Originally published at: https://boingboing.net/2020/06/13/these-evapolar-air-conditioner.html
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Breakthroughs in swamp cooler technology!
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When I was a little kid, we had a beast of a water cooler. We had to stop using it because it was constantly making me sick and triggering my severe asthma. So until we moved to Dallas we just learned to tolerate Tulsa summers. Of course, we generally had not only fans but attic fans which are awesome, if noisy.
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Massive BS. No user of a swamp cooler will get a 59 degree Fahrenheit reduction. You can never get a temperature reduction more than the wet bulb depression, and that depends on humidity.
Even in, say, 2 percent relative humidity, you’d get, at most, a 35 degree temperature reduction from 110 degrees to 75, assuming a 100% efficient evaporative cooling system, which this desktop model certainly is not. And you have to keep changing the air to maintain that reduction because the inside air becomes humidified and can’t be recirculated and recooled they way a regular conditioner can.
The problem is the bad math skills at Evapolar, who have miscalculated the difference between 1 degree of change in °C vs. 1 degree of change in °F:
The maximum drop in temperature is 59°F (15°C).
If you are looking to calculate the equivalent temperature that is correct: (15 °C × 9/5) + 32 = 59 °F. But that’s not the equivalent temperature difference, which is calculated: ΔT(°F) = 1.8 ΔT(°C)*, or 27°F in this case, not 59 °F.
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Of course. An “error” that more than doubles the effectiveness of their product. Well, it could be an honest mistake, as per Hanlon’s razor.
Seriously, though, good job finding where their math went wrong. Although a claimed reduction of up to 59F should already raise some red flags. What if it’s only 80F when you turn this thing on–will you have to make sure you don’t get frostbite?
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To produce cooler air, the heat energy must be removed from a relatively sealed space. With no way to remove the heat from the room, like a window air conditioner would, I fail to see how this unit would change the overall heat level in a room significantly enough to be effective.
Any cooling system I have seen, from refrigerators to cpu coolers, pump heat energy away from the area to be cooled, but that heat has to go somewhere. For a fridge, it is into the room the fridge is occupying. For this on-desk unit, it seems to be into the same room it is trying to cool.
It’s sweeping the heat under the rug by tying it up changing water from liquid to vapor. It does produce cooler air, but with more humidity. Eventually the cooler can’t evaporate water into the already m0ist air, more heat leaks in from outside, and your own sweat is no longer cooling your body.
Open the windows, flush the air, and start again. (Or leave them open and accept that the only place that will feel cool is right in front of the cooler.)
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Science! A giant warehouse store I worked at had installed swamp coolers instead of AC when they constructed our location, even though it is literally in a swamp. They only helped during very rare bone dry days.
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[Edit: Doh! RickMycroft beat me to it, in a less wordy way 
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With the closed system of a compressed gas air conditioner you force the heat out of the gas using a compressor to change states. With a simple evaporative cooler you have to pump the gas (water vapor) out of the house and start over with dry air.
The heat in the room air is absorbed by the water as it evaporates. The air does get cooler. The problem is that you can’t cool it again when it heats back up because now the air is saturated with water vapor and you can’t pull that trick again. So you need to pump it out and pump dry, hot air from outside that you can cool down using evaporation. That limits the utility of this desktop unit that doesn’t draw air from outside, because if it were able to cool down a room, you’d just wind up with a humid room that will heat back up and stay that way, only now with added humidity.
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They can take off the edge a bit in a dry heat, but that’s it.
And anything over €30 is seriously overpriced.
As long as your air isn’t saturated, just use a fan to help your natural thermal regulation - sweating.
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At some point, the BoingBoing Store is going to market straight up regular fans using the same kind of hype: “Use Alexa to Control this Vortex-based Direct Evaporation Cooler! It uses the science of fluid dynamics and psychrometrics to cool your body directly, providing instant relief from heat. Best of all, it works without using any harmful fluorocarbons, so you’ll be chillin’ in style as you save the environment. And right now it’s 97% off in the BoingBoing Store at only $67.00.”
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Special New Revolutionary Damp Dishcloths applied to the back of the neck!
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Yep. Here in arizona, older houses (primarily those built before the 70’s) were cooled via evaporative coolers. They do an adequate job, provided that:
- you leave windows open to allow the humidified air out, which will allow the cooler to suck in fresh air, humidify it, and blow it into the house.
- the supply air remains dry. During our monsoon season, the air gets very humid, and the swamp coolers loose their effectiveness right quick. (my informal term for running a swamp cooler during monsoon is ‘swamp ass’, because that’s about how one feels…)
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Absolutely; Just ask people in houston, TX, when it hits 90 degrees with 90% humidity out. People die in those conditions if they can’t stay cool.
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