Heat Loss - Interior Wall Temperature after time

[mdefense]

I am trying to calculate the interior wall temperature of an insulated tank. I want to model the as a plane wall for simplicity. Knowns: ambient (outside temp) -25F, thickness 3", thermal conductivity .04 W/mK, area 13.72m^2. Any suggestions?

 

[IRstuff]

You simply set up convection on the inside and outside, and solve the simultaneous equations for equal heat loss through the three regions.

TTFN
faq731-376

 

[corus]

I think it's a little more complicated if you have to consider if the tank is open and you have radiation from the inner surface to the outside. Equally, you'll have heat loss through natural convection (or forced convection if windy) and radiation from the outer surface of the tank, so your heat transfer coefficient will depend on the surface temperature.

 

[rmw]

You can find a lot of good design data here:

http://www.tranter.com/lc/platecoil-data-manual.pdf

rmw

 

[jharris3]

You have several steps before you go to the simple case offered by IRstuff.

You need to know the convection coefficient inside and out, though you could solve the problem for a range of combinations or use some published empirical data if available.

How good is the thermal contact between insulation and tank? Do you have an accurate representation of that resistence?

What is inside the tank that makes it hotter than outside? still air? moving air? hot air? other fluid? With a vacuum you could become very cold inside as the fluid is evacuated and find that the outside is hotter than inside.

For your first crack i would find some general values to go by and do the calculation that IRstuff says. Then go back and dig in deeper to check your answer which will become your head check against the more detailed effort.