Carbon fiber nanotubes.. Thoughts?
 

http://thermocomposite.com/TechPrese...iles/frame.htm

I wasn't aware of the fact that carbon fiber could have thermal conductivity "superior" to metals (think Cu, Al). Can anyone explain WHY this is?

Also check out the front page:

http://thermocomposite.com/

The NB heatsink of the future?

Looks like the structure of Diamond. Heat travel is strait. This page kind of explains it: http://thermocomposite.com/TestData.htm

Having a hard time deciphering their test data. Would like to see something run at 50-100watts as opposed to just 10. I think the stuff might go to shit at those wattages.

Interesting though. Would like to see a live example used on a CPU.

exceptionally good heat transfer but last i heard they were running at about $500 a gram, that is for a fine powder with no mechanical properties. They are not an engineering material yet.

If they can get them into a nice manufacturable form they are still going to be expensive enough for a long time not be useful plus im not sure if they like water.

Pure crystalline carbon is always very conductive it seems, no matter the allotrope. Graphite conducts well, but it always conducts at its best (again, better than most metals) if the direction of the heat transfer is parallel to the molecular "sheets" graphite is made up with. Too bad it wouldn't work in a heat sink.

Why wouldn't it work in a heatsink HAL? They seem to think it will.

The reason I made the NB reference was because of the fact that they:

1. Compare it to an Al heatsink of 1x1" demensions...pretty much what every NB uses
2. Use a 10w heatsource (kinda low, but one could argue that's the average NB output)
3. State that in large quantities it could be priced competitively with its Al counterpart.

A quote from their website:
Found here: http://thermocomposite.com/TestData.htm#TCtest

I should have an evaluation sample on the way soon.

Applications being targeted.
Laser and Plasma Nozzles-Gun Barrels
Self Cooling Brake Pads-Friction Plates
Heat Exchangers-Thermo Electric Coolers

I don't think 10 watts is going to be a limit. It was used as a testing example. It can handle 250 C degree heat loads and has higher thermal conductivity than AL and diamond.

Re-direction of heat transfer idea of bending the tubes sounds very interesting.
I'm picturing Thermo-Carbon tubing/heatpips. No water!!! Designing the entire case as a heatsink...

I bet i'll see this happen when I'm almost dead and don't care any longer.

The idea is it change heat transfer the way fiber optics did with communications.

Csimon:

How are you getting a sample? Did you contact them?

Bobo: what makes you say that they "won't like water"?

what im saying is that is unknown how they respond to water so you be careful. You wouldnt make a water block out of iron would you. What are the corrosion properties etc.

Yes I contacted Brad the CEO ...however they are only shipping eval materials to military atm. I'm on my own to get the materials ...they are only selling licensing to public individuals I gather.

On your own to get the materials? Where will you acquire them? I saw a few references on their site. How easy/hard is it to machine Carbon fiber nanotubes? I'd imagine that it is very brittle material.

Understandable that they would give the military the bulk of their attention. After all, the US military is a BIG customer with a BIG budget. They are probably working with DARPA.

...All very exciting stuff...

I said military but I meant gov. Possibly the same thing but idunno.
So where do I look ...the government? LOL

And I was also wondering ...what thermal paste would I use? Thermal pitch or regular as5?

I just can't believe they've applied to patent some geometry. pft

This stuff should be unreactive to water. It seems to have simliar properties to graphite and might be brittle. I also read it had aromatic ring structure so chemically it should be very unreactive.

Easy way to solve this problem is email the expert and ask him instead of argue among ourselves when none of us are experts in the field.

Intersting reads
http://thermocomposite.com/Documents/10Wattchart.htm

http://students.chem.tue.nl/ifp03/synthesis.html

http://thermocomposite.com/Materials.htm
Says more heat conductive nano carbons can be produced $3 per pound and with cheap equipment. $200,000 is cheap? I guess when compared to several millions and still in the lab phase.

Did anyone notice that the nanomaster.com and thermocomposite.com websites look eerily similar? I think I see what these guys are trying to do. They patent a geometry for bonding carbon fiber nanotubes (kinda of a cheap shot, whatever) some sort of heatsink or method for making heatsinks from CFNs (didn't read the whole brief, not going to lie here) and then they come up with a machine for "growing" CFNs.

So, you the machinist, buy a machine for $200,000 to grow CFNs and make CFN based heatsinks. You then pay thermocomposite a roylaty for using their design (bonding angles for CFNs), and then eventually sell your heatsinks to the public. So all they leave us is the leg work (manufacturing and selling to the public). That's nice of them. Good buisness concept, should anyone choose to dive in.

