Book Description

The results are presented of a research and development effort to further develop and improve the design of a regenerated desiccant drying and dehumidification system which has more than twice the energy efficiency of conventional warm air dryers. The baseline application is for large-scale commercial grain drying, although several other applications have been identified such as space air conditioning and kiln drying of lumber. The system has excellent potential for providing a significant degree of industrial energy conservation while incurring payback periods of two to eight years to recover the added capital investment over conventional less-efficient drying methods. Although the intended energy source for the system is solar energy, the basic energy saving technique is the liquid desiccant drying process itself such that virtually any thermal energy input can be used. The use of solar energy permits further energy conservation if the additional capital investment is justified. The major goal of the present study has been to improve the cost effectiveness of the desiccant regeneration system and establish significant design improvements over the regenerated desiccant drying concept developed in previous study phases. This goal has been achieved through the use of a straightforward evaporative technique for regenerating (reconcentrating) the lithium chloride desiccant solution, in place of using the previous packed column technique, and by using a steam condenser for heat recovery. The use of this technique resulted in a system cost reduction of nearly one-third and an efficiency improvement of approximately 10%, as well as a reduction in system size and complexity.