Joined: Jul 2011
Let me chime in the debate about the heat, aluminum and steel.
Fourier's law that considers heat transfer is :
q = k A dT / s
where q is the quantity of heat transferred (units:W), k the thermal conductivity of the material (be it steel or aluminum) (W/m.K), A is the heat transfer area (m^2), dT = temperature difference across the material and s = material thickness (m).
So, let's consider that the case dimension are similar. Doing so, temperature inside the case and outside the case (dT), area (A) and thickness numbers are not important. In other words, le's say that aluminum is "number 1" and steel is "number 2" in the following equations :
As said earlier, we have a similar case, but of different material.Which means that A1=A2=A, dT1=dT2=dT and s1=s2=s. Replacing these values in both equation gives :
Then, we look at the ratio q1/q2, it gives a simple direct answer (A, dT and s cancels out, as they have equal values):
Thermal conductivity of aluminum is 250 W/m*K and for steel (with 1% carbon) is 43 W/m*K and 16W/m/K for stainless steel. So, the ratio of q1/q2 gives:
q1/q2=5.8, for steel with 1% carbon and
q1/q2=15.6, for stainless steel.
Under similar load, the aluminum case will dissipate heat 5.8 and 15.6 times faster than steel (1% carbon) and stainless steel respectively.
So, under any given "impulsion" of X Watts towards the case (from heatpipe or air inside the case, or...?), the aluminum case will dissipate the heat faster, as Fourier's law tell us.