I would be curious regarding the size of the A/C unit on your 34' trailer? I don't know what A/S is putting on them today, but in the 2001/2002 era the biggest Penguin unit was 13,500 BTU. I can tell you that my first camping trip out with my 27' Safari was in full sun at 100 degrees. We couldn't get the trailer down below 85 degees in the day and at times approached the upper 80's in the trailer.
We did every test in the book and the air conditioner was running to specs. I did a lot of checking and I do agree it was working to the best of its ability. Personally I think the unit is undersized and to put one of these in a 34' unit would probably yield the results you are experiencing.
Now we did go up to Jackson Center at their request to check for potential air leaks. One concern was that the wrong size unit may have been installed. Another was that the refrigerator compartment may have been leaking heat into the ceiling. As it ended up neither concern was an issue but they did realign my door. I have never been out in 100 degree full sun situations since that initial trip so I can't say that we have resolved anything. So far all is good.
I have seen some 34' units with 2 roof A/C which tells me that cooling in some situations has been marginal. Airstream now offers an optional 15,000 BTU Penguin so obviously they and Duo-Therm know that a bigger unit was needed.
I done a lot of talking to folks with the new bigger trailers and I've learned that cooling has not always been up to their expectations. I added a full streetside awning this year to the Safari in hopes of keeping the heat load down.
One of my conversations with the factory was the design limits for air conditioning. For example in St. Louis home air conditioning is sized to maintain a 20 degree spread between outside and inside temperatures. I was told that A/S has no specification.
Jack
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Jack Canavera
STL Mo. AIR #56
'04 Classic 30' S.O.
'03 GMC Savana 2500
'08 Vespa GTS 250
Well, yoou're probably right there about the sizing! The sizing is probably based on (a) what size units are available and (b) how much do they cost, rather than a full engineering heat load analysis. You may be down to either adding another a/c or ducting all the cooling to the part of the coach where you happen to be at the time...
Has anyone ever tried spraying down the outside of the coach right after sunset to cool it down? It might dull that gorgeous polish job if you had hard water, and it pretty much implies that you have tolerant neighbors and a supply of water, but that might help in marginal situations....
In the driveway, our streetside points due west. Using the awnings on that side dramatically reduces heat gain into the trailer! Keeping the skylights closed during the day does also.
Spraying a trailer down with water is a great idea. Just make sure it isn't hard water. Ours at home leaves near-permanent water spots if you wash a vehicle with it.
Originally posted by jcanavera I would be curious regarding the size of the A/C unit on your 34' trailer? I don't know what A/S is putting on them today, but in the 2001/2002 era the biggest Penguin unit was 13,500 BTU.
Jack
Jack,
I checked the owner's manual this morning. The unit I have is a Dometic Duo-Therm 13.5k btu unit, Model #610015.306. I would guess it was probably the largest RV unit available in '94.
The owner's manual gives very explicit instructions to park the trailer in the shade, start the air early in the morning as it's easier to maintain a cool temp than to cool it down, use awnings, etc. etc. etc. All the stuff we already know. Basically, the owner's manual is telling me, in so many words, that the unit is inadequate to cool a hot trailer, but if you take all the right precautions it might be able to keep a cool trailer cool. So... now we know...
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
Originally posted by nds Is the Penguin 13,500 BTU (model #600315) suppose to be more efficient than the regular Duo-Therm 13,500 BTU (model #610015)?
Actually, I noticed on the trip back out to the trailer to put the manuals away that my DuoTherm does say "Penguin" on the control panel face... hmmm...
Mine is probably just the ten year old model...
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
Hmm, my friend (boltos, also asking A/C questions here) just ordered a new Penguin for his 23' 1970 Safari (which hasn't had A/C installed before).
I'm assuming he won't have a problem with this unit cooling this smaller trailer? I saw another posT regarding bedrooms remaining hot. Is this more with the larger trailers or will he be needing to get a fan to circulate air back to his bedroom too?
