Introduction: DIY Air Conditioner

Picture of DIY Air Conditioner

The story: We have a so hot summer here. We live in a rental house so i can't install a factory AC (and it's expensive too) I started to search for something which can help cooling our rooms and i finally found this "cooling box".

All of the parts for this project cost me 30$ and hopefully this is really working!!!

It can't beat a standard wall mounted AC but it can help to decrease the temperature from hot to tolerable!

Step 1: Watch the Video First!

The hole making process was 15 minutes! Really!!!

Step 2: #1

Picture of #1

A bought a styrofoam box which is made for deliver meals.

The box's size depends on you every following parts can be adaptable for the size of the box.

Step 3: #2

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I got a regular fan. This is 30 cm/12" nearly. I suggest to get as bigger as your box can accept!

Step 4: #3

Picture of #3

Set apart the fan we will use the first cover cage in the next step.

Step 5: #4

Picture of #4

Put the cage to the top of the box and draw around with a sharpie.

Step 6: #5

Picture of #5

Next come the 3 pipe heads. Draw them around as well.

Step 7: #6

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This is the expected result!

Step 8: #7

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Take a knife i used a Swiss Army Knife but you can use anything what you familiar to.

Cut a little bit smaller the hole to get a flat surface for the cage cover.

Step 9: #8

Picture of #8

Do the same with the 3 pipe holes but now you can cut exactly on the marks!

Step 10: #9

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Again this is the expected result!

Step 11: #10

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Take the fan and the pipes then put everything in its place!

Step 12: #11

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Here it is :)

This will be the final now the only left thing is to try it and see is it really works?

Step 13: Test

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I took the hole box to my son's room it's 15 m2/160ft2.

The starting temperature was 28.2 C/ 82.8 F.

Loaded the box with some soda bottle filled with ice then put back the fan and started it.

Step 14: Result

Picture of Result

After circa 40 minutes the temperature decreased 1 celsius.

It's amazing :)

I think it can't frozen the room but make it more liveable on a hot summer day.

Step 15: The End

Picture of The End

So this was so inspiring for me and i think if i load the box with more iced soda bottle and let it runs for more time i get even better results!

More is better than less :))

I suggest everybody to give it a try!!!

Thanks for your attention and see you next time with another interesting instructable ;)

That's the ShiftyWay :)

Step 16: Don't Forget to Check Out the Video!

Your support really helps for me! Thank you!


Daisytikityke (author)2016-10-02

This could be worthwhile if you directed the cool air and didn't expect it to cool the entire room. If it blew on you while sitting at a desk, or watching tv or even sleeping, it might make quite a difference even though the overall effect in the room might be minimal.

ZoubairC (author)2016-09-24

Do you actually need the pipes or is it optional? Just wondering...

deslok (author)2016-09-08

All of you have valid points. However in my case the electric is included in the rent so it's covered. I would use something like this in my mother's room which stays on the warm side at night. It would be a cost effective way of cooler the room off. (10' by 12') Six 2 liter bottles frozen and put inside should last eight hours I would think. Good build. Simple and low cost.

MarkP176 (author)2016-09-08

This is quite neat, but I can't help thinking that by the time you've used it a few times and either bought, or paid for the electricity to freeze all that ice, you might as well have just bought a basic second-hand portable AC unit. It's something I've been trying to convince myself not to do for a couple years now...
(If I *do* go for it, it needs to be in *winter* when the price won't be jacked up to astronomic levels to take advantage of desperate sweaty people who have just moved into somewhere with terrible ventilation... like where I am...)

They don't need any special installation, landlord / freeholder's permission, building modifications, dedicated hardwired power supplies, etc. And are cheaper than even the most cost effective window-box or permanent-install option. Just put it in the most appropriate room, run the warm/wet air outlet pipe through the nearest window (with or without the simple plastic-wedge attachment that prevents it getting squashed or the hot air being blown back in), plug it into a wall socket, and make sure you're able to get the condensation catch tank out of it and to a suitable drain without any huge drama.

