Author Topic: The Dubai Lamp  (Read 14252 times)

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Offline Twoflower

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Re: The Dubai Lamp
« Reply #25 on: April 09, 2022, 07:40:30 pm »
They seem to be available for sale in the UK, e.g. John Lewis. But are rather pricey at around £12 for the 60 Watt equivalent ones (  https://www.johnlewis.com/philips-60w-e27-led-non-dimmable-classic-bulb-clear/p6040141  ). Also, some express concern it is a 3000K colour temperature, rather than the warm white 2700K ones, that you normally get.
Wow, here in Germany we can get them for just below 10€ (£8). But still much more expensive compared to the 'normal' Philips bulbs (~3,50€ for 100W).

The 3000K might not be that bad. In the kitchen I have 4200K (with CRI >90) by intent. Direct comparing that to warm white it's a huge difference. But 3000K vs. 2700K might not be that bad. One might say: It depends. Especially where you plan to use it.
 
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Online MK14

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Re: The Dubai Lamp
« Reply #26 on: April 09, 2022, 07:59:00 pm »
Wow, here in Germany we can get them for just below 10€ (£8). But still much more expensive compared to the 'normal' Philips bulbs (~3,50€ for 100W).

The 3000K might not be that bad. In the kitchen I have 4200K (with CRI >90) by intent. Direct comparing that to warm white it's a huge difference. But 3000K vs. 2700K might not be that bad. One might say: It depends. Especially where you plan to use it.

That shop (John Lewis), is a large chain of department stores. Which tend to sell expensive items, for middle class people. So, when/if these ultra efficient LEDs are more widely available, the price in the UK (and elsewhere), could easily drop.

I'm unsure if the relatively high price, is because Philips are reluctant to sell LED lights with such long life times, as it could make them lose lots of customers, until the 20, 30 or even 50 years, life time is finished.
But it could be (the high price), because it is rather new to the market, expensive to manufacture (needs lots of LEDs, and possibly high energy efficient LEDs, could be more expensive as well, per individual LED), also some people think they have more expensive controllers and other circuitry, to significantly reduce the power consumption.
Also, it could be because many customers are put off by such big prices. Especially as those potential customers, probably are not concerned by saving a few watts per LED bulb, and believe they wil get the stated 15,000 hours lifetime, from cheap/standard/normal LED bulbs. Hence poor economies of scale, which tends to drive the prices up, compared to popular, mass market items.

I suspect those bulbs really will give close to 50,000 hours life time (because of expected very low operating/running/dissipation temperatures as so efficient and quality design/components), unlike many LED bulbs which claim e.g. 15,000 hours, yet seem to fail after around a year or so. Perhaps 5,000 hours out of the 15,000 hours, at a guess, then they seem to fail. Possibly in my case because the bulbs cooling is hindered (partially enclosed fittings and/or bulbs the wrong way up (pointing up to the ceiling, instead of down towards the ground), which is suppose to mess up the cooling patterns).

If they save perhaps 3 watts, then over 50,000 hours, and at around 30p per kilowatt-hour.
Savings would be around ((3 x 50,000) / 1000) * £0.30 = £45 (spread over the next 20, 30 or even 50 years, lol!).
Also, let's say the cheap bulbs are £2.50 each and ten (50,000 hours / 5,000 hours I approximately get = 10) would have been needed, then it's £12 instead of £2.5 x 10 = £25, which is also a nice saving.

I'd have to compare the 3000K warm light to the standard/usual 2700K warm light, to see if it bothers me or not. But certainly in some areas/rooms, it should be ok anyway, so these are useful things, especially in hard to reach, bulb replacement areas, such as any high up (ladder needing), outside lighting.
« Last Edit: April 09, 2022, 08:04:23 pm by MK14 »
 

Offline Twoflower

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Re: The Dubai Lamp
« Reply #27 on: April 09, 2022, 08:33:57 pm »
Same here. I think the'll last long time as the design uses rather relaxed constrains. If the last the stated 50.000h depends on many things. Temperature, probably even noise on the supply lines and so on. The stated 50years if you use it 3h/day enters a totally new range of potential failures. Like the glue that was used ages ago that get conductive over time. Or look at the aging effects visible at some of Noopys incredible die pictures.

I just replaced my CFL-bulbs after 15 Years in service. Since many of them showed signs of aging and one died. So the replacement to LED halved the power consumption. Hopefully the LEDs last as long als the CFLs. Chances are good as most of the fixtures are open and just 25W and 40W eq. But I don't think it is worth to change existing, but working LED bulbs.
 
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Online MK14

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Re: The Dubai Lamp
« Reply #28 on: April 09, 2022, 09:25:29 pm »
Same here. I think the'll last long time as the design uses rather relaxed constrains. If the last the stated 50.000h depends on many things. Temperature, probably even noise on the supply lines and so on. The stated 50years if you use it 3h/day enters a totally new range of potential failures. Like the glue that was used ages ago that get conductive over time. Or look at the aging effects visible at some of Noopys incredible die pictures.

That's exactly/similar to my experiences. A very long time ago, I had a light which was a bit of a nightmare to replace (outside, needed a ladder, fiddly light fitting, that needed unscrewing and careful disassembly, to avoid dropping its fragile glass part, from the ladder). So, I managed to get these supper long life (tungsten filament) bulbs. I can't remember exactly, but they had a design life of something like 20,000 to 60,000 hours or more (supposedly designed for aircraft or airport use, or similar).
It was around 40 Watts, a bit dim for 40 watts, but perfectly usable (60 watts, if I'm mis-remembering).

