Heat transfer through wall - Insulation thickness

Click For Summary
SUMMARY

The discussion focuses on calculating heat transfer through a thin aluminum wall with a thickness of 5mm, using thermal conductivity values and heat transfer coefficients. The equation used is 1/U=(1/h1)+(x/k)+(1/h2) to determine the overall heat transfer coefficient U. With h1=60 W/m2K and h2=40 W/m2K, the heat flow Q is calculated to be 600 W. The conversation also explores the impact of adding a thermal barrier coating with a thermal conductivity of 0.02 W/m,K on the wall temperature and questions whether the heat transfer coefficient h1 changes with insulation.

PREREQUISITES
  • Understanding of thermal conductivity and its units (W/m,K)
  • Familiarity with heat transfer coefficients (h1 and h2)
  • Knowledge of the heat transfer equation for conduction
  • Basic skills in using Excel for iterative calculations
NEXT STEPS
  • Research methods for calculating thermal barrier coating thickness
  • Learn about the impact of insulation on heat transfer coefficients
  • Explore advanced heat transfer equations for conduction, convection, and radiation
  • Investigate software tools for thermal analysis and simulations
USEFUL FOR

Chemistry students, engineers, and anyone involved in thermal management and insulation design will benefit from this discussion.

klopjob
Messages
1
Reaction score
0
Alright, chemistry student here. No previous experience with these types of problems. Doing an interdisciplinary student project where we have to insulate a thin aluminum wall.

http://i.imgur.com/8ztNq.gif

We have a x=5mm thin aluminium wall used for dividing two air flows. T1=308 K and T2=283 K. Aluminium has a thermal conductivity of k=220 W/m,K. Assuming the wall areas are 1 m2 we can use the equation

1/U=(1/h1)+(x/k)+(1/h2)

to determine the overall heat transfer coefficient U [W/m2K].

What are some reasonable values for the heat transfer coefficients h1 and h2? If we have these values we can calculate the heat flow Q [W] through the wall. For instance, using h1=60 W/m2K and h2=40 W/m2K, we get Q=U*dT=600 W.
Now say we want to put a thermal barrier coating on the hot side of the wall so that the wall temperature, Tw1, goes up by 10 K. The coating has a very low thermal conductivity of k=0.02 W/m,K. Is there a way to estimate how thick the coating needs to be to achieve this? Is there enough info to solve this, or do we need more numbers?
Does the heat transfer coefficient h1 change when we apply an insulation layer? Any help or tips would be greatly appreciated!
 
Engineering news on Phys.org
What type of heat transfer are you doing? Conduction,convection,radiation this is going to determine the equation. I'm not sure you are using the correct equation as I do nit know what type of heat xfer it is
 
Thermal Conduction

I haven't done much with insulation, and I don't really feel like crunching numbers, but you'll either have to pick a desired delta T (or Q or whatever you want) or you'll have to do iterations until you are satisfied. Excel worksheets usually work pretty well for stuff like this.
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 7 ·
Replies
7
Views
3K
Replies
7
Views
3K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
7
Views
2K
  • · Replies 34 ·
2
Replies
34
Views
6K