# Thermal Conductivity Question

1. Dec 8, 2015

### tina-duncan

Hello friends,

I am having a hard time understanding thermal conduction and was hoping someone could shed some light for me.

I am looking to protect a component from heat by placing a thermal barrier between it and the heat source, the heat applied to the surface of this barrier would be 150°C. I have identified a material with a thermal conductivity of 0.03W/mK, however I am unsure what thickness I would require to prevent any heat of greater than 50°C reaching my component surface.

I have been trying to use the equation Q=kA deltaT/d, however I feel this does not suit what I am trying to accomplish due to not knowing Q?

So my question is, is there another way I should be approaching this problem? Is there a way of calculating Q and then rearranging the above equation to solve for thickness?

Any help would be greatly appreciated.

Thanks,
Tina

2. Dec 8, 2015

### CWatters

I believe you need to know Q and the properties of whatever is on the other side of the object to be protected. For example..

Heat source (150C) -> Insulation -> object -> something -> Ambient Air (20C?)

If the "something" is a good thermal conductor then the temperature of the object will be nearer "ambient" than the heat source temperature.

What is the heat source? If it has a known power you might be able to estimate what percentage goes in the critical direction.