Extruded Finned Heat Sink Radiation Formulae
Use the following equation to calculate the radiation from an extruded (finned) heat sink.
Q = Radiation
Nf = Number of fins heat sink has
Ts = Surface temperature of the heat sink
TA = Ambient Temperature
= Apparent Emissitivity
( Apparent Emissitivity) is derived from the heat sink area and surface emittance.
Graph of apparent emissivity of 0.08
Graph of apparent emissivity of 0.8
References: "Thermal Radiation from Finned Heat Sinks"
Samuel Rea, S.E. West