LED for Area Lighting

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johnny watt

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Can a good case be made for considering the use of LED lighting for area lighting in place of pulse start MH lighting?
I see a lot of sales brochures with lots of words and pretty pictures but no hard data is included to maker their case.
 
If you mean outdoor area lighting then LED technology has improved a lot in the last year. Lots of cities have been testing LED street lights and the efficiencies of LEDs have been going up a lot. I think they're just getting to the level of being practical for area lighting. The latest design I've heard is the fixture is open with gaps between the rows of LEDs to allow air flow thru the fixture and to cool them better.

If you're considering buying these then insist on hard numbers from the manufacturer. Not all LEDs are the same. What is the efficency? Who do you buy the LEDs from? What is the color tolerance? Expect to pay a lot.
 
Depending on whose specs you believe, I have seen commercially available LED output only up to about 40 lumens per watt. Yes, you hear of higher, but they are still in development.

Fluorescent is above 80 Lu/W. HPS is up to 144 Lu/W.

They are generally costly.

Heat sink issues with LED's are still a major issue. Just look at all the LED traffic signals with LED's out! This is the real Achilles' heel of LED's.


Personally, LED's have a way to go before I would use them for area lighting.

IMHO

RC
 
These guys have been giving me the hard sell lately.
They are claiming the 80Lu/W
http://www.betaled.com/products.aspx

My thoughts were that the power supply would be the weak link.
They only warranty that for 5 years.
The only thing that I can think of that would make them worth considering is if there is some government cheese program to tip the scale.
 
Don't believe it. LED's do not get the Lumens per Watt a T5 gets. One more thing LED is a beam of light and not diffused.

Here are the top light produces in order. Note how far down the chain LED's are.

Low Pressure Sodium @ 183 to 200 Lumens per watt
High Pressure Sodium @ 150
Xenon Arc @ 30 to 150
28 Watt Fluorescent Tube T5 @ 104
36 Watt Fluorescent Tube T8 @ 93
32 Watt Fluorescent Tube T8 @ 60
5-24 Watt CFL @ 45 to 70
White LED @ 26 to 60
Hi-Temp Incandescent @ 35
Quartz Halogen @ 24
100 Watt Incandescent @ 17.5
 
dereckbc said:
Don't believe it. LED's do not get the Lumens per Watt a T5 gets. One more thing LED is a beam of light and not diffused.

Here are the top light produces in order. Note how far down the chain LED's are.

Low Pressure Sodium @ 183 to 200 Lumens per watt
High Pressure Sodium @ 150
Xenon Arc @ 30 to 150
28 Watt Fluorescent Tube T5 @ 104
36 Watt Fluorescent Tube T8 @ 93
32 Watt Fluorescent Tube T8 @ 60
5-24 Watt CFL @ 45 to 70
White LED @ 26 to 60
Hi-Temp Incandescent @ 35
Quartz Halogen @ 24
100 Watt Incandescent @ 17.5
Click to expand...

Let me add Pulse start Metal Halides they are typically about 110~135 Lumens per watts

Merci,Marc
 
Lpw

Lpw

Cree Inc. and Seoul Semiconductor have successfully tested LED outputs at 240 LPW. The testing does not substantiate continuous duty nor estimated maintenance levels. Research is still developing new doping methods using quantum dot prototypes discovered in the US.
There are high-bay luminaires being tested. The LED units are point method directional luminescence such as derekbc referred to in his post. The fluorescent lumens diffused outputs are still the most practical per product cost for Zonal Cavity coverage whereas outdoor lamping is a bit more spendy at existing technology. rbj
 
I have met with several salespeople on these products. One of the hardest things for me to get my head around is the cost and lifespan of the fixtures. For outdoor lighting I figure roughly 10 years lifespan. After that the light output will have dropped to the point of needing replacement. At that time I don't think it will be a retrofit but a complete replacement of the fixture. My opinion on this is because of the changing technologies, these same fixtures and components will not be available in 10 years. When figuring the cost savings (even at 1/2 the wattage needed in LED) over 10 years they will barely,if ever pay for themselves. There are costs associated with saving energy!

I am considering some small installations both indoors and outdoors but mainly from a showcase standpoint and the energy saved. I do not believe there will be overall savings from this technology yet but I think it's close.

I am now in the middle of LED exit light failures in buildings 10 years old or so. The light output of the LED's has deteriorated to the point they need replacing. Yes they have saved on maintenance costs over the 10 years but have they saved enough energy to offset the costs of replacement?
 
johnny watt said:
These guys have been giving me the hard sell lately.
They are claiming the 80Lu/W
http://www.betaled.com/products.aspx

My thoughts were that the power supply would be the weak link.
They only warranty that for 5 years.
The only thing that I can think of that would make them worth considering is if there is some government cheese program to tip the scale.
Click to expand...

*********************

I looked at their brochure. Frankly, it sounds hokey. LED's are coming, but they ain't nowhere there yet. I love them in flashlights, but even there the quality is wild.

When they invent "new" ways to measure light, hold on to you wallet!
 
I just finished installing over 60 LED fixtures. Fortunately(?) I didn't buy them, only installed.
39 were for parking structures-both municipal and private. Light output is different color than original MH. Energy savings is way down. I figure about 10 years before fixtures will need to be replaced
Others were on a building--security and pole lights. Maintenance is down to zero for all jobs.
I'm interested in the energy savings! The light output is measured in 2 ways--Scotopic and photopic.
Years ago when HPS was all over, Metal Halide made an appearance. The light was more pleasing to the eye--it was "bluer." Visibility was better.
Now with LEDs we will be seeing more on the measurement method.
Even though I have installed, I'm inclined to lean towards T5. Better light output, more options, etc.
I think this round of LEDs is a phase as is the corckscrew fluorescents.
Tune in next year...
 
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