Copper vs. Aluminium

[Exterous]

Slur, your knowledge of being a jerk off is irrelevant, but certainly adequate.
Congratulations you are a fool with a search engine!... This is something you would learn if you actually went to college and had to take anthropology. But chemistry man lets stick to the question at hand which is METALURGY not chemistry.... but maybe you can't read....You should spend more time actually reading and trying to comprehend, instead of crawling the internet in an attempt at trying to look cool in front of people who have better things to do. Hey I got something for you it's your AXX. Now if you'll excuse me I have better things to do than hand it to you all day.......
Yeah that's right you call me sir, and next time, I'll send you a bill.

This is why I love this place. So many friendly people willing to take a small part of their day to politely help others and debate ideas in a civilized manner

 

[waylander]

First of all, I'm not here to argue which of the metals is better. They are both good at what they do and there is a reason they are used the way they are. Like others have said the question posed could easily be answered by a quick internet search, or even by delving into your old chemistry book.

One of the reasons to be on this forum however, is to interact, if he feels that he would rather ask someone here than do one of the alternatives, that is his right as a member (even if it is annoying). If someone answers him then great for both of them.

Also, the computer (and other) "geeks" on this forum (and most of us are at least a little or we wouldn't be on a computer forum) are very defensive of what they perceive to be their expertise (whether they actually are or not) but a little politeness should be used to prevent flaming and other behavior that you probably wouldn't use face to face.

I personally skip over most posts that begin with "well you're a moron" type starts regardless of whether they may contain relevant information or not. At times it is very humorous to see how riled up people get on forums, IRC, chat rooms... etc.

I'm not totally immune to this type of online behavior, as my wife can attest to when she hears me yelling at team members on CSS quite often, but generally I use the same method for forums as I do in my business emails. Write it, save it, read it again 5 minutes later, then send it or edit it then send it. You can usually save yourself a lot of grief this way.


Just my 2 cents.

 

[Kodiak666]

I'd just like to say thank you to PhyberOptik for some well reasoned, well articulated, points! I appreciate it when people take the time to express themselves well; good written English rare on a forum.

I don't know about anyone else, but I've learned more than just about the relative merits of copper and aluminium here...

 

[Guest]

Copper is better at heat transfer, however it is heavier than aluminum. Also copper will tarnish after a while but aluminum wont.

Tarnish is a layer of corrosion that forms over copper, brass, silver, aluminum, and other semi-reactive metals as they undergo oxidation. It is analogous to rust, but with a slower rate of occurrence. Tarnish is mainly caused by chemicals in the air, such as sulfur. It often appears as a usually dull, gray or black film or coat over metal.

 

[rubix_1011]

Only 3 years (almost to the day) late on that argument.

 

[ouch1]

Lol yeah Rubix. Looks like we have been having of rash of "Frankstien'ed" threads lately.

 

[rubix_1011]

I'm just wondering how long people searched back threads to find these things...?

 

[Raviolissimo]

copper has a conductivity of about 9 watts/inch degree C; Aluminum, about 5 watts/inch degree C.

in other words, copper conducts heat almost twice as much as aluminum.

However, that doesn't mean the copper part will work better, because the primary "delta" in the thermal schematic is heat sink to air - regardless of whether the heat sink is copper or aluminum.

so, for a typical CPU putting out 50 watts, let's say it has a case to junction thermal resistance of .1 degrees C per watt. so you'll see a 5 degrees C rise from, well, case to junction.

then there's a thermal resistance across the interfact with the thermal grease, usually less than .1 degrees C per watt.

then there will be a gradient in the heat sink. the gradient will be bigger if the heat sink is aluminum - in the example, the tips of the fins might be 4 degrees C higher than the base (if it's aluminum), versus 2 degrees C (for copper).

then there's a huge temperature gradient from the heat sink fin to air. like 20 degrees, which would correlate to a thermal resistance of about .4 degrees C per watt, in the example. obviously related to how many fans you have blowing, etc.

i did these kind of calc's working as a mechanical engineer from about 1980 to 2004, then started studying animation in 2005.

a good example would be the Zalman 7000 (or 7700 ?) series. they have the same geometry with the same metal volume available in aluminum, or copper.

my guess is a website like
http://www.frostytech.com/

or some other tech site that has lots of heat sink reviews would have a comparison.

