System and method for improving the performance of desiccant dehumidification equipment for low-humidity applications

Dehumidifier apparatus of the solid desiccant type comprising a desiccant wheel (1) and wheel drive, a housing with internal baffles and air seals proximate to the wheel face to create plenums or sectors and prevent air from leaking between adjacent sectors, to create three paths for air to pass through the wheel;

• the sectors being sequentially a reactivation sector (3) to dry the desiccant to a low equilibrium relative humidity, a process sector (2) receiving all its inlet air from the outside air sector (33), and an outside air sector (33) to dehumidify another airstream (34), to provide pre-dehumidified air for the process sector (2) and all the supply air (36) needed for the reactivation sector (3).

Dehumidifier apparatus of the solid desiccant type having a desiccant wheel (1) and wheel drive, a housing with internal baffles and air seals proximate to the wheel face to create plenums or sectors and prevent air from leaking between adjacent sectors, to create four paths for air to pass through the wheel (1);

• the sectors being sequentially two reactivation sectors (3, 40) to dry the desiccant to a low equilibrium relative humidity, second and first process sectors (2, 44) to dry an independent air and/or gas stream which is sequentially passed through the two process sectors in opposite directions and may be recirculated from a space or process, ambient air, or a mixture of the two, and an outside air sector (33) to dehumidify another airstream (34) to provide all the air for the reactivation sectors (3, 40), the two reactivation sectors (3, 40) being disposed sequentially before the second process air sector (2), permitting different air sources and different heat sources to be used for the two sectors, the supply air (20) for the first reactivation sector (3) being ambient air which may be precooled to reduce the moisture content before being heated, and the supply air (42) for the second reactivation sector (40) being discharge air from the outside air preconditioning sector (33) and/or the purge sector (17), and a heating means (41) adding no moisture to the air.

A method for the dehumidification of air, said method comprising forming three air paths in a dehumidification apparatus, drying a desiccant wheel provided in said apparatus in a reactivation sector (3) to a low equilibrium relative humidity, drying return air from a process sector (2) and makeup air from an outside air sector (33), drying another airstream (34) in the outside air sector (33) to provide makeup air for the process sector (2) and all the air for the reactivation sector (3).

A method for the dehumidification of air in a dehumidifier apparatus of the solid desiccant type comprising a desiccant wheel (1) and wheel drive, a housing with internal baffles and air seals proximate to the wheel face to create plenums or sectors and prevent air from leaking between adjacent sectors, the method comprising forming three paths for air to pass through the wheel;

• drying the desiccant to a low equilibrium humidity in a reactivation sector (3), a process sector (2) receiving all its inlet air from an outside air sector (33), dehumidifying another airstream (34) in the outside air sector (33), to provide pre-dehumidified air for the process sector (2) and all the supply air needed for the reactivation sector (3).