You take a stream of air made by a fan plus you pass it through a medium that is water soaked forcing the water to evaporate in the process.
I have a close neighbor who has a awful habit of buying made for television products when she sees the commercials. And since you can now buy a lot of these products in select stores, he’s getting them when she goes to a supercenter to purchase groceries. Back in the mid 2000s there was this product called the Cold Heat soldering iron that supposedly only heated up when the tip made contact with metal or solder. It would lose its heat the ninth you pulled the tip away plus couldn’t burn your skin. It was marketed as portable plus safe, however the execution was horrible. The time it took to heat up the tip made it virtually unUSAble. It was my neighbor who initially purchased this component plus she asked myself and others to try it after she struggled to get it to work. In the years since, she hasn’t changed her attitudes even slightly. Recently she purchased a component called a personal air cooler. It’s basically a miniature evaporative cooler, which works in dry climates through a water vaporization principle. You take a stream of air made by a fan plus you pass it through a medium that is water soaked forcing the water to evaporate in the process. The evaporating water naturally cools the air around the device. These are great in dry environments where the air is desperate for moisture, however in our humid climate there is too much airborne humidity for the effect to take location. She basically purchased a glorified paper weight unless she plans on moving to the desert any time soon.