Alternative/creative AC options?

[firefifer]

I've been kicking around some ideas for air conditioning in a teardrop... I know two popular ways is to buy an AC unit and 1) either (temporarily or permanently) mount it to the side or in the toungebox, or 2) to have it detached from the trailer and run ductwork to the trailer. In my day-dreamy state, I'd like to think to think there are other ways and would like some thoughts/input. (I should probably state here that I don't *admire* the idea of having the AC detached from the trailer, but I have long-distance road trips in mind, where finding a campground to park and spread out at will not be possible. I would also prefer something that doesn't use a lot of electricity for the same reasons.)

First idea; create a swamp cooler that, instead of using water, uses dry-ice to cool the air. This would have to be a sealed box (like a really good ice chest) with perhaps metal pipes running through it that would be connected to the ductwork, and I was thinking it could be mounted in the galley. The trick is that it would have to cool the air without mingling with it (for obvious reasons), and not be accessed from the sleeping area. The last thing I want is to poison the sleeping area with CO2. As a fail-precaution, I would want a CO2 detector in the cabin area.

Second idea; going to an RV scrap yard and salvaging an AC unit. I don't know how this would (or wouldn't) work.... Any thoughts?

Third idea; obtain and modify and an AC unit from a vehicle and instal it in the teardrop. This would take some thought, but it might be doable. Hardest part would be running all the metal AC lines while achieving a seal that can be pressurized with the coolant. Also, the radiator would need a fan to keep it cool.


I would like to keep the electrical load to a minimum and am attempting to be creative to achieve that end. Ideally, I would like to have my primary electrical system a 12v system with the capability of shore power for long stays/at the house where it is available. Am I in dreamland and detached from reality, or are there some workable ideas here? Thoughts?


Thanks,
~ Firefifer

[Socal Tom]

Idea 1, won't work the dry ice will go quickly and it will start out blowing freezing air, then end up with swampy air.
Idea 2 would work, but use abut 3x the electricity of a5000 btu window unit.
Idea 3 what engine will you use to power the compressor frm the car. Not a reasonably workable idea. This would be very expensive in the long run.

I use the ducted system, it can run on a 1000 watt generator, it's got plenty of cooling for a TD and only cost $100.00 for the unit.
Tom

[edgeau]

Another option I have seen is to mount a window unit in the bulkhead between the galley and bed. Remember it is a small space and you don't need much capacity.

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[edgeau]

Oh and do you have dry heat or humid? If dry a simple evaporative cooler is very effective but useless in humid conditions

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[yrock87]

Option A may be workable if you switch from dry ice to an ice bath. The added thermal mass of ice blocks in water will work better than dry ice. Also less deadly. Use a trunk intercooler submerged in a cooler with water and blocks of ice. Blow air though and boom.

Not sure how long it would stay cold. But it may take the edge off.

[working on it]

Another option I have seen is to mount a window unit in the bulkhead between the galley and bed. Remember it is a small space and you don't need much capacity.

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Many people opt to not permanently install an A/C unit in their trailer. They'd rather haul them in and out only when thy feel it's needed. Here in Texas, an A/C unit is needed, often 8-9 months a year. So, I built mine into the rear bulkhead, so it would always be available. Even with all the extra ducting and peripheral gear my particular (peculiar?) installation required added in, I only added 55-65 lbs to total trailer weight, including drip tray (the unit itself only weighs 42 lbs). Since my trailer is over 1600 lbs, that isn't much. I bought the dimensionally -smallest sized unit, with simplest controls, I could find, so that if I ever needed to replace it with a slightly larger unit, I only need to enlarge the bulkhead hole where it resides. The 3/4" plywood holds it in firmly, without the vibrations most people associate with "window-shakers". It also has a start-up amperage of 4.8, and running at 4.6 amps, my on-board 2500 watt generator has no problem with it. It cools my un-insulated trailer very well, though the outside walls do sweat in the high humidity. I mounted my unit high up on the bulkhead, so the cool air could be circulated under the ceiling, and back at me indirectly (with or without a secondary fan). If I was to build another trailer, I would still use this type A/C , but sit it on the galley floor, with open access thru the hatch for exhausting, and any excess water wrung from the air would be directly dripped thru the floorpan (though, so far, my unit - like an 8k LG unit at home, seems to use up any excess without dripping).

LG model lw5012j.jpg (65.5 KiB) Viewed 1005 times

1. thru the bulkhead
2. located high overhead
3. powered by generator, or shorepower

[deoc4114]

I think the hardest part of sticking with a 12v system for compressor style ac would be the current necessary to directly drive the compressor, or the losses associated with the 110v converter.

