Wait, you think that if that unit was made out of copper & maintaining same capacity / fin area would have ANY tangible RL difference?
I would honestly doubt it...
As mentioned before in this thread, the thermal transfer coeficient of the material has VERY little to do with heat dissipation. The bottleneck is the fin-to-air convection.
If you have a plastic surface @ 100oC, it is cooling off in contact with air practically as fast as a 100oC metal surface of the same area in contact with air of the same temperature.
See this extreme example below:
Example - Heat Transfer in a Heat Exchanger
A single plate exchanger with media A transfers heat to media B. The wall thickness is 0.1 mm and the material is polypropylene PP, aluminum or stainless steel.
Media A and B are air with a convection heat transfer coefficient of air = 50 W/m2K.
The overall heat transfer coefficient U per unit area can be expressed as:
U = 1 / (1 / hA + dxw / k + 1 / hB) (1b)
The overall heat transfer coefficient for heat exchanger in
polypropylene with thermal conductivity 0.1 W/mK:
U = 1 / (1 / (50 W/m2K) + (0.1 mm) (10-3 m/mm)/ (0.1 W/mK) + 1 / (50 W/m2K))
= 24.4 W /m2K
stainless steel with thermal conductivity 16 W/mK:
U = 1 / (1 / (50 W/m2K) + (0.1 mm) (10-3 m/mm)/ (16 W/mK) + 1 / (50 W/m2K))
= 25 W /m2K
aluminum with thermal conductivity 205 W/mK:
U = 1 / (1 / (50 W/m2K) + (0.1 mm) (10-3 m/mm)/ (205 W/mK) + 1 / (50 W/m2K))
= 25 W /m2K
Solve for the 401 W/mK of Copper and you will see that it is again the same, ~25 W/m2K.
All that matters really is surface area.
The trouble is getting a surface in contact with air uniformly hot to facilitate the exchage through convection using as much of the surface as possible. Ideally the whole area of it at the same rate. This is ofc where plastics like the polypropylene would fail. It would get super hot over the heat element, and keep it there unable to use the entirety of its surface area to dissipate heat to air.
So this unit is failing only on size: it is just too small folks. Even if it was made out of solid copper or aluminum (far better overall conductivity than a CLC with water in it), it would be limited by the very small radiator. Throwing more "mass" to the system (water, metal, whatever) makes no difference. Throwing more conductive materials in the mix makes intangible difference once you hit conductivity values of metals.
Its all about surface area, and since aluminum is the lightest & cheapest of the "conductive enough" metals, it is the most widely used regardless of application. I would take the biggest rad/fin area every-time, and so should you.Edited by pcfoo - 8/26/16 at 7:18pm