is it possible to build our own 12volt air conditioner using chep meterials????

Answer 1

The common air conditioner is technically a kind of "phase change heat pump". This makes use of the fact that any gas will get hotter if compressed; when it expands, it cools. See:

http://commons.wikimedia.org/wiki/Image%3AHeatpump.svg

A working gas, say Freon or ammonia, is pumped around the loop by the compressor (4). The restriction or small hole at (2) keeps the pressure much higher on the hot side than on the cold side. So, as gas is pumped through the compressor, it is, well, compressed -- and it heats up considerably. Now, it's much warmer than the outside air. The hot gas passes through the hot coils (1) and cools down to something like the outside air temperature. But when it passes through the restriction, it *decompresses* -- it expands and cools to well below the inside air temperature. As it passes through the cold coils (3), it picks up heat from the inside and warms up -- just in time to be compressed again.

This is not a particularly efficient process, in practice. Air conditioners are great eaters of power. In your home, you can run an air conditioner as much as you like, so long as you can pay the bills and we don't all run out of coal to fire up the electric plants. You may trip a circuit breaker but most home wiring can handle an in-window A/C.

Things are different in a car. You've only got so much power to go around. Factory A/C is not run from the battery; the compressor is driven by the engine, usually through the serpentine (fan belt). Even so, it puts so much load on the motor that it's common to cause the radiator to boil over from the strain. Ironically, when it's hottest outside, you're stuck in traffic for hours, and you want the A/C the most, it's the worst time to use it.

If you're in a sedan, you don't have much room to install a roll-your-own A/C; if you can't get the factory A/C working, I think you're out of luck. If you're conditioning a van or perhaps some odd stationary application where all you have is 12 VDC, you have more room. You could, of course, just buy a cheap in-window unit, cut a hole and shove the hot coils out. You'll need a big inverter to convert enough power from 12 VDC to 117 VAC and you'll need to beef up the wiring from the battery but that's your problem. Also, I can't speak for the life of your alternator under this regime.

You can also buy small electric A/C units, some designed to run on 12 VDC. Building your own phase change heat pump is probably beyond the capacity of a garage shop.

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If it *is* a van and you're willing to try an alternative, you might consider a swamp cooler. The principle of the swamp cooler is simple: Water cools when it evaporates.

The simplest possible way to do this would probably be to put a box (evaporator) on the roof of the van and fill it with something like sawdust. You'd also need to mount a water tank on the roof, somewhere behind the box. The front of the box is open, with some sort of grill to keep the sawdust in and the birds out. Near the back of the box, cut a hole in the *top* and run ductwork down into the inside of the van.

You can run a small plastic line from the tank down into the van and back up again to the evaporator. If you want to be clever about it, you'd want to terminate the line in a series of small holes, so the water will spray out more evenly over the sawdust. Put a valve in the middle of the loop where you can reach it. You don't need a large flow; you just want to keep the sawdust damp.

Now, when you drive, air will be rammed into the box and exit through the duct into the van interior. It will be more humid but it will be cooler. If you're in a dry climate, the additional humidity may not be objectionable -- and may actually be more comfortable than very dry, cool air.

If you're in Louisiana, though, this might not seem so good. You could beef up this simple design by letting the cool, moist air escape to the outside instead -- but not before it's passed through a junk truck radiator. You run hoses between the radiator and the van interior and mount a little centrifugal blower. This way, the radiator is cooled by the moistened air and in turn cools the relatively dry air inside. I can't speak for efficiency.

You might even dispense with the sawdust in this scheme and just rig up your water line to spray the radiator directly. Thus, it's evaporator and heat exchanger in one.

One advantage of this scheme is that you really can use a junk radiator; it doesn't matter if it leaks just a bit, since it's not under any pressure and there's no water inside.

All this depends on a moving vehicle. If you're stationary, you'll need a fan to pass air over the evaporator. It will still be far more efficient than a conventional heat pump with fans *and* a compressor -- and cheaper, too. My grandfather cooled his entire restaurant in Atlantic City with a swamp cooler; the evaporator on the roof was as big as a small car. Still, much cheaper than a heat pump.

Let us know how it works out.

Answer 2

The fruity liquid from brother probably goes in a small container of sorts that is set in front of one of the little things that the air comes out of. Do not know of any other way to make an air conditioner make a better smell.

Answer 3

Get a bucket with a lid. Drill a hole at the topside of the bucket. Install a 12-volt fan blowing outwards. Put lots of ice into the bucket. Turn on fan. Voila.. instant homemade airconditioner! You'll need to replace the ice every once in a while though!

Answer 4

sure. it'll have enough cooling power to keep a matchbox cool for at least five minutes. the compressor will have to be tiny to function at such low voltage.

Answer 5

No just buy a new one cause at the end you will end up buying a new one any way.So that way you wont spend money.