Abstract: A humidity controller (12) for an outdoor storage container (10) is installed with a clearance fit in an apertured portion of a vertical wall (11) of the container (10). The humidity controller (12) comprises a frame assembly (13) to which a bed of solid desiccant material (14) and a transparent cover (15) are secured. Solar energy incident upon the transparent cover (15) is transmitted into a passageway between the bed of desiccant material (14) and the transparent cover (15), thereby heating air in the passageway and also heating a surface of the bed of desiccant material (14) exposed to the air in the passageway. Moisture adsorbed on bed of desiccant material (14) is vaporized by the solar energy, thereby establishing a concentration gradient for moisture in the bed of desiccant material (14) such that moisture is drawn toward the passageway for vaporization.

Abstract: This invention relates to the use of desiccants in conjunction with an open oop drying cycle and a closed loop drying cycle to reclaim the energy expended in vaporizing moisture in harvested crops. In the closed loop cycle, the drying air is brought into contact with a desiccant after it exits the crop drying bin. Water vapor in the moist air is absorbed by the desiccant, thus reducing the relative humidity of the air. The air is then heated by the used desiccant and returned to the crop bin. During the open loop drying cycle the used desiccant is heated (either fossil or solar energy heat sources may be used) and regenerated at high temperature, driving water vapor from the desiccant. This water vapor is condensed and used to preheat the dilute (wet) desiccant before heat is added from the external source (fossil or solar). The latent heat of vaporization of the moisture removed from the desiccant is reclaimed in this manner.