CREE fixtures exceed High Pressure Sodium Vapor

Lighting Science Group Corporation (OTCBB:LSGP) today announced that the City of Raleigh, NC has issued a purchase order for 141 Optimized Digital Lighting™ (ODL) low bay fixtures for use in the Raleigh municipal parking deck....

Lighting Science's low bay fixtures contain an array of CREE Xlamp LEDs powered by LSGP's patented ODL technology which ensures maximum performance, long life and reliability. The attractive, durable fixtures consume only 75 watts which is 25% to 50% less than the high pressure sodium (HPS) lighting fixtures which will be replaced. Lighting Science's low bay fixtures provide cool white light with excellent color rendering resulting in a substantial improvement in night vision when compared to the orange/yellow light emitted by HPS lighting fixtures.

http://www.lsgc.com/press/pr061204.pdf


Looks like with the CREE products, general lighting is finally comming of age.

This is pretty cool, since many HPS bulbs have a color rendering index of only 20%, add in the improved efficiencies, plus much improved color rendering, can only make one smile.

I never really liked the HPS, back when they started replacing the mercury lamps I found I couldn't see much at night, especially in the rain.

NewBie said:

Lighting Science Group Corporation (OTCBB:LSGP) today announced that the City of Raleigh, NC has issued a purchase order for 141 Optimized Digital Lighting™ (ODL) low bay fixtures for use in the Raleigh municipal parking deck....

Lighting Science's low bay fixtures contain an array of CREE Xlamp LEDs powered by LSGP's patented ODL technology which ensures maximum performance, long life and reliability. The attractive, durable fixtures consume only 75 watts which is 25% to 50% less than the high pressure sodium (HPS) lighting fixtures which will be replaced. Lighting Science's low bay fixtures provide cool white light with excellent color rendering resulting in a substantial improvement in night vision when compared to the orange/yellow light emitted by HPS lighting fixtures.

http://www.lsgc.com/press/pr061204.pdf


Looks like with the CREE products, general lighting is finally comming of age.

This is pretty cool, since many HPS bulbs have a color rendering index of only 20%, add in the improved efficiencies, plus much improved color rendering, can only make one smile.

I never really liked the HPS, back when they started replacing the mercury lamps I found I couldn't see much at night, especially in the rain.

Click to expand...

Rain? ..... What is this rain?????
On Topic. I think this is really cool. It's about time LEDs came into practical use other than tail lights and traffic lights.

From LSG's Low Bay Fixture Data sheet:

http://www.lsgc.com/brochures/LOWBAY FIXTURE.pdf

2500 Downward Lumens
75 Watt

That's 33.3 lm/W, right?

Of course that takes into account ALL losses (fixture, optics, driver) but still doesn't seem too efficient to me...

You might be quite surprised if you were to look into a lot of losses in fixtures out there...

It is like the fixture designers were just cobbling things together...to maximize profits.

One should also consider where the lumens are going, are they hitting the actual areas that need to be lit. Remember, most parking garages are just cement, and cement isn't all that great at bouncing light around...

Ever notice, especially at night with HPS lighting, how everything looses most of it's color, and it is more like a black and white (or amber and black) movie?

One of the things eyes are really good at, that folks often forget, is seeing contrast. That especially includes color contrast. Light something up with HPS, you loose 80% of the eye's ability to distiguish color, and things get harder to see. It is one of the reasons that Color Rendering Index is so important. HPS is ~20% and White LEDs are 70%. So you get nearly 3.5x the color contrast back, and all of a sudden, you need less light to distinguish things.

brickbat said:

From LSG's Low Bay Fixture Data sheet:

http://www.lsgc.com/brochures/LOWBAY FIXTURE.pdf

2500 Downward Lumens
75 Watt

That's 33.3 lm/W, right?

Of course that takes into account ALL losses (fixture, optics, driver) but still doesn't seem too efficient to me...

Click to expand...

I do believe you are looking at the really old model, that used 84 older LEDs (the efficiency makes them look like they were the old OSRAM Golden Dragons?). The test date was 4/12/2006. If you click on photometrics on that old one on the website, you will see the details. Here is a direct link:
http://www.lsgc.com/brochures/LLI040605A LB-84-1 PHOTOMETRICS.pdf

The new XR-E were not out yet, and if pointed down, the majority of their lumens would be downward lumens. If they were the XR-E (and maybe the new fixture is using those-to get the HPS claim?), the total lumens would work out to 6720 lumens with 84 watts in the LEDs.

