Prove me wrong, please?
edit: thanks for all the great comments, this is really helpful. My main take-away is that it does work, but requires dry air. In humid conditions it doesn’t really do anything.
Spouse bought this thing that claims to cool the air by blowing across some moist pads. It’s about as large as a toaster, and it has a small water tank on the side. The water drips onto the bottom of the device, where it is soaked up by a sort of filter. A fan blows air through the filter.
- Spouse insists that the AIR gets cooled by evaporation.
- I say the FILTER gets cooled by evaporation.
- Spouse says the cooled filter then cools the air, so it works.
- I say the evaporation pulls heat (and water) from the filter, so the output is actually air that is both warmer and wetter than the input air. That’s not A/C, that’s a sauna. (Let’s ignore the microscopic amount of heat generated by the cheap Chinese fan.)
By my reckoning, the only way to cool a ROOM is to transport the heat outside. This does not do that.
We can cool OURSELVES by letting a regular fan blow on us = WE are the moist filter, and the evaporation of our sweat cools us. One could argue that the slightly more humid air from this device has a better heat transfer capacity than drier air, but still, it is easier to sweat away heat in dry air than in humid air.
Am I crazy? I welcome your judgment!
That is not an air conditioner. An air conditioner needs a compressor, evaporator and condenser, this has none of them. What you have is a desktop evaporative cooler. Your theory of how it works is correct, the energy to evaporate the water is pulled from the air, that cools the air. But yes, the heat and moist air still stays in the room. Note, this only works in places with DRY air. If you are in a tropical location with humidity, this will not work because the air is already close to saturation with water.
There are large rooftop versions of this called swamp coolers, installed in places that have short hot dry summers, they work because the heat is still transported outside the building.
I’m renting a house with a swamp cooler. I’m sure they can be nice, but the effectiveness of mine ranges from “barely” to “not at all.”