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Portable 12V Air Conditioner --Cheap and easy!

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This project is my dad's $10 solution to a $500 solution to a $25,000 problem. As I have previously mentioned around the site, my Dad owns an electric 1979 Ford Courier pickup, and is cool enough to let me drive it around. We absolutely love it, and wouldn't trade it for a Tesla Roadster, but one of the few problems with electric cars is heating and cooling. In a gas car, heat is provided by the 80% of the gas that is wasted as heat, and air conditioning is provided by a crankshaft-driven compressor system. Many EVs use hair dryer elements and fans for heat, and some, ours included, feature a powerful gasoline-burning heater.

(Update from 4-22-08: I'd forgotten that I mentioned the gas heater on here. Last fall the gas tank and heater were removed, and a ceramic heater was built in. It works great, although not quite as fast, and doesn't use gas.)

However, air conditioning is trickier because the shaft of an electric motor doesn't always spin. Some have used a compressor driven by the motor shaft anyway, while others have turned a compressor using a separate motor. Finally, my dad came up with part of the concept for this system. It pumps ice water through an evaporator core, which has fans that blow air through it. It is very simple, but we found what we were looking for at Sporty's Pilot Shop. They sell air conditioners built into ice chests for prices ranging from $475 for a basic model to $625 for a 24V, dual fan model.There is also an ArcticAir unit for $4750 with a full compressor unit. However, we like our $10 version better. I saw the ArcticAir display at EAA AirVenture Oshkosh this summer, and our unit is more compact and puts out cooler air. All you need is materials, basic construction/assembly and wiring skills, and a bag of ice. Let's go!

Update, 5-12-08: 100,003 views! Yay! I'm no Kipkay, but I'm still proud.
 
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rbfe4ch475 years ago
hey there cameronss, love the idea. in fact had to go out and build one myself. i made a couple of modifications to it. i put a vented drain cap on the top and put the fans so they blow on the heater core. the warm air then is blown over the cold heater core thru the chest and out the vent. i also added a little on/off switch to it. i fly on helicopters and it gets mighty hot sometimes, this was the perfect little idea to cool off with. thanks for the idea.
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I was wondering about doing the same thing you are would it be better to blow into the heater core or is that just a theory cause id like to know i want to build a good one for my shop. also i considered using dry ice on those extra hot days to keep the water even cooler. we have a fridge in the shop so ice could keep coming and keep it cool all day. i might need 3 or 4 of these though its like 800 square feet. let me know what you think.
xvitox 03CR2504 years ago
ummm dry ice= bad idea for anything like this...it wont work and if you seal up the area, as in to keep it cool inside, you fill the room with CO_2_ which brings about a very drowsy feeling. I know cuz that happened when I purchased Dry Ice one day and got stuck in traffic...and me and my girlfriend had the windows up. And it felt really good but we started getting sleepy.
CameronSS (author)  03CR2505 years ago
You cannot cool your shop using ice that is frozen inside the shop. Ice is water that has had enough heat energy removed for it to solidify. If it is frozen in a freezer, all of the heat energy that is removed (and then some) is dispersed from the coils on the back of the freezer. Since all of the heat is being dispersed back into the shop air, you won't cool anything. Since your shop is stationary, you might as well just get a cheap window unit. It will blow cold air, but all the removed heat will be blown outside, and you won't have to replace ice and water.
it is actually better to blow into the heater core. the fans are more efficient for blowing. i made another one for a guy that worked better when i used a flexible pipe for a dryer. i added another fan to that so that two fans would blow on the heater fan and the added fan would suck that air thru the dryer vent. the dryer vent allows the person to be able to direct the air to whereever you would like. if interested, i could send you some pics of this one. the are a blast to make and if you have a dremel, that will make life easy. thanks for the comment.
CameronSS (author)  rbfe4ch475 years ago
Don't let the FAA see it, they'd probably yell at you for it not being TSO'ed. ;-)

I'm glad to see that another person built one, and even more so because it's in the application that KoolerAire was trying to gyp $500 for.

