 exocet_cmI am the law - Judge DreddPremium
join:2003-03-23
New Orleans, LA
kudos:2 | reply to Jon
Re: Liquid Cooled LED Bulbs said by Jon:Do LEDs get hot enough to require cooling?
My LED floods almost burn your fingers when touched. This is probably the reason why they have massive heat sinks on the base. |
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 alkizmo
join:2007-06-25
Pierrefonds, QC
kudos:1 | reply to Majestik
said by Majestik:I'm not home to turn the lights on and off.
If I am going to leave a light on it might as well be LED.
You should invest in something like this
»www.levitonproducts.com/catalog/···itch.htm
It's very cheap and gives the illusion of the house being occupied (as lights turn on in the evening and off in the morning). |
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exocet_cmI am the law - Judge DreddPremium
join:2003-03-23
New Orleans, LA
kudos:2 | alkizmo  , have you used this before? If so, I'll send you a PM so I don't hijack this thread but that looks nice and might be applicable to a situation I have. |
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TheMGPremium
join:2007-09-04
Canada
kudos:1 | reply to alkizmo
said by alkizmo:said by Majestik:I'm not home to turn the lights on and off.
If I am going to leave a light on it might as well be LED.
You should invest in something like this » www.levitonproducts.com/catalog/···itch.htmIt's very cheap and gives the illusion of the house being occupied (as lights turn on in the evening and off in the morning). That website is expensive!
Got one of those from Home Depot for a little less than $40 a while ago. |
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 MajestikWorld TravelerPremium
join:2001-05-11
Tulsa, OK | reply to alkizmo
said by alkizmo:said by Majestik:I'm not home to turn the lights on and off.
If I am going to leave a light on it might as well be LED.
You should invest in something like this » www.levitonproducts.com/catalog/···itch.htmIt's very cheap and gives the illusion of the house being occupied (as lights turn on in the evening and off in the morning). I live in a gated condo community. The homes here are cedar and stucco. They are replacing all the cedar wood with a textured hardy board and my unit is scheduled for this in two years. While checking/fixing any termite damage,replacing barrier,and possibly replacing insulation they will be wiring these lights with sensors. Also perfect time to install wiring for any cams we want to mount before closing up.
If not for this I would be getting these.
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The adventure continues...Sanctuary.... |
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AndrewW
join:2009-03-07
Toronto, ON
kudos:1 | reply to TheMG
Amazon has it for $33.70, see here »www.amazon.com/Leviton-VPT24-1PZ···PT24-1PZ . Honeywell has a similar unit, »www.amazon.com/Honeywell-Econosw···PT24-1PZ . |
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alkizmo
join:2007-06-25
Pierrefonds, QC
kudos:1
1 edit | Yeah sorry guys, I thought I was linking home depot's website. Here in Canada I can buy them for 30$. Very neat stuff especially since they auto adjust for the time of he year. Here we can have sunligth as late as 9pm in mid summer and darkness as early as 3pm this time of the year.
Edit- be sure to read amazon reviews before buying any model. Some brand/models have reset/crashing problems. |
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 Subaru1-3-2-4Premium
join:2001-05-31
Greenwich, CT | reply to Jon
12V at 700mA with a max of 1A still needs cooling highest I've hit with a heatsink was 110F the higher you go the dimmer the light output. |
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I had my first E27-based LED lamp, a Utilitech from Lowe's, fail on me last month. |
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 SparkChaserPremium
join:2000-06-06
Downingtown, PA
kudos:3
 ·Verizon FiOS
| reply to Jon
said by Jon:Do LEDs get hot enough to require cooling?
As Subaru pointed out they can get pretty hot. The Switch lamp has 10 LEDs (I think) and if they all draw a watt it doesn't seem like much but it's all concentrated in a very small area and difficult to get it out.
I thought this was a decent article on it
»www.geek.com/articles/gadgets/re···2012096/
They took an interesting approach and it will be interesting to see how it works out.
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"Facts do not cease to exist because they are ignored." - Aldous Huxley
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TheMGPremium
join:2007-09-04
Canada
kudos:1 | reply to Jon
said by Jon:Do LEDs get hot enough to require cooling?
These high power LEDs do.
While LEDs are a step ahead in terms of efficiency, they still waste a significant amount of power as heat. In terms of turning electricity into useful visible light, even LEDs are somewhat inefficient (up to about 22% if my information is correct).
Now imagine how crazy bright a 100% efficient light source would be! |
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| reply to Jon
said by Jon:Do LEDs get hot enough to require cooling?
High power LEDs always require cooling. Any high power LED is on a board designed to mount to a heat sink, much like a CPU heat sink. Heat is dissipated through the back into the heatsink. If you use one of those 5 watt or higher LEDs with no heatsink, it'll burn itself up in short order.
This isn't because it's a lot of thermal energy there, it's because the LED is such a small unit, that it doesn't have the surface area to dissipate the heat buildup on it's own. So it would get VERY hot, even with a meager few watts of power. |
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 AVDRespice, Adspice, ProspicePremium
join:2003-02-06
Onion, NJ
kudos:1 | reply to TheMG
said by TheMG:Now imagine how crazy bright a 100% efficient light source would be!
you mean how cool.
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* seek help if having trouble coping
--Standard disclaimers apply.-- |
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SparkChaserPremium
join:2000-06-06
Downingtown, PA
kudos:3 Reviews:
·Verizon FiOS
1 edit | reply to TheMG
said by TheMG:said by Jon:Do LEDs get hot enough to require cooling?
