CFL on steroids any risk?

degree. I work in, but not for, a hospital, and we, as the landlord are rel amping approximately 1,000,000 s.f. of space including everything from ORs through research labs to animal, bacterial and plant facilities. You may be t, very safely, that in many of the labs and procedure rooms, CRI, Kelvin a nd Color are critical at many levels.

Kelvin & Color being controlled primarily via the drivers, not the emitters .

that is confused. CCT is determined by the emitters, of which those lamps h ave at least 2 of different CCT, or 3 R G & B. Adjusting the PSU determine s which gets how much current, thus determining final CCT. It does not of c ourse determine the CCT of each separate LED emitter, those are fixed by th e LEDs themselves.

NT

Tabby:

You are about 3 years behind the times with LEDs. Suffice it that that is an eternity in the lighting business. And about covers your very nearly complete ignorance of what is in the market today.

Peter Wieck Melrose Park, PA

My yard light and my porch light are base down.

Every other lamp in my house is base up. I would think that is true for many people, probably most.

I have only a couple of incandescents left, most were converted to CFL and then as CFL got harder to find and LED cheaper, to LED.

If it's true these should not be mounted base up, then manufacturers have been way overselling the benefits. In particular the supposed longer life of the more expensive bulb does not really exist, if it's only true base down.

many people, probably most.

d then as CFL got harder to find and LED cheaper, to LED.

been way overselling the benefits. In particular the supposed longer life of the more expensive bulb does not really exist, if it's only true base d own.

Note that lamps designed for base-up applications such as spots and PARs ar e designed for base-up applications.

Otherwise, look carefully on the packaging for standard Edison-Base lamps. Most will either have an icon indicating base position(s) or some verbiage to that end. Those that do not are designed for base-down installation. Ple ase also note that this goes all the way back to incandescent lamps, with e arly 3-way lamps marked for base position.

s/

Is one example specifically applicable to HID lamps.

Putting a lamp out of position is not immediately fatal, but it will shorte n the life of the lamp.

Peter Wieck Melrose Park, PA

Given that most applications are base up, would there be an advantage to choosing CFL vs LED?

My LED bulbs seem to have a heat sink. CFLs don't, I've taken a couple of failed ones apart to see what's inside. Is there gas inside the envelope of an LED, so it transfers some heat to the bulb shape?

Any heat source generates convection air flow, as long as the fixture isn't enclosed.

Now I know what's inside an LED:

Er no, that is what's standard fare for domestic lighting.

NT

Is GB really that far behind the rest of the world? Or is it just you?

Peter Wieck Melrose Park, PA

I'm just letting you know what's in the shops. Really I don't know what your problem is. And am not interested.

NT

Yeah, that's a problem with all lighting. Most fixtures (luminaires) are enclosed.

Here's an example of a melted MR16 5watt 12v LED lamp: The lamp is the upper right is the way the lamp looked when new. The wrinkled looking lamps are what happened when they were run in a badly ventilated light fixture. Notice how much the plastic has shrunk when over-heated. The PCB in the lower left is the back of a 60 LED array and consists of 10ea 82ohm(?) resistors and a diode bridge. I haven't bothered to decode how the LEDs are wired.

The LED front view is in the upper right. The lamp in the upper left in an MR16 incandescent light. It's made of an aluminized glass reflector, aluminum frame, and ceramic base. I think it's rated at 20 watts. All were mounted with the base facing upwards.

I couldn't find the original listing, but I think it's the 60 LED (5 watts) version of this light:

What happened was that I replaced about 20 incandescent MR16 lights on some overhead track lighting. The light fixtures were miserably ventilated and were killing 20w incandescent lamps at an alarming rate. Replacing them with LED's was suppose to reduce the heat load. Instead, it melted the plastic case instead of blowing the filament. Burning down the house was averted because the house was full of hot plastic smell and the smoke alarm was screaming. Oops.

Moral: The plastic materials used in most LED's are not as heat resistant as the glass and ceramic materials used in incandescent and CFL lighting.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

Thanks. There's some good info there. Now having looked at the guts of a number of LED lamps I can see where heat dissipation is more of a problem than I realized.

It's probably worse than with CFLs because of the concentrated area where the heat is produced, right?

What isn't obvious to me, having looked at the internals, is why the orientation would have more than a trivial effect. That heat looks pretty trapped no matter where the base faces.

