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exocet_cm
Free at last, free at last
Premium
join:2003-03-23
New Orleans, LA
kudos:3
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.


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).


exocet_cm
Free at last, free at last
Premium
join:2003-03-23
New Orleans, LA
kudos:3

alkizmo See Profile, 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.


TheMG
Premium
join:2007-09-04
Canada
kudos:3
Reviews:
·NorthWest Tel
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.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).

That website is expensive!

Got one of those from Home Depot for a little less than $40 a while ago.


Majestik
World Traveler
Premium
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.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).

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.
--
The adventure continues...Sanctuary....

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 .



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.



Subaru
1-3-2-4
Premium
join:2001-05-31
Greenwich, CT
kudos:1
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.



disconnected

@snet.net
reply to tschmidt

I had my first E27-based LED lamp, a Utilitech from Lowe's, fail on me last month.



SparkChaser
Premium
join:2000-06-06
Downingtown, PA
kudos:3
Reviews:
·Verizon FiOS
reply to Jon

said by Jon:

Do LEDs get hot enough to require cooling?

As Subaru See Profile 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.
--
--
--
"Facts do not cease to exist because they are ignored." - Aldous Huxley

TheMG
Premium
join:2007-09-04
Canada
kudos:3
Reviews:
·NorthWest Tel
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!


Raphion

join:2000-10-14
Samsara
Reviews:
·Verizon FiOS
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.


AVD
Respice, Adspice, Prospice
Premium
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.
--
* seek help if having trouble coping
--Standard disclaimers apply.--


SparkChaser
Premium
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


cableties
Premium
join:2005-01-27
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.
--
Splat



Draiman
Let me see those devil horns in the sky

join:2012-06-01
Kill Devil Hills, NC
Reviews:
·Verizon FiOS
reply to alkizmo

said by alkizmo:

said by Lurch77:

On the manufacturers website, in the article I linked, and in one of my earlier posts here, it says they can be used in any position.
»www.switchlightingco.com/specs.html

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.
--
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!


StepR
Code Warrior
Premium
join:2000-11-06
Elgin, IL
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.



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.


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.


Raphion

join:2000-10-14
Samsara
Reviews:
·Verizon FiOS

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.


tschmidt
Premium,MVM
join:2000-11-12
Milford, NH
kudos:9
Reviews:
·G4 Communications
·Fairpoint Commun..
·Hollis Hosting
reply to tmh

said by tmh :

Seems like snake oil to me.

Why do you say that?

A fluid carries heat away from the die very effectively. The exterior of the bulb has a large surface area allowing heat to radiate and conduct away.

/tom


tmh

@verizon.net

said by tschmidt:

said by tmh :

Seems like snake oil to me.

Why do you say that?

A fluid carries heat away from the die very effectively. The exterior of the bulb has a large surface area allowing heat to radiate and conduct away.

/tom

It is difficult to see from bulb, but the added surface doesn't appear to be very significant.

For example, water cooled CPUs have radiators with an enormous heat transfer surface, plus forced air cooling to boot. I don't see any similar benefit to simply filling the globe with liquid.

TheMG
Premium
join:2007-09-04
Canada
kudos:3
Reviews:
·NorthWest Tel

said by tmh :

It is difficult to see from bulb, but the added surface doesn't appear to be very significant.

For example, water cooled CPUs have radiators with an enormous heat transfer surface, plus forced air cooling to boot. I don't see any similar benefit to simply filling the globe with liquid.

The added surface area is quite significant. In most LED bulbs, it is only the metal base which acts as the heat sink. The outer lens/cover/bulb does not contribute to cooling at all, since it is filled with air, which is a pretty good insulator.

Filling the inside of the clear bulb with liquid allows heat to be conducted to and therefore dissipated through the outer clear bulb.

Also, CPUs generate several times more heat than an LED bulb. The type of CPU that PC enthusiasts watercool with radiators typically dissipate in excess of 100W. Quite often, video cards are also cooled in the same loop and the same radiator, meaning anywhere from 200W to as much as 800W may need to be dissipated, depending on the system.


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1

Can't we all agree that a LED bulb shouldn't need to be water cooled?



leibold
Premium,MVM
join:2002-07-09
Sunnyvale, CA
kudos:10
Reviews:
·SONIC.NET

I don't think so. Doesn't it make sense to expect a longer useful life from a water cooled LED bulb then a cheaper LED bulb based on the same LEDs (same power) without the added cooling ?
It is heat that kills electronics (both LEDs and their power supply / driver circuits).

I do not expect cheap LED bulbs to perform to expectations and we are already hearing the first reports of early death of LED bulbs.

The only reason for me to be skeptical about these bulbs is that mechanical business of the expansion cylinder. Is this really going to stay sealed over years of in/out motion ? What happens if the bulb starts to loose fluid ? Does the water end up where it is most likely to cause the biggest harm (power supply) ?
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Lurch77
Premium
join:2001-11-22
Oconto, WI
kudos:4

1 recommendation

It's not water. It's liquid silicone. Your point about losing material is valid, but it most likely won't bother the electronics. Potted electrical components are surrounded by silicone.



SparkChaser
Premium
join:2000-06-06
Downingtown, PA
kudos:3
Reviews:
·Verizon FiOS

1 recommendation

reply to leibold

it's full of liquid silicone, which dissipates heat from the 10 LEDs (12 LEDs for the 100-watt version). Warmer silicone moves toward the glass exterior, where heat dissipates into the air; as it cools, the silicone drops back toward the bulb's heart. Think of a lava lamp this works basically the same way, said Dave Horn, chief technology officer at SWITCH. You just can't see the gloopy circulation.

»www.switchlightingco.com/lqd.html

I have to go turn on my Lava Lamp (yes, I do have one )
--
--
--
"Facts do not cease to exist because they are ignored." - Aldous Huxley



alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1

said by SparkChaser:

Think of a lava lamp this works basically the same way, said Dave Horn, chief technology officer at SWITCH.

And lava lamps don't work upside down.


SparkChaser
Premium
join:2000-06-06
Downingtown, PA
kudos:3
Reviews:
·Verizon FiOS

1 recommendation

said by alkizmo:

And lava lamps don't work upside down.

but.... the heat source is in the center of this lamp and the bottom of the lava lamp.


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1

said by SparkChaser See Profile
but.... the heat source is in the center of this lamp and the bottom of the lava lamp.

Satisfying explanation.
Thnx