We picked up a clearance/ floor model portable A/C over the winter. It's a 10,000 BTU model, and we paid $150 for it from Home Depot. I plumbed the exhaust outlet for the hose into the old fresh air intake grille in the side of the bus.
Some pics and a lot more blathering about the project here on my bog:
http://www.brownland.org/blog/2007/06/11/drivers-ac-for-the-bus/
We're also going to move the unit to the bedroom when parked, so I have to find a place to dump the exhaust back there. Those snazzy angled and radiused GMC windows likely preclude me from using its window kit on one.
We're leaving later this week for a trip to the Midwest, where we'll surely get a chance to test it out. I can almost feel that cool breeze on my neck now.
I'll keep ya posted,
Brian B.
What a great deal, let us know how it works OT.
Bill
Brian,
Have lots of fun on your trip!
Don't be an "Air Hog" Lol
Nick-
Brian, Maybe you could use the same type of connections that they use in the home central vacuum systems. they just snap together once you have it plumbed. that way you could plumb it just about anywhere you want. But having not seen the unit you have I'm not sure what you have to over come. Just trying to give you another idea or angel to think about.
WVaNative
Well Brian, after going in and looking at your pictures I don't think my idea will work as the hoses coming out the back of your A/C unit are a lot larger than the central vac systems. I know you will figure it out though.
WVaNative
Brian, Get a piece of acrylic or plexiglass and cut to fit a window opening then bore a hole for hose to fit and you will have a good looking fix for your problem. HTH Let me know how this thing works I might try to find one.
We had one of those portable 10K BTU units at work. It cooled really well, but it only had one hose - exhaust. It pulled in a lot of hot, humid air. I think the two-hose models would definitely work a lot better. A (fairly) easy exhaust idea might be down through the floor. I'm not really familiar with GMC's, though. There's one good thing about living in the South in summer. Any A/C design that can keep one comfortable here will pretty much work well in most places. This past Saturday it was 95° out with high humidity. My singer 15K Carrier could almost keep my bus cool. Once I was out of the direct path of the sun, the compressor started cycling. I'll be curious to see how it does when I install the additional 8K window unit in the bedroom. It'll be ducted up from the 3rd bay. I'm sure I'll need another unit in the front, but that'll come later.
David
David, are you putting the AC unit in the bay? I want to do this eventually to mine. If you did, how did you handle the ducting? Did you remove the oem shround from the ac unit and make your own? Can you, or anyone else who has done this post a few pictures?
Brian,
That looks almost exactly like the unit I have to cool down my house. It works pretty good.
One thing to consider. The pipe/plug for the condensation trap.....I would put a hose on it to
keep it drained. On mine it started to smell I had to use bleach to get it back clean. A real
pain in the backside.
Just a thought...
Skip
Quote from: John Z on June 12, 2007, 06:29:57 AM
David, are you putting the AC unit in the bay? I want to do this eventually to mine. If you did, how did you handle the ducting? Did you remove the oem shround from the ac unit and make your own? Can you, or anyone else who has done this post a few pictures?
There have been a few that have used window units like this. It's not installed yet; I've got to solder longer wires for the control panel and haven't gotten around to it. Basically, I used a 4" X 12" duct boot and cut a hole through top of the unit (the 'room' side) so the blower blows directly into the insulated flex duct. This duct will go up through the bus floor to a supply register near the ceiling. I used duct board and made a panel... I'm not sure what you'd call it. It goes around the front of the unit where the coils are. This will also have a duct connected to it, but as it's the return, it'll be a bit bigger. This will go up to a filter grill mounted in the bedroom wall. I have an angled piece of duct board the width of the unit and about 5" deep that directs the hot exhaust down. Once I've figured out where to locate the unit in the bay, it'll blow down through the floor of the bay.
I'll have to put some sort of air intake on the bay door. What I hope to use is a piece of the stainless mesh from a parts MC-8's condensor door. I bought the lower piece that has the profile similar to the rub moldings around the bus. I'll cut it about 10" long and cut out a corresponding section of the alum. rub molding. Then, I'll have to cut a hole in the bay door for the air intake. This way, if it doesn't work out, I just have to replace the molding to cover the hole.
Right now, the A/C unit itself has been 'modified' but not installed. Once I've made a bit more progress, I'll get some pics of it. The 8K - 10K BTU window units are pretty cheap and efficient, so hopefully I'll be able to run it and the roof unit, along with other items, without any problems on 30 amp power. As hot as it's been and will be, I'm sure I'll get this done fairly soon!
