Cooling towers are widely used not only for commercial and industrial purposes but also for cooling power plant. In Korea, coal-fired power plants and nuclear power plants are generally located on the coast, while most combined-power plants are located inland and use cooling towers to condense steam. The operation rate of power plants in Korea highly depends on government energy policies. In the future, it is expected that the need for cooling tower water for inland power plant will increase. Since power plant is one of the massive water-consuming facilities, methods for water saving of cooling tower should be prepared. Also, in the industrial sector, plume is constantly raising social conflicts between residents and manufactures. Basically, similar technologies can be applied to water saving and plume abatement. In this study, the performance of the condensing module (outdoor-air-condensing method) using outside air was tested first. This module has an advantage in that cooling heat source is not necessary. But an excessive increase of fan air volume is required. We tested a membrane-dehumidification method that selectively transfers water vapor by applying a membrane module. The results showed that membrane module required a large amount of energy to generate vapor pressure difference and it had a disadvantage in energy usage. Since the membrane method considered requires a high bypass airflow for higher dehumidification, it also has a disadvantage similar to that of the outdoor air module. Finally, the dehumidification/regeneration module (heat-pump method) gave the best performance in terms of water saving and plume abatement.