Maybe. LED's are certainly more efficient. Lumens/watt LED 100 CFL 60 Incandescent 16 For equal amounts of light output (lumens), a CFL lamp takes 1.7 times as much power to produce that light as does an LED. That's a big difference, but not as spectacular as the 6.3 times jump from incandescent to LED.

You're concerned about "heat" with measured in Joules where 1 joule = 1 watt/second What I think you want is the final operating temperature of the device to make sure that it doesn't melt plastic, degrade the LED's, destroy electronic components, or set fire to the vicinity. The final temperature has many parameters, most of which are NOT the same for LED and CFL. For radiation loss, the surface area of a CFL lamp is larger than the equivalent LED, and is therefore a more efficient heat radiator. While the LED might waste fewer watts than the CFL light heating up the room, the CFL will remove the heat from the lamp more efficiently because it has a larger surface area. The LED compensates for its smaller size by using aluminum heat sinks, while the CFL has a larger thermal mass by using ceramics. Lots of other differences making a general conclusion rather difficult.

Also maybe. The various lamps will move heat using conduction, radiation, and convection. All three mechanisms are involved in determining the final temperature of a lamp. In a light fixture, the ability of move air through the fixture to remove the heat via convective air currents is restricted. Without air flow the temperature of the lamp will rise. If the air flow is uneven, there will be hot spots on the lamp surface. Some lamps are more tolerant to heating than others. My plastic case MR16 LED lamp was probably the least tolerant. High temperature halogen incandescent lamps are quite happy at much higher temperatures. LEDs lose half their light output going from room temp (25C) to operating temperature (100C) which is why LED heat sinks are much better and larger than CFL which can tolerate higher temperatures.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

I doubt that's true. Flash power, the first 3 seconds of operation for an LED, might be 100 lumens per watt, but I think 60 is more realistic.

I'm not sure that's the case. Surface area makes a difference for both rad iation and convection, but the temperature difference is what really drives the heat transfer. The plastic globe area of an LED equivalent lamp runs much hotter than the curlicues of a CFL. (I haven't measured, but that's w hat my fingers tell me when changing both while hot.) (and that's probably because an LED doesn't have vacuum inside the globe, it has air that's in contact with the emitters)

I don't think the majority of the heat dissipation from a CFL is from the c urlicues. But if even a portion is, then the orientation will make no diff erence. Air will flow through them base up or down about the same.

Heat radiation is not significant at LED operating temp. Ditto for most of a CFL, but the end filaments do run hot.

All heat produced by both does get dissipated, it can't be trapped else the thing would get endlessly hotter & self destruct.

Why does orientation matter? With a 20w CFL, the ballast silicon is vulnerable to high temps. Ballast down it gets cool air flowing slowly upward past it. Ballast up it gets hot air past it, reducing life expectancy. The tube OTOH doesn't care either way.

NT

The Dubai Lamp range is comprised of four LED bulbs, each of which is avail able in ?cool daylight? and ?warm white? co lors. There?s a 1-W, 200-lm E14 candle bulb, 400-lm E27 classic bul b and a 600-lm E27 classic bulb. Philips says it designed the filament LED bulbs to replace 25-W, 40-W, and 60-W incandescent bulbs, respectively. The bulbs run off Dubai?s 220-240-V mains voltage.

The above article is from very nearly two years ago. 150 - 175 l/W lamps ar e common in the commercial market, and readily available in to consumers wi th a just a bit of effort. A bit more costly, perhaps - but if one is in a region where the Utility is subsidizing prices, you may not notice.

That Home Depot or whatever passes for a Big-Box store at whatever location will not be selling either the latest, nor certainly not cutting-edge tech nology. They WILL be selling whatever may be mass-produced at the lowest co st with the highest margins.

Most of the discussions here are based on assumptions that are - at least - three years out of date.

Suffice it to understand:

LED Lamp drivers get HOT. These are drivers, not ballasts. The amount of heat generated is in direct proportion to the amount of light generated as function of emitting surface. Linear emitters

spread the emitter heat out, and allow (relatively) tiny drivers making not

-much heat. Most of these lamps are also "universal" inasmuch as they may b e run in any position. And, their lumens-per-watt is not massive, either.