David
Brian,
You will be very disapointed in the amount of actual cooling you'll get. The single hose portables are very ineffective in even moderate humidity because their exaust must be made up with hot humid outside air. I had 2 in my bus and even after I ducted outside air into their condensors they were very unsatisfactory. I'll ilustrate the problem. If the air outside is at 90 degrees and 80 % rh and the inside is at 70 degrees and 60%rh an air flow of 100 cfm from outside to inside brings in 9700 BTU/h. Most of these portables have exaust airflows of over 150 CFM. So to get 10,000 btu/h of 'cooling' you are bringing in almost 15,000 BTU/h. DON"T waste your money or time trying to make portables work. The best choice is a ductless split, next best an appropriately mounted window unit, next best is an RV basement unit,then roof warts.
Regards
Jerry 4107 1120
Thanks for the advice and comments, guys.
Jerry, bear in mind that this unit will supplement my existing 15k "roof wart" unit in the center of the coach. In the driver's position, the rooftop unit is only about 10' away from this unit. So hopefully, the rooftop will handle the bulk of the dehumidification duty while we're in humid climates. I realize that it's not a perfect solution, but might provide just a little more cooling than the rooftop alone. I can also use the fan-only function to pull some cooler air off the floor behind me and put it back on my neck.
When we're not traveling, I use the unit in my upstairs office at home to supplement our central air, so it does double-duty. Here in Colorado, there's not as much issue with humidity.
Cheers,
Brian
Brian-like what others have said, I have had both the single hose and now the double hose at my house, and can say without a shadow of a doubt that the double hose works much better since you're not drawing in hot outside air. I would suggest that you put another hose around the intake on the side and have that hose also feed to the outside. Course one of the ways you can get by is to open the closest window to the unit.
Even though you live in Colorado, anytime you head east in summertime, you'll be in humidity. Let us know how it works. I would think that a two hose unit would be great to use the components to make your own basement air-since they are relatively cheap and many (like mine) have electric heat too. On my two hoser at the house, the front cover comes off and it would be a relatively simple project to simply extend the controls just by adding electrical wire to it (no thermocouples). Good Luck, TomC
Brian,
I'm curious, how well your rooftop cools your bus, do you have any data? I also have a Buffalo and have posted several times how well my new ductless split, (rated at 18,000BTU/h) cools. Sitting in the sun on a day when the outside temp was 92 and rh 43% the ductless split held the entire bus (I was using another fan to circulate air from front to back) at 68 rh 60%. It did this while running 80 % of the time.
I'll wager you'll be cooler with the portable shut off, this will certainly be true when the outside humidity is high.
Regards
Jerry 4107 1120
Hey Jerry:
I don't have any real data on the rooftop effectiveness, just some passing observations... but it seems to cool the area near it OK. In humid climes, a lot of condensate pours off the roof when it's running. The rooftop is in the front lounge area, about 1/3 of the way from the front to the back. So the back area either needs another rooftop OR some other A/C style.
The problem with the driver's area of the bus it that it's almost uninsulated, because of the expanse of glass, steel cap, and front dash areas. We've found that we can cool (and heat) the bus much more effectively when we hang a heavy blanket just aft of the driver's seat at the step-up and use fans to circulate the air aft. I've considered creating a more permanent barrier of plexiglass and door, like some band buses I've seen, and using an automotive-style driver's A/C system or ductless split like yours to cool the driver. The portable A/C is just a stop-gap. We'll have to see if it helps at all... or makes matters worse, as you suspect.
We still have the coach heat and defroster and it works amazingly well during the heating season whilst underway. A single ducted RV propane furnace does OK when parked, since we don't typically use the coach in very cold weather. When we're plugged-in, we also use elec. radiant heaters.
The coach A/C is long gone, sad to say.
Thanks,
Brian
Brian,
This may not do you much good, since I have a 4103 and you don't, but this was my solution....
The front of my bus has a license plate frame that flips up and out of the way with a compartment behind it. This is also where the fresh air intake for the drivers vent and heater core was, but I have removed the heater core and will probably never replace it there.
I've stripped out everything under the dash from the drivers panel to the passenger wall. It's now insulated with blue 1" styrofoam and a layer of reflectix.
Where the fresh air vent was I installed a 6Kbtu window air and built a duct around the exhaust to blow it out the old vent hole.
The little A/C draws 5.4a and will run from my elcheapo inverter.
I also built shelving around it and put a duct down through the floor into the spare tire bay to provide incoming air for the exhaust.
While sitting, it keeps the front 1/4 of the bus comfortably cool in about 85° outside temperature. We have a swivel house fan in front of it to move the air up and farther back into the room along with a 12V furnace blower on top of the fridge to blow warm air toward the front.
When moving, I can put a board on the lower step up to the salon area and keep the driver and passenger seat cool.
