Dear all,
It is clear that thermal conductivity of copper is better than aluminium and specific heat of copper is less than that of aluminium. So it is clear that copper will transfer more heat. But aluminium is preferred in automobile radiator and many other heat transfer application over copper. Is there any other reason for that?
There are several reasons for using Aluminum in radiators. As stated above, aluminum has recently become a cheaper base material to buy, but it is also lighter, which is important in an industry that is so concerned about efficiency. As well, the solder that used to be used to join the copper tubes of a radiator caused buildup of materials on the interior of the tubes. The industry then turned to brazing, which was effective at solving the problem, but it was also more expensive. Hence, aluminum makes a better choice for most automotive applications.
As stated above, the cost and weight are two most important selection criteria. Also, Aluminum can be easily formed in various shapes and can be easily extruded. This makes them a better choice for heat exchangers which employ micro channels for better heat transfer (such as car radiators). However, for certain applications such as HVAC, people still prefer heat exchangers coils made of copper tubes. One of the advantages of copper is that if there is a leak, it can be easily fixed (unlike Aluminum). I have seen researchers starting to produce extruded micro channel tubes with copper recently.
Yes, It's true that weight and cost criteria are very important in automobile radiators, and that leads to use of Aluminum than Copper.
Aluminium vs copper coils interesting link
http://www.achrnews.com/articles/87135-aluminum-vs-copper-the-great-condensing-coil-debate
Dear Pandya
As my colleagues declared, the use of a high conductivity copper is supposed to be better than the use of Aluminum. However, aluminum is preferred in cars radiators industry. In addition to another reason, which is the copper with the existence of water corrodes, causing Mad green called a patina, a dielectric material that reduce the thermal conductivity significantly.
Regards
One more point I want to mention here that copper is better at conducting heat than aluminum, but aluminum is able to radiate the heat into the air better than copper because of its lower density.
The best practical coolers have a copper base, usually heat-pipes, and aluminum fins. Copper is better at heat transfer and aluminum is better at heat dissipation, so good heat-sinks have a copper base that quickly/efficiently gets the heat away from whatever is being cooled, heat-pipes that quickly take the heat away from the base, and the heat-pipes are attached to aluminum fins that quickly dissipate heat. Some coolers are just a block with a copper base and aluminum fins. The aluminum absorbs heat away from the base and dissipates it at the fins.
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