Their advert would be too old to find on the internet now, but I found something similar:
Quote
Clear Incandescent Rough Service Light Bulb, 40 Watt, Long Life - 10000 Hours, 2700K Soft White, E26 Medium Base, 260 Lumens
In my case it said something like, typical life can extend to 35,000 hours or more (from memory).

But to my significant disappointment, after around 2.5 years, the glass cracked (probably due to temperature extremes and changes over time), and the bulb hence broke.
A bit like the glue failure, you mentioned.
50 years is pushing it for many electronic components. Even the lead-free solder joints can break/crack from the temperature changes, during on/off operations, in theory. Like the xbox red ring of death (I think rumored to be the lead-free solder cracking, under the GPU, because of temperature cycling/changes), but used as an analogy to ultra long life LED light bulbs. Capacitors can easily fail, as well as many other components. Resistors can drift in value too much, and so forth.


But I don't think it is worth to change existing, but working LED bulbs.

I've got exactly the same dilemma, and come to a similar conclusion. Wait until the current bulbs burn out and/or stocks of replacements run out, before choosing which ultra efficiency LED bulbs to get. Unless it was the old filament bulbs, which do use relatively huge amounts of power now,compared to modern alternatives.
« Last Edit: April 09, 2022, 09:54:03 pm by MK14 »
 

Offline james_s

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Re: The Dubai Lamp
« Reply #29 on: April 09, 2022, 09:53:50 pm »
I'd have to compare the 3000K warm light to the standard/usual 2700K warm light, to see if it bothers me or not. But certainly in some areas/rooms, it should be ok anyway, so these are useful things, especially in hard to reach, bulb replacement areas, such as any high up (ladder needing), outside lighting.

A lot of halogen bulbs are 3000K and have been for many years. The only time you're likely to notice is if you have a mix of different color temperatures in a room. I've been amazed at how quickly the brain adapts to treat any light source as "white".
 
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Online MK14

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Re: The Dubai Lamp
« Reply #30 on: April 09, 2022, 10:02:14 pm »
A lot of halogen bulbs are 3000K and have been for many years. The only time you're likely to notice is if you have a mix of different color temperatures in a room. I've been amazed at how quickly the brain adapts to treat any light source as "white".

That makes sense, and is encouraging. Also, as I see it. Assuming the 50,000 hour life expectancy is genuine and easily achievable. Then (depending on daily hours usage, assuming 3 to 6 hours daily, hence 25 to 50 years life) those LED light bulbs essentially last forever (in our living perception of them, depending on current age) and also use virtually no power, especially the 2.3 watt 40 Watt equivalent versions. I bet/suspect some older devices, when switched off, but which keep a low power transformer active. I.e. the primary has mains voltage on it, and the on/off switch is connected to the secondary part. Perhaps use 2.3 watts, even when supposedly switched off and/or any small transformers (chargers and things), left switched on but not connected to anything.

I.e. 2.3 watts is arguably next to nothing, especially compared to many other things, especially anything that heats things up on purpose (heating, hot water, etc).
I'm amazed so much light can come from a mere 2.3 watts (40 watt equivalent), it could be run off batteries, for a period of time. Perhaps 1.5 weeks or more, from a charged car battery (if it worked at 12 V, that is). Quite amazing.
« Last Edit: April 09, 2022, 10:07:04 pm by MK14 »
 

Online MK14

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Re: The Dubai Lamp
« Reply #31 on: April 09, 2022, 11:21:21 pm »
Just in case anyone was interested in what I was talking about before (that broke prematurely, after 1.5 or 2.5 years approx, due to ruptured glass package) is interested in those long life, perhaps (10 years +) 25,000 plus hours life, tungsten filament (incandescent), now relatively old fashioned 40 watt light bulbs. An old packet of them, are reviewed, here:

 

Offline BrokenYugo

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Re: The Dubai Lamp
« Reply #32 on: April 10, 2022, 04:47:22 pm »
That incandescent is mostly relying on the cheap trick of running the filament colder, 230 lumens is more like what one would expect from a 25 watt bulb (on the high end), a 40 watt bulb is usually ~400 lumens.
 
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Online MK14

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Re: The Dubai Lamp
« Reply #33 on: April 10, 2022, 06:19:22 pm »
That incandescent is mostly relying on the cheap trick of running the filament colder, 230 lumens is more like what one would expect from a 25 watt bulb (on the high end), a 40 watt bulb is usually ~400 lumens.

I don't think I realized that, at the time. Because they cost me a small fortune. It was probably something like a couple of decades ago. It was perhaps £10 or £20, for around 2 or so, when a £1 or so, could probably buy one or even a pack of 5 or 6, standard bulbs.

I absolutely hated changing the light I mentioned above (needing a ladder, screw-driver, and lots of fiddling with). So, was very pleased with the deal.

Anyway, although a (approx) 450V rated tungsten filament bulb, was what I bought for the 240V AC mains (at the time, now supposedly 230 V AC, by jiggery pokery with the specifications), as far as I know. High voltage bulbs, were not available for sale, anywhere I looked, at the time. But also, I wasn't looking, as I didn't realize that method, was what they were using, to create the super long life bulbs.

TL;DR
Yes, I was probably partly conned out of some money, at the time. But it was well worth it, as a couple of decades ago, bulbs would burn out after around 1,000 hours (2,000 hours, with some harder to get, longer life ones). Which meant fairly frequent bulb changing. I remember (could be mistaken), it felt like one or two bulbs would burn out (they seemed to LOVE burning out, as you switched them on, when cold, sometimes with an annoying bang, although I think they later introduced statuary internal fuses for the bulbs, to stop them blowing out fuses, in your UK fusebox (old days, going back a number of decades), when they blow, and arc inside, temporarily using a huge current and hence potentially (sorry about the pun) blowing a physical wire fuse in a box, which now nowadays, is often circuit breakers, which just have to be flipped back on).

