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Air conditioner hot air exhaust

PostPosted: Sun Aug 28, 2005 11:32 am
by Steve_Cox
Has anyone done anything like this to displace the hot air and condensation? This is a 5000 btu a/c. The cold side gets down to about 56 degrees with the thermostat turned all the way down, and the hot exhaust at the 3 inch blower in the upper left hand corner runs at about 118 degrees when the unit is under a load. Under a normal load setting at 72 degrees inside the hot side runs around 100 degrees or so at the hottest. The blower is a 3 inch Attwood engine room blower. $3.00 at the marine surplus store, new, old stock. It was really loud, sounded like a hair dryer on 12 volts so I reduced it to 6 volts and it still did the job only quietly. The ambient temp was 94 degrees and the humidity was in the 90's as well. The 3/8 inch drain lines worked well, I put one in each corner in case the TD is a little out of level. Still don't completely trust the drains however and am going to glass in the pan under the a/c and run another drain from that and tie all three together. I'd like to find a blower that runs on 120v, any ideas?
Image (hot side cover removed for photo)

Steve in St Augustine

PostPosted: Sun Aug 28, 2005 12:02 pm
by Woody
Steve_Cox
Yes , but I used a 6 inch round bathroom 80 cfm (Lowes $19.00) exhuast fan for the quieter operation and reduced the exhaust end to 4 inch for a smaller hole. The bilge blowers are nice for cfm and 12 vdc, awful loud though. I tried that first way to loud. The 120 vac exhuast fan is better and since you are going to use shore power any way why not the blower also. Have used it for over a year with no problems

PostPosted: Sun Aug 28, 2005 12:33 pm
by Steve_Cox
Thanks Woody that's exactly the kind of data I was looking for. I appreciate your help! Hope to see you at Anastasia.

:thumbsup: :thumbsup:

Steve in St Augustine

PostPosted: Sun Aug 28, 2005 12:35 pm
by mikeschn
I'll have to try something like that on the Lil Diner! Thanks for sharing.

Mike...

PostPosted: Sun Aug 28, 2005 1:42 pm
by Woody
Your welcome, see you at Anastasia. I try to post once in awhile useful info :lol: :lol: :lol:

PostPosted: Mon Aug 29, 2005 10:12 pm
by The R/C Man
Hey Steve!

That looks like a good idea... I am trying to figure out the best way to vent mine. I may just box in the back as you did and then add a vent on the side of the tear.

PostPosted: Mon Aug 29, 2005 10:23 pm
by Dennis Smith
Do you have a vent on the other side of the trailer to let outside air into the cavity?

PostPosted: Tue Aug 30, 2005 7:47 am
by Steve_Cox
Dennis Smith wrote:Do you have a vent on the other side of the trailer to let outside air into the cavity?


That box the A/C is in was sitting on my workbench, had the cold side of the A/C stuck into a box a refrigerator came in to test it. Still trying to decide on the air inlet, but thinking it might come from 2 sources, one inside and one outside the TD. Saw a great picture the other day on the forum but don't remember whose it was, they have a vent right under the a/c inside the TD. I've also been considering 2 ducts, one inlet and one outlet running vertically out the bottom of the TD just behind the bulkhead at the foot of the bed area. I'd like to keep the whole thing concealed and not have holes in the sides if possible. But, those screw in deck plates for boats arn't a bad option for the side of the TD. Closed for travel, open for cooling.

Woody! how did you do it?

Steve in St Augustine

PostPosted: Tue Aug 30, 2005 8:20 am
by Woody
Woody! how did you do it?


Simply stated:
I mounted the A/C in the lower galley bulkhead. I then boxed in the rearend of the unit,( leaving the cooling air intakes open on the sides) then ductedthe hot exhuast flow into a 6 inch 120 vac blower then reduced it to 4 inches and piped out the side wall. Why the side wall, I did not want a hole in the floor for water damage or water intrusion when driving. The cooling air comes from inside the lower galley cabinet via vents in the cabinet doors and under the hatch when closed I have a gap and also cut a vent hole in the bulkhead to allow cabin air to be introduced on the cooling side also. I don't have a roof vent, with a window slightly opened, this air exchange allows the unit to cycle longer and aids in dehumidify the air while cooling down the cabin.

I found that if you pull the air from the hot exhuast side it aids in heat removal better than trying to push it through the heat exchanger. The A/C mounted fans installed in most units will not push the cooling air through the heat exchager fast enough with a restriction, they don't like being contained or restricted even a little bit, without the help form a auxillary fan setup pullng air through it would simply over heat and shut down. The main goal here is to have the unit breathe well and do it well for proper operation to prevent overheating and eventually damging the unit itself. The concept is similiar in operation to the image posted, but more compact, so I don't lose all that vauable real estate for storage. I hope this answer your question some what

PostPosted: Tue Aug 30, 2005 8:54 am
by xe1ufo
Hey Woody:

How about some pictures?

PostPosted: Tue Aug 30, 2005 4:18 pm
by Steve_Cox
Thanks once again Woody,
that's two times in one thread.. What kind of beer truck should I send to your house? Besides a big one.

Steve in St Augustine :D

PostPosted: Tue Aug 30, 2005 6:47 pm
by Woody
Steve_Cox
We can square up at Anaststia in October :twisted: But If you really, really want to send a beer truck my way. I will foward you the name of our local distributor here in my area. See I am helping you for a third time in the same thread to save some money also on freight for the Beer :lol: :lol: Always there to help :roll:

Your welcome

PostPosted: Tue Aug 30, 2005 6:51 pm
by Woody
xe1ufo wrote:Hey Woody:

How about some pictures?


I think there are some in my personal gallery, if not I will put some in

PostPosted: Tue Aug 30, 2005 7:12 pm
by xe1ufo
Woody: I just ran through all the pictures of your personal galleries, and there were none of the a/c system specifically, except for the exit of the exhaust system. Thanks in advance!

PostPosted: Tue Aug 30, 2005 7:40 pm
by Woody
xe1ufo wrote:Woody: I just ran through all the pictures of your personal galleries, and there were none of the a/c system specifically, except for the exit of the exhaust system. Thanks in advance!


I found one and placed in my personal gallery it is the last picture there. When I find the others I will post them. It is the original prototype installed for a test run during my build. I went through others but this one fit my needs better and tested better for the size. So I stuck with this configuration after all.