Gasoline powered A/C unit?

[bgeddes]

While I seldom post here, I do read here a lot. Many creative people with simple solutions to potentially complicated problems.

I have a need for an air conditioning unit to use without access to electric power. The converted window-unit-in-a-box A/C setup on this site got me to thinking. Would it be possible to build a gasoline powered unit. Research has led me to believe the easiest way to accomplish this would be to relocate an automotive system. Not only are they quite powerful, (8000-12000 btu depending on who you ask,) attaching the compressor and other components to a gasoline engine would not be terribly complicated. Guessitamation says 3-4 hp should be enough for this task but a 6 hp would probably be my pick as I plan to muffle the engine to a reasonable level. A little creativity might even allow me to idle down the motor, or perhaps with electric start, run on demand.

Anyone ever tried this? Am I overlooking something that would make this a deal breaker?

Buying a 120dB cheapo generator and running a big box store window unit would work but that setup be loud and not so neighbor friendly.

[eamarquardt]

Sure it's possible if you're willing to put the time, energy, and money into it.

Things to consider:

You don't need that much power to cool a teardrop so an automotive unit will probably be overkill. Overkill in air conditioning isn't good as the air won't be dehumidified as it would be with a properly sized unit. Even a small window shaker can be a bit overkill for a small teardrop.

If you use an inverter generator and a window shaker the a/c unit will cycle on and off automagically using its thermostat and the generator will ramp up and down to match the load. All automagically w/o any attention on your part. A "home brew" unit would require some complicated (complicated being a relative term) controls to duplicate this behavior.

Most gas engines suitable for what you want to do aren't designed for quiet operation so you'd have to add more muffler and perhaps an enclosure to match the sound level of a quality generator.

You could buy a window shaker and a generator and be up and running in an afternoon. A home brew will be a LOT more work.

With a generator you have a flexible supply of electricity for virtually any use. A home brew a/c unit will only be an a/c unit.

Window shakers are CHEAP. Particularly at the end of the summer. Generators are not but unless you scrounge up a used automotive a/c unit from a junker and an suitable gas engine it isn't gonna be cheap either and you have a lot of fabrication ahead of you to make it work.

Do you have the equipment to evacuate and charge an automotive system. You'll need a vacuum pump and a refrigerant service manifold. You'll probably have to have refrigerant hoses custom made to meet your needs. Not a problem but not cheap either. You gotta do it right or it may not work.

If you put your mind to do something, virtually anything is possible. That said I think a window shaker and inverter/generator is a lot easier to assemble and a lot more flexible as it will provide both a/c and electricity, and most important it will be a lot more "automagic" to operate. Start the generator, turn on the a/c unit, and forget it as it will take care of itself till it runs out of gasoline.

I've moved a few aftermarket automotive a/c units from one car to another. It isn't that difficult to make them work but you'll need more controls for the gas engine and a fan of some sort to blow air over the condenser. Again, it could be done.

Just my two scents.

Cheers,

Gus

[Shadow Catcher]

I have looked at this and alternatives for some time and have one paper on an experimental unit that used a small motor cycle engine, but it runs up against the short cycling problem as it is built for a bunch more cubic feet. The trucking industry makes a unit for cab cooling that is diesel powered but it is bunch of $$$$.

[jstrubberg]

The problem I can see with using an automotive unit is airflow. If you've sat in traffic on a hot day, you know how well those units work without a large volume of air flowing over the condenser. I would think you would have to use a large fan to move enough air over the condenser to make this work, which sort of lands you back in the not-so-neighbor-friendly zone.

[MtnDon]

Honda / Yamaha inverter generator + window shaker.... both are reliable, readily available, ready to go now, and about as quiet as you are going to get with anything you build up yourself.

[pchast]

I don't know of an Adsorption Cycle air conditioner in normal
manufacturing at this time. 3 way refrigerators are available
So they should be out there. The air would still need a small
fan for movement.

[Shadow Catcher]

There are absorption cycle AC units of a number of sizes and you could power one with a fire, the level of complexity however makes them impractical for a small trailer. I have some information if some one seriously wishes to try.