The invention relates to a method for operating a compressed-air supply
system (1), which supplies
compressed air to connected compressed-air consumers (16, 18; 20) via at least one compressed-
air line (24), wherein the compressed-air supply
system has at least one compressor (2), an
air dryer (5) and a switchover valve (12), the
air dryer (5) having a granular adsorption
desiccant (10), the switchover valve being actuable by means of an electronic control device (14), in a first switching position (A) of the switchover valve (12) moist
compressed air generated by the compressor being passed over the grains of the adsorption
desiccant in a
drying phase, as a result of which the adsorption
desiccant absorbs
atmospheric moisture from the moist
compressed air, and in a second switching position (B) of the switchover valve (12) dry compressed air taken from the compressed-air supply
system being passed over the grains of the adsorption desiccant in a regeneration phase, as a result of which the adsorption desiccant releases
moisture to the dry compressed air, which is then subsequently discharged to the surrounding area (28). According to the invention, a
water load value indicating the current
water load of the adsorption desiccant is ascertained in the control device, the
water load value is determined by means of at least two numerical values, and the switchover valve (12) is controlled with respect to the start and the duration of the
drying phase and / or the regeneration phase depending on the water load value.