TL;DR attempt 2, to actually be short
Yes conned, but hated using ladder and fiddly fitting, so pleased as 1,000 hour bulbs pop rather frequently.

EDIT:
In case anyone is wondering. There were old CFL types of bulbs available, a while back. But the early ones, tended to be rather expensive, take ages to be at anything like full brightness (e.g. a minute or so), a bit hard to buy, massive/heavy, light quality wasn't that good, sensitive to breaking if turned on/off too violently (I've broken some that way), and unsuitable for electronically controlled lamps (i.e. dimmers, some types of mains timers (i.e. TRIAC etc ones) or light level automatic (when dark) switchers etc).
« Last Edit: April 10, 2022, 06:31:01 pm by MK14 »
 

Offline BrokenYugo

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Re: The Dubai Lamp
« Reply #34 on: April 10, 2022, 06:47:07 pm »
I wouldn't call it a con, they have legit applications, which you used one in by the sounds of it. Definitely a bad idea for general purpose lighting in easily serviced fixtures though.
 
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Offline amykTopic starter

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Re: The Dubai Lamp
« Reply #35 on: April 10, 2022, 07:49:10 pm »
Here is a leaflet and advertising webpage, about the Philips ultra efficient LED bulbs:
https://www.lighting.philips.co.uk/consumer/ultra-efficient

Apparently (  source probably this:  https://www.electronicsweekly.com/blogs/led-luminaries/philips-goes-210-lm-w-bulbs-fanfare-done-earlier-2021-08/  but I may have read a number of websites, so it could be elsewhere  ), the EU new regulations, as regards the efficiency labeling, is rumored to have persuaded Philips to release these new LED ultra efficient ranges.
The box in the first link still appears to have Arabic text on it, so I suspect this is the same design as the original Dubai lamp... but there's only one way to find out!

 
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Online MK14

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Re: The Dubai Lamp
« Reply #36 on: April 10, 2022, 08:01:31 pm »
The box in the first link still appears to have Arabic text on it, so I suspect this is the same design as the original Dubai lamp... but there's only one way to find out!

I think I noticed that, as well. I'm hoping to buy a limited quantity (maybe 2 of them) of those bulbs, in around a weeks time, if things go to plan. If I do, I'll try and remember to report back on that arabic text and what I think of them.

My theory is that such product advert things, were prepared a very long time ago. So, that 'old'/existing box, was all they had available. So, that was used by the official photographer, to prepare that leaflet. If it needs mass leaflet printing and upper management approval, it could of been 6 months (I'm guessing) or more, before the product was really ready. I.e. The actual box for sale, may not look iike that, anyway I hope to buy one/some, fairly soon, so I can find out for sure.
Also, many products these days, are for highly global markets, and some boxes do seem to come with a huge number of different (foreign) languages, printed on them. So, that could also be why it has some Arabic writing on it.

Although around £12 is rather expensive. Lights which are on most of the time, and especially when difficult to change, are still probably worth using that type, when they next need changing.
£12's at the current UK £0.30($0.45 approx), per kilowatt-hour, will pay for itself in electricity savings alone, compared to a normal 60 watt equivalent LED light, so call it approx 3.5 watts saving, every:
£12 / ((3.5 / 1,000) x £0.30) = 11,429 hours, which is around 1.5 to 2 years, depending on how often it is left on for.

Hopefully, in the future, the price will come down, they will become more available, and perhaps better in other ways (such as being closer to 2700K, if possible, and, as other(s) have said, if it really makes a significant difference).
« Last Edit: April 10, 2022, 08:09:03 pm by MK14 »
 

Offline james_s

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Re: The Dubai Lamp
« Reply #37 on: April 11, 2022, 06:56:29 am »
Just in case anyone was interested in what I was talking about before (that broke prematurely, after 1.5 or 2.5 years approx, due to ruptured glass package) is interested in those long life, perhaps (10 years +) 25,000 plus hours life, tungsten filament (incandescent), now relatively old fashioned 40 watt light bulbs. An old packet of them, are reviewed, here:

It's trivial to make an incandescent lamp last tens or even hundreds of thousands of hours, simply run it at a lower voltage than it is designed for, lifespan goes up exponentially as voltage drops. Unfortunately efficiency in terms of lumens per watt falls about as quickly as the lifespan increases. Long life incandescent bulbs have been around for many years, but have a substantial efficiency penalty. A 60W long life bulb is about as bright as a 40W standard bulb. It's even worse in 240V land, 240V incandescent lamps are significantly less efficient than 120V bulbs.
 

Online MK14

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Re: The Dubai Lamp
« Reply #38 on: April 11, 2022, 01:01:29 pm »
It's trivial to make an incandescent lamp last tens or even hundreds of thousands of hours, simply run it at a lower voltage than it is designed for, lifespan goes up exponentially as voltage drops. Unfortunately efficiency in terms of lumens per watt falls about as quickly as the lifespan increases. Long life incandescent bulbs have been around for many years, but have a substantial efficiency penalty. A 60W long life bulb is about as bright as a 40W standard bulb. It's even worse in 240V land, 240V incandescent lamps are significantly less efficient than 120V bulbs.

