# How do you calculate the radiative heat transfer coefficient?

May 22, 2016

h_(rad) = εσ(T_1^2 + T_2^2)(T_1 + T_2)

#### Explanation:

The Stefan-Boltzman law relates the total amount of radiation emitted by an object to its temperature:
ε=σT4
where:
ε = total amount of radiation emitted by an object per square meter (Watts ${m}^{- 2}$) (emissivity)
σ is a constant called the Stefan-Boltzman constant
= 5.67 x 10-8 (Watts ${m}^{- 2}$)${K}^{- 4}$
T is the temperature of the object in K.

Radiative heat transfer is a comparison of an actual materials emissivity to a “black body”.

Radiative exchange between two gray, diffuse surfaces may be characterized by calculating the radiative heat transfer coefficient as shown below:
h_(rad) = εσ(T_1^2 + T_2^2)(T_1 + T_2)