Energy Conservation & Lighting

Re: 1. LED or Induction is recommended for Bay lighting, Street lighting, gang ways, sub-ways, etc. Is such lighting can replace T-5 tube lights use in small component manufacturing units at table top height?

Sure, why not, as long as you pick a light that is small enough both physically and with respect to light output.

Re: 2. LED or Induction light manufacturers claim 50,000 to 100,000 Hours life; then what about electronic driver life or control power supply and side effects on power lines?

Very appropriate concern. I've seen discussions (maybe on CR4, maybe somewhere else) about early failures of LED lights due to capacitor failure, which seemed to be blamed on Chinese capacitors.

I guess I wrote to thank you for calling my attention to Induction lights--so, thank you!

I can't offer much more except common sense--if the electronic driver fails on an induction lamp, can it be replaced? At what cost? Can the induction lamp manufacturer(s?) refer you to satisfied customers that have gotten 100,000 hours of life out of an induction light? (100,000 hours is about 12.5 years of 24/7 operation.)

Ask similar questions to the LED manufacturers.

(I assume you're not looking to buy 1 light, but instead some fairly large quantity.)

Thanks everyone for useful comments. Yes I am looking for bulk quantity for 60X250 Mtrs manufacturing facility plus 1100 mtrs street lighting. All types of supplier supported by their lighting engineers presenting their case. For example: one LED supplier claimed that his lamps life is 100,000 Hrs. When I asked him to give guaranty in writing he says he can give for one year only. When I offered him Annual maintenance contract he quoted for 11% of capital cost; which is normal for any power electronics industrial product. I worked in various types of industries like civil construction, shaving blade manufacturing, electronic component manufacturing, wafer fab, etc., every industry got it's own suitable lighting requirements. Most lighting engineers look at commercial point of view trying to force their products. For example: Semiconductor component manufacturing requires Halogen spot lights to aid T-5 tube lights fitted above them & shaving blade hardening furnace require special twin tube light at the roll out stage to detect bow formation. Similarly small metal-film resistors manufacturing operators require halogen or filament lamps to check color code bands.

For energy conservation, LED is the WORST and most inefficient lighting, for area lighting purposes.

An ordinary, Halogen Filament lamp will give 14 times more area coverage, or visibility than an LED of the same power. The LED concentrates all the light, with its plastic lens, into a small spot. This spot is brighter than the same area, lit by a halogen lamp but ONLY at this spot. All around the Halogen lamp it is lit with the same brightness while all around the LED is darkness, except in front, where the lens concentrates the total light output into a small spot.

LED is ONLY useful for directional lighting or lighting a small spot.

CCFL last longer than LEDs and has light output in ALL directions, with many times more area brightness than the same wattage LED.

Fluorescent lamps give more brighter area coverage for much less power than LEDs.

Induction lamps, mercury vapour lamps, Sodium lamps, CFL, CHID, are ALL more energy efficient at area lighting, to get the SAME, all around illumination.

Some of these lights contain Mercury but I have never heard of anyone dying of Mercury poisoning in the 100 years of their use. Mercury poisoning does not kill.

Red LEDs have Gallium Arsenide as a waste product. Arsenic does KILL and if waste from LED manufacturing gets into rivers it can transfer the poison into food crops.

Re: An ordinary, Halogen Filament lamp will give 14 times more area coverage, or visibility than an LED of the same power. The LED concentrates all the light, with its plastic lens, into a small spot. This spot is brighter than the same area, lit by a halogen lamp but ONLY at this spot. All around the Halogen lamp it is lit with the same brightness while all around the LED is darkness, except in front, where the lens concentrates the total light output into a small spot.

Hmm, I'll have to look into that (because I never thought about it)--I always just looked at lumens per watt and assumed that those lumens could be distributed in various ways (by lenses, reflectors) but that still the lumens per watt was a good measure of light output per unit of (electrical) power. Now, I guess I'll have to start with the definition of a lumen, I guess that's a measure of light flux--i.e., an amount of light distributed over an area--I probably won't do that today, especially as I am not the OP.

If someone could educate me on this point, I'd appreciate it. I guess to phrase the question in a way that could help me if answered: Given two light sources, both with the same lumens (and lumens per watt, just to make things easier), one with the light focused into a beam, one with the light distributed "spherically in all directions", will the focused beam be brighter by a very large factor because all the light that could have been distributed equally in all directions is concentrated in a much smaller beam.

If lumens, or lumens per watt is not a good measure of absolute light output per unit of power, what is a better measure?

With respect to Mercury poisoning does not kill.: I don't know, but I'm pretty sure it can cause brain damage. Something to be careful of, in any case.

"Total Luminous Flux" (Lumens), was the original measurement of a light source output. It was measured in a big sphere with thousands of light detectors all round the light source, in a big ball. Each light sensor measured the lux reaching it and the total was given for the sensors all around, as the Total Luminous flux. This was a very big and very expensive measuring device.

It was noted that each of the sensors around the sphere gave the SAME measurement, from the Lamp inside the sphere, because the lamp gives out equal amounts of light in ALL directions. So to make a cheaper measuring device, it was agreed that you could measure light reaching just 1 steradean of the sphere. (There are 12.56 steradeans that make up the sphere surface). So you only need the sensors for this area only. As the light is equal in ALL directions then you measure 1 steradean and multiply by 12.56 to get the Total luminous flux. This is how the modern measurement is done.

LED manufacturers CHEAT this measurement by using a focused LED, giving ALL its Total Luminous flux onto the single steradean measuring area and then multiply by 12.56, as if it was only 1 steradean of the light, when it is in fact all the 12.56 steradeans of light are already focussed into one spot by the lens. This gives a very wrong measurement and is NOT Total Luminous flux but is 12.56 times MORE than the Total Luminous flux. You can see that something is wrong with the measurement, if you look at a single LED with 2 different angles of output. The Lumens given for the 30 degree LED are very much MORE than the Lumens for the 60 degree lamp BUT the total luminous flux should be the SAME at ALL angles, if it were really the TOTAL luminous flux.

Oh! Mercury was used for making Hats and Hatters worked in Mercury, breathed mercury, soaked their hands in Mercury 12 hours a day for many many years. They did not die BUT if you read Alice in Wonderland, you will know how Mad they became from the very extensive Mercury exposure. Sucking on a few broken fluorescent lamps is not enough to cause this kind of problem but I don't recommend it.

Thanks very much! (And I gave you a GA--I don't normally report such actions, but since I was thanking you anyway...)

You may be uninformed or unaware, but you are wrong. Of course there are many ways to meet lighting needs, and sometimes LED solutions are not available or simply don't work, or are often not cost effective.

But they often do produce the most efficient lighting solutions, with very nice color rendition and good spectral effectiveness, especially in the last two years.