I seem to remember being persuaded to buy them, because there was very tempting adverts for them. Claiming they would last for a huge number of hours, perhaps 35,000 hours, with a 20,000 hour rating (numbers very approx, from memory). They were expensive, but seemed a good idea, for any very hard to replace light bulb areas. I can't find the advert from a very long time ago, but there is a modern advert, which is a bit similar, here:

https://www.conservastore.com/product/conserve-energy/long-lasting-light-bulbs/longest-lasting-incandescent-light-bulbs/60-watt-frosted-or-clear-long-life-incandescent-light-bulbs-10000-hrs-12-pack/

Quote
60 Watt Long Life Incandescent Light Bulbs 10,000 Hrs, 12 pack
$54.00

Some folks just like the look and feel of an incandescent bulb These give you incandescent feel while offering very long life at 10,000 hrs.

The advert really made it seem attractive to buy. Saying something like, "Ever wonder how Airports have so many runway lights, which seem to last a long time. Well Get the same bulbs here, with our special offers. Get the same huge life expectancy that they get with airport runway lights. Buy now, just £25 for a pack of 2 (or 3 or 4 ?), including postage and packing". N.B. I'm trying to remember an advert from perhaps a couple of decades ago, so could easily be wrong, in the finer details.

I sought of partially knew that (inefficiency), at the time. But don't think I realized, it was an exponential effect, nor that using much higher rated voltage bulbs (if available), would do the same thing. Without needing to pay sky high prices, for some very long life light bulbs (tungsten filament).

Are you sure that 120V incandescent bulbs, are more efficient than 240V directly equivalent bulbs ?
Do you have any sources for that information ?

It doesn't make a lot of sense. Because a 60 Watt bulb, with the tungsten filament, suitably adjusted for operation on 120V AC or 240V AC, should have roughly the same energy consumption (60 Watts), roughly the same life expectancy (1,000 hours seemed to be a common standard), and as far as I know, the same light output at 60 Watts of heat, assuming the filaments, are broadly compatible.

If anything, I thought it was the other way round. The lower the bulb voltage, especially as regards tiny/small very low wattage bulbs. Such as 1.3V Torch Bulbs (1.3V accounts for the significant voltage drop, especially with old Carbon/Zinc Battery technology, from long ago, when such torches were popular), for use with a single 1.5V AA battery. Are usually, significantly worse as regards brightness, bulb burn life and efficiency. Whereas 12V or 24V bulbs, are usually much better.
« Last Edit: April 11, 2022, 01:15:03 pm by MK14 »
 

Online themadhippy

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Re: The Dubai Lamp
« Reply #39 on: April 11, 2022, 01:51:29 pm »
Quote
Are you sure that 120V incandescent bulbs, are more efficient than 240V directly equivalent bulbs ?
Do you have any sources for that information ?
no figures ,just experience  of using pairs of 120v par 64's  to get more punch from the beam than the equivalent  240v version.I believe its down to the filament being smaller so focuses better at smaller beam widths
 
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Offline james_s

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Re: The Dubai Lamp
« Reply #40 on: April 11, 2022, 06:51:19 pm »
Are you sure that 120V incandescent bulbs, are more efficient than 240V directly equivalent bulbs ?
Do you have any sources for that information ?

It doesn't make a lot of sense. Because a 60 Watt bulb, with the tungsten filament, suitably adjusted for operation on 120V AC or 240V AC, should have roughly the same energy consumption (60 Watts), roughly the same life expectancy (1,000 hours seemed to be a common standard), and as far as I know, the same light output at 60 Watts of heat, assuming the filaments, are broadly compatible.

Absolutely, it's a simple matter to look at the specifications on the package. A 120V 60W incandescent lamp produces about 800 lumens for example, while the 240V version is only about 700 lumens. You can see the same effect by looking at the lumens per watt of different wattages of lamps. All else being equal, the higher the wattage, the more efficient. A single 150W lamp produces significantly more lumens than a pair of 75W lamps.

It actually makes a lot of sense when you consider what needs to happen for a bulb of the same wattage to be higher voltage. The current has to be lower, so the filament has to be longer and thinner. A longer and thinner filament has greater thermal losses due to having a much greater surface area. Both lamps consume 60 watts of electrical input, both produce a lot more heat than visible light but the 240V lamp with its longer and thinner filament produces a significantly greater ratio of heat to visible light. This is one reason low voltage halogen lamps are (were) so popular, a low voltage lamp has a compact and relatively thick filament so it is considerably more efficient even when transformer losses are factored in.

The lowest voltage flashlight (torch) bulbs are more efficient than the higher voltage bulbs, but higher voltage has an advantage when you look at the whole system. Higher voltage means you can have greater wattage (so a brighter bulb) while the percentage of losses in the switch, terminals, internal resistance of the batteries, etc is lower. When you only have 1.5V to work with it doesn't take much resistance to result in a significant percentage of loss. If you start with 6V the same resistance is a lot less significant.
« Last Edit: April 11, 2022, 06:54:10 pm by james_s »
 
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Online MK14

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Re: The Dubai Lamp
« Reply #41 on: April 11, 2022, 09:37:11 pm »
Absolutely, it's a simple matter to look at the specifications on the package. A 120V 60W incandescent lamp produces about 800 lumens for example, while the 240V version is only about 700 lumens. You can see the same effect by looking at the lumens per watt of different wattages of lamps. All else being equal, the higher the wattage, the more efficient. A single 150W lamp produces significantly more lumens than a pair of 75W lamps.

It actually makes a lot of sense when you consider what needs to happen for a bulb of the same wattage to be higher voltage. The current has to be lower, so the filament has to be longer and thinner. A longer and thinner filament has greater thermal losses due to having a much greater surface area. Both lamps consume 60 watts of electrical input, both produce a lot more heat than visible light but the 240V lamp with its longer and thinner filament produces a significantly greater ratio of heat to visible light. This is one reason low voltage halogen lamps are (were) so popular, a low voltage lamp has a compact and relatively thick filament so it is considerably more efficient even when transformer losses are factored in.

