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Steady 1D slab

Plane-wall conduction

Inputs

User-entered conductivity at the stated material and temperature condition.
Area normal to the assumed one-dimensional heat flow.
Uniform thickness through the plane wall.
Surface temperature at the named hot-side boundary.
Surface temperature at the opposite named boundary.

Results

Conductive heat rate hot → cold

1,000

Plane-wall thermal resistanceRth

0.06

K/W
Heat flux hot → cold

400

W/m²
Q̇ = kA(Th − Tc)/L; Rth = L/(kA)

A first-pass number, not a code check, certification, or approval. Read the method and its limits below. What this is and is not.

Nearby: Sensible heat · Heat-exchanger ΔTlm · Thermal radiation exchange · Convection heat rate

Method

Formula, when it applies, and when it does not

Calculate conductive heat rate and thermal resistance across a uniform plane wall from conductivity, geometry, and surface temperatures.

Q̇ = kA(Th − Tc)/L; Rth = L/(kA)

When

  • Steady one-dimensional conduction
  • Uniform plane wall
  • No contact resistance

Don’t

  • This is steady, one-dimensional plane-wall conduction using one user-entered conductivity. It excludes contact resistance, convection, radiation, thermal bridges, multilayer interfaces, temperature-dependent properties, phase change, transient response, and insulation selection.
OpenStax conduction reference