The cooling capacity is still limited, sure, but it's way higher than this kind of solution unless you either have an industrial-spec freezer or plan on buying large amounts of readymade ice from the supermarket. It can be about equivalent to what a wall-socket fan-heater can produce (ie about 2-3kw of heat extraction, rather than production), which may produce a very welcome 5 to 10 celcius of cooling (...heating) after an hour or two (which can also be spread across multiple rooms if you keep it running continually and leave the connecting doors open), or rather more straight away if you stand in front of it. Sort of like a car AC system, in fact.

rdeclue (author)2016-08-28

When you make ice in the freezer you do it by transferring heat from the water through the condenser in back of the fridge to the ambient air. You are paying the electricity to freeze the water, then paying the electricity to melt the ice by removing the heat from the air that you paid the electricity to put in the air in the first place. Absolutely zero delta heat in the home. At least a window air conditioner sends the heat outdoors and you actually get net cooling in the home.

Halite (author)rdeclue2016-08-28

This is true if you are using the cooler in the same room as your freezer.

Maybe your freezer is in the garage?

It's kinda obvious that this AC is for a single room, maybe a bedroom or tent. Of course it's not the most efficient but it is a much lower cost and more portable than a commercial AC.

MarkP176 (author)Halite2016-09-08

...did you just say "air-conditioned tent"?!

You, sir/madam, are an unsung genius.

One of these + 2-man tent set up in the lounge (just enough space if you move the coffee table out) = much smaller airspace to cool and the cooled air can be trapped with reasonable effectiveness whilst still allowing some fresh-air ventilation. Especially if the cooler is put in the doorway and the zips closed down around it, as it's essentially blowing in cool fresh air.

It's a bit eccentric, but if it means the difference between a night spent turning into a raisin lying on a wet bed, or getting a decent sleep, sign me up.

GeneM28 (author)rdeclue2016-08-28

True but you forget the cooling effect of the evaporation that also would be occuring

sudss (author)GeneM282016-08-28

Cooling "effect." There is a reason why these devices, more commonly called "swamp coolers" or evaporative coolers are only used in warm DRY climates. Evaporative coolers, even professionally built commercial models should only be used in dry climates. EC is a simple process and the same as sweating where a fluid transfers heat by evaporation. If possible, wearing a wet TShirt and standing in front of a fan would be more effective and cool more actual body surface are and would not depend on the twice cooling needed by cooling air, moving it and then trying to cool the skin. Obviously sanitation is also important because you will be inhaling the "mist" and whatever algae may be in your water of fan. Use of real EC devices require a high degree of maintenance and sanitation if you plan on using it regularly. While this plan or any device that will blow almost any liquid across your skin will work, just remember the possible health effects.

Halite (author)sudss2016-08-28

Couldn't the health issues be effectively eliminated by rensing with bleach between use?

MarkP176 (author)Halite2016-09-08

Or just putting bleach in the ice...

ScottaBlanchat (author)sudss2016-08-28

Totally agreed. This will not be a viable source of cool in the humid environment.

In some commercial swamp coolers, the cool, humid air never enters the living space. Instead, there is a metal heat exchanger, where the cool, humid are is used to cool the air on the room without any direct contact. This causes the humid air to warm up, and it is exhausted outside the house. Homemade swamp coolers can indeed be homes to various molds and other microbes, and care should be taken not to let them be a health hazard.

That is interesting. Why aren't they more popular in places I'm from, like Kansas? That place is super humid.

No, the outside air needs to be dry for an EC to work. It enters the EC hot and dry, cools by evaporation of water, then exits cool and humid. The simplest EC's just dump that cool, humid air into the room. But you can also run that long one side of, say, a thin metal plate, and run the room air across the other side. That way, you can cool the room air without bringing in extra water. Of course, it makes the cooler more complicated and expensive, and you lose a little bit on the cooling. Some parts of Kansas might be dry enough, but I've seen them mostly in the Rockies and the Southwestern States.

Doesn't look like an EC to me. The water is FROZEN -- it is the melting and subsequent warming of the water to room temperature that provides the cooling, not the evaporation of any water.

It takes 184 BTU's to melt a pound of ice and warm the water to 70 degrees. It takes 970 BTU's to evaporate a pound of water. It takes 10,000 BTU's to cool a 10x10 room and 5000 BTU's to keep that room cool considering normal insulation levels and air leakage. Filling the cooler with water or water and ice would be far more effective if the humidity level is low enough for evap cooling to work.

No question -- evaporation has much greater potential for cooling than melting. Evaporation does mean that the water used is lost forever, so even if the climate is dry, one might want to think carefully about consuming water in this fashion. With ice, the same water can be used again and again, albeit at the cost of even more energy than it would take to run an efficient air conditioning unit to produce the same amount of cooling.