The lowest voltage flashlight (torch) bulbs are more efficient than the higher voltage bulbs, but higher voltage has an advantage when you look at the whole system. Higher voltage means you can have greater wattage (so a brighter bulb) while the percentage of losses in the switch, terminals, internal resistance of the batteries, etc is lower. When you only have 1.5V to work with it doesn't take much resistance to result in a significant percentage of loss. If you start with 6V the same resistance is a lot less significant.

Thanks for the detailed explanations. I'm somewhat fascinated, because I didn't realize there was any appreciable incandescent efficiency difference, between differing mains voltage countries.

The nearest thing to a definitive link I've been able to find, is here:
https://en.wikipedia.org/wiki/Incandescent_light_bulb#Electrical_characteristics

From the link (wiki) above, it seems to give the respective Efficacy (lm/W)'s as 14.2 for 120V 60W Filament bulbs, and 230V 60W as 12.2, agreeing with what you are carefully explaining.

Some discussions about that subject area, show a wide range of diverse, disagreeing comments. Such as here:
https://www.quora.com/Are-100w-bulbs-in-America-brighter-than-in-the-UK-The-American-version-would-draw-more-amps-with-the-lower-voltage-outlet-than-the-220v-counterpart-If-not-why-would-bulbs-with-2-different-amperages-give-off

Some say that 60 watts of heat energy is 60 watts of heat energy, so it must (should) make the same amount of light, due to the laws of Physics.

Others still seem to say that it could be because of differences, between the real life, life expectancy of the real life bulbs (as opposed to what the American bulb manufactures are claiming, is the expected life expectancy (burn life), of those bulbs). I.e. European Bulbs are expected to generously outlast the stated 1,000 hour lamp burn life, whereas greedy big business USA bulb manufacturers, want a shortened life expectancy, so they can sell more bulbs and hence make a bigger profit.
TL;DR
The real reason for the difference, might be that the USA bulbs (claimed perhaps 1,000 hours), are really 750 hours, and hence more efficient, but the European 1,000 hours, really last for 1,250 .. 1,500+ hours, and hence are less efficient.

Also, although on the one hand you are right:
A single 150W lamp produces significantly more lumens than a pair of 75W lamps.

Another way of looking at it, is that the two 75W lamps, could be separated out into optimised lighting positions, giving a more even and bigger spread of light, than a single 150W lamp, in a single position, in a room. I.e. in real terms, the pair of 75W lamps, may give better lighting, overall. Even though they are less efficient, than a single 150W lamp.

TL;DR
To be clear, I'm NOT trying to disagree with you here. I'm just trying to confirm, an interesting/new (to me, at least), fact about these increasingly obsolete incandescent bulbs.
« Last Edit: April 11, 2022, 09:39:54 pm by MK14 »
 

Offline james_s

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Re: The Dubai Lamp
« Reply #42 on: April 11, 2022, 10:08:05 pm »
Some say that 60 watts of heat energy is 60 watts of heat energy, so it must (should) make the same amount of light, due to the laws of Physics.

But they don't put off 60 watts of heat energy. An ordinary 60W 120V A19 lamp puts out about 57 watts of heat and 3 watts of visible light. Now it's true that if you put a 60W bulb inside an opaque box that box is going to put out 60 watts of heat no matter what type of lamp (or indeed no matter what device) is inside that box consuming 60 watts of electricity but in most applications the lamp is used to produce light and the heat emitted directly from it is a byproduct. If you removed the glass from a 60W lamp and immersed the filament in a cooling fluid (and ignored the fact that in the real world the resistance would drop dramatically) the filament would still consume 60 watts of energy, but it would produce 60 watts of heat and no visible light, so the efficiency is then 0%.

Remember that when speaking of a lamp, efficiency means only the amount of visible light emitted relative to the energy consumed. It's always going to give off as much energy as it consumes, but we ignore output that is not in the desired form, ie visible light.
 

Online MK14

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Re: The Dubai Lamp
« Reply #43 on: April 11, 2022, 10:34:10 pm »
Some say that 60 watts of heat energy is 60 watts of heat energy, so it must (should) make the same amount of light, due to the laws of Physics.

But they don't put off 60 watts of heat energy. An ordinary 60W 120V A19 lamp puts out about 57 watts of heat and 3 watts of visible light. Now it's true that if you put a 60W bulb inside an opaque box that box is going to put out 60 watts of heat no matter what type of lamp (or indeed no matter what device) is inside that box consuming 60 watts of electricity but in most applications the lamp is used to produce light and the heat emitted directly from it is a byproduct. If you removed the glass from a 60W lamp and immersed the filament in a cooling fluid (and ignored the fact that in the real world the resistance would drop dramatically) the filament would still consume 60 watts of energy, but it would produce 60 watts of heat and no visible light, so the efficiency is then 0%.

Remember that when speaking of a lamp, efficiency means only the amount of visible light emitted relative to the energy consumed. It's always going to give off as much energy as it consumes, but we ignore output that is not in the desired form, ie visible light.

Sorry my fault/mistake. I poorly reported back on that thread, I linked to, earlier. I meant that the 60 Watts of heat, then emits visible light, from that heat energy, regardless of if 115V or 230V, generated the 60W, in the first place.

