A model is developed which describes the heat transfer profess between the rotating wall of a desorber and an adjacent bed of wet, granular solids. A heat-balance integral method is used. This solution includes the effects of water evaporation near the wall and a thermal contact resistance between the wall and the first layer of particles. The model allows for water evaporation before the bulk bed temperature reaches the saturation temperature of the water. Experimentally measured evaporation rates compare favorably to those predicted by the model. In particular, the water evaporation that occurs before the bulk bed temperature reaches the water saturation temperature is predicted.