Use this engineering calculation for a transparent preliminary estimate or independent arithmetic check when geometry, materials, loads, operating conditions, and units are defined consistently.

First Kelvin Per Watt (K/W)

Required number input.

Second Kelvin Per Watt (K/W)

Required number input.

Total thermal resistance of two one-dimensional heat-flow layers connected in series at the same heat rate. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Total Kelvin Per Watt (K/W)

The resulting total kelvin per watt returned as a number.

• Heat-transfer estimates depend on geometry, contact resistances, radiation, convection regime, temperature-dependent properties, fouling, phase change, and boundary conditions. Tabulated coefficients and COP values are operating-condition specific.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check assumptions against drawings, measurements, current material data, and the applicable design code. Apply required load combinations and safety factors, then obtain qualified review and testing for consequential designs.

• Composite Wall Thermal Resistance

  Area-normalized thermal resistance of two plane solid layers in series, d1/k1+d2/k2; excludes film resistances.

• Heat Conduction Fourier

  Steady one-dimensional conductive heat-transfer rate through a plane layer from conductivity, area, thickness and temperature difference.

• Convective Heat Transfer

  Newton-law convection heat-transfer rate hAΔT with a supplied convection coefficient at the stated flow condition.