Operation of displacement ventilation (DV) and evaporative cooled ceiling (ECC) system is modeled.

The DV/ECC model was validated experimentally at different supply conditions and fixed load.

Desiccant dehumidification was added to DV/ECC system for operation in humid climate.

DV/ECC performance is optimized using genetic algorithm for minimum energy cost.

DV/ECC operation at optimal conditions reduced cost by 28% compared to DV/chilled ceiling system.