Related Resources: heat transfer

### Convection Heat Transfer Coefficients Equations and Calculator

Simplified relations for natural convection heat transfer coefficients for various geometries in air at atmospheric pressure for laminar flow conditions.

Convection Heat Transfer Equation and Calculator

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 Geometry W/m2 · °C (ΔT in °C, L or D in mm) Btu/h · ft2 (ΔT in °F, L or D in ft) Vertical Plate or Cylinder hconv = 1.42 (ΔT / L)0.25 hconv = 0.29 (ΔT / L)0.25 Horizontal Cylinder hconv = 1.32 (ΔT / L)0.25 Open Horizontal Cylinder Calculator hconv = 0.27 (ΔT / L)0.25 Hot Surface Facing Up Horizontal plate (L = 4A/p, where A is surface area and p is perimeter hconv = 1.32 (ΔT / L)0.25 Open Horizontal Plate Calculator Horizontal plate (L = 4A/p, where A is surface area and p is perimeter hconv = 0.27 (ΔT / L)0.25 Open Horizontal Plate Calculator Hot Surface Facing Down Horizontal plate (L = 4A/p, where A is surface area and p is perimeter hconv = 0.59 (ΔT / L)0.25 Open Horizontal plate (L = 4A/p, where A is surface area and p is perimeter hconv = 0.12 (ΔT / L)0.25 Components on Circuit Board hconv = 2.44 (ΔT / L)0.25 hconv = 0.50 (ΔT / L)0.25 Small Components, Wires in Free Air hconv =3.53 (ΔT / L)0.25 hconv = 0.72 (ΔT / L)0.25 Sphere hconv = 1.92 (ΔT / L)0.25 hconv = 0.39 (ΔT / L)0.25