This is a project in progress and is always evolving. We've added a piece of reflectix to cover the Windshield and covered that with a sheet so it doesn't look quite as "Beverly Hillbillies" this cuts down a bunch on the heat through the windshield.
We also have an 8Kbtu in the bedroom installed in the roof curve, which I'm not thrilled about, but does work well, especially with another blower fan forcing the cold air forward to the kitchen area.
This A/C draws 7.0a so my total amp draw is 12.4a for 14Kbtu.
This setup works a lot better than 2 Coleman roofairs that I had before on my Winnie.
I have plans to install another 6Kbtu in the floor near the galley and vent it upward.
If you want, I can take some photo's and post them.
Dallas
GO BUSSING!
Brian,
I see from your picture that you have a front cap. If you also have a rear cap I'd strongly recommend a conventional window AC in the rear. I have a 10,000 BTU/h Sears energy star unit (got it for $100 in a September clearance sale) there in mine And it cools the rear half of the bus very well by itself. I have added a couple of louvered openings on the sides of the cap to supply outside air to the 'outdoor' portion of the unit and ducted straight back from the rear of the unit out through another louvered opening centered in the rear face of the rear cap. A window unit installed similarly has none of the issues that the portables have. The window unit is quieter than any of the rooftops and if I open the bathroom door to separate the bedroom & bathroom from the front of the bus it easily maintains 70 in the back on a 100 degree day. I do wish I'd have done one thing differently in installing the ductless split. It would be better to have the indoor portion on the curb side, that way most of the cooled air would bathe the driver. A 12000BTU/h ductless split's outdoor unit will fit easily in the old condenser area. Whereas I had to modify the 18,000 BTU/h outdoor unit to fit.
Regards
Jerry 4107 1120
Brian.....you have great a web site.
About "portable A/C"......problem with this version that it only come with One hose instead of two hose for condenser side....another word single hose will cause low cabin pressure instead of being neutral or zero pressure. What this mean after turn on a few minutes it will starve for more ambient air to cool condenser while slightly cooled air coming out of evaporator.
To improve this single hose or duct version is to add second hose to condenser's inlet and route it to outside. However exhaust hose that came with being small, should be use for condenser inlet and add a larger hose to allow expanded (warmer) ambient flow more freely to outside. I suggest to have a grill lower front of coach for your hose's inlet while other to wherever there is vacuum effect while traveling.
Bottom line is to keep both inlet & outlet condenser's air out of cabin or room area.
Better yet....do what Jerry Liebler or Ed Roelle or Dallas have done.
FWIW
Sojourn for Christ, Jerry
Brian,
I had one of those in my bus for the same purpose as you (driver's air). It worked great. I routed the exhause and condensation out the floor and never had a problem. I had ideas to try to mount it under the front dash eventually, but soon gave up on that idea.
These are great little units if you're just using it to blow directly (like on the back of your head). And mine had a heating element in it too. The heater actually worked better than the air conditioner.
Jimmy
Great responses, guys! Wish I had of researched my A/C options before we went with this "impulse" buy. Sojourner Jerry's explanation of the low cabin pressure now makes sense to me (I'm a little slow when it comes to visualizing airflows and the like). And Jerry Liebler's suggestion of a window A/C in my back cap (yes, I have a square aftermarket one) is a great suggestion. Dallas gives some nice ideas, too.
I like the price points of the window units, and they seem to be more efficient that the RV rooftops. Does anyone have exterior pics of a rear cap installation of a window A/C?
Thanks, folks!
Brian B.
Another thing you can do which will help a bunch is change the colors of your Buff. The dark colors you have look great but soak up a bunch of BTUs. Take your infrared heat gun or your hand and check the temps of other RVs on the next sunny day in a RV park. Compare a stark white surface with anything else. Will be much cooler. Even some very light colors surprised me how hot they were compared to bright white.
Our old bus is medium blue with stainless sides. Both get very hot in the sun, the stainless would, as they say, 'cook eggs'. I coated the roof with white and it made a huge difference. Our 4107 sitting beside it with the mostly white color scheme was not much hotter than ambient air temp. Not that I do not like your colors, I do, but white is where its at for cool.
All the glass we have in a Buff makes it tough to do anything but cook in the drivers seat. Something I may put in the Buff that the old bus has are the OEM fans, three of them. Makes for a nice, albeit not always cool, breeze. :) One directed toward the copilots seat helps her too.
PS. 1:25 PM. Just went outside with the infrared heat gun. Old bus skin (med blue) in the shade 66 degrees. Rear panel covering where rear window was in direct sunlight, 103 degrees. :o Cream colored metal hood on Cub lawn mower right next to bus was 82 degrees. (Buff is inside now.) For an easy 20-40 degrees difference I'll stick with mostly white.