Wet cooling tower systems are typically considered to be more efficient than dry cooling towers in terms of cost and energy usage, mostly because the transfer of excess heat occurs at a much faster rate when water (or a similar liquid that can absorb heat easily) is used. Dry cooling towers rely on convection, or air streams of different temperatures, to absorb extra heat from the equipment and transport it outside. The process might seem a little less convenient than what is used in evaporative cooling towers, but many businesses still benefit from these systems and therefore still use the same dry cooling processes that the first cooling towers used.
So what exactly causes people to use dry cooling towers if they generally aren’t as efficient?
One main point that factors into picking a cooling tower system is how you want your cooling tower to look — this is something that might sound overrated, especially since the aesthetic quality of industrial systems really isn’t indicative of how well the systems work. But for consumers, who usually only see the exterior of the building, the aesthetic quality of cooling towers is important. The problem with wet cooling towers is that they produce streams of air filled with water vapor, and this air looks a lot like smoke. Even though it only contains harmless water, it makes the entire building look much less appealing and it could even cause consumers to think that the business is much less environmentally conscious than it claims. For this reason, many businesses choose to go with dry cooling towers.
Additionally, businesses may also choose to use dry cooling towers for maintenance reasons. Since no water is used during the cooling and evaporation process, the system doesn’t need to be refilled with water (since some of it escapes when it evaporates). Cleaning the system is also considered to be easier with a dry cooling system because there’s no cooling liquid that needs to be filtered and diluted so that leftover particles don’t build up too much.