PalletM (author)GeneM282016-08-29

There is no evaporative cooling effect when the ice is in sealed plastic bottles. It would take 50 pounds of ice to make any substantial temperature difference in a 10x10 room. Sit in front of the exhaust air and you will feel a small difference but no real difference in the rest of the room. As rdeclue said, you are just moving some heat from the minimally cooled area to the kitchen, plus paying for the electricity to do it. A fan moving all of the room air will do more.

How can comments be positive and constructive when the claims are not supported by the science ?

TJLee089 (author)GeneM282016-08-28

The ice in the soda bottles melts. It does not evaporate. There is no evaporation. The discussion regarding "swamp coolers" is irrelevant.

You also have to remember that the heat added by the freezer may be able to scheduled at a time when the house does not need to be cooled. I very effectively cooled a room during a hot, humid New Jersey summer in a similar way. I had a full-size refrigerator in the room that I did not need to use to store frozen food. So during the day, when I was away at work, I froze several 1-gal milk jugs in the freezer. I kept a fan running in the window, and that kept the room at a maximum of around 90 deg. F. Any "excess" heating from the fridge, in effect, got dumped out the window. The room was going to reach 90 during the day no matter what I did. When I got home from work, the room was a few degrees below 90, and the sun was low in the sky (but the temp. outdoors still near 90). I closed the window, pulled the frozen jugs out of the freezer, set them on top of a little storage cabinet, and set up the fan to blow air over them. Even though the outdoor temp. rarely dropped below the mid-80's through the night, I was able to bring the room down to the mid-70's and sleep comfortably.

I did forget to provide a tray under the jugs the first night, and woke up to find a small swamp on the floor. After that, I put a couple of plastic trays under the jugs, and just dumped the condensed water down the sink every morning.

Note that this was a rental room, the fridge was provided with the room, and I did not have to pay for the electricity I used. I would never use this method if I had to pay for the electricity, or if I had to buy a fridge and devote at least part of it to room cooling.

Instead, put the water in the system to evaporate. If the fridge to freeze the ice was in the same room, you only move the heat across the room and created even more heat by the refrigeration compressor. 4 gallons, 32 pounds of ice (must have had a big freezer for a refrigerator), 128 pounds of ice created 5000 BTU's of energy absorption. A 10 x 10 x 8 foot room needs 2500 BTU's per hour to stay cool by 15 degrees. Even more to cool the room down before 2500 BTU's to maintain the lower temp. Plus, a fan moving air increase conduction through the walls and window. The fan motor generates heat. The refrigerator generates 400 to 500 BTU's of heat per hour. The numbers just don't add up. You only had an hour or so of cooling capacity. Sounds like you may have got some early cooling then slept through as the room warmed up. The fan kept the air moving for some evaporative skin cooling effect.

MarkP176 (author)PalletM2016-09-08

That's still useful, then. If you can stand to stay asleep and ignore the room warming back up, because your senses are dulled due to, well, being asleep, then you don't need the AC to keep running (same as how commercial systems often have a "sleep timer" mode where they only work for an hour or two then turn off for the rest of the night - and so do central heating systems, for that matter). But that slight reduction for the period whilst you're trying to get comfortable and nod off can be crucial.

(forgot to mention -- the milk jugs had been used, cleaned out, and refilled with water. It wasn't actually milk that I was freezing & thawing every day ;-)

Sjons (author)rdeclue2016-08-28

I think she just wants to feel cooler, maybe not so worried about all the science

AlainC1 (author)Sjons2016-08-28

So important to remember the simple purpose of it. Agree with you Sjons.
So many experts in thermodynamics with boring selfish demonstrations !!!

rusty2926 (author)2016-08-31

Nice video but a 2 degree drop isn't much for all the trouble and expense. I bought a $15 box fan from my local store and place it in one of my windows and then opened another window in my house and could feel a drop in temp within 10 minutes. You can play with it and see which way works best for you, either blowing in or blowing out. It works on the same principle as the whole house fans they seem not to use anymore.