These guys have a decent write-up on a 12v system:
http://www.revoltev.com/2013/08/02/the- ... -solution/

Not sure what kind of battery capacity you'd need to give a decent run time for camping.

[dancam]

With your third idea what do you plan to use to turn the a/c compressor?

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[Shadow Catcher]

I played with a couple of ideas after doing the Frigidaire hack one involved looking at small engine driven system and if you do a search of "Experimental investigation of an automotive air-conditioning system driven by a small biogas engine"
However this gets you into campground restrictions on running a generator after 10PM which you encounter in many camp grounds.
One other process used heat and an adsorption chiller which could be powered by a camp fire or propane. There is nothing available commercial but wit a lot of development and it might be possible.
Most RV AC units are 13,000 btu or higher way too much for a tear, what you would get including a lot of sound (they are rather noisy) is that it will short cycle. cool for a short time and shut the compressor off, not doing a good job of dehumidifying.
The detached 5,000 btu unit is quite and at least in our case could fit under the teardrop if I wished it to.

There is one individual that mounted this on top of his tear.

[firefifer]

Well, pretty much in dreamland then..... Lol
...Not the first time, and chances are, won't be the last.

Thanks for the replies ya'll, there's takeaway from all of them and have given me more to consider and ideas to take behind the barn and shoot (e.g. Idea number 2). Lol

For idea one; thanks for the input, it's appreciated. A swamp cooler would prolly be better....

Idea two; well, it was an idea.

Idea three; To be honest, I hadn't thought about how to power the compressor. That would complicate things...


At the moment I'm not sure what I'll end up doing, but I'll kicking around hopefully viable options. I live in the Pacific Northwest so a swamp cooler-style AC system would work most of the time as long as I didn't wander to the humid Deep South for too long, although I would like to travel to the Eastern Seaboard with it. We'll see what happens.

One other process used heat and an adsorption chiller which could be powered by a camp fire or propane. There is nothing available commercial but wit a lot of development and it might be possible.

Interesting. I'll look into this.

[booyah]

If you want to get all crazy research stirling engines.

They can either create movement off of a temperature difference (used for generating electricity) or can use movement to create a temperature difference (read: used to cool or heat based on lower energy consumption)

https://en.wikipedia.org/wiki/Stirling_engine

I know Coleman made a stirling engine based electric cooler, (read truck fridge) that was very efficient, but not very commercially viable.

A fun concept if you are into building your own toys...

[Tomterrific]

I've had this idea for a long time, longer than most have been alive! As an efficient electric blanket warms by heating the body instead of the air, then a cool sheet would be ideal. You'll need to make your own as I know of none available. Use many feet of vinyl tubing, like aquarium air line, and attach it to the surface of a sheet. Pump cool water through the sheet.
Hey! You asked for creative ideas.
Tt

[working on it]

I've had this idea for a long time, longer than most have been alive! As an efficient electric blanket warms by heating the body instead of the air, then a cool sheet would be ideal. You'll need to make your own as I know of none available. Use many feet of vinyl tubing, like aquarium air line, and attach it to the surface of a sheet. Pump cool water through the sheet.
Hey! You asked for creative ideas.
Tt

Here's one; I considered it after a minor racing heatstroke in 2005. Not too comfy while sleeping, I would think.

[facethewolf]

As long as we're thinking outside the box....
There is another group of people that use 12V air conditioning for low-volume cabins. And they already have air conditioners engineered for exactly the use you are talking about. Longhaul semi-truck drivers use a 12v air conditioner so that they don't have to idle the engine while they sleep.
http://www.autoclima.com/pagine/eng/impianti-condizionamento-su-misura/condizionatori_da_parcheggio_camion_fresco.lasso
These are ideally what I am thinking of. They can be mounted on the roof or vertically on a wall. BUT they are not available in the U.S. and good luck finding a similar brand.

There are a few American brands that do the same thing but don't have the same form factor.
http://www.arcticbreeze-truckac.com/

Alibaba has a few similar models. Not sure if you want to go that route.
https://www.alibaba.com/showroom/truck-sleeper-air-conditioner.html

Also it seems that regardless what brand you get, they are more than triple the price of a normal a/c unit
Since they are professional truck drivers, it seems they don't mind paying a lot of money for such a system.

Someone should talk to the truck air conditioning brands to broaden their market.

[GuitarPhotog]

The first of those Truck Sleeper A/C units I looked at takes 12 VDC @ 60A, or 720W/hr. You could run one for 1 hr if you have a 125AH battery.

Those are made for over-the-road diesel trucks which usually have 2 or 3 250AH batteries, so power is not an issue, but you can't run one for long on the size battery banks we use.

<Chas>