I'm no fan of HPS, and you'll get no argument from me about the low CRI of HPS. In that sense, I guess the thread title is correct – The LEDs' CRI did exceed the HPS. But so does the CRI of a 4W nightlight bulb exceed HPS. So, no big deal.

Your posts seem to have a lot of 'maybes' and if's that leave me unconvinced. Tell me, how many lumens did the claimed 75W low-bay fixtures put out?

Or is it your position that since the CRI of the LEDs exceeded the HPS by a factor of 7:2 that only 2/7 of the lumens are need to 'exceed' the HPS?

What Newbie said is not only a question of total lm, but how this lm are distributed and CRI affecting the visual effect.

From many time, lighting designers claims for the use of Metal Halides instead of HPS for street/roads lighting, due to its better visual perfomance, although MH has lower lm/w efficiency than HPS.

Lm is just one part of the ecuation to consider in lighting

I have no idea brickbat.

If you want to buy one, and send it to me, I'd be more than willing to check it out.


Another item folks often forget about, is the human eye adjusts, or adapts to the lighting situation. I see the effect of this when I am out rockhounding, away from civilization, during the night time. It is amazing how little light the human eye actually needs. Some nights, star light and/or moonlight are plenty to navigate with, and on other nights, an even output flood light is great, since you retain most of your vision, and your eye adapts rapidly back to no flashlight. From actual use and experience, flashlights that have a hotspot pretty much thrash your vision, unless your hotspot is on the item you are looking at.

There is an area between scotopic and photopic, called mesotopic, that often is forgotten about.

There are a number of other interesting mechanisms for one to further consider:
http://sightresearch.net/files/retinex.htm


They have found plenty of examples where the simple theories are quite wrong, were lab experiments don't work they way they should, and a number of the accepted ideas are even in question. An example would be this one, which does explain quite a number of the anomalies:
http://www.sightresearch.net/index.html

Kinnza said:

Lm is just one part of the ecuation to consider in lighting

Click to expand...

That is so very true!!!

Coincidentally, I saw a pre-recorded speech about HPS vs. mercury-vapor in my public speaking class last week. The speaker argued in favor of HPS rather than MV because they substantially decreased light pollution, didn't disrupt nocturnal wildlife, and consumed much less power. The orange glow, instead of white, was a big part of the improvement. Another benefit the speaker didn't mention was that if they didn't produce enough light (as you mentioned, NewBie), you'd have a great excuse to use a flashlight!

Strange that this new fixture still uses X-lamps instead of X-REs. I would think that they'd upgrade to the XR-E without hesitation, given that the only cost would be the difference in prices of the actual emitters. They could produce identical output with less power consumption.

TigerhawkT3 said:

The speaker argued in favor of HPS rather than MV because they substantially decreased light pollution, didn't disrupt nocturnal wildlife, and consumed much less power. The orange glow, instead of white, was a big part of the improvement.

Click to expand...

The first part (decreased light pollution) is a myth. LPS emits at a single wavelength that is relatively easy for astronomers to filter out but the HPS used in most of the US emits over a much broader spectrum than even MV. Yes, MV is less efficient but we've had a viable replacement for street lights in metal halide for a number of years now. Once you factor in that metal halide emits a spectrum much more favorable to scotopic vision than HPS it's actually more efficient. Despite the supposedly equal or greater number of lumens, many complained about the dimness of HPS relative to MV when the change was made here in the late 1960s/early 1970s. Additionally, the white color of metal halide doesn't clash with the natural nighttime light sources (moon, stars) in the way that the orange HPS does. The speaker should also have mentioned that HPS basically results in the loss of most peripheral vision. Just for this reason alone its use in streetlighting should be banned. I personally look forward to the day when LEDs become efficient enough to replace HPS en masse. I just hope some uninformed politician doesn't get the brainstorm to use either amber or warm white so they "match" the HPS that they are replacing.

*******, I wish these were in the mix when I sourced light fixtures for a utilities company a few months ago, I probably would have gotten to see a sample up close and personal =)

Yeah, too bad. If you still have the position, you could probably ask for and receive a real data sheet on these fixtures.

