Infrared radiation is the transfer of energy from one object to another by infrared electromagnetic radiation.
Radiation heat transfer is totally different from conduction and convection in several ways:
1) Conduction and convection involve the transfer of thermal energy by direct contact between particles requiring the presence of matter
2) Radiation transfers thermal energy by electromagnetic energy and does not require any matter between the radiating source and the receiving object
3) Radiation will occur by electromagnetic emission and absorption
4) Conduction and convection is linearly proportional to the temperature difference between two materials. Energy from the surface of an object is proportional to the fourth power of its temperature
This is the way the sun warms up the earth, since the sun's temperature (6,000K) is much higher that earth's, the radiation flows from the sun to the earth, and is absorbed by the earth warming up the surface. It is relevant to virtually every industrial process on the globe.