Evaporative coolers only certainly work in naturally dry environments
I try to avoid the products you see pitched on infomercials, especially any that make wild promises.
Those copper plated fry pans are a nice example, because they’re rife with quality control complications.
Reviews online range from people loving them to others tossing them into the trash. It’s not just limited to cookware, as I’ve seen everything from UV-light PC sanitizers to towel shams with insufficient promises for absorbency. Whenever 1 of these products ends up being successful, you’ll officially see it show up on normal store shelves under a unusual brand and product name. Others never fully reach that status, especially these silly “personal air coolers” that are promising people an a/c that they can locale on their desks with no strings connected. The company says to fill it with water and watch the magic unfold, however they fail to tell you that nothing about this technology is new, novel, or special. These personal air coolers are simply tiny evaporative coolers. You put water inside, it soaked a filament material that is blasted by a small fan on 1 side. As a natural process, the air going through the wet filament will drop in temperature as it comes out the other side. As the air forces water to evaporate, the temperature of the air drops in the process. This is an amazing natural process, however it only certainly works in dry environments. If your intention is to cool a tent in the middle of the woods with 78% humidity outside, there will be too much water in the air to begin with.