Window Air Conditioer

[BUR]

I know this was discussed about a year ago on the board, but that was about splitting the unit. I am considering putting the whole unit in my spare tire compartment under the floor in the front of the bus.
I would build distribution boxes on the front of the unit and put duct work (flex hose) to the driver, passenger & dash areas. I currently have two Duo-therm high efficiency Brisk Airs 13,500 BTUs, that I'm
not overly impressed with. My coach is a 1980 Prevost LeMirage that is very well insulated and I don't have enough cooling up front while I'm on the road. The unit that I am thinking about is 15,000 BTUs.,
115V 12 amps. Comments please.  BUR

[Lin]

I, like you, am not satisfied with my cooling while on the road.  The PO installed the front rooftop in the middle of the living area, which is rather far from the driver/copilot.  I made do last summer by curtaining off from the unit forward.  It worked somewhat but not great.  I have considered several different options.  One is putting a window unit in the spare tire compartment.  Are you 100% sure that you will not want to carry a spare tire.  I have also considered getting one of those portable units and putting right in between the driver and copilot.  That would not be a permanent install and would be in use just for summer travel.  It would have to vent somewhere.  Maybe down into the spare tire compartment.  Another thought I had was to install another rooftop all the way up front.  It would pretty much be just for travel and would probably deal with the problem.

[luvrbus]

Guys put a Red Dot or any other brand with a compressor driven off the engine they have about 2 or 3 times the BTU's of a window unit and have enough BTU's to cool the hot air from the windshields.These guys will build you one for 900 bucks or so http://www.ackits.com    good luck

[Nick Badame Refrig. Co.]

Hi Bur,

I'm with luvrbus on this one... it would be way more efficient and way more btu's with a dash system.

This 15,000 btu window shaker, what are the dimentions? Two problems I can think of is the front compartment you want to

put it in. Will it fit?  and will you be able to disapate the hot condencer air form the unit properly?

Nick-

[gus]

BUR,

Before you do anything else try this, it made worlds of difference for me.

"One good hint which I read in a S&S magazine and put to good use is to cut a hole in the plastic housing directly below the air duct in a rooftop AC so the air comes straight down to the floor in one big blast instead of taking a 90* bend and being diffused. I covered the hole with a louvered floor vent cover from HD and it looks as if it was made that way.

My 4104 went from unbearable in really hot sunny weather to bearable and even comfortable sometimes! My biggest problem is the fwd AC is too far aft to really cool the driver and the aft AC is too far aft to really help the front."

One thing you must do is make a sort of box inside the AC housing so all the air goes straight down and none goes to the side. I did it with blue 1" foam home insulation. this ensures that no air goes astray or and eddy currents interrupt air flow.

[NewbeeMC9]

Pics Gus!!!

we need Pic's


We have some of those same complaints and I really hadn't thought about it.

[Chopper Scott]

I'm in the same boat as far as cooling the driver seat with all that glass in the windshield. I mounted a 24 volt fan on the dash and that really helped a lot. If it's really hot and I'm going very far just a house type 110 fan blowing air towards the front makes a world of difference if I'm running the gen for the air anyways. Later

[JohnEd]

You really need to get the over the road engine AC compressor and dash air installed.  That $900 sounds very reasonable.  In addition you can add another expansion coil and fan in the rear of the bus and have the entire thing deliciously cool at the moment of your arrival.  You NEED this ability and doing it this way will actually save you money over the "window in the spare bay" approach.  4 times the cooooling and costs less.

You have air infiltration.  The interior of the coach really sucks when you are underway and any leak will start acting like a very large hole as speed increases.  Get your Noncontact infrared temp gun out and take a drive with a helper.  Start shooting around the front of the bus in all the nooks and crannies, and find the warm spots.  Work you way back and go into all the cupboards and stuff and look for those sites where it is warm.  FIND OUT WHY and plug the holes with expanding foam.

Install sheets of the reflective bubble insulation or sheet foam on any flat surface you can get to in the engine bay that is common to the interior.  Get a "Wet Wrap Kit" and insulate the exhaust and manifolds and turbo.  That will cool the engine bay dramatically and ALSO give you just a little bump in horse power and MPG.  Then u b cool!

Go and look at a Pre RV engine bay and note all the insulation and how they did it.

