DIY ac fo free

>>1208111
i just don't understand why someone would make this up. what is the reason?

>>1208111
Compression of air cools it. It needs wind power in a specific direction to work. It's not exactly rocket science.

>>1208111
This is the worst thing I have seen on /diy/. Making poor people waste resources like this is just criminal.

Here's some diy refrigeration that actually works:
https://en.wikipedia.org/wiki/Pot-in-pot_refrigerator

>>1208119
oh fuck no. Compression of air causes air to heat up, if you let the compressed air cool down and then let it out, you can cool stuff down, otherwise no cooling

>>1208111

God, not this again.

I already got into an argument with some guy last time this came up. I'm not bringing up the math again, but the upshot is that it's a few orders of magnitude short on how much compression would be required to see real results out of it. It works in theory, but you would need winds comfortably measured in mach number to see it work in real life.

Consider that an an air compressor uses a significant amount of power and a big metal piston/housing to move, even in a fairly large unit, a few tens of cubic feet a minute of air. Conveniently, it also shows about the right amount of cooling effect when the air that's been compressed is blown out a hose.

...this thing is claiming to do the same thing with the inertia of a light breeze. You know, what you can get by waving a large paper fan. It's just not gonna happen.

The reason they have people saying it "works" is because they were installing them on shit-ass, literal tin huts with no windows. No shit giving even some moderate ventilation to a metal shed in midday sun cuts the temperature inside significantly.

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>>1208123

Yes, the air compresses and gets hot on the intake side, radiates/conducts a little bit of heat away on the outside, and then expands again on the other side, cooling it down slightly.

But, as previously stated, there is nowhere near enough kinetic energy in wind to make it work.


As an aside, I just noted that retarded opening statement "...similar to the effect when you exhale into your hand with an open mouth or with pursed lips." For fuck's sake, that's not adiabatic cooling, that's the normal evaporative cooling from the slight amount of sweat on your hand, plus a good helping of the increased convective cooling experienced by ANYTHING in a moving airstream.

Have these people even heard of the term "wind chill"?

Fuck, this makes me irrationally angry.

>>1208131
You actually need a radiator system for something like this to work.

>wind chill

That has nothing to do with this.

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>>1208111
Imbecilism at its best.
Compressed air is hotter than uncompressed that freezer works, by compressing gas ( for example Freon) then compressed gas is hot moved by back of freezer where big radiator is to dump extra temp, then it going threw reductor and is decompressed on other side radically drooping temp in result.

The effect of cooling wind on human skin is just simply forced evaporation. if you force evaporation of liquid here water the water changing statre from liquid to gas and this process cooling down skin.
Experiment to try is take any cloth dump it in room temp water 22 deg .. lets air in room has 22 deg as well,
Put thermometer in side cloth , if humidity will be high the dump cloth should be stable around 21 - 22, then force air flow around it ( fan will do ) check as temp measured by thermometer inside cloth start drooping.
this is not a F** Rocket Science

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>>1208111
There's this vortex tube thing that cools air using only compressed air and a tube by means of black magic (aka: scientific stuff beyond my understanding), no moving parts. This old Tony did a video on it.
Buy yeah, running air though a bottle cut in half is just plain stupid, also.... [DESIGNATED]

>>1208173
>You actually need a radiator system for something like this to work.

Very, very technically, the walls of the bottles are supposed to act like a radiator. And, again, very, very technically, it DOES work. It's just that the actual temperature difference it produces is well below the noise threshold of any sensor in existence.

>That has nothing to do with this.

Re-read my post.

>>1208111
This is old news though.

I have a cold air gun I sometimes use on my lathe, it takes a fuckload of air movement and the air can't have moisture in it or the frost will clog up the cold air gun.

Air compressor air goes in one end, it swirls around inside the tube, hot air blow out a vent hole and cold air comes out the nozzle on the other end, pretty neat--but for machining sometimes a cutting fluid is better (lubrication).

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>>1208111
If placebo works.

If they're replacing a wall with this then I could see it helping due to increased airflow... or if it's going in a window then perhaps it allows some airflow while keeping the sunlight from warming the space due to the cardboard blocking it?

>>1208283
yeah that's the kind I have, it does blow cold air.

it uses a lot of compressed air to do it, though.

Very unlikely to be efficient enough to be worthwhile.

>>1208111
build underground you will always be cool or look into permaculture building techniques they build things to stay cool

>>1208173
Ignorance at its finest ladies and gentlemen. Go read what wind chill is. They even gave an example of it in their Indian ac with blowing through your hand or a straw.

>>1208111
you should need a physics degree or at least a relevant trade certification to be able to publish this kind of shit. giving people false hope is the worst.