In many engineering applications, either the suppression or the enhancement of dehumidification is desired. If so, the dehydration in air-conditioned space can be solved, less condensation water pollution can be achieved, or the dehumidification process can be more efficient. In this study, the effects of various surface treatments were explored to enhance or suppress the condensation. It was found that optical observation to the appearance of water droplets was the best solution. A USB microscope is able to discover a droplet as small as 13 um in diameter. When the first droplet was found, the corresponding surface temperature was considered as the dew-point temperature in the circumstance. A cold-plate platform, which is cooled by cool water from a refrigeration circulator, was designed and established. The surface temperature can be regulated by settings of the refrigeration circulator. Tests of step-wise temperature drops were performed. The original surface was made of aluminum alloy Al-5083. Spin-coated, blasted, anodized, Teflon-coated, and polymer-coated surfaces were prepared on the same substrates. The results show that the polymer-coated surface exhibited an effective dew-point of 2.95°C higher than the original surface. On the other hand, the Teflon-coated surface exhibited an effective dew-point of 1.025°C lower than the original surface. In this study, a platform and methodology were established and further surface treatments can be explored in the future.
Key words: Dehumidification, condensation, surface treatment, blasted, wettability