Looks like they are making some very interesting flashlights, one CPF'er bought one, and likes it, especially for the price:
http://candlepowerforums.com/vb/showthread.php?p=1776118#post1776118

Magnetic switch, rated for 100 meters submersion, etc...wow 39 dollars:
http://store.lsgc.com/LC-2000-CR123A-BATTERY-POWERED-WATERPROOF-LED-FLASHLIGHT-P10C4.aspx

Their rechargeable adjustable output light for 59 dollars:
http://store.lsgc.com/LR-4000-LONG-LIFE-RECHARGEABLE-LED-FLASHLIGHT-P9C4.aspx


I also ran into some of their advanced liquid cooling information, micro-fluids and two-phase heat transfer for the low bay fixtures (sounds like heatpipes to me...):
http://ww2.wpri.com/Global/story.asp?S=4953380&nav=menu20_13_13

The "heatpipe" technology:
http://www.celsiatechnologies.com/products.asp

.

NewBie said:

Looks like they are making some very interesting flashlights, one CPF'er bought one, and likes it, especially for the price:
http://candlepowerforums.com/vb/showthread.php?p=1776118#post1776118

Magnetic switch, rated for 100 meters submersion, etc...wow 39 dollars:
http://store.lsgc.com/LC-2000-CR123A-BATTERY-POWERED-WATERPROOF-LED-FLASHLIGHT-P10C4.aspx

Their rechargeable adjustable output light for 59 dollars:
http://store.lsgc.com/LR-4000-LONG-LIFE-RECHARGEABLE-LED-FLASHLIGHT-P9C4.aspx


I also ran into some of their advanced liquid cooling information, micro-fluids and two-phase heat transfer for the low bay fixtures (sounds like heatpipes to me...):
http://ww2.wpri.com/Global/story.asp?S=4953380&nav=menu20_13_13

The "heatpipe" technology:
http://www.celsiatechnologies.com/products.asp

Click to expand...

i like the heatpipe addition. should help out alot as they add more emmiters to each light. then they can transfer the heat to the housing of the light without adding to the power needed to cool them. means for bigger lights though, soon i see household lights will be all solid, no bulbs to change, and the leds will be heatpiped to the housing.

This is an interesting idea, although I would like to see how these LEDs stack up to a Metal Halide lamp of the same total wattage in a good fixture. MH already puts HPS to shame in just about every outdoor lighting application I've seen it -- color rendering is quite good, and the color temp is more natural looking. Even though MH lighting genreally looks dimmer than HPS, I find it much easier to see what is going on, especially in the rain. I think that comparing the LED to MH would be a more fair comparison.

2xTrinity said:

MH already puts HPS to shame in just about every outdoor lighting application I've seen it.

Click to expand...

MH burn out a lot more quickly than HPS. Just my own experience with smaller lights, like you might use outside your house.

Personally, I can't stand the blinding twinkle of LED streetlights. MH lights seem softer with less glare, especially with rain on the windshield.

Lower maintenance, better CRI and less energy consumption are great, but from a public safety standpoint, these lights are hazardous. I wish they would put them behind the same glass globes as MH lights, just to soften the glare.

The cities often seem to be going for these super-cool tone LED's too. They seem unnatural. I miss the warm colors, they seem easier on my eyes, whether it's oncoming headlights or overhead streetlights.

We're starting to see quite a few of the streetlights in Torrington, CT. replaced with the LED units. I kinda like the clean white light. I'm a little nostalgic of the orange Sodium Lights. It will be interesting to see how long these last in the field. It also gives me some hope that LED's will eventually be a viable alternative to headlights.

rattletrap1970 said:

We're starting to see quite a few of the streetlights replaced with the LED units. I kinda like the clean white light. I'm a little nostalgic of the orange Sodium Lights.

Click to expand...

I feel the same way.

I like the clean white color of LED light, but when I am driving I sometimes find it seems to have more glare on my eyes. It's the blue in the light.

I bought some cheap chinese LEDs, they basically give off a very yellowish white light. It uses thicker phosphor so only a small amount of blue gets through. When one first sees the color, it is a little ugly, but if one uses them to illuminate a room, it is very soft on the eyes. It almost feels like a lantern. And colors show up fairly well under it, despite the light's yellow color (only blue colors appear darker). I was thinking why could they not use these types of LEDs for street lighting? No glare, easy on the eyes, and better than sodium lamps. They could probably even get a little better color rendering, and higher efficiency, by combining red-orange emitters (610nm) with greenish phosphor converted LEDs.

Like many other drivers, I would prefer softer light on my eyes while driving at night, even if the light has a strange yellowish color. It does not have to be a nice white color light to have decent color rendering either.