Definitions in air humidification
| Terms | Definition |
| Isothermal humidification | Humidification with hot water vapour (almost no change in air temperature) |
| Adiabatic humidification | Humidification by cold water evaporation (causes air temperature reduction) |
| Aerosols | In adiabatic humidification, water is atomised into micro-fine drops in the order of magnitude between 0.1 µm and 10 µm, so-called aerosols, by various mechanical processes. |
| Enthalpy control | In adiabatic humidification with enthalpy control, the thermal energy required for evaporation is completely controlled by preheating before humidification, depending on the supply air humidity, and the desired target air condition is achieved with the humidifier. This control method enables particularly efficient operation of the humidification system. |
| Absolute humidity | Absolute humidity indicates the actual content of water in the air, usually in g/kg, i.e. grams (water vapour) per kilogram (dry air). |
| Relative humidity (RH) | Degree of saturation of the air with moisture, i.e. describes the ratio of the amount of moisture currently present in the air to the maximum amount of moisture that can be absorbed by the air. The amount of moisture that can be absorbed by the air depends decisively on the air temperature. The warmer the air, the more moisture it can absorb (exponential increase). |