Comments on How is this air conditioner possible?
Parent
How is this air conditioner possible?
Lately I've been seeing ads for a portable air conditioner that only needs to be plugged in, with no venting or other connection outside the room it is supposed to cool. That makes no sense. You can't just poof away heat, only move it elsewhere. Real air conditioners use electrical power to push heat from in the room to outside, which is why they are vented outside. However, a stand-alone unit has no place to push the heat that isn't right back into the room it is trying to cool.
Here is a picture from an ad showing the device just sitting on a desk:
Here is a snippet from the same ad that supposedly "explains" how it works:
It pulls surrounding warm air into the unit, moves it thru a precision-engineered internal cooling chamber, and delivers a concentrated stream of cold air directly into the room. No refrigerant. No compressor. No window kit. No tools. You plug it in, press a button, and the room drops 30 degrees in under two minutes.
This seems like a blatant fraud. But I've been seeing these ads for several months on web sites of major corporations. I would have thought such a fraud would have gotten the attention of authorities by now and been shut down, or by the site owners to protect their reputation.
What's going on here? Is there some physics I'm missing that makes this possible?
Post
Relax, the laws of thermodynamics still hold.
The device may well cool you down if you provide some sweat for it to evaporate. I'm sitting (and sweating) in front of a fan as I type this and it's cooling me very nicely ...and heating the room at the same time of course.
I was curious. and found the pictured device on Mr. B's A.com site.
The "room drops 30 degrees in under two minutes" claim is absurd. Consider the power needed to raise room temperature 30 degrees in 2 minutes. Now try to get those kW from the device's 2000mAh battery that "lasts 24 hours". A few mWminutes to lose 30 degrees? Server-farms world-wide would be hammering at the manufacturer's front door if it were true!
Is it an "air conditioner"? I suppose adding momentum to some air molecules is arguably a change of condition, but that expression is conventionally used to describe a heat-pump that transfers heat from/to inside to/from outside. This device doesn't!
It's a fan!
Mr. B's site says it weighs over 300kg. Whaaaat? Portable?? Desktop???
There are variants that exploit phase-change i.e. the device provides the sweat and pushes the cooler air resulting from the latent-heat capture. Misting systems depend on this ...and they work. I'm tempted to add one to my patio as our summers get really hot these days.
This device ...they don't make bargepoles long enough to tempt me to touch it.
1 comment thread