Point-source emitters such as the CREE XHP35 will make up to 706 lumens at 350 ma. - which translates to 183 lumens per watt. Really. And that was in troduced in 2018, and is commonly found in your MagLite, if you want a "rea l world" application. It runs at 150C at the junction - which is tiny, so t hat heat is easily managed. And as it is a direct DC device, there is no se parate driver in a flashlight application. In a lamp application, that driv er gets quite complex as that same emitter may run anywhere from 5500K with a CRI of 50 to 2700K with a CRI of 90.

The technology is still evolving. And it is NOT where it was even a year ag o.

Tabby, for the record, you give us all a deeper understanding of the term " invincible ignorance". Thank you for that!

Peter Wieck Melrose Park, PA

ilable in ?cool daylight? and ?warm white? colors. There?s a 1-W, 200-lm E14 candle bulb, 400-lm E27 classic b ulb and a 600-lm E27 classic bulb. Philips says it designed the filament LE D bulbs to replace 25-W, 40-W, and 60-W incandescent bulbs, respectively. T he bulbs run off Dubai?s 220-240-V mains voltage.

are common in the commercial market, and readily available in to consumers with a just a bit of effort. A bit more costly, perhaps - but if one is in a region where the Utility is subsidizing prices, you may not notice.

on will not be selling either the latest, nor certainly not cutting-edge te chnology. They WILL be selling whatever may be mass-produced at the lowest cost with the highest margins.

- three years out of date.

ht generated as function of emitting surface. Linear emitters

ot-much heat. Most of these lamps are also "universal" inasmuch as they may be run in any position. And, their lumens-per-watt is not massive, either.

at 350 ma. - which translates to 183 lumens per watt. Really. And that was introduced in 2018, and is commonly found in your MagLite, if you want a "r eal world" application. It runs at 150C at the junction - which is tiny, so that heat is easily managed. And as it is a direct DC device, there is no separate driver in a flashlight application. In a lamp application, that dr iver gets quite complex as that same emitter may run anywhere from 5500K wi th a CRI of 50 to 2700K with a CRI of 90.

ago.

"invincible ignorance". Thank you for that!

They may be available, but they're not what's in the shops, so not what you find in people's homes. As I said. That you think a driver/ballast produce s more heat than the LEDs borders on funny.

NT

Download all 1518 jpegs using wget.exe -nd -r -A jpg

That's correct, if you include:

1. Losses through any lenses or reflectors.
2. Losses in the switching power supply.
3. Losses in any power factor correction circuitry.
4. AC power is power factor corrected.

Easy enough to measure. I have enough junk from my flashlight tinkering to measure lumens, but not with any great accuracy. Here's how I do it with flashlights, bicycle headlights, spot lights, and any light that generates a round spot on a wall.

I found new LED "flood" light in my collection.

750 lumens 12.5w Notice that there's plastic diffuser in front of the LEDs.

Plugging it into my Kill-A-Watt watt-guesser, I measure:

12watts 15VA 0.78PF (power factor) which seems about right. Luminous Efficacy = 750lumens / 12watts = 63 lumens/watt So, you're correct if I include all the losses.

However, the numbers I provided were for the raw LED at room temperature and does NOT include all the losses.

Might as well grind the numbers for CFL. I found one of these in my collection:

1700 lumens 26 watts Measuring with the Kill-a-Watt meter: 26watts 37VA 0.70PF Luminous Efficacy = 1700lumens / 26watts = 65 lum/w

Hmmm... looks like the LED (with the diffuser) is almost as bad as CFL. I suspect the diffuser loss is what's causing the lower efficacy for the LED, but I don't have LED bulb handy to prove it. I'll see if I can find or borrow one, at least with a glass lens, not plastic. According to this chart: the LED floodlight should have been about 100 lum/W.

Temperature (C or F) is not the same as heat (calories) which is not the same power (watts) which is not the same as energy (joules or watts/second). Also, there are several different types of efficiencies and efficacy: "Energy Efficiency of White LEDs" (2009)

Overall luminous Overall luminous efficacy lum/W efficiency LED screw base lamp (120 V) Up to 102 Up to 14.9% 9- 32 W compact fluorescent 46 - 75 8 - 11.45% (with ballast)

Kinda looks like the LED produces about twice the light output of the CFL, for the same amount of input power. However, my measurements say they're about the same.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

They are found in both our houses. That you wish to make a virtue of ignorance is what is funny in a sad sort of way.

Peter Wieck Melrose Park, PA