Individual LED passive cooling

[xmai77]

Has anyone tried using something similar to this to passively cool individual LED's?

They're small individual aluminum heatsinks. Do you think it'll keep a Cree XR-P cool?

If not, maybe having an enclosed area with two fans might work (see attached drawing)...the aluminum can be picked up anywhere. The picture was drawn using MS Paint in 3 minutes. I'm primarily concerned with the heat transfer between the LED and the aluminum sheet. I'm afraid it might not conduct enough so the heatsinks might not even be doing their job.

 

[xmai77]

Nobody interested?

 

[pwreef]

Why? Someone on here (FishMan?) even made a fixture where each LED could be individually aimed. In the end he found that there is no point. It easier to just slap them onto a solid heatsink. What you propose will probably work fine as long as you are not overdriving the LEDs too much. But its a lot more work.

 

[der_wille_zur_macht]

With good airflow and proper matching to your power level those sinks will work great. The question of "why" would depend pretty heavily on the parameters and goals for a particular build I guess, but I can totally imagine all kinds of situations where the typical massive heatsink is not desirable.

Regarding your drawing - if you're attaching the LEDs to an aluminum box like that, and blowing a fan down it, and you size it properly, you probably don't even need the heatsinks on the inside.

 

[xmai77]

With good airflow and proper matching to your power level those sinks will work great. The question of "why" would depend pretty heavily on the parameters and goals for a particular build I guess, but I can totally imagine all kinds of situations where the typical massive heatsink is not desirable.

Regarding your drawing - if you're attaching the LEDs to an aluminum box like that, and blowing a fan down it, and you size it properly, you probably don't even need the heatsinks on the inside.

I've never dealt with these sort of high powered LEDs before so I really have no idea how much heat they generate. I live in Canada and shipping from HeaksinksUSA is way too expensive, that's why I am searching for cheaper alternatives.

How well does passive cooling for these LEDs? I've tried to do some searches here but I can't seem to find anything substantial...

Would those individual heatsinks be enough for cooling or is a fan necessary?

 

[Gorgok]

I live in Canada and shipping from HeaksinksUSA is way too expensive, that's why I am searching for cheaper alternatives.

I live in Texas and total cost from HeatsinkUSA was way too expensive... China cost less even with over half its price being shipping. vOv

Those things look like what is normally found on southbridge chips, sometimes northbridge too. A southbridge can run at around 4.5W i believe and the little heatsink alone should keep the temps under 50C even with little to no airflow in a closed computer case.

Now, while this can be used for some comparison, a few things have to be kept in mind. A LED will run for high loads for extended times, while a SB may peak only for a short period and then go back down to practically off. The LEDs have a lower wattage than the 4.5W of a SB, even when being run at 1A (3.7W i think for XP-Es). You also have other cooling other than the single HS on each LED, though even that would probably work.

 

[kcress]

Why don't you look around in here at some existing builds. There are dozens! You will see lots done cheaper than using big heavy finned heatsinks.

 

[der_wille_zur_macht]

If your goal is cheap and readily available heatsinks, go to a hardware or big box store and get some aluminium u-channel. In a reasonable size, it is cheap and effective as long as your power density is not too high. Anecdotally, the common 1" size seems fine at one LED every 3" at typical 3w power levels as long as there is either a fan or correct provisions for good airflow (i.e. they aren't buttoned up in a totally enclosed hood).

 

[mussel and hate]

There are free heatsinks on the curb every garbage day contained within the oatmeal steal PC tower corpses that decorate every third tree lawn in suburbia. Bring a #2 phillips a medium slot screw driver and some pliers. Take what you need and leave the husk.