Evaporative air coolers are sometimes called mini air conditioners or personal air conditioners. They are not air conditioners. Here’s an overview of how they work.
1. Water is poured into a tank (and some also have garden hose connections for constant operation).
2. The water is wicked up or absorbed by absorbent material.
3. A fan pulls air through the material which has the effect of causing heat in the air to evaporate water out of the absorbent material. As you likely know, evaporation removes heat, and that makes the air cooler. Think about water evaporating off your skin – it makes your skin cooler. The cooler air is blown out of the unit. A good evaporative air cooler can lower the temperature of the air by 8 to 20 degrees.