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THE FEUTEX TOOLKIT

Composite Wall Heat Flow

Combine two solid layers and surface convection into total heat transfer.

Thermal workspace● Runs in your browser
01 Your input
02 Your result
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FormulaR″=1/hi+L₁/k₁+L₂/k₂+1/ho; Q=AΔT/R″.
Sources and model references

Worked example

Inputs

Layer 1 thickness
0.1 m
Layer 1 conductivity
1 W/(m·K)
Layer 2 thickness
0.05 m
Layer 2 conductivity
0.05 W/(m·K)
Inside film coefficient
10 W/(m²·K)
Outside film coefficient
20 W/(m²·K)
Wall area
10 m²
Inside minus outside temperature
20 K

Expected results

Area-normalized resistance
1.25 m²·K/W
Overall U value
0.8 W/(m²·K)
Signed heat flow
160 W

Load the example in the workspace to reproduce these results. Display rounding does not change the underlying calculation.

How to use this tool

  1. Enter every input in the labeled units; use measured or independently specified properties.
  2. Check the stated model assumptions before calculating.
  3. Interpret the output as a model estimate and verify it independently for the intended application.

Try this example

{
  "l1": 0.1,
  "k1": 1,
  "l2": 0.05,
  "k2": 0.05,
  "hi": 10,
  "ho": 20,
  "area": 10,
  "delta": 20
}

Accuracy and scope

One-dimensional steady conduction, constant properties, no thermal bridges or moisture effects. Educational engineering estimate only; not structural or safety certification, equipment selection, or operating recommendations.

Is my data uploaded?

This tool runs locally in your browser. Input and output are not sent to a processing server. Copy or download your result before leaving the page.