HTH,

John

John

[CAROLINABOY]

coleman and dometic both i believe saells the ceiling unit with the vent in place and it will open and close with a slide of the finger check camping world for cost i think about $85.00

[gus]

I could take pics but that wouldn't help for different kinds of AC.

If you remove the AC plastic cover from inside you will see the air duct coming down from the rooftop AC unit and the way to do it will be obvious.

The whole idea is to keep the air from being diffused horizontally
to the ceiling so it comes straight down to the floor.

I also use a small fan to blow the air onto the driver.

I've seen those covers in CW also but I did mine before they were available. They probably got the idea from the same guy I did! Mine only cost about $2 also!

[BUR]

I want to thank all of you for your input, and some very good input at that. I will  use this info. and try to decide what direction to go. It's like most every other thing I've done on this project, no simple answers.   BUR

[BUR]

I tried the simplest and lowest priced fix to my air problem. The results are are better than I thought they would be. I took the shroud down and cut hole directly below the air discharge and installed a 4" round heat duct vent. I cut all of the plastic off of the back side of the vent, so it wouldn't interfere with the air flow to the front and back discharges. The air flow up front now is, I have air to the upper window level from the front vent and I have air between the driver and passenger seats at almost floor level from the 4" vent. May not be the solution to my problem, but a hell of a start and the 4" vent doesn't really look like an add on.    BUR 

[jjrbus]

 Wehn traveling with the AC on I noticed that there was a cold spot on the floor about 3 feet behind the drivers seat (poltergiests?)  I placed a small oscilating fan there and it made a noticeable difference in the drive/pass area. 

                                                         JIm

[Ed Hackenbruch]

The PO made a little L shaped wooden box that takes the cold air that goes out the back of my rooftop ac and brings it back to the front of the bus. Makes a big difference on the amount of air that gets up front. He also made it so that there is a little wooden , ( for lack of a better word ) plug, that you can take out on the back side if you want the air to go equally to the front and the back.  The long leg that fits alongside the ac is only 30x8x2  inches and the shorter leg that fits along the back of the ac is only 8x8x2 inches. The thickness is only 2 inches so it does not hang down any more than the ac does.  He used a piece of tin for the top and thin wood paneling for the bottom with 1/2 X 2 inch wood for the side walls. 6 screws hold it in place to the ceiling and i doubt if it cost him a buck to build. Probably had the tin and wood left over from other projects and only had to buy the screws.

[gus]

BUR,

You're almost there. I think when the weather gets really hot you will need to block that front vent.

The idea is to block all the air going out the front and back of the AC shroud and make all of it go straight down to the floor. That way you get max blast from the AC fan and the cool air mushrooms out to the side on the floor. I also use a fan where the air hits the floor just like Jim says, it works great when extra cooling is needed.

The air that goes out at 90 degrees to the shroud just dissipates and is never felt, at least that is the way mine works. All that air movement is wasted when it has to turn the 90 degree corner.

I used 1" blue foam insulation board to make a square duct for the air coming straight down to the shroud bottom where you have your round duct. No air goes to the side. If I ever wanted side air I just remove the foam board.

My bottom shroud vent is a rectangular vent cover for home floor heat/AC outlets and looks as if it was mfg that way.

This wasn't my idea, I read about it in a motorhome magazine about a year ago, but it more than paid for my subscription!!

[luvrbus]

Wilbur, has nothing to with your cooling but I would sure like to see a photo of the purple and gray paint job on your bus after Mike Wilson finished   good luck

[buswarrior]

From the busnut engineers of long ago, directing the cold straight down is a good thing.

IIRC...

Think of AC as a need to "fill up" the coach with cold air....not so much a mixing thing....

Some physics, "Delta T" - the change in temp from incoming to outgoing, the AC is able to drop the temp of a hotter incoming charge further than a cooler one.....

So, directing the cool air sideways, along the ceiling, thinking we're "cooling off" the hotter air up there, means the AC sucks in moderated temp air, which it doesn't drop the temp as hard on.

Directing the cold air straight down, where it wants to go anyway, means there will be relatively hotter air up at the ceiling for the AC to suck in, which it will be able to take more heat out of.

Some improved efficiency of the thermal transfer involved if the temps are farther apart to start with.

No doubt, one of you physics majors can 'splain this better than I can.

happy coaching!
buswarrior