This type of heat transfer is called convection, and since it relies on fluid flow it is closely related to fluid dynamics . Finally heat can be radiated by thermal radiation. Standing in sunlight one can feel the sun's warmth even though the sun is millions of miles away and separated from us by a vacuum. There is no air or water in space to carry the heat to the earth, but the sun's thermal radiation reaches us nonetheless. This is an example of radiative heat transfer.
Heat transfer has a huge number of applications.
In addition to these applications it happens that the equations that govern heat transfer are the same as those that govern mass transfer. These two fields are often studied together under the general heading of transport phenomena. Problems involving the transport of chemical species and other particles include the study of pollutant movement through the ground and water and the cleaning up of those pollutants, design of smokestack scrubbers, design of chemical reactors and transport of gases and nutrients in the ocean and in animals, humans and fish.