I HADDA DREAM! well an A/C idea

[coal_burner]

Hey eamarquardt. No need to get upset. I'm not AT&T. All i did was try to get the correct formulas out there so that others could plug in their own numbers for their own campers with different sizes, number of people, thickness and type of insulation.

BTW, if anyone wants to take windows into account, a single pane of glass has an R value of about .3.
If you run the above formula a second time with the window R value and window area. then add the result of that to the result of your wall formula, you will get a better idea of how much heating/cooling you actually need. (remember to subtract the area covered with windows from your wall area before doing the first calc.

A few years ago i installed a phase change thermal storage unit (that's what these are usually called) into a residence a few miles from my home.
It was a packaged unit about 3ft cubed. The freon coils submerged in the water/ice were made of 3/16" copper separated from each other by only about 3". The inside of the unit looked like it was about half filled with copper!
This guy actually bought the unit to freeze at night when the outdoor temperature was cooler, then thaw during the hottest part of the day when the compressor would have to pump the heat up a higher thermodynamic hill. It didn't save him much money, but he was doing it as a green thing.
The V.A. hospital in downtown Detroit does something similar using a chilled brine reservoir of a little over a million gallons buried under their parking garage. We could chill that down to about 40 degrees overnight when our time of use pricing was close to free, then pump that water through our air handlers until it reached about 60 degrees during the day(any warmer and you lose most of your dehumidification).

[eamarquardt]

Hey eamarquardt. No need to get upset. I'm not AT&T. All i did was try to get the correct formulas out there so that others could plug in their own numbers for their own campers with different sizes, number of people, thickness and type of insulation.

Apparently you don't recognize my teasing too well. My objective was to get people thinking. My formula is correct (I promise I didn't go in and edit it) but when I plugged in the numbers I got screwed up and didn't do the math right and forgot to show the division by 4 (the r value). I, just as you did, put a disclaimer that I may not have been right, but my calculations were a start. If you redo the math correctly using the formula I posted we both come up with exactly the same number (740 btu/hour heat gain for the teardrop).

The point of the forum is to have fun sharing what we all know. If I'm not having fun, you won't hear from me, or if I think your views might be dangerous I'll say so as tactfully as I can or in a PM (but remember MARINES are not trained in TACT). So THERE!

Cheers,

Gus
Son of Naval Officer
Son of Marine Officer
Marine Officer
Father of Marine just back from Iraq

[Conestoga]

I'm a newcomer to this thread, and I'm going on a tangent via this post from last summer:

I have thought long and hard about thru the floor air ducts. A pair of 4" pvc pipes with tees and ells to deliver the cooled air ( or heated) to the tear with a couple small fans. The a/c unit could be placed under the tear out of the beating sun and a shroud ( air box) would be used to gather the cooled air for delivery. I know there are thermostat access problems and others but it's out of site.

I haven't built a tear yet, but I'm thinking it out. What I did with my 2nd yurt was "vertical circulation" for cooling. A yurt is round and there is a hole high in the center of the roof, which acts like a chimney when it's open. Wind comes around the hill and under the floor. We sleep cozy under blankets when others are whining and using air conditioners. (2 yurt pix in my album)

The low ceiling on a small trailer is a drawback in summer.. but air ducts/vents in the floor is possible. Maybe make the top pop or add on an extendable chimney for summer camping?

[Arne]

I looked into everything I could think of, including wine cellar coolers (too $$).... and got right back to a 5k btu room unit or a pet cool.... either one works. The 5k is less hassle as it is usually built in... the pet cool takes a bit of set up... and is more money..

[Shadow Catcher]

If you are going to disassemble something why not go with a window shaker. We found a 2000BTU pet cool could not actually cool our 208CF teardrop, in Northern Ohio. the new set up will use an adapted window shaker using two 4" marine deck plates and duct with the thermostat inside the unit.

[mikeschn]

This arrangement is kinda adapted too!!!



Mike...

[eamarquardt]

I'm a newcomer to this thread, and I'm going on a tangent via this post from last summer:
I haven't built a tear yet, but I'm thinking it out. What I did with my 2nd yurt was "vertical circulation" for cooling. A yurt is round and there is a hole high in the center of the roof, which acts like a chimney when it's open. Wind comes around the hill and under the floor. We sleep cozy under blankets when others are whining and using air conditioners. (2 yurt pix in my album)

The low ceiling on a small trailer is a drawback in summer.. but air ducts/vents in the floor is possible. Maybe make the top pop or add on an extendable chimney for summer camping?

I don't think he is thinking about an a/c unit at all. Just using the draw of a chimney and vents in the floor to encourage natural air movement and thus feeling cooler without any mechanical doo dads.

Cheers,

Gus

[Conestoga]

Gus, you're right. Anybody who has used a coal or wood stove (properly) knows how that kind of draft works. In this case I guess we could call it a "summer chimney" since we're trying to get rid of warm air. This principle works great in the yurt as I mentioned above.

This is what they do on boats, a cowl vent:


Now I'm not saying to use that exactly, just invert it and ponder what would work under a trailer. If it has decent ground clearance or drop floors adding vents/ducts might not be too difficult. (?)

The chimney on top, hmm... giraffe-mobile

[eamarquardt]

Yup,

I thought you were just talking about airflow. Not sure you'd have enough vertical height to get it to work well but worth a try. Used to have a boat with a couple of cowl vents. Swinging at anchor (I used to go to the Calif. Channel Islands a lot) two vents would provide a lot of fresh air. Particularly when the wind was blowing 30 to 40 knots as is common in some of the anchorages, ha.

Cheers,

Gus

[Tadlan]

I built a chiller for my fog machine a few years ago, you know, to make the fog hug the ground during Halloween. The fog machine sits on top, blows hot fog through a pipe into an ice chest, does a loop through the ice in a galvanized mesh tube, and exits through a pipe cold enough to stick to the floor. I then used it about a month ago as a quick air conditioner when my house ac pooped out, it was 110 degrees, stores were closed, and my wife was super frustrated. I attached two computer fans to the pipes, one blowing in the top and one out the bottom. It cooled our bedroom pretty well. I was thinking of doing some experiments with copper pipe at the bottom of an ice chest. A lot of us take ice chests with us anyway. I will check how much ice is eaten in the heat exchange of an hour and see if it is worthwhile. The cool thing about ice is that most of the heat energy is used up in the change from solid to liquid. As long as it doesn't eat up all the ice, the ice chest and the food will remain at a low temperature. I would also have a spring timer connected to the fans and run them only for an hour or two while we first lay down to sleep. I primitive camp most of the time. I will not be able to run an ac. I'll let you know how my experiments turn out.

[vtx1029]

I've wondered if you could adapt a dehumidifier to work as a small ac unit...

[Larry Drake]

Check out this webiste for the worlds smallest air conditioner.
http://www.iceqube.com/miniqubenew.asp www.iceqube.com

[Larry Drake]

I had a talk with the Iceqube people. Their units are used to cool electronic enclosures. Neat little AC, but 1,000 BTU's for $1,100! Too bad.

They said they talk to a number of people every week about a small unit for campers but have no plans on developing anything for our market.

[Weirdnerd]

You can buy them made, an avoid the hassle of having to make one, or, you can look at this and try to make your own knock off...

http://www.katscoolers.com/store.php?PHPSESSID=59664f429a6e68f27bed637138a58627