This paper summarizes the investigation of an active desiccant, total energy recovery hybrid system pilot site installed during the fall of 1999. The hybrid system was assembled from a combination of commercially available airhandling modules, a standard total energy recovery module, and a customized active desiccant wheel cassette designed to integrate with these standard components. Significant performance advantages were recognized as a result of the combination of both “passive” and “active” desiccant technologies.

The dehumidification capacity of the hybrid system was shown to be very high, the cost of operation very low, and the overall system cost-effective. After two years of operation, the system has performed reliably and as anticipated. Most importantly, the system resolved numerous IAQ problems plaguing the dormitory facility by providing effective humidity control and increased, continuous ventilation air in accordance with ASHRAE Standard 62 recommendations.

The system was equipped with a direct digital control system, including full instrumentation, data trending, and remote monitoring capabilities. A detailed description of the system, installation details, samples of actual performance data, and documented energy savings are presented. The performance of the hybrid approach is compared with that of the original conventional cooling system serving an identical, opposite wing of the same facility.

Units: I-P