What primarily involves heat transfer by convection?

The heat transfer by convection is combined with the actions of heat conduction, energy storage and transfer of energy by mixing motion of fluid particles.

heating of solid from a liquid source

Explanation:

Convection heat transfer is the process of heat transfer in which a fluid is heated by a heat source that causes the fluid to rise up due to a change in its density. The convection current ensures that warmer and less dense fluid always rises up. The convection heat transfer may also occur in solids that are in contact with liquids.