What material property is used to measure heat transfer capacity?

[ajensen]

I am designing a part that needs good heat transfer capabilities (heat fins) and am comparing a few potential materials. Which property is it that tells me how good its heat transfer capability is? Thermal conductivity? Specific heat capacity? Does a higher number mean better heat transfer?

 

[MintJulep]

If you are looking at a steady-state situation thermal conductivity will be most important to you.

If you are looking at transients the specific heat capacity will also be important.

 

[ajensen]

I have an LED emitting a fairly constant amount of heat so sounds like thermal conductivity is the winner. Thanks for your help.

 

[IRstuff]

Why reinvent the wheel? Aluminum is the material of choice for most heat sinks.

TTFN

FAQ731-376
Chinese prisoner wins Nobel Peace Prize

 

[ajensen]

I was looking at an Al alloy, but yes you're right. The straight Al turned out to be better.

 

[zekeman]

Copper, better than aluminum by factor of 2.

 

[IRstuff]

Ultimately, the heatsink is limited by the heat transfer coefficient of the air itself, so there's a point of diminishing returns on the choice of heatsink material; otherwise, one might just as easily propose using diamond as a heatsink material. But, it would be a wasted effort, since the improvement in overall heat transfer is very limited.

TTFN

FAQ731-376
Chinese prisoner wins Nobel Peace Prize

 

[dvd]

Specific heat, thermal conductivity, emissivity, geometry, mechanical properties, manufacturing practices, ..., it is difficult to design heat transfer devices without some knowledge of heat transfer and the material mechanical properties required for manufacturing, assembly and useful life.