The DryCool™ HD  uses a  refrigeration system similar to an air conditioner to remove   heat and and moisture from the incoming air. In addition a HoneyCombe® desiccant wheel downstream of the evaporator coil removes further moisture from the airstream in a vapor state. The HoneyCombe® desiccant wheel is operated with two separate air streams. The supply air stream is pulled from the conditioned space and in controlled amounts from outside. The reactivation air stream is generally taken entirely from outside.