000.
Compare that to Induction Lighting
that has been around for over 15 years (and is actually well represented here
in Maryland) and is one half to one third the cost of LED, impervious to heat
or cold and lasts twice as long (100,000 hours instead of 50,000).
And the lamps and ballasts are both
replaceable in induction.
Until very recently, almost all LED
fixtures were disposable. Once they reached their rated life, the circuit
boards were not replaceable at the end of useful life so you have to throw them
away - not very ecological. Since most current LED Street and parking lot lights
do not contain removable, replaceable boards you are essentially buying a throw
away fixture. Hmmm….
This is an unnecessarily high
fixture cost and though they are ecologically benign in the life cycle energy
usage arena, as circuit boards, they are toxic and difficult to recycle. The
Pentagon is buying a whole series of lay in LED fixtures. Again, if the light
source and boards are integrated and not replaceable, why buy a disposable
fixture and call it Green when you can get almost the same life from a $2
extended life T8 lamp?
Now let’s look at some other
options:
I recently completed a series of
open parking garages in NJ near the ocean - a very tough environment. We
replaced thousands of 175-watt MH fixtures with two lamp and three lamp T8
vapor tight four-foot fixtures for under $100 each.
Actually, we started out with three
lamp 105-watt fixtures and the client said it was too bright and we went to a
two lamp T8 fixture at 70 watts and still increased the light 40% as well as
cut consumption over 60%.
In some areas around the periphery
we installed daylight ballasts for further savings.
This specially designed fluorescent
vapor tight with an application specific interior asymmetric reflector saved
more than the LED’s by 20%, and the fluorescent lamps last 42,000 hours and
cost $4 to replace.
These fixtures were ONE FIFTH the
cost of LED. LED fixture lasts 50,000 hours. Ours, replace the lamps at 42,000.
A closer alternative to LED is
Induction lighting. INDUCTION is an excellent option for parking lot and street
lighting. I recently completed a project for JFK Airport Terminal One and the
exterior lights and parking garages.
We are also involved in an ongoing
replacement of all the 30,000 HPS streetlights in the Town of Islip NY.
Those fixtures cost under $300, use
half the energy, improve light (and safety) by 30% and will last 100,000 hours.
Induction parking lot or street
lights will last 100,000 hours and can use the same design like the metal
halide fixtures I saw at RDU and BWI airports on my way here today. Yes, I flew
and offset too.
They use half the energy of metal
halide and cost again under $300 per fixture.
The down side, if any, to Induction
is they do use a very small amount of mercury in their amalgam technology,
about the amount found in a can of tuna fish. But since the lamps are only
changed once every 100,000 hours they use less overall than fluorescent because
there are no lamp changes. NO Maintenance.
And then there’s Cold Cathode - the
next generation after compact fluorescent. It’s dimmable, flashable,
waterproof, very small, and lasts 25,000 hours. Induction lasts 100,000 hours.
So the answer, as in most well
thought out designs or retrofit applications…
* consider the current environment
* consider the needs of the client
And the answer is APPLICATION
SPECIFIC.
SOMETIMES A $100 FLOURESCENT FIXTURE
IS A BETTER FIT THAN A $500 LED FIXTURE.
And sometimes a client wants to spend more for the exotic technology,
politics or other factors. “Look, I don’t care we WANT LED!” Go figure.
And sometimes LED is the best answer
too.
As always, we try to give the best
solutions to save energy, improve the lighting environment, and be educate on
true life cycle costs.
In the end, you the client
must decide. After all it’s your facility.
Bob Gilbert
for Hunt Consulting, Laurel, MD
www.huntconsulting.net