Metal vs Plastic heat conductivity

[Neotuck]

I have been wondering what would work better at conducting heat as Plastic has a thermal conductivity rate of 913 (W/m)/K while a Metal tile has 60 (W/m)/K.  At first I assumed more would be better but after running a test with the pictures below I see it moves heat slower.  Can some one explain this? 

The center chamber is filled with solid hydrogen and the two side chambers are filled with O2.  As seen in the picture the side that uses metal tiles cools faster than the one with plastic tiles

[Rotintin]

I've been wondering whats best for cooling stuff down, thanks for doing the test. I'm also curious as to why.

[pg13]

My guess would be the thermal capacity of the plastic is much higher, also it says on the plastic block "slow heating" I think, which is kind of a hint that it's not too fast at conducting.

[Neotuck]

2 minutes ago, pg13 said:

My guess would be the thermal capacity of the plastic is much higher, also it says on the plastic block "slow heating" I think, which is kind of a hint that it's not too fast at conducting.

I don't see "slow heating" but I agree the capacity is much higher than metal

[Lacost]

In theory plastic is the better conductor, which means that more energy can be transfered through it in less time.

 

The thing that separates metal tiles apart from plastic tiles in your test is the thermal capacity. This means that plastic needs more "coldness" to lower temperature initially but once equilibrium is reached, plastic pulls ahead. The limiting factor in your test however is the thermal conductivity of the gas phase you want to cool since plastic can only transfer heat on adjacent tiles.

 

Try to set up a new test where the plastic and metal tiles have the same temperature as the cooling medium. This way you can knock out thermal capacity from the equation since no cooling/heating has to be done on the tiles themselves.

[Lutzkhie]

culprit is the specific heat of the material
tungsten has 0.134 (J/g)/K while plastic has 1.92 (J/g)/K, which means plastic requires more energy before its temperature drops by 1K
try other refined metals just for experimenting