Drying removes water and other liquids from gases, liquids, and solids. The term is most commonly used, however, to describe removing water or solvent from solids by thermal means. Dehumidification refers to the drying of a gas, usually by condensation or by absorption with a drying agent (see Chapter 32 of the 2021 ASHRAE Handbook—Fundamentals). Distillation, particularly fractional distillation, is used to dry liquids. It is cost effective to separate as much water as possible from a solid using mechanical methods before drying using thermal methods. Mechanical methods such as filtration, screening, pressing, centrifuging, or settling require less power and less capital outlay per unit mass of water removed. This chapter describes industrial drying systems and their advantages, disadvantages, relative energy consumption, and applications. Mechanism of Drying Applying Hygrometry to Drying Determining Drying Time Drying System Selection Types of Drying Systems