To determine the optimal and maximum air flow through an adsorber, some influencing factors play an important role. These include essentially the physical properties of the desiccant, the geometry of an adsorber and the ambient conditions, such as temperature and humidity.
In order to determine the ability of a ventilation dryer and to quantify the efficiency, the adsorber index can be used. This is determined by the mentioned influencing factors. An optimum adsorber index of 1.0 (100%) is achieved with a long loading time and low residual humidity. In bad conditions, ie at low loading time and a high residual moisture, the adsorber index is low and reaches a limit.
In practice, an adsorber index of 0.7 has been found to be optimal. With this value, a maintenance interval of approx. 1 year is aimed for (depending on the application cycles) as well as a residual air humidity after drying of an average of 10% RH and a dew point of approx. -12.5°C.