Design challenges: 2200~ + lumen single diode

Hello CPF,



This is my first post and I'm hoping it will be worthwhile, after some reading about LedEngin issues, and looking over comparable products I have a number of questions for your community.



1- What sort of raw heat do LZC-00CW40's produce at 1000mA?

2- Have any of you used TEC/Peltier for cooling these?

3- If theoretically possible, could the LED withstand 50C ambient if the cooler is placed near it.

4- Does anyone have experience with using pure copper heatpipes instead of heatsinks?

5- Are there any alternative solutions which could fit under 15mm~ and produce at least 2200 lumen?

6- What is the actual burnout temperature of these diodes? (Tested not from manufacturer)



The final product will be placed in areas which can withstand 250C+ radiating heat and optics. Anyone who can provide any valuable information will be given production samples.

Hi Z,

I guess you are talking about a fixed light, not a battery-fed flashlight? (Hey, its CPF! Just a question of time..)

Lets see.. The "LZC-00CW40" will have a voltage drop a bit under 50v. Thats 50w at 1 Amp. The 2200 Lumen which are radiated away as light, not heat, sum up to not more than 5w, so I'll stick to 50w heat ;-)

TECs are horribly inefficient. The numbers depend, but none will ever go above 10%.. Which means: 50w heat to transfer from the LED, 500w heat to remove from the TEC's hot side. Which could make sense in some cases: Think about the TEC as a strange heatspreader: The hot side is way larger, so it could turn out to be easoier to cool. Second advantage: TECs survive higher temperatures than LEDs. Cooling a hotter object (heatsink) is easier than cooling a not-that-hot object: You can easily lower the temperature of a red-glowing piece of metal by some hundred degrees by simply blowing a little air over it.

50° ambient? With that, you could theoretically cool your hot side of the TEC down to 50° too. Be happy to reach just a few dozen degrees higher than that, in real life though ;-)
Anyway, a TEC highly depends on cooling the hot side. If it gets too warm, the cold side no longer is cold at all. As far as I remember, this wasnt linear at all..

What do you mean with 15mm? The LED size?
What space is available for the whole setup?

The LED wont burn out at once. The "phosphor" will degrade first, turning the LED more blue. The junction will degrade, which lowers output and rises resistance and all. It would only burn out from too high current, when the die bonding wires melt.

250° heat? Use glass optics and a dichroic mirror reflecting all heat away. Have a look at the diy-projector building crowd, they have similar problems. Sometimes called "IR mirror" or "Hot mirror". Maybe find a photography filter large enough to fit in front of the optics? 60mm diameter should be enough.. Those will reflect away everything above 1000nm, which crudely translates in something like "reflects IR away generated by heat under 800°C".
Thats only the radiated "heat", not the heat passed by the walls, for example.


All in all: The physics behind all this is fairly simple. You will need a fairly large setup (shoebox?), it will eat a lot of electricity (less than 1kw), it wont be cheap in time and money. But absolutely possible and hell of fun to build!

Hope it wasnt just general, already known info from me? Keep us updated!

Manuel