Abstract: An improved dehumidification system for automotive use includes a rotating, wheel like heat exchanger with axially open cells that carry a water adsorbing material. Opposed ambient air and heated air flows, covering opposite halves of the wheel, continually adsorb water on one side and are recharged on the other side. Alternating radially closed cells between the axially open cells carry no desiccant material, but receive a cross cooling flow, on the water adsorbing side of the wheel only, to remove the heat released during the water adsorption process. The desiccant recharging process on the other side of the wheel is not disturbed by the cross cooling flow.