Written by Jerry Ratzlaff on . Posted in Thermodynamics

Heat radiation ( $$Q$$ or $$\phi$$ (Greek symbol phi) ) (one of three ways to heat transfer: conduction, convection and radiation) is the flow of energy through electromagnetic waves such as infrared, light, microwaves, etc.

### Heat Radiation formula

$$Q = \epsilon \sigma A \Delta T^4$$

$$Q = e \sigma A \left( T_o \;-\; T_e \right)^4$$

Where:

$$Q$$ = heat radiation

$$\epsilon$$ (Greek symbol epsilon) = the emissivity of the particular body and is a number between 0 and 1

$$\sigma$$ (Greek symbol sigma) = Stefan-Boltzmann constant

$$A$$ = cross sectional area

$$\Delta T$$ = temperature differential

$$T_o$$ = absolute temperature of the object emitting

$$T_e$$ = absolute temperature of the environment

Tags: Equations for Heat