Heat Transfer out of enclosure with heat source

[bripo18]

I'm new here, hoping for a little heat transfer help.

It has been a long time since I had to do any heat transfer problems and I'm a little rusty. Here is the problem:

Im going to be mounting some avionics equipment in a closet on an airplane. The heat dissipation from electronics is only 35W. I want to know what temperature the closet will reach before the temperature will remain constant. The closet can be assumed to be a rectangular tube. It is 60x10x32 inches. The closet is made from .50 inch Aluminum honeycomb panel (2024). Assume the air ambient at 68 degrees.
I am looking for rough numbers, it does not have to be exact. Formulas and explanations would be greatly appreciated.

Thank You!

 

[IRstuff]

Closet temperature needs to be a function of how the heat escapes the closet. If the closet is perfectly insulated, the interior will have infinite terminal temperature

TTFN
faq731-376

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[chicopee]

Here is a link

http://www.learnthermo.com/examples/ch04/p-4b-2.php.

Equation 8 is what you want. Apply that equation to each vertical and horizontal surface. Your problem will be to determine an equivalent "k" value for the honeycomb structure, "Hi" and "Ho" values for vertical and horizontal surfaces. Afterward, equation 8 can then be transformed in an equivalent form q=ΔT/ R (where q is actually dq/dt or the 35 watts value ); then for each surface you apply the equivalent form resulting in six different q values which added up will be 35 watts. Factor your ΔT (=Ti-To) from the "1/R's" and calculate for Ti.