 

[ouch1]

lol here we go again.

 

[kennith13]

Copper and aluminum are both effective materials for heat sink construction, but they have different requirements. If you want to know why, consider a great chef's kitchen.

Aluminum sure can move heat, if it has been done right. It very efficiently absorbs and transfers heat to it's environment and things that interact with it. This works great for bacon in the morning, and even for boiling water, but isn't so good for a large, thick filet mignon. That cold slab of beef sucks the heat right out of the aluminum, and there isn't any left to keep up the cooking. Many people who buy aluminum cookware have a lot of trouble doing steaks properly for this very reason. Aluminum has a low thermal capacity, and a very high thermal conductivity.

As such, aluminum just wicks heat away with little concern for anything else. It won't wick as much as copper, but it sure will move it quickly; Dumping it's capacity as soon as any heat leaves the sink, and quickly soaking up more.

Copper moves heat as well, even if it hasn't been done all that well. Copper very efficiently absorbs and transfers heat as does aluminum. It does it faster, as well. That said, copper has an incredibly high thermal capacity. That big fat steak just can't suck up all the heat that copper will hold on to, and this is where copper and aluminum differ in requirements. Copper won't readily dump all the heat energy it picks up, because it holds so much of it before it changes temperature to any great degree.

That leaves us with a problem. Copper needs help. Somehow, you have to remove all that heat from the copper, as it will just hold on to it otherwise. A copper heat sink can work much better than an aluminum one, but you have to either have loads of pipes and lots of fins and airflow, or you need peltier/water cooling with excellent transfer to help it out.

The thermal capacity of copper, when compared to an aluminum heat sink of the same design, completely removes the benefit of using copper in the first place without help. As a matter of fact, a poorly designed copper sink can be much worse than an aluminum model.

The best way to use the materials is being tried nowadays, and that is combining them. As with most good things, they work better together than apart.

 

[Professor Alameddine]

Aluminum has much lower anisotropic values (1.22) compared to copper (3.16). This results in lower vibrational entropy which microscopically (quantumly) means much lower thermal capacity leading to lower heat storage levels than that of copper. So, yes! while copper tends to conduct and accelerates heat diffusion much faster than aluminum, copper's higher vibrational entropy stores heat energy longer while it is being transformed from thermal to vibrational entropy back to thermal, and that is why its release speed of heat is significantly lower than that of copper. so while for cooling heat diffusion is faster in copper, heat release is lower in copper and higher in aluminum. For heating, not quite so! while for coils inside the warmer medium (condenser is now inside the room) heat is dissipated faster by aluminum coils, which is what we need to get warm, evaporator coils outside in colder temperatures need to be copper so that they absorb heat faster, and store heat longer.

 

[Shadow703793]

^You noob! DON'T BRING UP DEAD THREADS!

 

[Conumdrum]

Wow, the pefessor is smart. What was the chap meaning to bring to this conversation, long long after the barn doors closed and the cow is long dead and eaten?

But he's smart, just short on the concept of time and common sense.

 

[kennith13]

He said the same thing I said, but dolled it up with 50 cent words, and then bungled it in the middle so it doesn't mean anything.

Vibrational entropy: A function of variance within a system being calculated, relating to it's readiness or resistance to change based upon various subatomic probabilities, or thermodynamic properties. Doesn't always mean the same thing, depending on the level of the system being analyzed.

Quantum=More accurately relating to subatomic.

By his post directly, copper dissipates heat energy at a lower rate than copper.

What he was trying to do is more directly describe the system being explored. Were it not for the bungle in the middle, it would have been a very valid contribution to the thread.

There is nothing wrong with him posting here this late in the game when he has something constructive to add, so don't chastise him for bringing back a dead thread. He is leaving more information for a future search to find, to help an uneducated user out who may have a question on the subject.

I hope he comes back in and fixes his minor mistake so the information is valid. This sort of information clears up all the idiot arguments that populate the internet. What he has to say matters. Now, he said the same thing I said, but he didn't dumb it down for you like I did. It's good to have the complex version as well, for those who are interested.

 

[randomizer]

I saw AlaskaFox and chuckshissle and new this was a necro thread without looking at dates.