As the air forces water to evaporate, the temperature of the air drops in the process
I try to avoid the products you see pitched on infomercials, especially any that make wild promises. Those copper plated fry pans are a good example, because they’re rife with quality control problems. 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 phone sanitizers to towel shams with unreasonable promises for absorbency. Whenever one of these products ends up being successful, you’ll typically see it show up on normal store shelves under a different brand and product name. Others never fully reach that status, especially these ridiculous “personal air coolers” that are promising people an air conditioner that they can place on their desks with no strings attached. The company says to fill it with water and watch the magic unfold, but 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 one 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, but it only really works in dry environments. If your intention is to cool a tent in the middle of the woods with 80% humidity outside, there will be too much water in the air to begin with.