Painting Intercooler Black - Better heat dissipation?

[celicapain]

No. you idiots. there are two types of thermal transmission, conduction and radiation. unless your talking about serious thermal gradients then in most applications conduction is a much greater component of heat dissapation than radiation. i,e intercooling, nearly all the cooling effect comes from cool air physically touching the core, heating up and flowing away, to be replaced my more air. having a discussion about how to improve the heat radiating properties of a metal surface just isnt applicable. again, idiots.( i had a poo day)

[GasedT18]

Yes, yes celicapain. It's not an unreasonable hypothesis to test either empirically or to rule out testing by showing theoretically that the scale of the effect is insignificant - but to do neither is a bit slack.

I don't have the time at the moment to do the sums and modelling but someone might like to get the ball rolling. I'm also more inclined to just try to measure any effect.

It makes one wonder why coolant radiators typically black? Just a tradition?

Changing the roughness of surfaces or introducing turbulence may be more fruitful. It may be that some black coatings increase the micro-surface area...?

The following url might be a good starting point.

Note that there are more than two types of thermal transmission.

http://en.wikipedia.org/wiki/Heat_transfer

D

[TERRA Operative]

Talking of intercoolers, is there anywhere (preferably close to Brisbane) that can make me a custom sized intercooler?

I need one that's about 650mm wide, 250mm high and 50mm thick, with the end tanks on the top and bottom exiting at opposite ends.

[Stefan]

From the the Garrett site (Garret FAQs

Will a FMIC block flow to my radiator?
No. Since the intercooler allows air to pass through it, airflow to the radiator will not be blocked. However, using an intercooler core that is too thick and does not allow air to pass through it quickly or completely and airflow to the radiator can be restricted which can lead to potential overheating problems.

I want my car to remain a sleeper/stealth. Can I paint or anodize my intercooler so it is not easily visible?
Yes! It is not uncommon at all for an intercooler and endtanks to be anodized black to keep attention away from the car and help it maintain a sleeper appearance. A very light coat of paint on the core and endtanks is also another option, usually much cheaper and easier than anodizing, with a negligible performance loss.

[celicapain]

Yes, yes celicapain. It's not an unreasonable hypothesis to test either empirically or to rule out testing by showing theoretically that the scale of the effect is insignificant - but to do neither is a bit slack.

It makes one wonder why coolant radiators typically black? Just a tradition?

Changing the roughness of surfaces or introducing turbulence may be more fruitful. It may be that some black coatings increase the micro-surface area...?

Note that there are more than two types of thermal transmission.

D

I think its a reasonably unreasonable hypothesis :
I suspect the main reason radiators were black was cosmetics more than physics, i notice that most new cars use a bare aluminium core, so i dont think thats really an indicator of their being an advantage either way. if anyone has a yen for mega maths than you can combine the equations on Gased T18's wiki link with this wiki link http://en.wikipedia.org/wiki/Thermal_radiation allegedly you can mathematically model how color will effect heat transfer. I sure aint offering though
also, what are the other types of heat transfer other than cond/radi? i know about convection but have always considered it an offshoot of conduction rather than a alternate transfer method.

[GasedT18]

I don't want to be too much of a pain celicapain (a bit of pain can be a good thing) but read what the Wiki article has to say! (same to you TERRA Operative). celicapain, you would or should know, or will know, if you have done or will do HSC/VCE level physics/chemistry.

Don't be afraid of formulas and models they are only tools - the main thing is to look at the relation of terms and get a feel about what they represent before one starts plugging in values.

I didn't know new cars use bare aluminium cores, maybe an engineer actually did the sums (or an experiment) and showed how manufacturers could save money without compromising efficiency or perhaps it is that grilles now don't allow the radiator/IC to be seen so much?

D

[Mos]

Do the maths, radiation is a very low percentage of heat transfer for the case of a charge cooler. Earlier in the thread I plugged in some values for best-case-for-radiation and worst-case-for-conduction and the difference was in the order of 3 or 4 orders of magnitude (iirc).

So the hypothesis that radiation is worthwhile is not reasonable. However, if celicapain made that statement based on a gut feeling, rather than previous relatable experience, then one could argue that the reasoning wasn't reasonable

Mos.

[amichie]

What about copper versus aluminium. Isn't copper a better thermal conductor?

Shouldn't black copper work better than bright aluminium.

[celicapain]

frig it. doing maths, will post when done.

[oldcorollas]

What about copper versus aluminium. Isn't copper a better thermal conductor?

Shouldn't black copper work better than bright aluminium.

ggggooogle

http://www.engineeringtoolbox.com/th...ity-d_429.html

aluminium is 5 times that of steel, copper is 8.. does it make a difference? no.

reason? it is convection of heat to AIR that causes loss of heat.
the conduction thru that 0.5mm? of copper or aluminium from inside to outside makes sooooo little difference.

why do people keep confusing "BLACK COLOUR" with "BLACK BODY"...
and emissivity has buggerall to do with heat loss at what is not much more then BODY TEMP..... if the IC was 500deg or 1000deg, then emissivity is important..


to put it into perspective... on that link
copper - 400ish
aluminium = 250ish
air = 0.024

so copper/air = 16667 times
and Al/air = 10417 times...

so yes, technically copper is better and might make 0.00001deg difference but..... this needs to be put into persepctive

[celicapain]

currently machining out a solid chunk of diamond for my intercooler, AND YOU THINK YOURS IS A BIG DOLLAR BUILD!

[amichie]

.

why do people keep confusing "BLACK COLOUR" with "BLACK BODY"...

So why does a black car parked in the sun get hotter on the inside than a white car parked in the sun?

[celicapain]

Cause heat absorbtion and radiation are not the same thing.
Light is radiated energy, and when comparing how something is HEATED by radiation then colour very important. i.e black surface absorbs more energy than a white surface which will reflect some of the light.
still doing maths, this are hella comlex sums to do with any accuracy. Anyway at this stage im 10000% sure that conduction has a much greater effect than radiation, just gotta finish the maths to prove it.
Also Gassedt18, had another look at that wikilink, still cant find that mysterious third method of heat transmission

[amichie]

cause heat absorbtion and radiation are not the same thing
sunlight is radiated energy, and when comparing how something is HEATED by radiation then colour is the only varaiable

I thought they were reciprocal processes (at equilibrium) in the absence of electronic absorption or emission.

[celicapain]

I thought they were reciprocal processes (at equilibrium) in the absence of electronic absorption or emission.

Nice phraseology!
Im not sure, I dont think the laws of thermodynamics allow for reciprocal processes except on paper. dont things always end up with equally distrbuted energy after a long enough time?