MarkP176 (author)rusty29262016-09-08

(FWIW having windows open with a powerful fan blowing between them did jack-shiz because the air was too warm and too humid, and I just ended up having to stand directly in front of it to get any benefit. It certainly didn't cool the inside any, because indoors and out had achieved equilibrium... so as soon as you were out of the flow, or the fan was turned off, it was unbearably sweltering again)

MarkP176 (author)rusty29262016-09-08

There have been days were I would kill for a 2 degree reduction of my indoors temperature, as that would be the difference between being an immobile, naked puddle of uselessness lying on the floor with a fan blowing over me, and being able to at least put on some underwear and do a few basic tasks despite still sweating like crazy. Obviously if a bigger reduction was needed, other solutions are available, like a portable A/C unit (you don't HAVE to use a permanently-installed one...), or putting the ice in the bath then topping it up with cold water and jumping in. Or if you haven't got a bath, distributing it amongst several ziploc bags and tying them against various strategic parts of your body (eg that bit of your back between your shoulders) using the belts from various bathrobes.

VinnyL1 (author)2015-08-02

A better way of doing it, like this that is; is more insulation altering the shape of a vessel ice is frozen in, routing the air differently or both so that each cycle through there is more efficient thermal transfer. A box with in a box would likely be required. Why don't I design it? I like my AC and the solar panels are quite affordable these days. However if someone who is mote into physics, I would focus on thinking inside the box for this particular example.

Also I would look into various substances to lower the temperature of the ice or to make it stay frozen longer. Sawdust might even prove to be good, as it dramatically increases the strength and insulating properties of the ice at the same time; it's called pykrete. Just as I'm double checking the spelling on Google it turns out someone already figured that one out, So there you go...

dougstrickland (author)VinnyL12015-08-02

I'm curious about a slight variation on what you suggest - to create a baffle system that routes the air around many bottles, instead of across the tops of the bottles as this does.

Of course ice will speed up the melting process, applying its energy over a shorter period of time - which may or may not be helpful.

Also, you are increasing the humidity, through so little it might be unmeasurable. condensate forms around the bottles as they warm (less so in arid places) and will evaporate and exhaust into the cool air.

I think this is a good project that has many useful ideas. Thanks!

MarkP176 (author)dougstrickland2016-09-08

Well, that's essentially a heat exchanger, which is an important part of any actual dedicated heating or cooling system. So, yeah, it'd be a good idea, so long as you're happy exchanging a lower "set point" for more frequent exhanges of heat absorbtion elements (IE the ice or freezer-blocks). What balance you want to strike is entirely up to you and your situation ;)

VinnyL1 (author)dougstrickland2015-08-02

Sadly more cooling = faster melting; that why you need more insulation. You will most likely be collecting the rooms humidity not producing it; what you are up against is where & how to deal with it. It's a challenging project, but there are some practical applications behind the principals; home insulation and ventilation would be the first one I think of. Depending on where one is intending to use this I still say solar is the way to go if it's an option for your living situation. It's much more affordable and efficient than most people think. Prices continue to drop, instillation options are increasing and we all know about the cost of a kWh. I don't see that falling anytime soon; especially since out grid is completely outdated. Unless you live in Texas, they do their own thing; I would imagine it's in better shape. Well good luck, I can't find my glasses and can barley read what I'm typing and it's about dinner time.

LaysDIY (author)VinnyL12015-08-03

Enjoy your meal ;)

LaysDIY (author)dougstrickland2015-08-03

Thank you too!

Nokota (author)VinnyL12016-08-28

I made a version of this using those blue ice packs in the plastic. They freeze in less than two hours but provide cold for nearly five. I made a little AC with a computer fan that takes three of them in a triangle, and shoots air through them with insulation all around to keep the warm air exterior to the setup from melting the packs any faster. Since they freeze much faster and more effectively than they thaw, I just rotate two sets of three packs through the freezer. And I have a nice little personal AC to shoot cold air in my face. Couldn't cool a room, but my point stands, those blue ice pack things...

MarkP176 (author)Nokota2016-09-08

Dammit, I've got loads of those, including some with concave channels for resting bottles on (which mean they form natural, if rather large heat exchanger tubes through a stack) and a more flexible version that's essentially ethylene glycol in a silver-foiled disposable ice-cube sheet thing. Wish I'd thought of it before. Though I might also have to get a separate freezer just for cooling the blocks/packs, unless I abandon the idea of keeping anything in the freezer other than icecream every summer.

Also have a coolbox with a peltier cooler on the top that can be run off 12v (from a car or via an adaptor)... it wouldn't do much good for providing cooling by itself, but it could help slow the warming of the blocks.

Just need to find a cheaper, more standard coolbox of the right dimensions for the peltier lid that I can cut up without destroying my normal one. It gets hellish hot in my apartment sometimes, even when the outside isn't really that warm (...and weirdly, sometimes the reverse), but I can't quite justify the cost of a real AC, even though I own the place, because it'd only be run for about five or six days a year.

