The dehumidification principle of a rotary dehumidifier is to use silicone gel coated on the rotary wheel to physically adsorb water in the air onto a porous synthetic silicone gel. Then, in the regeneration zone of the rotary wheel, the water vapor adsorbed on the silicone gel hole is heated and vaporized to the inlet of the AC heat exchanger, forming high-temperature and high humidity air. Then, when passing through the heat exchanger that has been cooled by indoor cold and humid air, condensed water is discharged due to dew point differences.