"The owner's manual gives very explicit instructions to park the trailer in the shade, start the air early in the morning as it's easier to maintain a cool temp than to cool it down, use awnings, etc. etc. etc. All the stuff we already know. Basically, the owner's manual is telling me, in so many words, that the unit is inadequate to cool a hot trailer, but if you take all the right precautions it might be able to keep a cool trailer cool. So... now we know... "
roger,
my manual sez the same thing, common sense i guess.
...in terms of efficiency and overall comfort, believe it or not. Here's why: Bigger is Not Better
That's a great plan for the unit on your house.
The issue here is how RV units are used. First of all, most of the electricity used is not directly metered to the individual trailer, as I understand RV parks. (No experience whatsoever, so feel free to correct me here!) Second, trailer use is almost by definition on a temporary basis, so quick cool-down requirements should be considered.
Re: Well, that kind of sizing is actually better...
Quote:
Originally posted by drboyd ...in terms of efficiency and overall comfort, believe it or not. Here's why: Bigger is Not Better
That's a great plan for the unit on your house.
The issue here is how RV units are used. First of all, most of the electricity used is not directly metered to the individual trailer, as I understand RV parks. (No experience whatsoever, so feel free to correct me here!) Second, trailer use is almost by definition on a temporary basis, so quick cool-down requirements should be considered.
Don
For a fixed dwelling unit such as a house, I agree with the article. It presumes, however that the heating load is calculated as a fixed amount. With an RV, there is no attic, the insulation is only 2", and the sun can be relentless on a hot, sunny day without shade. So, the potential for varience is substantially greater in an RV than a house. The problem here is that the AC units mounted on a 34' trailer are just not up to the task of cooling off a hot trailer with constant BTU input from the walls, and unless you have the very latest AC units, a 30 amp circuit isn't enough to power two AC units on a single trailer.
So, as a practical matter the 13,500 BTU AC unit runs at max for hours on end, removing lots and lots of moisture, but is unable to cool the trailer as there are apparently more BTUs of heat coming in than the AC can cope with. Hence the advice from Airstream to park in the shade, use awnings, etc. etc.
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
So, I'm still wondering about hosing the unit down to cool it off....
The real limitation here appears to be the service amperage per foot of coach length.
Given that water spots are BAD, we'd want to use distilled water, right? If a pound of water in evaporation absorbs roughly 1,000 BTU, wouldn't a couple of gallons (16 pounds or so) give you about an hour head start? (Assuming that it all evaporates, yada, yada, yada)
How about collecting distilled water from the condensate drain, and spraying the roof with it?
Now, I know what you'll say: Don, that's a lame-o/wacko idea, because when the unit only condenses significant amounts of water when the humidity is up, and evaporatively cooling the outside of the coach is thus markedly less effective under conditions of high humidity.
And you're right. Oh, well.
Maybe a couple of gallons of distilled water in the truck to give it a head start....
Roger, if your unit is only 13,500btu, why not upgrade to a 15K unit? I am not sure of price up there, but a 15K unit here in sunny South Florida is $499.00.
And, of course, since the one you have now works well, just a tad too small, maybe you could sell it to someone here on the list with a smaller trailer, and get at least part of your cost back.
It is just an idea, and would be better than buying a block of dry ice to put in the bedroom every night to cool it off.
Terry
(in Florida)
Was in air conditioning for 15 years before retiring.
Rating for air conditioning is : regular airconditioning is for every 12000 btus is rated for 500sqft. ,,,, Heat pump 12000 btus , 400sqft. Most instulatins are under rated, because you must consider heat load== insulation, number of windows, airstream is metel, number of people, where parked. Most trailers have one of fiber class, when conpressed is about 1/8 inch thick ,with an r-vaule of about five.
If you install duck work in sealing, make the out put from the airconditioner curved so it will force the air through the duck. If it is at an 90 degree angle coming out , the turn is = to 25ft of duck. The curve is = to 10ft restricted static air pressure. The motor on the airconditioner is reated at so much cfm and static air pressure flow, that should be on the manfactures ratinf lable just inside the unit.
Anothe alternative is if you do not have tenting or very little tinting on the windows, you may consider doing this. Tomy
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