Copper vs. Aluminum

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Mean416

Mean416

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Hey fellas.

So I've been doing some work with my engineering consultancy lately involving the use of copper conductors, and have had to look at both electrical and thermal conductivity of aluminum vs. Copper. I knew for a long time that copper was more efficient than aluminum as a heat exchanger but I had no idea how big the difference was.

Just looking at thermal conductivity, aluminum has only about 60% of the ability that copper does for a given size.

So that got me to wondering, I bet many of the common overheating issues we hotrodders have is due to using aluminum as a heat exchanger.

Question I have is, are there any aftermarket radiator companies producing copper radiators?
 
I do not know anything about engineering or thermo dynamics,
but my race cars always run cooler with the aftermarket aluminum
Radiator than with the copper OEM even if they are recored.
 
Mean416 said:
Hey fellas.

So I've been doing some work with my engineering consultancy lately involving the use of copper conductors, and have had to look at both electrical and thermal conductivity of aluminum vs. Copper. I knew for a long time that copper was more efficient than aluminum as a heat exchanger but I had no idea how big the difference was.

Just looking at thermal conductivity, aluminum has only about 60% of the ability that copper does for a given size.

So that got me to wondering, I bet many of the common overheating issues we hotrodders have is due to using aluminum as a heat exchanger.

Question I have is, are there any aftermarket radiator companies producing copper radiators?
Click to expand...

Glen-ray Radiators - All New Licensed Mopar Chrysler Dodge Plymouth Radiators

www.restorationradiators.com www.restorationradiators.com
 
Mean416 said:
Just looking at thermal conductivity, aluminum has only about 60% of the ability that copper does for a given size
Click to expand...

That is true but ...

The junction between the fins is the only place heat is transfers and a copper brass radiator the fins are soldered with lead based solder and that is a worse conductor than copper/brass so it about evens out, but the copper/brass is still more efficient.

There is nothing wrong with aluminum radiators, if you built a copper/brass with the same design as an aluminum it would be a little more efficient but the added efficiency might be offset by the added weight.

As for copper /brass radiator makers

US radiator is a us based rad builder. They can customer build a rad that will meet your needs
 
The only reason OEM use aluminum these days is because of cost. Most aluminum radiators will be 3 or 4 core to do the job a 2 core copper one would do.
 
There's more to heat transfer than just the conductivity of the material. With a vehicle radiator there's the heat exchange of the fluid to the tubes, and then the conduction of the heat through the tubes and the finsm and finally the heat exhange with air. The last is largely convective and will involve both the tubes and the fins. I remember being surprised in one class excersize that the fins can be designed so that they will make the heat exchange worse! IIRC that was a passive convection excersize. My point is only that aluminum's disadvantages can be largely overcome in this particular regard. That doesn't make the observation of the differences in coduction any less interesting - its certainly an important factor
 
U.S. Radiator built me two copper/brass radiators.

usradiator.com

US Radiator - US Radiator

For over 50 years, U.S. Radiator Corp. has been in the business of providing cooling system confidence. Correct Radiator Fit And Performance
usradiator.com usradiator.com
 
The design of the heat exchanger ....i.e. size, spacing and number of tubes and fins will
determine how efficient it is.
 
Agree with Mattax.
Solder & brass are poor conductors of heat, but a necessary evil in the construction of copper radiators. The benefit of the alum is that the tubes can be made wider 1.00" or 1.25", versus 1/2" for copper. Better heat shedding fins can be used with the alum. The overall result is that the alum rad is better at cooling.
 
This is straight from US radiators website. Read the test process and note the temperature drops shown.

1699108279509.png
 
Mean416 said:
This is straight from US radiators website. Read the test process and note the temperature drops shown.

View attachment 1716162086
Click to expand...
This was what I was going to post. Ultimately, copper brass does out cool aluminum, but it's not cheap. At all. The Optima radiator is what I have planned for Gladys, my ford truck, bot of course I cannot get it done anytime soon. That's actually very similar to what Ford had her originally equipped with, being an F250HD and having the Camper Special package. I have an aluminum 2 row in her now, with 2 rows of 1.25" tubes and while she does not over heat, the temp starts creeping up in traffic with the A/C on. She cools back down some on the road, but there's room for improvement and I know the radiator is where it is.
 
My experience is years ago I paid good money for a "super desert special deluxe lol" custom copper radiator from a big source like mentioned above and it sucked for cooling at idle. I replaced it with a cheap champion off ebay and changed nothing else, problem solved, we figured the water was spending too much time in the radiator. Now we have several cold case radiators with the 1.25 tubes and all have been stellar so far on the street, three are 500+hp stroker small blocks. I will also add we all run flowkooler water pumps, high flow t-stats and adequate fan setups whether electric or mechanical.
 
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As I stated earlier in the thread, the reason alum is superior is because of the superior finning that can be used with the large tubes. There is also something about the turbulent coolant flow through the larger tubes. I will try & dig up the article & post it.
 
All I can offer.... 6 cars. 340 hopped x 3400 stall auto, 2 x 383 x 4 gear. 2 x 440 x auto and a 4 gear x Hemi. ALL run the factory copper radiator and they ALL run on the thermostat!

Aluminum being superior... well....
 
lead69 said:
My experience is years ago I paid good money for a "super desert special deluxe lol" custom copper radiator from a big source like mentioned above and it sucked for cooling at idle. I replaced it with a cheap champion off ebay and changed nothing else, problem solved, we figured the water was spending too much time in the radiator. Now we have several cold case radiators with the 1.25 tubes and all have been stellar so far on the street, three are 500+hp stroker small blocks. I will also add we all run flowkooler water pumps, high flow t-stats and adequate fan setups whether electric or mechanical.
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I should clarify that my post above had nothing to do with the cooling properties of aluminum vs copper but the design of the radiator. On all my cars it took a 3-4 core copper high efficiency radiator to cool the same as a modern 2 core/bigger tube aluminum radiator and the aluminum is cheaper now and lighter. I miss the days of getting my copper radiators performance recored for $200, back then the only aluminum radiators available were more expensive and designed for a chevy.
 
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My take on all this is that a properly designed and constructed copper radiator will put cool an aluminum equivalent. Same should also apply to intercoolers as well.

Obviously if it's built or designed poorly it's not gonna work well. But given an otherwise equivalent aluminum or copper unit the copper one will have a substantial amount of extra thermal capacity.
 
My plan is to talk with US Radiator, tell them my application and see what they recommend. It's gonna be around 1K no matter which way I go anyway. lol
 
RustyRatRod said:
My plan is to talk with US Radiator, tell them my application and see what they recommend. It's gonna be around 1K no matter which way I go anyway. lol
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That's a good plan. Curious what they come back with.

I wonder if, with an intercooler, if you would see a better temperature drop and therefore power...
 
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