Roof air conditioners

[JohnEd]

Sean,
I thought it was common practice and I think it is a shame that it isn't. I had window airs that were designed that way back in the day.  In Palm Springs there is an outfit that sells a "AC PowerBooster" device that is no more than a mister for your compressor condenser coils.  I have been told that it makes the AC unit work noticeably better.  Problem is that that Colorado River water clogs up the spray heads in short order.  BUT IT WORKS.


Guess I will have to stop telling that lie.  Thanks Sean.  Can you tell me how much better that feature would make the AC work?  Worth bending a little sheet metal for?


john humbled again

[wal1809]

I do intend to plug some holes.  Under the driver side window is a covered or upholstered board.  On the other side of it is a large electric panel.  Seems to be the heart of the bus electronics.  It is open on one end kind of back and to the left of the driver seat.  I can guaranty it is escaping some cold air in the bus.  Because of this discussion I started going over areas where I knew of that were open to the outside.  I remember this is one because a lot of the wiring comes into the bus through this 8 x 16 inch hole.  While driving down the road I stuck my left hand in front of it and could feel a rush of cold air.  So be it cold I would imagine the opening or beyond is creating a vaccum and drawing out the inside air.  NOt a little but a lot.  This will be fixed.  It and anyothers I can find.  It is hot during the day here right now.  July and August are nothing short of freakin brutal here.  So with pluggin the holes and the 1 inch foam board attached to the bay roofs under the floor I should be able to gain quite a bit.

[Sean]

...  Can you tell me how much better that feature would make the AC work?  Worth bending a little sheet metal for?
...

Sorry, I can't tell you.  HVAC is not my strong suit, and my feeble brain cells are only managing to hang on to the barest minimum of the thermodynamics I studied in college -- don't ask me to explain "adiabatic process" either.

I will tell you, though, that it involves more than bending sheet metal.  On roof airs, the evaporator coil is lower than the condenser coil, so you actually need to pump the condensate up before you can spray it on the condenser.  This is likely the real reason why Dometic and Coleman-Mach don't bother.  As we discussed in another thread, RV air conditioners in general are not particularly efficient, because neither regulation nor competition forces them to be.  I think Carrier was hoping to compete on the efficiency front, but as you see, they could not hold on (although their market timing could hardly have been worse, either).

-Sean
http://OurOdyssey.BlogSpot.com

[JohnEd]

Sean,

HVAC is not my strong suit

You don't have a short suit.

my feeble brain cells are only managing to hang on to the barest minimum

Some of us that have just reason to be humble are really damaged by your humility.

John

The ones I had had a "slinger" on the fan to lift/throw the water at the condenser coils.  It must have worked as the things rarely put out any water.  Being condensate and pretty much distilled water, the coils never showed any sign of oxide or salts.  Shame to give up that free boost. 

[JohnEd]

Remember my OLD Winnie?  I cut the AC run profile from "high and short cycle" to low and 50/50 cycle for 5 min.  Almost eliminated noise and made the place really comfy.  Did the same for the propane furnace in winter.  The "upgrade"?  I put that shrink film over every window.  Cost me next to nothing.  The windows not only allow sunlight radiation heat loading but they leak air badly. Despite their being seized up and inoperable for ventilation they leaked air and that aluminum frame was a really BAD heatsync loss.  I put a strip of weather proofing on the wall around the window so the film wouldn't touch the metal and taped to the wooden paneling.  Otherwise I had water running down the wall off of the points where the film touched the metal.  Not a noticeable loss of"cold" in the AC mode but it had to be a drain of thesame magnitude.  When parked for extended I even put it over the windshield using that"channel stuff" that Frost King makes for the nonshrink stuff.  I eventually had the shrink on all the windows that didn't open and left it year round and had the removable stuff on the rest.  The shrink on the windshield was so clear that I have driven with the stuff on there in winters past.  Absolutely no water running down the dash and rusting the framework after that fix.  crawled all around and under the interior of that old girl gluing foam board and shooting foam and using putty where needed but I am certain that what I did to the windows made more of a difference than all the other stuff combined.  If I ever had a gift for Y'all....this piece of info is it.

John

[wal1809]

Thank you for the gift!!!! what is shrink film?

[Chopper Scott]

It's this film that shrinks.... I couldn't help myself!!

[Van]

Don't worry John, I know what you are talking about ( I knew it wasn't a film about midgets)

[JohnEd]

go to your local home improvement center and visit the weather  stripping dept.  Its about half way down on the left....about eye level.  No No....you went to far!!!Ask the nice man to show you his stock of "FROST KING products. 

Some of this stuff has a role of tape that is double sided sticky after you peal the covering.  Put a run of that around the window and peal the covering tape off to expose the sticky surface.  Press a piece of film over the window and make contact with the tape.  Be neat but don't worry about wrinkles.  Cut the excess from around the window up close and neat next to the tape.  Press it all around to make sure it is securely stuck.  Then take your wife's hair dryer and warm a section of the film.....magic, it shrinks to drum tightness and is crystal clear.   Heat it all over and especially the wrinkles......all done.  Move to next window and repeat.  Presto storm window that is air tight and, did I mention, crystal clear.  Cleans like a window using Windex.

There is another product that uses thicker soft plastic sheeting.  It is clamped in a clever rail system that you stick up around the window perimeter.  More washable on both sides.  Not as clear/transparent but a great product.

FROST KING for the internet works too.

Hard to believe that you don't know about this.  Summer and winter works like double pane glass.

John

[JohnEd]

I couldn't help myself!!
Scott,

Work harder on that.   Reeeely apply yourself.  I now you can do it. Now, bare down sharply. ten smiley faces....I know the feeling.

[wal1809]

No sir I never heard of it.  Thank you for telling me what it is though.  I'll have to check it out.  Right now I can't see this product as looking like it fits when you stick it on and shrink it with a hair dryer.  I do believe I would like to see it installed before I bought it.

[NewbeeMC9]

It's not expensive and removable if you don't like it

[wal1809]

I read their website and they did not mention if it could go over the existing window tint.  If it works as claims I would like to put it ove rthe front windshield.  Although fixing the middle AC worked so far as cooling I still roast a little when the sun is beaming into the front.  Kind of like a greenhouse effect.  I might have to run over to home de and try some of this out.  This isn't like the muffler bearing trick on the new dude is it?

[robertglines1]

I have a 20 inch ceiling fan mounted above driver..its small enough you don't hit it when you walk up the center isle..also mirror window tint down to the visor area helps with front sun..fwiw

[JohnEd]

That is on the right track. How about the drivers side window?  In the winter I had a fibre  glass block that I put in the vent and CW makes a pad cover that you affix with snaps that are in the kit. That is thought of as "winter" insulating stuff, and that is all I use mine for, but if the us gets too hot to use I am sure it would get put up for heat insulation.  You will want it for winter use anyway as the vent "rains".  I think mine was $25 in the day but may be cheaper since China arrived.

Look at CW's site for more ideas.

I know I would be uncomfortable without my two dash fans and my front windows are only 20 or so inches high and the top 3 inches are blocked with a blind.  I have always wondered how the Iggle guys coped sitting under those 7 foot tall windows driving west in the late afternoon.  If you have any window down low behind a dash that you have no visibility thru, put mirror film on that also.

Keep track of everything you do and how much it improved the situation and maybe a "how to post can be put together for all.  I have never seen all the stuff I know of in one spot and there must be a ton more.  I mean, since you are going thru it yourself right now and all.  And have all this time on your hands.   Idle hands and the devil's work shop stuff.

John