Here is a quote (for the exact wording) from the actual link, repeated here, for convenience:

https://www.quora.com/Are-100w-bulbs-in-America-brighter-than-in-the-UK-The-American-version-would-draw-more-amps-with-the-lower-voltage-outlet-than-the-220v-counterpart-If-not-why-would-bulbs-with-2-different-amperages-give-off

Quote
Bob Siegerdt says 100 watts is 100 watts. The filament for either bulb would be emanating the same amount of heat & light regardless of the input parameters.

I agree but the proportion of heat and light may differ. According to Wiki a 100 W, 230 V bulb puts out 13.8 lumens/watt but a 110 V version, 17.5 lm/W.

The difference might be due to the geometry of the filament. The higher voltage bulb needs to have very thin wire so it is usually of coiled coil construction. Maybe this affects the light output.

Another factor could be the longevity of the bulbs. Longer life bulbs run at a lower temperature but have lower efficiency. It could be that the US bulbs run hotter at the expense of bulb life. Thus they provide more profit to the manufacturer.

For more on this topic see The Great Light Bulb Conspiracy Full Page Reload

Also, someone saying things, very similar to what you are saying:

Quote
Seems awfully many incorrect answers. For reasons I do not exactly know light bulbs work better at lower voltages. Therefore a 100 W bulb at 120 volts gives more light than on 230 volts, about 23% more assuming both are rated to 1000 hours. To get same amount of light at 230 volts one might have to cut the life to about 250 hours.

In Finland trams run at 1000 volts. Because that works badly with bulbs older trams had four 250 volt bulbs in series. Newer ones have have separated the voltage for internal lighting from the driving voltage.

More examples of similar disagreements:

Quote
Its the power that makes light’s intensity. Although the voltage and current would be different in the US, a 100 W bulb in either country is still a 100 W bulb.

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The wattages are the same.

The temperatures of the filaments are the same.

Therefore the surface areas of the filaments are the same, and the amount of light emitted is the same.

What is different is that the 110 Volt filament is shorter and fatter than the 220 Volt filament, to keep everything above the same despite the lower voltage and higher current.

No, the brightness is the same ( or it would be if you could still buy 220 volt 100 watt bulbs).


The following is what I really should have said:

Quote
100 watts is 100 watts. The filament for either bulb would be emanating the same amount of heat & light regardless of the input parameters.

Then it goes back to agreeing with you:

Quote
For the same wattage a thicker wire is used and it is more rigid and can be run at a higher temperature giving more light without burning out.

I use LEDs for every thing except the oven light and that is only used for a few minutes a month.
 

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Re: The Dubai Lamp
« Reply #44 on: April 12, 2022, 07:16:41 am »
A 120V 60W incandescent lamp produces about 800 lumens for example, while the 240V version is only about 700 lumens. You can see the same effect by looking at the lumens per watt of different wattages of lamps.

TL;DR
Just to be clear. I somewhat agree with you, and your explanation as to why the 120V 60W lamps, are more efficient than the 240V versions.

It's deceptively difficult to properly/accurately interpret the situation. Because, changes to the filament design parameters, have to take place to restore the 1,000 hour life, between the 120V and 240V versions. Also, the exact definition/quality of the 1,000 hours burn life, might vary between the US and Europe/UK. Which could also confuse/complicate the issue. Because any genuine increase in burn life, the Europe/UK versions gain. Would be expected to respectively reduce the efficiency, between the 120V/240V lamp types.

I wonder if there is much difference between 120V and 240V LED bulb, efficiencies and burn life expectancy.

It can be tricky when trying to directly compare things between the US and Europe/UK, because standards, laws, and other things are different. E.g. Even the size of Gallons is in disagreement between the US and UK, and measurements are not necessarily done in the same way.
E.g. Is a 1,000 hour burn life or 800 Lumens, truly identical between the US and UK ?

Anyway, it does make a fair bit of sense. That a 120V lamp filament would be thicker, and hence take longer to thin out, intuitively speaking.
 

Offline james_s

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Re: The Dubai Lamp
« Reply #45 on: April 12, 2022, 06:44:01 pm »
A 120V 60W incandescent lamp produces about 800 lumens for example, while the 240V version is only about 700 lumens. You can see the same effect by looking at the lumens per watt of different wattages of lamps.

TL;DR
Just to be clear. I somewhat agree with you, and your explanation as to why the 120V 60W lamps, are more efficient than the 240V versions.

It's deceptively difficult to properly/accurately interpret the situation. Because, changes to the filament design parameters, have to take place to restore the 1,000 hour life, between the 120V and 240V versions. Also, the exact definition/quality of the 1,000 hours burn life, might vary between the US and Europe/UK. Which could also confuse/complicate the issue. Because any genuine increase in burn life, the Europe/UK versions gain. Would be expected to respectively reduce the efficiency, between the 120V/240V lamp types.

I wonder if there is much difference between 120V and 240V LED bulb, efficiencies and burn life expectancy.

It can be tricky when trying to directly compare things between the US and Europe/UK, because standards, laws, and other things are different. E.g. Even the size of Gallons is in disagreement between the US and UK, and measurements are not necessarily done in the same way.
E.g. Is a 1,000 hour burn life or 800 Lumens, truly identical between the US and UK ?

Anyway, it does make a fair bit of sense. That a 120V lamp filament would be thicker, and hence take longer to thin out, intuitively speaking.


Yes, the life is the same. You can see further examples of this, look at long filament decorative lamps like the sort used to light sheet music and paintings and such, they are even lower efficiency than standard lamps because the filament is stretched out so long.

