Space shuttle pannels..The ultimate heatsink?

[vinsanity286]

I know the general public could probably never get a hold of these but wouldn't they be an amazing led heatsink? I remember in 6th or 7th grade there was a NASA demonstration for my school and the instructor took a propane torch to a piece of the panel. He shut the torch off and held it in front of me and told me to touch it. I cautiously touched it and it was cool to the touch!!!

Now does anyone know if this material just resists being heated up or does it just conduct heat insanely fast. Seems to me it would be great to get a hold of!

 

[KuoH]

It acts as an insulator, not a heatsink. It would probably be worse than a piece of cardboard at keeping an LED cool.

KuoH

 

[thermal guy]

At my job we spray thermal barrier coating.Someday I'll spray some on a heat sink and see how much of a difference it makes.

 

[Marduke]

Those tiles on the shuttle would make the absolute worst heatsink. They are a thermal insulator, not a conductor.

 

[greenpea76]

If those tiles were heatsinks, the crew would burn up as well as the shuttle itself. Fireball!!!!

 

[mighty82]

That would probably be the worst hatsink ever. The flashlight would never get hot, but the led would burn out in 5 mins. A heatsink is suppose to get hot, it's suppose to "steal" the heat from the led.

 

[kramer5150]

Oops... other way around

AFAIK pure copper and Aluminum are the most thermally conductive commonly available metals.

 

[vinsanity286]

Boy do I feel dumb. Kinda had a feeling they were insulators. Thanks for clearing things up. Now if we could just hire NASA to develop a heatsink that

works that good:laughing:

 

[olrac]

The shuttle is covered in refractory tiles they have an incredibly low coefficient of heat transfer. Think heat mirror, reflecting the thermal energy

 

[greenstuffs]

Boy do I feel dumb. Kinda had a feeling they were insulators. Thanks for clearing things up. Now if we could just hire NASA to develop a heatsink that

works that good:laughing:

Aluminum, Copper or Silver are good heat sinkers.

 

[AvidHiker]

I agree with the above posts. Heatsinks require high thermal conductivity whereas heat shield material has extremely low TC.

Anyway, space shuttle tile is truly amazing stuff. I believe there are at least two types, one is a fibrous type of low density fused silica the other is reinforced carbon-carbon composite. My choice of major when entering college as an engineering student was pretty much sealed when I witnessed a demonstration by the Materials Science & Engineering department (Lehigh University) where a piece of white shuttle tile (~2" cube) was taken out of an oven and placed on a table. It was still glowing red hot and the professor just casually picked it up with his hand less than 10 seconds after removing it from the oven. Soon you could see that the surface had cooled but the interior continued to glow - an extremely large thermal gradient. That's another amazing thing about fused silica, it is essentially immune to thermal shock - I think it has one of the lowest coefficients of thermal expansion known. It is a glass however, and therefore not the best material for structures under serious stresses.

Anyway, it would be great for the outside of a flashlight that gets really hot, or maybe even a lens in the dense form. But it'd be a fragile light!

 

[Yucca Patrol]

Boy do I feel dumb. Kinda had a feeling they were insulators. Thanks for clearing things up. Now if we could just hire NASA to develop a heatsink that

works that good:laughing:

No worries. Sometimes a thought, even if it is misguided leads to something good. Imagine how nice it would be to put some of this between the actual heatsink and your batteries to keep them from heating up too much under heavy use.

 

[Crenshaw]

im sure NASA has some top secret super heat conducting stuff....:huh:

Crenshaw

 

[turbodog]

Oops... other way around

AFAIK pure copper and Aluminum are the most thermally conductive commonly available metals.

Silver is the best electrical and thermal conductor. Copper follows. Gold is farther down the line, but above aluminum.

You DID say commonly available. I'd rule out gold on several factors, but silver's fairly easy to find and cheap enough.

 

[JimmyM]

This goes way beyond the realm of commonly available, but Diamond is the best thermal conductor, but unlike good thermally conductive metals, it's the best electrical insulator. It's becoming more and more common to find CVD (Chemical vapor deposition) Diamond coatings. I had a wild thought in the back of my head... Use CVD diamond for the emitter pad on aluminum heat sinks. It will take just a tiny amount of it to electrically insulate the emitter from the aluminum yet provide superior thermal conductivity. Now all I need to do is build a CVD rig...

 

[stitch_paradox]

How about gold? Gold are great for electric conduction, but would it make a great heat sink?

 

[Mr. Zenon]

I am fortunate to own a flown tile from Endeavour. It is one of my prized possessions. My tile was removed in 1995 due to a micrometeoroid impact. Right now, it is sitting in a plexiglass enclosure.

The HRSI (High-temperature reusable surface insulation) tiles are relatively lightweight and fragile. The top black surface is a glass-like china surface. Beneath the black surface is a silica which is considered hazardous to humans (and why my tile is enclosed in a display case and not handled without gloves). It seems as if I were to drop my tile onto a hard surface, it would shatter.

Remember, aluminum melts at 800º, some of the HRSI tiles of the orbiter can withstand 7000º. The tiles are a thermal protection barrier, not a thermal transfer system.

Shuttle tiles are extremely difficult to come by. They cost NASA about $5000 each (and there are are 31,000 on each orbiter). They are also prohibited for any type of export and are still considered to be a protected technology by the United States.

 

[Stillphoto]

Couldn't let this topic go without mentioning this stuff:
http://www.unitednuclear.com/aerogel.htm

 

[Patriot]

Couldn't let this topic go without mentioning this stuff:
http://www.unitednuclear.com/aerogel.htm

Good link! Thanks.

 

[2xTrinity]

Silver is the best electrical and thermal conductor. Copper follows. Gold is farther down the line, but above aluminum.

Silver/Copper are the best electrical conductors by cross sectional area. Aluminum is a much better electrical conductor than silver or copper by weight.

How about gold? Gold are great for electric conduction, but would it make a great heat sink?

Gold is actually a slighly poorer conductor than copper or aluminum, but it's used in electrical contacts (usually plated over copper) because it doesn't corrode.

As for heatsink materials, copper is hands down the best, as not only is conductivity better than aluminum, it also has a higher specific heat capacity (amount of heat energy it takes to raise the temperature of a volume of material by a degree).

No worries. Sometimes a thought, even if it is misguided leads to something good. Imagine how nice it would be to put some of this between the actual heatsink and your batteries to keep them from heating up too much under heavy use.

Where this would be good is as an insulator for incandescent "hotwires". Isolating the bubl assembly and reflector with an extremely good insulator would be great, as there you want to AVOID heating up the light as much as possible, whereas with LEDs you want to use the light as a passive heatsink.