College dorm life sucks if you live in an area that frequently reaches temperatures above 70 degrees Fahrenheit. Especially if it gets humid there. Approximately 90 percent (maybe even more; this is a guesstimate) of college dorms don’t have air conditioning, and there’s not much you can do about it. A giant window air conditioner can get expensive, plus it’s inconvenient, and some colleges might not even allow you to have it. Well, we’re going to get around the rules here and show you how to make your own air conditioner that’s also very environmentally friendly. Sounds crazy, but it can be done, extremely cheaply mind you if you happen to have some of the materials laying around. Basically, in layman’s terms this is just an icebox with a fan on top. But it is really much more complicated then that. With a little elbow grease and some spare time (and some technological knowledge; if you don’t have it find someone who does), you can be the envy of all your dorm buddies by having the coolest dorm room in the building. Literally.

Let’s start this project off by listing the materials you’ll need. You can buy a lot of these things on eBay for under 10 bucks or most are sold at your local hardware store. You’ll be needing:

An ice chest-something small with a hinged lid is preferable; if it doesn’t have the hinge you can buy one pretty cheaply and screw it on. A 12 qt size that will hold about a 7 lb bag of ice is a nice choice.

Heater core-this might run you a little bit more cash than the rest of the items, but is free if you know someone salvaging parts from an old car; can be found on eBay for pretty cheap if you get lucky. Also available for approx. $20 at an auto store or less at an auto salvage yard

Box fans and blade guards- can be free if you have them lying around; pretty cheap on eBay or an online electronics store like Newegg or All Electronics (120mm 12VDC)

Bilge pump-available for 10 bucks for a 500GPH unit at Wal-Mart. Why even go anywhere else?

Hose-again, you may have this lying around, but it can be a dollar plus for a few feet at an auto parts or hardware store

12V plug-can be cut off an old charger or car accessory, pretty cheap at an electronics store if you’re too lazy to cut. Won’t run you more than 5 bucks

Caulking-Hardware store. Cheap. Or lying around.

Inner tube piece-you may or may not need this. Get it off a blown bike tire, or ask around at your hardware store. Read on to see if it applies

Wire, wire nuts, screws…-Lying around. If you’re not much of a builder, mooch off someone else. If you must, they’re like 2 bucks at Home Depot, but you should be ashamed of yourself for having to buy these

Ice- No explanation necessary. Just get a bunch of it. Oh, and you’ll be needing a screwdriver, drill, and cutting tools. Something sharp. Don’t hurt yourself.

Okay, first step. The lid to your ice chest actually is two lids with a middle cavity. Take your heater core, center it on the underside of the lid, and mark its outline with a Sharpie. Then cut a rectangular hole only through the first layer of the lid. Mark the inside circles of the fans on the outside of the lid and cut two circular holes. Try this with a saw blade on a rotary tool. Wear safety glasses! You should have a rectangle on the inside and two circles on the outside.

Second step, attach the fans and the heater core. All you have to do for the fans is drill a small pilot hole in the two corners of the fans and put a small screw into the bottom hole into the lid. Leave the top hole open if you want to install fan guards later. Flip the lid upside down and get ready to attach the heater core. Grab some silicone caulk, and do some beads of it around the rectangle in the lid you just cut. It should be centered, straight, and with the nozzles pointing in, which should fit the edges when you put down the lid. You may have to cut off the output for a proper fit.

Third, the bilge pump gets attached. The pump should have a twist-off base, so twist it off and glue it to the bottom of the cooler, angled so the pump’s output (with the hose you will attach) can access the heater’s input. You may want to add spacers between the pump and the bottom of the cooler to encourage water flow. Now it’s time to put on a hinge if you don’t have one. Screw one side of the hinge to the lid and the other side to the cooler. You should know how to do this.

Fourth, add the hose. Attach from the output of the pump to the input of the heater core. It doesn’t matter which nozzle goes on which, but it may be noisy. You can attach the drain hose to the output to make it quieter. A bicycle inner tube piece can catch drips and condensation on the heater core, secured with a huge rubber band, but if you attach the drain hose, you might not need it. Install fan guards by drilling holes into the top of the fan and securing the guards on it with a screw.

Fifth, wiring comes in. This is as easy as wiring gets. All the parts you have should have both a red and a black wire (fan, bilge pump). Attach them together with wire nuts, and make sure everything’s flowing in the right direction. Fans blowing out, pump pumps through hose. Check. Now, solder the wires together or put a switch in the power cord. Zip ties will hold everything together nicely.

Now, you’re squared away to operate. Fill the cooler about a quarter of the way with ice, pour in a half gallon of water, and plug it in. If you put in a switch, techies, you might want to flip it. You have my permission to celebrate if it works, ’cause that process was fairly lengthy. The pump should be humming away and all is well. Open the lid a few inches to let the air. flow through. If the cooler has a handle, flip it over to hold the lid up. That works extremely well. You may need to dump in ice as it melts, but that’s it for maintenance. You are now hooked up! The fan should cool your room pretty well, considering how small dorms are. Have the fan facing you (which is the back of the cooler) and you will notice the air getting significantly cooler. Your roommate will thank you.

From instructables.com Portable 12V Air Conditioner Posted by CameronSS; Pictures by CameronSS Viewed August 16 2007