LaysDIY (author)VinnyL12015-08-02

Thanks :)

Mix salt with ice can effect more cooling power!!!

MichaelJMcFadden (author)LaysDIY2015-08-02

Yes! Salt w/ ice is MUCH more effective. At one point this past winter the "starter coil" (?) for my old fridge burned out. I was able to isolate the problem and check online for replacements, and I found brand new coils for less than $10! Ordered one, spent about five minutes installing it, and save myself $1,000 on a new fridge!

HOWEVER... for a week or so I had no refrigeration AND I had a fair amount of stuff in the freezer. Fortunately it was quite cold outside at night (sub 20s) so I filled about twenty 1 liter bottles with moderately salty water which would freeze at about 25 degrees, left half of them out over night, and then switched them with the bottles in the fridge freezer as the previous bottles began to melt. The nice thing about the salt water is that its "negative energy" began pouring out at a lower temperature (i.e. around 25) thereby helping to keep the frozen stuff in the frozen actually frozen, while fresh water ice would have largely kept things at around 32, with lots of stuff around the edges of the outer boundaries actually becoming completely unfrozen.



LaysDIY (author)MichaelJMcFadden2015-08-03

What was the ratio (salt-water in 1 liter)?

Thanks :)

MichaelJMcFadden (author)LaysDIY2015-08-03

I tried several, from about 1 oz to 1 cup. I believe a 1/4 to 1/3 cup / liter brought the freeze temperature down into the mid to high 20s. I still, as a matter of course, keep a few liters in my freezer like that generally since I have the room, it fills up air space, and if my freezer/fridge DOES go out again I'll have a nice built in extra cushion of time before having to worry about anything actually defrosting.

jweir43 (author)MichaelJMcFadden2015-08-04

AARGH, please don't mix fps and cgs units. Either 50-60 ml / liter or 1/4-1/3 cup / quart is just fine.

jms4th (author)jweir432016-09-01

The truly scientifically literate among us have no difficulty translating on the fly between metric and imperial units. For example, my favorite unit of length for really precise measurements is the nano-fathom.

MarkP176 (author)jms4th2016-09-08

Always been fond of "nanoparsecs per microfortnight" myself...

(which is apparently a reasonable analogue for metres/second :D )

MichaelJMcFadden (author)jms4th2016-09-01

I prefer the picostone myself... :>

Did you know that a grain of salt weighs (ok, masses...) about 100,000,000 picograms?

MichaelJMcFadden (author)jweir432016-02-07

LOL! Noted for future refrence. I'll just call my lier bottles "quarts." :>

LaysDIY (author)MichaelJMcFadden2015-08-06

Thanks for the recipe!

And good luck with your freezer this time ;)

^ now THIS *is* a valid use for the saltwater idea ... keeping frozen things from thawing out :) ... even if it doesn't exactly reach a four-star "deep freeze" rating (which needs 0'F, not 20~30'F), and so still reduces the safe storage time, it at least means you can use up the stuff in a controlled fashion over a week or two.

Nokota (author)MichaelJMcFadden2016-08-28

Ooohh, that IS a nice idea!

MarkP176 (author)LaysDIY2016-09-08

Only if you've got a ready, high volume source of ice. It doesn't make the frozen water absorb any more heat, or do it more effectively, it just does it *faster*. So the air coming out is cooler, but the ice melts faster... and once it's gone through the phase transition from solid to liquid, it quickly comes up to room temperature, as it's that transition that takes the most energy out.

(similar to the supposed trick of using soda bottles with salted crushed ice in them to keep a coolbox colder for longer ... no, they just bring it closer to or even below freezing, which is bad news if you're carrying non-freezable stuff in it, and then lose all cooling ability much sooner than they otherwise would have. And at the end of it you've got salty water that you can't even drink, rather than lukewarm fresh water)

And if you HAVE got that, then you've probably also got a high powered freezer... which, unless you've got some way to efficiently vent the heat from its condenser pipes to the outside, will be working to warm up your house ... and, as it's not 100% efficient, will make more heat than the ice can help remove.

Unless you really really need sub-zero air instead of merely cooler, slightly drier/more moisture-absorbent air, I'd recommend just using plain ice...

About This Instructable



Bio: Making is my passion!
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