Here's a new one for us... our 34' TT has a single A/C unit mounted mid-ships. It's working fine, entirely up to its rated output. The problem is that it's not getting to the bedroom!
It was 97 degrees here yesterday, and the bedroom was still toasty at 11PM last night!
Other than putting an electric fan on the floor pointed toward the bedroom, anyone got any ideas how to improve the A/C circulation to the rear?
All of my other trailers were short enough that it wasn't a problem. The motorhome had two roof airs, so it wasn't a problem either.
We're sweltering and my wife's getting cranky!!! Help!!!
Roger
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AIR 2053 “A generation which ignores history has no past and no future.” Robert Heinlein 2006 Bigfoot 25B25RQ towed by a 2001 Born Free 23RK moho
Well, Jack and I were talking about some of the units getting an underpowered A/C unit. I think the 13+k BTU units are best for anything longer than 19'. I think the standard model on some of the smaller rigs is 11+k BTUs I have noticed that on a fair number of the larger Airstreams, they have two units.
Jack also had some success with getting some door seals adjusted at the factory.
Just a few off the top thoughts.
Eric
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I don't have an answer for you, Roger... just some questions since we've been concerned with how well the heat pump/AC will do in really hot weather.
How hot does the living room get during a 97 degree day?
How hot is ambient temperature at night, and how hot is the bedroom getting?
I have heard of someone installing tiny computer muffin fans between the upper door support and ceiling to move some air to the back, and we've talked about sleeping on the couch if the bedroom gets hot... rather than buying a second AC.
I had a similar problem on my 27 footer. The rear a/c outlet was relatively close to the rear bedroom but the airflow was obstructed by the folding door bulkhead. I did a temporary fix by using a piece of cardboard and directing the air up and over the bulkhead. It is still in place, thought about getting some fancier cardboard and making it permanent
I am not sure if it would work on your 34' unit, that is one huge unit to cool down.
Well, you have two basic alternatives: Use the existing unit "smarter" or add another one. Being smarter will be cheaper, I promise.
Directing the airflow to the back of the coach will obviously help a bunch - whether you use ducting, cardboard or a fan. Whatever works for you. Don't forget - the more apparent effort you put into it, the more the spousal unit will appreciate it!
The next subset of the "smarter" alternative is to reduce the heat load coming into the coach. Does the bedroom window face west? Put a shade over it! Matter of fact, shading any sun-struck windows will make a big difference. for a bigger difference, park under some monster tree for shading the whole coach.
On my old Scamp, there was no ventilation in the bathroom and it got unliveable in Texas summer heat. I ran a duct (actually a PVC pipe) along the ceiling into an adjacent cabinet and then a flex duct through the cabinet forward into the bathroom. The pipe simply projected into a hole I cut into the inner AC shroud and into the cool air section. On the bathroom end, I used an air vent outlet that I found in a store that sold van and pickup parts. I covered the duct with material that complemented the interior liner.
I think a larger version of the same idea would work in most Airstreams that I have seen. There are all sorts of things that could be used to form a suitable duct. Depending on the AC maker, the duct may just have to go through the outer wall of the inner shroud or may have to go through an inner wall as well to get to cool air.
I could do something very similar in the International, but I am working on a 130 watt Peltier effevt heater/cooler for the bathroom instead.
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John W. Irwin
2005 Classic 28 "Sabre-Dog III"
2004 Silverado 2500HD Duramax/Allison
WBCCI Region 9 Webmaster, #9632
...that sounds good, although I can't quite visualize it.
On the Peltier heater/cooler, don't forget that the unit is effectively a heat pump. If you're trying to cool the bathroom, you'll need a place to dump the heat produced by the other side of the unit. It'll also condense water if the bathroom is damp enough, so keep that in mind.
I don't know what the efficiency is on a Peltier unit, but a 1,300 watt a/c unit would probably do about 12,000 btu/hr (that is a wild SWAG, boys and girls!), so at a max your Peltier will do 1200 btu/hr, about a tenth of a ton. If the efficiency is as much lower as I suspect, it may be half of that.
The heat (or cold in the winter) will be vented into the main room of the trailer for the AC (heater in winter) to take care of. Keep in mind that my International has a phone-booth size bathroom. I don't need huge cooling/heating capacity since the bathroom is inside the outer insulation of the trailer.
Nice thing about the Peltier junction, a flip of a switch makes it a heater or a cooler depending on the season.
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John W. Irwin
2005 Classic 28 "Sabre-Dog III"
2004 Silverado 2500HD Duramax/Allison
WBCCI Region 9 Webmaster, #9632
What the heck are you guys talking about?? Must be some kinda European setup? I saw something like it at Lowe's , I think? An a/c unit you can set inside your room but how the heck does it get rid of of the heat?? Looked like a dehumidifier to me.
I know in the computer rooms at work we would use portable "robot" a/c units, but would have to run a discharge duct up thru the ceiling to get rid of the condenser heat. They would also have a catch basin to get rid of the condensate water.
They note that the efficiency of heat pumping is pretty low, between .4 and .7. That compares to about 2.5 for a typical airconditioning unit with a compressor.
The bad news here is that the 130 Watt Peltier cooler will then remove about 130 times 0.7 = 91 watts of heat. That's 310 btu per hour, roughly the amount of cooling you would get by placing a couple of cold (40 deg) six-packs of beer on the counter in the bathroom and letting them warm to 80 degrees over the course of an hour.
Then again, it doesn't sound quite so bad if you say it that way, huh?
Thanks for all of your suggestions. I really like the ducting approach. I may have to see how that might work in my coach.
Thank God, the heavens opened up Wednesday afternoon and dropped the temps from the mid 90s to the low 70s for both Weds and Thurs nites!
I did ALL of the usual stuff, parked in the shade, used the awnings to shade the sides, used the attic vent fan in the BR(yes, that was apparently a factory-installed option in the pre-Fantastic Fan era) to vent the heat.
The problem was that the trailer had been in full sun during the trip to the campground, and then the bedroom on the curb side (last 5' without awning) was in the direct sun for several hours. The living room was reasonably cool with the air, until I directed ALL of the output to the rear, then the LR heated up. I decided it should be cool at least SOMEWHERE in the trailer, so I opened the LR ducts back up. I left our oscillating 14" desk fan at home (never again) so I didn't have any other way of moving the cool air to the rear.
Once it cooled down, it wasn't a problem to keep it cool, but it was still over 80 in the bedroom after midnight. It didn't cool down until sometime over night. Of course, the hull, the furnishings, and everything had heated up, so it took a LONG time to cool everything back down.
We'll have to see how it does on the weekend of the 11th!
Roger
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AIR 2053 “A generation which ignores history has no past and no future.” Robert Heinlein 2006 Bigfoot 25B25RQ towed by a 2001 Born Free 23RK moho