Hillbilly air conditioner

[alan0043]

Hi Everyone,

 

Has anyone ever used or built a hillbilly air conditioner ? If you have. How well does it work ? The reason that I am asking this question is because the air conditioner in the truck is not working. The first trip for the truck this year is going to be the '16 ECR. I don't need air conditioning going to the rally because I usually travel after dark. The only time I need to have a cool truck is traveling home. That is because of the time of day. The past two years it has been warm going home.

 

I want to talk to people at the rally that has worked on or know what to look for. I know that the system is low or out of Freon. If there are parts that need replaced I can do that kind of work. Maybe I just don't have any faith in the repair shops. Who knows, it could be an o-ring or two. Time is not my friend right now. I have a couple of things that I need to finish before I travel to the rally. I do have a old cooler for this project.

 

Is there anyone going to the rally that knows the air conditioning systems on the trucks ? If so, I would like to pick your brain for help on what to do.

 

Al

[RickW]

Al, I have a vacuum pump and gauges that I can bring with me to the ECR if you would like to borrow them during the rally. Like you I am not an A/C guy but google is my friend.

[Star Dreamer]

After seeing my father in law almost blow his hand off from a defective freon can trying to recharge an AC, I have decided to let the pros do it. Also you should have a system to capture the old freon and be evioromently friendly and not let it out to the air we breath.

 

We had our Freightliner recharged last spring and it ran about $400. Hopefully it is still charged but it is too cold here still to test it.

 

Dave

[RandyA]

Hi again, Al

 

Yes, the "Hillbilly Air Conditioner" caught my eye. I made a pile of these in my younger years and all were better than nothing. I guess my greatest genius effort was to put an upright 55 gallon metal drum in the back of my '56 Studebaker pick-up with a 12 volt pump and 1/2" garden hose running into and out of a surplus add-on automotive air conditioner head in the truck cab. We still had an ice house where I lived and it was not overly expensive to get several nice blocks of solid ice to pack the drum, add a little water and drive in the cool. The nice thing about this system was it did not add humidity to the truck cab and solid ice frozen to well below 0F had significant cooling power.

 

When we would go to the State Fair and had no hook-ups and only a small sputtering 1200 watt generator I would take a homemade hillbilly AC. It would work well to cool a hot camper bedroom off at bedtime when filled with solid ice from gallon milk bottles that had been frozen over several days in a home deep freezer, but it was basically useless when filled with the small hollow ice cubes available today.

 

If my aging memory serves me correctly it takes 144 Btu hour to change one pound of ice at 32F to one pound of water by raising it 1 degree F. Cooling the cab of a big truck to a comfortable temperature, considering the heat loss of a moving vehicle, outside temps, sun or shade, etc. is going to take something like 20,000 Btu or more per hour. On a really hot day it can double. That's a whole lot of ice!

 

If you can find some solid ice blocks for your hillybilly AC and blow the air up your pants leg you might be more comfortable. But, as far as cooling the moving truck cab - well, probably not.

 

The photos are of the last one I made using surplus computer cooling fans. Note I did add directional louvers.

 

 

 

[SuiteSuccess]

Had to know if it could be done, then Randy's done it . He's one of those guys that could build the Taj Mahal out of broomsticks and duct tape.

Seriously, Al, get it to the rally and surely someone will help figure it out. If not plenty of places around Crossville, Knoxville to probably get it fixed.

[KodiakJack]

I recall driving through death valley as a kid where you could rent a window mounted swamp cooler on one side of the valley and turn it in on the other. These units simply hung on the outside of a rolled up window and scooped up air and blew it into the car. Don't recall what the media was that you watered down but the faster you drove the more cool (humid) air would flow through it and into the vehicle. Worked well and was a heck of a lot cooler than without it. Wonder if there are any of those still around?