My air conditioner is in a helicopter! Yay!
in chinook helicopters we have a system that cools water, then pumps it through little tubes in a vest that we wear to cool you down. it works well in an aviation application where you will be sitting not moving for a very long time with lots of ambient air blowing all around.
awawawaw5 years ago
Woohoo! I just bought my ice chest to start mine and have the fan mounted so far. My first one will be cooling my 86 Accord for the 95+ days in Sac, CA. The second will be a gift for my father-in-law for his almost completely restored 1969 Nova. Target has a really nice cooler that has a "compartment" in the top for cell phones, keys, etc. This compartment works perfect for a 4.5" muffin fan. When mine is complete, it will still look like an off the shelf cooler. Go to target.com and search for "Igloo Ice Cube 14-qt. Cooler ". Hopefully mine will be completed in a week or so. (wish I had it today.... 101 forecast!!!)
Just went to check something on my ice chest and it looks like Target.com doesn't have it anymore. The one that comes up as the Igloo Ice Cube is 17" cubed. Mine is only about 12" cubed. It looks the same though........ I put all my parts together and ran a test. With 4 cups of ice and about a gallon of water, the air coming out was 58 degrees. As soon as I finish modifying the heater core (soldering on elbows) I'll post pictures and maybe an instructable.
CameronSS (author)  awawawaw5 years ago
Picture! Picture!
Still prototyping, but here is an idea. Ford Escort Heater Core: new at Kragens for $40, shown with the ends cut short and elbows soldered on Attwood T-500 Bilge Pump: $17 at Walmart ComAir Muffin Fan, 12V, 102CFM, Free from the garage Igloo Ice Cube 14qt ice chest: $15 at Target Heater hose: free (going to change to vinyl tubing for flexibility) Rocker switches: free from garage, one for pump, one for fan AC Adapter for Testing, 12V, 4.5Amp: from the workbench So I am into this for $72 so far, but I am buying most items new . Hoping to finish by the weekend.............
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hagrawal32 years ago
hey i have also made an a.c. com. heater and it works great!!!!!
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hi buddy cool great reply me on callonkirti@yahoo.com i like ur projecy

Can i have its report?
hoamattroi28 days ago

tuyet voi

I built this instructable over 3 years ago. Works great! One word of advice.... The thicker the ice the better. Convenience store ice will melt after about 35 minutes
tom_fl7 months ago
hey i know this is quite late, but how do you even get air for the vent to work? isnt it building up a vacuum inside the box with no holes for air?
Muzhik9 months ago
One slight disagreement/modification: I agree not to use salt water as your circulating fluid. BUT... Fill plastic bottles (pop, juice, whatever) 3/4 full with a 10% salt solution and freeze those. Put those in the cooler and then pour in tap water to circulate. The frozen salt water in the bottles will stay colder and stay frozen MUCH longer than an equivalent amount of frozen tap water. You get the benefits of the colder salt water with none of the corrosive effects. Plus, you can keep spare bottles in the freezer, so you can quickly recharge your cooling system.
ewind1 year ago
First of all, this is a fantastic instructable and I'm grateful that you shared it with us. Thank you.

I was wondering if I could pick your brain, get your opinion and what not. I'd like to use this concept, but marry it with the solar ice maker idea. And try to make it into a self-contained air conditioning system that could replace the AC unit for a 28' - 30' class C motorhome. Basically, it seems to me that I would need to scale down the solar ice maker and scale up your design to make it work. Would a 100watt solar panel be enough to run the mechanical parts in your design, do you think?

Could this design work with a larger heat element? Do you think it could cool a motorhome of that size (which is a relatively small space, usually about 95 - 150 sq. ft. of space)? The way I'm thinking is whatever melt ice is coming out of the heat element can be routed back to the ice maker, so it's essentially on this continuous loop with minimal amounts of water lost.

Anyway, sorry for the questions. This is a really exciting tutorial, though. Thanks again for posting it!
CameronSS (author)  ewind1 year ago
Between the bilge pump and the fans, they're rated for about 3A total. At 12V that's 36W, so if the solar panel is actually putting out 100W, that should work. Keep in mind that solar panels are often quite optimistic, and that output drops dramatically with clouds.

The basic design could be scaled to any size. I won't presume to make an estimate on how well it would work to cool a motorhome, but it could at least blow cold air on your comfiest chair.

I'm not familiar with solar ice makers. With the amount of solar panels you're talking total, I wonder how hard it would be to find a high-efficiency traditional air conditioner that you could run off those panels instead.
Here's a heat sink assembly that may help the project:

Super Cooler! Peltier Heat Sink & Fan
http://www.goldmine-elec-products.com/prodinfo.asp?number=G19056
tazz17816 years ago
While its a great project, its not all that green. For example, where does the ice come from? A machine that produces heat to make Ice and uses harmfull gases to do so. So, for the continued cost of the ice, whether buying it daily or having your ice box run more so you can provide your own ice, your really not saving any money or the enviroment.
CameronSS (author)  tazz17816 years ago
The ice box runs whether we use the ice or not. We can turn it off, but that only shuts off water, not power to the freezing mechanism.
Yes, the ice box runs regardless, but it runs more to freeze water. How about using solar panels to run your portable cooler, or to charge the battery? Then you would have a somewhat "Green" portable AC.
CameronSS (author)  tazz17816 years ago
Well, why do you think I'm tying to win? I don't need another bike...
Cameron-- I live in Texas, Waco Texas, and so far this 'spring' we have hit 101 and 102 in my area. I have a 1993 Honda Civic, 200,000 miles on it, and the air is/has been gone now for a year and a half. This is one of the most brilliant ideas I have ever come across. Hat's off to you and your Father. I am late on this in terms of 2007, but I have a question if you could take a stab at it, I would be most grateful.
Do you think this design will cool a 4 door Civic to a comfortable level here in Texas when it is 100 outside? I suspect we would go harder on the ice, ie, it will melt quicker, but I am an older disabled person that has a harder time as I age with the heat. I sure would like to hear what you have to say to my questions.
I also wanted to say that I know the head of the physics department at UT Austin. I am going to ask him if there is a way to add something to the water to make the ice/cold last longer. Without using salt, and non-corrosive to the heat exchanger. If he gives me a good answer, I will let you know. one more thing- may I have you and your fathers approval to build your idea??? Tahnks so much, james
Why on earth would they put something on Instructables if they didn't want people to build it? This is what this site is based on, which is showing other people how to build what you built.
CameronSS (author)  jpnagle593 years ago
A Civic is pretty small, so it probably would. The ice wouldn't tend to melt any faster, it just wouldn't be as effective in a larger volume. Keep in mind, though, that a seven-pound sack of ice only lasts a couple hours, so it may not be cost-effective for all-day cooling unless you can find a place that has free ice. Here in Topeka, the Lindyspring water plant often dumps gallons of ice out on the lawn...a place like that would be good. Of course you can build it! That's the point of Instructables-to show what you built and how you built it, so that others can do it themselves.
Thank you CameronSS...hats off to you and your father...
The CC license he attached to this instructable would indicate that you were allowed to build this, and to modify it to your own needs: "This license lets others remix, tweak, and build upon your work non-commercially, as long as they credit you and license their new creations under the identical terms. Others can download and redistribute your work just like the by-nc-nd license, but they can also translate, make remixes, and produce new stories based on your work. All new work based on yours will carry the same license, so any derivatives will also be non-commercial in nature. "
...and which "harmful gases" might those be, and in what way are they harmful?
My "ice box" runs more? How much more would that be?

And agritzmacher has a point - how do you think electric cars are charged?

The raw materials and manufacture of Prius batteries requires 10,000 miles of transport, literally across the world: http://www.carkb.com/Uwe/Forum.aspx/car-driving/9345/A-Prius-Causes-More-Pollution-than-a-Hummer

Virtually all CFL bulbs - which we will be required to buy soon - are made in Chinese factories, fueled by "dirty" coal power plants. And they contain mercury, which, if the bulb breaks, requires approximately 6 types of tools and materials, and 14 steps (including cutting out a section of your carpet, if that's where it broke) - depending on who you ask.
CameronSS (author)  lloydrmc2 years ago
Point 1: Do your research. Power from a coal power plant is cleaner than power from a gasoline engine.

Point 2: A CFL typically contains 4mg-5mg of mercury. The energy saved compared to an incandescent translates to something like 15mg-20mg less mercury vapor at a coal power plant.

Point 3: I made it to Level 2, I guess.
Do YOUR research!
Point 1: Power plants in China (where virtually all CFLs come from) are NOT in any way shape manner or form: "cleaner than power from a gasoline engine". They have no scrubbers or any other type of pollution control whatsoever! In some Chinese cities, the smoke from power plants and other pollution literally makes it difficult to see for any distance, even at midday. http://news.nationalgeographic.com/news/2007/07/070709-china-pollution.html

Point 2: Try actually reading my comment. My comment was NOT about the impact of mercury on the environment in general but rather what a nightmare it is to have to clean up after a mishap with a CFL that we are going to soon be FORCED BY LAW to purchase, e.g.: http://www.maine.gov/dep/rwm/homeowner/cflreport/appendixe.pdf

Have you ever actually used a high-lumen CFL (such as a replacement for the soon-to-be-outlawed 100W Edison bulb)? It is recommended that they only be used in applications where they will be on for at least ten minutes, because it takes 5+ minutes for them to reach rated output

CameronSS (author)  lloydrmc2 years ago
Okee dokes. Have fun.
The same reasoning can be applied to electric vehicles plugged into the electric grid to charge... Just sayin'
bryan31413 years ago
I'm thinking to myself: "self...why not just run the tubes through the top of the cooler and put the heat exchanger and fans in their own enclosure, thus eliminating the open icewater in the jostling car." I think I may follow that advice. I'm thinking 3 holes through the top of the cooler: cold water supply to the exchanger, used water output to the cooler and condensation return to the cooler...or, if I have a clean enough heat exchanger, maybe I'll run the consdensation collector into a drinking bottle...fresh cold water on a hot day is always a nice thing.
OGM bryan31411 year ago
I made one of these a couple years ago for my plane. Unable to leave the lid open, obvious reasons, I reversed the fans. I bought a transmission cooler and filled the void space in the lid with foam. Other than that it is the same. I love the remote idea, it is genius. As the cooler sits way in the back, not great for the pilot and co-pilot. cars could place it in the trunk.
thats not exactly true, that screwdrivers dont do anything, someone i know was using a flatblade in a wreckless manner and managed to stab himself almost completely though his palm
Yeah, but the point is that it's easier with a drill. If you miss with a drill, you make a hole in yourself. Sure you can hurt yourself with a screwdriver, but you can just as easily hurt yourself with a fork, a pair of headphones, a pile of pebbles, or a kitten.
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