Recently, many studies on dehumidifiers of lower flow rate of liquid desiccant which adopt plate type heat exchanger with internal cooling have been in progress. If lower flow rate of liquid desiccant maintains thin liquid film on the heat exchanger surface, heat and mass transfer performance would improve, stability of the liquid film increases, and entrainment of desiccant droplets does not occur. In this study, wettability of liquid desiccant along the vertical surface of a plate type heat exchanger has been investigated. Liquid desiccant was supplied on the top of plate heat exchangers which have different groove gaps. Through visualization test, it is found that plate heat exchanger of 1.0 mm groove gap shows the largest wettability. As mass flow rate of supplied liquid desiccant increases, the wettability of liquid desiccant becomes enhanced. An experimental apparatus was built up to measure regeneration performance of liquid desiccant. Regeneration performance test was carried out for various type of plate type heat exchanger. The wettability of liquid desiccant enhances and film thickness gets decreased by the grooved surface treatment. Thus, it is found that moisture discharge rate and mass transfer coefficient of liquid desiccant can be enhanced.
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