My parents bought this "air conditioner", but I am very skeptical that this can cool a room, or even cool anything.
I doubt that it even has a cooling element, I suspect that it is just a fan + humidifier.
But even if this device had a cooling element, it still couldn't cool a room:
If air is cooled, the resulting heat can't just vanish, it has to go somewhere, because of the 1st law of thermodynamics (energy conservation). In a normal full-sized air conditioner, the air is cooled and the resulting hot air is blown outside. But in this mini "air conditioner", the heat cant go outside, it can only stay in the room, keeping the room at the same temperature.
Am I missing something or is this a scam as I suspected?
In response to a comment: I'm interested in using this cooler in Germany, where the relative humidity is typically 70%.
Best Answer
The fan+humidifier is the cooling element for this unit. It uses purely evaporative cooling to reduce the temperature of the system. It can do this because the phase change between liquid and vapour requires energy. By just passing a convective current of relatively dry air over a liquid water reservoir, heat is taken from the air to evaporate the water. This results in the humidified air being a lower temperature than before it entered the humidifier.
In this case, the heat doesn't just vanish. The heat lost is stored in the latent heat of vaporization of the water. If the vapour in the room were to begin condensation, the heat in the room would start to increase.
Basically, you're just using the humidity as a sort of thermal battery. You're able to store some of the heat in the room in the form of increased relative humidity, instead of having it go towards increasing temperature directly. The energy doesn't leave the system; it's just taken a different form as internal energy of the phase.
You can only remove so much heat this way, and the rate of heat removal decreases as the room's relative humidity approaches 100%. If you want to use that for constant cooling, you will need some way to remove the moist air and replace it with dry air (one that doesn't involve a dehumidifier that puts heat back into the room).