Anyone looked into these magic room AC units that only use water?

[BronYrAur]

I keep seeing ads for room air conditioners that only require you to fill them with water, and just like magic, "freezing" air comes out. They make wild claims that they save 300% on your energy bill, etc. What are these things, just evaporative coolers? Certainly that aren't absorbers. Something tells me that the air coming out is not "freezing". Just curious if anyone has looked into them.

 

[PEDARRIN2]

I think they are (or used to be) called swamp coolers. They cool by the latent heat of evaporation which would cool, but I don't think freeze. They would add humidity so may have limited impact on the overall feeling of coolness.

 

[IRstuff]

Since you are adding water, it has to be evaporative. You save money because you don't have any electromechanical refrigeration. But, it's nowhere near freezing and if the humidity is high to start with, it's not going to do much at all.

https://www.ebay.com/itm/333998853624?epid=1600858659&hash=item4dc3e20df8:g:ZdwAAOSwL75gm-iN

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[BronYrAur]

The claim on some of these advertisements literally uses the word "freezing" to describe the temperature of the air coming out. Others say "ice cold." That's why it peaked my interest but also makes me suspicious. All you do is add water and you get magic free air conditioning

 

[3DDave]

A misleading advertisement? Shocking!

Also, it's spelled "piqued."

 

[EnergyProfessional]

If it is magic, it must be real! Why would we doubt a device that violates a whole thermodynamics text book?

Sounds like a swamp cooler and in dry climates it works. But you can as well spill out a bucket of water in your home for the same effect at lower cost.

In non-arid climates, yikes, have fun sweating even more! On the upside, you can eat the mold if you ever get hungry.

 

[Compositepro]

Yes, those are swamp coolers, and they only work well in low humidity climates. Even then, good outside air ventilation is required to remove the humidity from the room. They will not work in a closed room because the relative humidity will quickly reach 100%. In dry desert environments swamp coolers work very well. It is possible to freeze water through evaporation alone.

 

[LittleInch]

If you read closely they claim this because you can store some parts of it in a freezer hence you're just blowing air over an ice block...

You can get some which have an external evaporative system which cools water and keeps the humidity outside but you need s lot of water and space normally.

A cooling tower is basically an evaporative cooler.

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Also: If you get a response it's polite to respond to it.

 

[MedicineEng]

Ohhh... The fun that I had once in a HVAC exhibition with a seller that was trying to fleece me that solution as a "low cost air con" system...

In a place with a semi-tropical weather pattern where 9 to 10 months of the year temperatures range between 25-31C and RH 80-100%...

After trying to bend the laws of physics to his wishful thinking and do some hypnosis on me, he gave in when I started asking him about mold and Legionella...

It were a funny 15 minutes or so. At least for me.

 

[Artisi]

As MedicineEng pointed out, completely useless in other than low RH and increasing to completely useless as RH increases.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[FacEngrPE]

There is a relative of the swamp cooler that is somewhat useful OUTDOORS in moderately humid environments.

These also work OK taking the edge off of a hot shop, as long as they are set in the doorway, and do not recirculate any shop air.

I agree with the opinion above that swamp coolers are often sold to the unwary, to be used situations that they are ill suited for.

 

[LittleInch]

The only ones that ever seems to make sense to me are indirect coolers. E.g.

https://www.condair.co.uk/knowledge-hub/direct-and-indirect-evaporative-cooling-strategies

https://www.drenergysaver.com/cooling-systems/evaporative-cooling/indirect-evaporative-cooling.html

But they are still very dependant in RH. I think anything more than 70% their performed really suffers.

Internal ones are just a joke or at the least need an equal amount of air being exhausted as going through the cooler.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.