Differences between wet air cooling and conventional air cooling
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Many new construction projects these days are switching from conventional air cooling to wet air cooling. Does anyone have experience using wet air cooling? What are the advantages compared to conventional air cooling?
By wet air cooling, does the poster mean the type with water spraying or the type that atomizes water into mist?
It’s the type where water is sprayed directly onto the air-cooling fins.
This type of water-cooled air cooler has high requirements regarding water quality; it needs softened water such as deionized water. The water consumption is not high, and compared to dry air cooling, the heat exchange area can be significantly reduced. However, the operating costs (for water and electricity) are higher. Still, extra care is needed to prevent freezing and condensation during winters in the north. You can specifically consult professional air cooler manufacturers such as GEA, Haikongding, and the like.
For newly installed units, wet air cooling can be considered. If an existing unit has insufficient air cooling capacity and needs to be upgraded, water atomization facilities can be added to the dry air cooling system; the water droplets are then sprayed onto the surface of the air cooling fins. This approach might be necessary in summer but not in other seasons, resulting in lower costs.
The difference between wet air cooling and dry air cooling lies in the spraying of misty water onto the finned tubes of the air cooler; the evaporation of water on these finned tubes enhances heat transfer, thereby reducing the outlet temperature of the oil, which in turn helps to minimize further cooling needs
The limit temperature drop for wet air cooling is the wet-bulb temperature of the air, while ordinary air cooling relies on the dry-bulb temperature of the air； Wet cooling utilizes the latent heat of vaporization of water, while conventional air cooling makes use of the sensible heat of air ； Wet air cooling consumes more water compared to conventional air cooling, but it has a higher heat transfer efficiency, especially in summer ； Wet air cooling requires less space and has a smaller heat exchange area compared to conventional air cooling ； Wet air-cooled systems have high water consumption but low electricity consumption
The principle is similar to that of closed-loop water systems; if softened water is used for spraying, the amount of evaporation remains high. It is necessary to reduce the temperature from over 100 degrees to around 70 degrees, and a considerable amount of heat needs to be removed – the latent heat of water must be eliminated through evaporation.