The thing I think you and some on those other threads are overlooking is that light output is not dependent on filament heat output, but on filament *temperature*. A standard lamp filament runs at 2700K and the hotter it is, the more the output shifts toward visible light and the more efficient it is but the more rapidly it burns out. Anything that draws heat away from the filament will require more energy input to maintain the same temperature, and if you can keep the heat in the filament then it will require less input energy for the same light output. Indeed there are high efficiency incandescent lamps which employ an IR reflective coating on the inside of the capsule to direct heat back at a precisely positioned filament and those lamps managed about 800 lumens output from only 40W electrical input. A similar thing applies with your house, the better insulated it is, the less energy you will have to consume to maintain the temperature. If you could completely eliminate heat losses from convection, radiation, and conduction through the lead in wires and supports, an incandescent lamp could be 100% efficient but in the real world of course this is impossible. You cannot reflect anywhere near 100% of the IR back at the filament nor can you have a filament that is not connected to metal wires or supported by something.

Most lamps are filled with an inert gas rather than a vacuum. The increased pressure inside a gas filled lamp reduces the rate of tungsten evaporation of the filament but increases convective losses. Below about 40 watts or so the convective losses start to get too significant so vacuum fill is used instead in order to keep the efficiency reasonable.

For LED lamps the input voltage makes no real difference, a buck converter can be made to operate efficiently at any line voltage.
 
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Re: The Dubai Lamp
« Reply #46 on: April 12, 2022, 07:04:23 pm »
Yes, the life is the same. You can see further examples of this, look at long filament decorative lamps like the sort used to light sheet music and paintings and such, they are even lower efficiency than standard lamps because the filament is stretched out so long.

The thing I think you and some on those other threads are overlooking is that light output is not dependent on filament heat output, but on filament *temperature*. A standard lamp filament runs at 2700K and the hotter it is, the more the output shifts toward visible light and the more efficient it is but the more rapidly it burns out. Anything that draws heat away from the filament will require more energy input to maintain the same temperature, and if you can keep the heat in the filament then it will require less input energy for the same light output. Indeed there are high efficiency incandescent lamps which employ an IR reflective coating on the inside of the capsule to direct heat back at a precisely positioned filament and those lamps managed about 800 lumens output from only 40W electrical input. A similar thing applies with your house, the better insulated it is, the less energy you will have to consume to maintain the temperature. If you could completely eliminate heat losses from convection, radiation, and conduction through the lead in wires and supports, an incandescent lamp could be 100% efficient but in the real world of course this is impossible. You cannot reflect anywhere near 100% of the IR back at the filament nor can you have a filament that is not connected to metal wires or supported by something.

Most lamps are filled with an inert gas rather than a vacuum. The increased pressure inside a gas filled lamp reduces the rate of tungsten evaporation of the filament but increases convective losses. Below about 40 watts or so the convective losses start to get too significant so vacuum fill is used instead in order to keep the efficiency reasonable.

For LED lamps the input voltage makes no real difference, a buck converter can be made to operate efficiently at any line voltage.

Thanks, that is a very nice answer.   :)

I see. There use to be a lot of those 'novelty', long tube/filament bulbs, in the UK. In places like shaving/mirror lights, picture frame lights and other similar uses. It had never dawned on me, that there was a reasonable quantity of electricity (watts, not huge, maybe 15W, but big, compared to the relatively small light output), going into it, and yet very little actual useful light coming out.
But now you mention it, that makes lots of sense.

It reminds me a lot about soldering irons, especially from quite a while back (before temperature control was common place). The actual wattage, didn't necessarily tell you its temperature, because if it was an old style, massive type, hence with huge heat losses, it still didn't get that hot, but enough to melt solder. Where as, a tiny, low mass, fine tipped, hence little heat losses, relatively low wattage soldering iron, perhaps 15 watts, can get quite usefully hot.

So of course (completely obvious, now you have persistently mentioned it, i.e. hindsight). Any bulb, which instead of having an optimally small compact filament, that simply turns the (perhaps 60 watts, like we mentioned earlier), because of it being 120V AC mains supply in that country, can have the best/maximum efficiency level. I.e. biggest lumens per watt, just like you have been, repeatedly saying.

But, anything that worsens that scenario, such as 240V AC mains countries (as you said, it needs a thinner and longer filament, to cope with the higher voltage), big long decorative filaments, poorly designed light bulbs, long life ones, etc. Need much more heat, just to make a much lower amount of actual usable light output.
Hence the lumens per watt (efficiency), is significantly worse.

Pity they couldn't have invented some kind of thermos flask like glass tube, that goes round the filament, which both highly insulates the filament, and reflects the non-visible IR (heat) radiation, back onto the filament, to make it considerably more efficient. Which is what (or similar to), what you mentioned in the quote above, but with a possibly different design.

I suppose, even the LEDs may one day become obsolete. Replaced by who knows what. Maybe some kind of semi-conductor material, which with almost 100% efficiency, converts all electrical power, into light, within the visible ranges that are desired (100% CRI, or whatever the terminology is).
Or perhaps, almost 100% efficient LEDs, will become that technology.

Hopefully one day, fusion (power, or whatever is needed) will be invented, practicable, economically viable, and then made available, to help keep planet Earth going, without it getting into difficulties, such as very bad weather, and other effects of climate change.
EDIT: Made this post a little more accurate/better, slightly/moderately. But basically as it was.
« Last Edit: April 12, 2022, 07:39:14 pm by MK14 »
 

Offline james_s

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Re: The Dubai Lamp
« Reply #47 on: April 13, 2022, 07:00:22 pm »
Pity they couldn't have invented some kind of thermos flask like glass tube, that goes round the filament, which both highly insulates the filament, and reflects the non-visible IR (heat) radiation, back onto the filament, to make it considerably more efficient. Which is what (or similar to), what you mentioned in the quote above, but with a possibly different design.