In that case I'm seriously considering applying for a patent on my geometry and that way by the time they realize a better approach ...they'll be knocking on my door! Hehe

I'll patent a cone shaped heatsink. I think it has more surface area than a pyramid and easier to "grow"

LOL. Nice one, rice!

Personally, I'm not sure a thing like geometry should be patened.... maybe I should say "bond angles"? Kind of a grey area. I'm thinking of a lot of applications for this stuff. Think about having engine blocks made of "carbon fiber nanotubes". Then again the combustion chamber runs in the neighborhood of 1,000C and this stuff is only rated to 250C..... I don't know. Maybe.

maxSaleen, you've got it exactly wrong.
An engine block that leaks heat through good thermal properties of its material is leaking energy that should be going into pushing the pistons.
Ideally the material would not absorb any heat at all, and hence all energy would go into super-heating the gasses causing them extra expansion and hence kinetic energy to the pistons.
The reason we cool an engine block is due to the fact that metal does have a low specific heat and metal also has a degree of thermal expansion.

This is ture.

What I was trying to say was have the engine block "air cooled".

No one here seems to find all this very exciting. Surprising.

I don't see it as practical, maxSalen, and I suspect others feel the same way. There are way too many "wonderful cures" for the problem of heat. 99.9% of them never pan out, despite loads of initial hooplah.

Already there are commercial ceramics with thermal properties around isotopically pure diamond (3,000 range vs 380 for copper and 420ish for silver). However, thats in one plane only, and in the other plane I remember it was like sub 100.
Even with Cathar's focused cooling direction in the last couple of years, it is still the case we need to flow heat in both directions?

on and aside they have tried to make an adiabtic (fully insulating) engine block. Car companies have probably spent of the order $ billions developing it but never got it to work. The main reason is if the engine walls are 700c then the fuel ignites when entering the cyclinder and you get very bad knock. High conductivity engine walls are good but air cooled engines have problems associated with getting air to them and the final thermal jump to air.

Im right in thinking that this is a start up. Be very careful with startups as the famous engineering intergrity can go out the window when you want an IPO and if its not built yet the final costs are yet to be fully known.

Fully insulated adiabtic blocks. Might work in a maybe in drag racing were the type of fuel like methanol can be used or Diesel engine where the fuel needs high temps to ignite. Wankel would be interesting as it produces too much heat.

In a gasoline engine with temps that high the fuel will detonatate before the piston even reaches TDC. That's isn't just a case an average case of really bad knock, it's your engine internals exploding.

Anyways, piston engines or things of the past. We need to move towards electric cars. Last I heard 2 hr charge at $.50 and you get 40 miles.

Since you brought up electric engines, rice, did any of you guys see Mistubishi's Lancer Evoution VIII concept? It had independant electric engines at each wheel, making a total of like 260hp. 0-60 time wasn't that spectacular (high 5s) but the cool part is that each wheel's speed can be independantly controlled. How cool is that? The ultimate all wheel drive.

http://www.mixedpower.com/modules.ph...rticle&sid=724
230mpg. Now that is a number to brag about. How many people can say they can get 230 mpg. Now that's 1337
BLitz modded a prius with a turbo setup that gets 200 hp.

$25K car, get govermnt rebate, spend it on the turbo, save money on gas and you have good commuter with enough power. Modify it for even more MPG for additional $3k and you would save enough money on gas ( lets consider the fact gas will go up i price) in 2-3 years to pay off that $3k investment

I don't even know why 250 hp or more is required for street driving? When does anyone need that type acceleration or even use it?

Plug in hybrids are good, they have advantages but they do reduce MPG on highways, if not precharged like you suggesting (y you even need to use the gasoline engine when you have a truck full of batteries is anyones guess, but its nice to have it there if needed). 250mpg is like 200 miles of pure elctirc then a IC on 50 miles or something.

You can get knock with diesels as well, and even special fuels if you have a full adiabatic cylinders by definition the walls are combustion temprature. Even for wankels. Plus you cant get metals to go that high a temprature so it doesnt matter.

Ultimately you have to move to something like hydrogen and the question then is if you use IC or electric/ fuel cells. Your standard IC engine can get very close to current fuel cells and probably allow high perfromance as well if wanted.

IC engine? Could you elaborate bobo? Never heard of one before.

Sweet link, rice.

full adiabatic cylinde doesn't exist in the real world. If it did the walls would not absorb any heat and heat would all go out with the expansion gas and out the exhaust and burn the bumper.

I understand what you are saying though as the walls would get too hot and detonation would occur if these walls weren't watercooled and that is why they failed.

Anyways, when in kindergarden they said electric cars would be around 2000 and they are still working on it because we got into the SUV craze.

internal combustion?