These high power LEDs do. While LEDs are a step ahead in terms of efficiency, they still waste a significant amount of power as heat. In terms of turning electricity into useful visible light, even LEDs are somewhat inefficient (up to about 22% if my information is correct). Now imagine how crazy bright a 100% efficient light source would be! Osram reports a blue with 53% and an IR at +70%.
One of the problems with the white is there is a combination of efficiencies LED, Phosphor, Droop. It's hard to even find out efficiency. e.g. Philips spec shows efficacy. lm/w
If you look at the luminous flux vs. color temp you can see the difference in phosphors.
As for heat, the specs for Philips latest is at 85C. You can see here why you want to keep it cool
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"Facts do not cease to exist because they are ignored." - Aldous Huxley
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| reply to Lurch77
LEDs cannot dissipate heat like incandescent.
The heat is what then destroys the diode.
Solutions are to mount the diode on a heatsink (or as close as possible). This is why we see these large, heavy designs.
I watched a demonstration at my work by a facilities engineer. The campus where I work is moving to replacing all incandescent and FL to LED as it becomes viable. There is an enormous incentive to cut down on powerloss, along with "green" carbon credits. And I suppose some "write-off" with the bean counters to move this way (employs people to plan, purchase, replace).
Anyway, the demonstration had T8 -> LED bulbs, outdoor LEDs replacing Sodium lamps, Exit sign replacements, and now places where lighting was never thought of...kick panels, railings, corners, gutters, directional walkways, ... embedding... There is are so many possibilities with LV lighting and LEDs now. Ideas are moving from throwing a light pattern to creating light from the surfaces. And saving energy (prox sensors) with dimming and active lighting.
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 DraimanLet me see those devil horns in the sky
join:2012-06-01
Kill Devil Hills, NC
·Verizon FiOS
| reply to alkizmo
said by alkizmo:Yes but then the water cooling doesn't work. The hot part of the bulb is at the top, so the water gets hot near that area, but doesn't cycle with cold water, as the cold water is already at the bottom. Convection only works if heat is generated at the bottom for it to move up and push down the cooler water. Anyway, LEDs are still way way way way overpriced. They are only worth it for dimmable purposes or ON/OFF stuff like motion sensors. 20$ LED 12,5W = 60W equivalent 2.50$ CFL 13W = 60W equivalent Yeah... overpriced LED is overpriced. $12.97 for a 12.5w 60w equivalent LED bulb here. The part you're discounting is cold use and dimming operations where CFL is sub-par at best. There are valid reason to use a mixture of incandescent, CFL, and LED's in a typical household.
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IF YOU FIND ANY MISTAKES IN MY WORK...Please consider that they are there for a purpose. I try to please everyone and there is always someone looking for mistakes! |
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 StepRCode WarriorPremium
join:2000-11-06
Elgin, IL
 ·WOW Internet and..
| reply to Lurch77
I bought some LED bulbs at Menard's two weeks ago. A two-pack was $10 for 40-watt equivalent at 8 watts. I needed three bulbs for my dimmable hanging fixture. The heat sink is not visible. The light portion was cool to the touch, but the heat sink was hot, so I wondered if the bulbs truly burned at only 8 watts. |
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alkizmo
join:2007-06-25
Pierrefonds, QC
kudos:1 | reply to Draiman
said by Draiman:$12.97 for a 12.5w 60w equivalent LED bulb here. The part you're discounting is cold use and dimming operations where CFL is sub-par at best. There are valid reason to use a mixture of incandescent, CFL, and LED's in a typical household.
I didnt discount either things.
quote:
. They are only worth it for dimmable purposes or ON/OFF stuff like motion sensors
By ON/OFF stuff means not burning out from constantly turning on/off and that they are full bright for motion sensors.
I just find them overrated for their price and their high risk long amortization time when it comes to 100W equivalent bulbs (for motion sensor lights). They'd have to not break for several years before breaking even, and then several more years to have SAVED you enough money to justify the risk.
I'd use them for dimmable lamps since those are typically 40W equivalent or less, so they cost less. I could leave the lamps on 24/7 for mood lighting without worrying about being wasteful. However, my wife hates their color vs. glowing filament.
Anything else than dimmable lamps or motion sensor can use CFL for the same electricity cost and no investment. |
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 tmh
@comcastbusiness.net | reply to tschmidt
said by tschmidt:Liquid cooling is a clever idea, liquid is a much better thermal conductor then air.
That's true, but in this case liquid is an intermediate transfer medium. The liquid must transfer its heat to air, otherwise it will get hotter. I don't see any difference in bulb design to improve that. So heat transfer to the environment is no more efficient than before. In fact, it is less so. The liquid is at a lower temperature and so would need a greater surface to effect the same heat loss.
Seems like snake oil to me. |
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| said by tmh :said by tschmidt:Liquid cooling is a clever idea, liquid is a much better thermal conductor then air.
That's true, but in this case liquid is an intermediate transfer medium. The liquid must transfer its heat to air, otherwise it will get hotter. I don't see any difference in bulb design to improve that. So heat transfer to the environment is no more efficient than before. In fact, it is less so. The liquid is at a lower temperature and so would need a greater surface to effect the same heat loss. Seems like snake oil to me. This is how large transformers have been cooled for more than half a century, minus the see through casing. If it's snake oil, it must be some pretty good snake oil. |
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