I suppose, even the LEDs may one day become obsolete. Replaced by who knows what. Maybe some kind of semi-conductor material, which with almost 100% efficiency, converts all electrical power, into light, within the visible ranges that are desired (100% CRI, or whatever the terminology is).
Or perhaps, almost 100% efficient LEDs, will become that technology.

Well they have tried something a bit like that, one example is this http://lamptech.co.uk/Spec%20Sheets/IN%20WC%20DuroTest%20120-65G30IRC-E26.htm where the entire bulb had a reflective coating. In the early 2000's Philips refined this concept using a small spherical quartz capsule with an IR reflective coating within an outer bulb. There is a cost to this though, any IR reflective coating is going to reflect and absorb some amount of visible light as well, and even just a layer of plain glass reflects a significant amount of light which then bounces around inside the bulb and turns into heat. The filament loses heat in three different ways, radiation, convection and conduction. The IR coating attempts to deal with the radiated losses but then if you have a gas fill that results in convection losses, and the lead wires and filament supports result in conductive losses. Ultimately there is only so much you can do to optimize this, and for better or worse technology has marched on and all development of incandescent lamps has stopped, we've passed the pinnacle there and all attention is on other technologies now.

I'm pretty confident that LED of one sort or another is the future of lighting, mass produced LED lamps such as the Dubai lamp that started this thread have already reached 200 lm/W which is a substantial fraction of the theoretical maximum of around 600 lm/W representing 100% efficiency. LEDs continue to improve steadily.
 
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Re: The Dubai Lamp
« Reply #48 on: April 14, 2022, 06:08:06 pm »
Well they have tried something a bit like that, one example is this http://lamptech.co.uk/Spec%20Sheets/IN%20WC%20DuroTest%20120-65G30IRC-E26.htm where the entire bulb had a reflective coating. In the early 2000's Philips refined this concept using a small spherical quartz capsule with an IR reflective coating within an outer bulb. There is a cost to this though, any IR reflective coating is going to reflect and absorb some amount of visible light as well, and even just a layer of plain glass reflects a significant amount of light which then bounces around inside the bulb and turns into heat. The filament loses heat in three different ways, radiation, convection and conduction. The IR coating attempts to deal with the radiated losses but then if you have a gas fill that results in convection losses, and the lead wires and filament supports result in conductive losses. Ultimately there is only so much you can do to optimize this, and for better or worse technology has marched on and all development of incandescent lamps has stopped, we've passed the pinnacle there and all attention is on other technologies now.

I'm pretty confident that LED of one sort or another is the future of lighting, mass produced LED lamps such as the Dubai lamp that started this thread have already reached 200 lm/W which is a substantial fraction of the theoretical maximum of around 600 lm/W representing 100% efficiency. LEDs continue to improve steadily.

Thanks for the link, it made an interesting read. Ignoring that (to me, at least), it looks a bit like an ugly-duckling (sorry!), it's a clever attempt, at making more efficient, lamps. I presume what happened, is long ago, they went through various possibilities, and were not especially successful, with most of the (tungsten filament) ideas. Except perhaps, the Halogen (and similar gases) types.
But they did develop, other solutions. Such as fluorescent tubes and Sodium lamps. Which did work out, and enabled much more efficient lamps, in previous decades.
I think the compact florescent lights (CFLs), were potentially good and promising, in the past. But, there seemed to be a number of them, which had cut too many corners (in my opinion), in its construction and component quality/specifications. Resulting in sub-par optical quality, efficiency and burn-life. Possibly even a fire risk, in some cases and/or undesirable feature of sometimes having the base of the units, over-heat and make a bad smell. Which happened to me, occasionally, when CFL lamps were somewhat common place, and usually with very cheap CFLs.
I prefer quality CFLs, but did sometimes try the very cheap ones, in case, they were any good. It was usually those, that tended to fail early (or even almost immediately), sometimes filling a room with a rather bad burning electronics smell. Which I hope was not poisonous/harmful to peoples health.

I rather like Neon, and similar lamps. Apart from the tiny (NE-2 and similar), ones, many people are familiar with. They did make some amazingly big (think piggy bulb sized and maybe bigger), which I found seemed rather cute. With my expectation, of them being very economical with electricity and very long lasting. But, unfortunately, they seemed to have come from an era, of a VERY long time ago. They were perhaps originally manufactured in the 1940s and 1950s (years, complete guesses on my part). So, it has been rare to see them (age dependent).

So, it is a pity, they couldn't invent some kind of similar bulb, with just gases inside it (ideally NOT using any toxic metals), which uses very little power, is very efficient, and produces lots of, hopefully mainly white light.

I suppose, LEDs, are the modern way, of achieving, a somewhat ideal light bulb. Very high efficiency, low waste heat generation, somewhat ideal light colour, instant on, very long burn life expectancy (50,000+ hours is achievable), affordable cost and no bigger than standard tungsten filament lamps, of the past.
Also, minimal consumption of any rare (and especially toxic) materials, and finally minimization of harm to the planet.
 

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Re: The Dubai Lamp
« Reply #49 on: April 18, 2022, 10:50:28 pm »
I'm hoping to buy a limited quantity (maybe 2 of them) of those bulbs, in around a weeks time, if things go to plan. If I do, I'll try and remember to report back on that arabic text and what I think of them.

I haven't bought those lamps yet, my plans changed, maybe another time. But, fortunately, BigClive has produced a suitable video on those bulbs, today. Here it is:

« Last Edit: April 18, 2022, 10:55:26 pm by MK14 »
 
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