Three types of heat transfer

What are the three types of heat transfer ?



This short review gives the reader an overview of the three types of heat transfer, namely, conduction, convection and radiation.


Introduction to the three types of heat transfer


Heat is transferred via solid material (conduction), liquids and gases (convection), and electromagnetic waves (radiation). Heat is usually transferred in a combination of these three types and randomly occurs on its own. As a result, it is important to understand those three phenomena taken separately. For instance, the thermal environment of a building is influenced by heat fluxes through the ground (conduction), and the building envelope (mostly convection and radiation).


Convection

three types of heat transfer
Convection, heat flux through liquids and gases

The first type of heat transfer is convection. Convection is heat flux through liquids and gases. gSKIN® Heat Flux Sensors can measure convective heat flux (see picture on the left). Good examples of convective heat flux are:

  • Feeling much colder when it is windy.
  • Feeling much colder in water of 25°C than in air of 25°C.
  • Sensing principle in heat flux based mass flow sensors.

Conduction


The second type of heat transfer is conduction. Conduction is heat flux through solid materials. Interestingly, gSKIN® Heat Flux Sensors can also evaluate precisely conductive heat flux (see picture on the right hand-side). As an example of conductive heat flux, one can find:

  • Touching a hot cup of coffee
  • Thermal influences in precision instruments. Learn more
  • Measurement of heat output from chemical reactors.
three types of heat transfer
Conduction, heat transfer through solid materials

Radiation


three types of heat transfer
Radiation, heat flux through electromagnetic waves

The third and last type of heat transfer is radiation. Radiation is heat flux through electromagnetic waves. Lastly, gSKIN® Heat Flux Sensors can assess radiative heat flux. Practically, radiative heat flux can be identified in different phenomena:

  • Feeling hot when standing close to fire.
  • Measurement of solar power.


Recommended readings to go further


Tired of reading ? Discover our videos about heat transfer !

  • Convective heat fluxes: measurements with the gSKIN sensor available here.
  • Heat flux explained: Why felt and measured temperature are not the same available here.