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Comparison of thermal conductivity and heat dissipation of copper and aluminum

Aug 11 , 2021

First, explain a concept: Copper absorbs heat faster than aluminum, and copper does not dissipate heat faster than aluminum.

1. The radiator with a pure copper base is generally equipped with a fan with high speed and large air volume to increase the heat dissipation capacity of the copper base.

2. Someone introduced a copper-plugged and copper-inlaid radiator. The reason is that copper is used to quickly remove heat and then quickly dissipate through aluminum fins.

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Why is it said that copper absorbs heat faster than aluminum, but copper does not dissipate heat faster than aluminum?



Material Thermal conductivity K (W/m2K)

Material specific heat 

capacity J/kg.K

density kg/m3

copper

401

  0.39*10^3

8.9

aluminum

237

  0.9*10^3

2.7


Concept explanation: The heat transfer coefficient used to be called the total heat transfer coefficient. The current national standards and norms are uniformly named the heat transfer coefficient. The heat transfer coefficient K value refers to the heat transfer through an area of 1 square meter in 1 hour when the air temperature difference between the two sides of the envelope is 1 degree (K, ) under stable heat transfer conditions, the unit is watts/square meter Degree (W/K, where K can be replaced by ). Thermal conductivity refers to the heat transfer through an area of 1 square meter in 1 hour for a 1m thick material with a temperature difference of 1 degree (K, ) on both sides under stable heat transfer conditions, in watts/meter Degree (W/mK, where K can be replaced by )


From the table parameters, it can be seen that the thermal conductivity of copper is about 1.69 times that of aluminum. Therefore, using copper and aluminum to make a heat sink with the same cross-sectional area, pure copper can take more heat per unit time than pure aluminum. Aluminum absorbs heat quickly", the first half sentence has been demonstrated.

 

Concept explanation: The definition of specific heat is "the amount of heat required to increase the temperature of a unit mass of material by 1 degree", and the unit is J/kgK.


From the table above, it can be seen that the specific heat capacity of copper is smaller than that of aluminum. Copper reduces the temperature by 1 degree, and the heat dissipation should be smaller than aluminum. In this way, copper should dissipate heat faster than aluminum?

 

But notice that the density of copper is 8.9kg/m3, while the density of aluminum is only 2.7kg/m3, which is close to 3.3 times that of aluminum. Therefore, the same volume of the heat sink is made, and the quality of copper will be nearly 3.3 times larger than that of aluminum. The heat capacity of the material is still nearly half larger than that of pure aluminum. As the heat capacity increases, the heat dissipation becomes slower. Through the explanation of the above theory, we have also found the reason why "copper does not dissipate heat faster than aluminum". When choosing a radiator, you can use this theory. If you choose a pure copper radiator, you should choose a fan product with a higher speed and a larger air volume to avoid the heat of the copper from being unable to dissipate and causing a cooling bottleneck.

The heat dissipation part is more complicated. It is generally believed that the advantages of aluminum are as follows:

 

1. Cheap, low density, easy to process, the hardness of aluminum alloy is much better than pure copper, and it provides the largest heat dissipation area within the range that the motherboard/buckle can withstand (the heat dissipation area should be the largest for the heat release rate) Influence)

 

2.Going back to the above specific heat capacity problem, the same volume of copper absorbs the same heat and the temperature rises slowly, which also makes the temperature difference of copper relative to the surrounding environment low, which is not conducive to the fastest heat release:

 

Copper conducts heat quickly, has a high cost, and has a high enthalpy. Simply put, copper itself transfers heat quickly, but the speed of transfer to another substance is questioned. In the heat conduction baton competition, the heat conduction between copper and the next substance interface The capacity must be regarded as thermal resistance.    ---more info refer to www.sinolumi.com



 


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