Later,

J

[RandyA]

Jack, I remember the window mounted swamp coolers. I would "think" that one could duplicate the device by reverse engineering a small humidifier with a paper media pad. All one would need is the media pad, a water source (small 12V pump and a water source - perhaps a reclaimed gallon milk jug?), and a piece of 4" PVC pipe to hold the pad capped on one end with holes drilled in the side to direct air into the vehicle. Of course, it would only work efficiently in a low humidity environment - not with the wet east coast air.

 

On AL's AC system - yes, it is best to leave it to the pro's. If the system is "open" it will need to be repaired and vacuumed down to remove all moisture. Other problems might exist like a defective compressor electric clutch, bad compressor or expansion valve. If Freon is low there has to be a leak somewhere that must be fixed. A system with low freon that still has enough pressure to keep the system going will freeze the evaporator. There are a host of problems that could be the cause of no cold air. I have the tools (and license) to troubleshoot the system but they are not with me and I am not there. In any event adding freon (R134) from one of the auto parts store cans is a crap shoot without gauges to measure both the low and high side pressures of the system in relation to the ambient temperature. Too much freon will create dangerous pressures on the high side if the high pressure switch is defective and raise evaporator temps. Just adding R134 is not always the answer to an AC that is not cooling - doing so blindly can cause costly damage to your system.

[alan0043]

The first thing we would need to know is what does it do? Besides not work, does it cool a little at speed, no cooling at all, no air flow? Does the compressor kick on? We need more info.

 

Hi Everybody,

 

The truck does not cool at all. It does blow air. I don't know if the compressor kicks in or not. A few years ago, the air was not cold. At that time the compressor did work. I added Freon that had an additive in it to help seal up any leak. The lights under the hood for the air conditioner showed at the time the truck needed Freon. I am thinking whatever leak the system had back then it still has today. I am not afraid to replace any parts before I would have a professional fill the system. I can replace parts for half the cost of a repair place. It might be as simple as an o-ring.

 

Randy, Thank You for doing the calculation on heat loss. I also like your posting of your home made air conditioner. I am glad that you liked the old idea of hillbilly air conditioner. I just need some cool air blowing on me when driving. I have a story about that went the wife and I would travel. She always needed a blanket when we traveled. The funny part was, it was over she head. lol. It would be nice to have the windows closed to keep the noise down.

 

I want the 'Thank' everyone for willing to help me. It would be nice to trouble shoot the problem on the truck with extra eyes looking on.

 

Has anyone replaced their whole air conditioning system ? If so, what was the cost ? What parts seem to fail the most ?

 

Please keep any ideas coming,

Al

[Jack Mayer]

You will not have to replace the entire thing. The most likely thing is a hole somewhere. Often that hole is in the line that feeds the rear unit. That is the first place to look, IMO. But heed Randy's advice. It is fine to try to track down obvious leaks. But beyond that you have to take a systematic debugging approach and simply replace what you find wrong. I did it that way on my truck - I ended up replacing the line that feeds over top of the engine.....it had rubbed a hole in itself. Once that was done I had a dealer vacuum it down, test it and refill. The testing part is critical. No sense adding coolant to a system that will not keep it in. There is simply no way to predict the cost. It just depends on what is wrong.

[alan0043]

Hi Everybody,

 

With the size of the sleeper on the truck I do not have a rear unit. The sleeper size is 42". That could help save some time diagnosing things. There has to be one place that would have more of a chance for a leak over another. All help is being appreciated. I have a feeling that some of you guys have a story to two about looking for leaks. How would the professionals look for the leak ?

 

Al

[SuiteSuccess]

Alan,

 

In the old days used to be able to add refrigerant with dye and could see where dye leaked out. I would assume that may still be available.

[Alie&Jim's Carrilite]

If you want to do a leak check you can put a can of 134a in it and use a spray bottle with soapy water in it. Spray things down and look for bubbles. When looking for bubbles DO NOT pay any attention to the random sized bubbles that first formed when you sprayed it. The bubbles from a leak will be all the same size and may take a few minutes to reveal themselves. If it is a large leak, you may have a difficult time finding it with soapy water because it could blow all of it away before it formed a bubble.

There is 134 with dye available. The kit usually comes with a UV pen an glasses.