2. Radiation drying

2.1 Different types of radiant energy supply

The various sources of electromagnetic radiation that can be used to heat the product and provide it with the energy to vaporize the water required for drying are discussed below. It should be added that convective exchanges with the air around the product in the dryer (depending on its temperature, speed and rate of renewal) and the presence (or absence) of a closed enclosure around the product and/or the rate of air renewal in the enclosure are all part of the drying problem, but are too often neglected.