Frictionless Calc

Multi-Layer Heat Transfer Calculator

Build a one-dimensional thermal resistance stack with as many solid layers, convection films, and contact resistances as you need.

1. Choose what to solve for

Positive heat flux is defined from Side A → Side B. When solving for a temperature or layer property, enter a signed heat-transfer value consistent with that direction.

2. Boundary conditions

How the model works

This calculator assumes steady-state, one-dimensional heat flow through elements in series. Each element contributes an area-normalized thermal resistance:

Solid conduction: R'' = L / k
Convection film: R'' = 1 / h
Contact resistance: R'' = R''contact

q'' = (TA − TB) / ΣR''
Q = q'' A

For a flowing fluid, velocity alone is not enough to determine h. The convection coefficient depends on geometry, flow regime, fluid properties, and the applicable Nusselt correlation. Enter h directly, or calculate it from a known Nusselt number using h = Nu·k/Lc.

3. Thermal resistance stack

Elements are evaluated from Side A to Side B in the order shown.

Results

Total R''
—
Overall U
—
Heat flux q''
—
Heat rate Q
—
Side A temperature
—
Side B temperature
—

Layer-by-layer temperatures

LocationElementR''TemperatureΔT across element
Calculate to populate the temperature profile.

Assumptions and limits

  • Steady-state, one-dimensional heat transfer with every element in series and the same heat-transfer area.
  • Material properties and convection coefficients are treated as constant at the values entered.
  • Radiation is not modeled separately. If appropriate, it can be incorporated only through a justified effective heat-transfer coefficient.
  • A flowing fluid layer is represented as a boundary-film resistance. This calculator does not model the fluid bulk temperature changing along its flow direction.
  • Velocity is optional information only. It is not used unless you independently obtain a Nusselt number or convection coefficient appropriate to your geometry and flow.
  • Transient storage, phase change, internal heat generation, multidimensional effects, fins, and parallel heat paths are outside this model.