The direct application of an evaporative cooling system is impractical in Taiwan due to local hot and humid weather conditions. In this study, a hybrid cooling system utilizing an evaporative cooler coupled with a chemical dehumidifier is investigated. The solid desiccant, or silica gel, which could be regenerated by solar energy, dehumidifies the incoming air while the evaporative cooler effectively cools it down to the indoor comfort condition. An optimal design approach including a sensitivity study was performed during the computer simulation process. A systematic result was obtained providing design information, such as the desiccant consumption rate and solar collector area needed for indoor comfort air‐conditioning.