False Tongue Box?

[Rhinoman64]

My first post and it's a design question for you. The profile that I'm building is similar to the Square Teardrop in the design library. The front is flat (33" tall) and then angles back and connects to the 4' high roof.

I had a thought last week that instead of mounting the A/C in the cabinets at the foot of the bed, I could build a false tongue box that is open to the cabin (like the Camp Inn trailers) and mount it there. The box would be almost the full 33" height, 18" deep and would be almost five feet across (the width of the trailer). Looking at the front from inside the cabin, there'd be a 19" high cabinet with sliding doors to access the lower portion of the tongue box. Above that would be cabinetry that would house the A/C on the left, a 24" open space to act as a headboard, and on the right side a cabinet that would house my battery, fuse box, etc. behind a hinged panel. The electrical switches would be mounted on the panel.

The advantage I see is that instead of having to be creative with the A/C ventilation, I can simply partition the front of the A/C unit from the back and put vents in the front and side of the tongue box. I'd having matching vents on the opposite side to vent the battery.

So, do any of you experienced builders see a flaw in my thinking? Is there any disadvantage you see?

Thanks,

Bryan

[Carl01234]

Sounds like a good plan. I toyed with the idea, and would have been simpler than what I did, but I had already extended my 4x8 trailer to 5x10 and didnt want to add the 20" more to it. If I was building 8 or 9 ft long, i would do it. Saves you quite alot cabinet space in the back.

[noseoil]

Make sure you have plenty of airflow for the heat exchange to dump the hot air outside. Typically, a window unit will need full airflow (in) from the sides & top of the unit, & unrestricted movement of air out the back through the coils to dump the heat.

I've seen an installation where the owner complained about a 105 degree outside temperature being the limit for his unit working, but it was the factory installation which was to blame. They had put the ac in a box without adequate venting, so it wouldn't run properly in hot weather (when you need it most). Here in Tucson, 105 is just getting warm & there's no reason for a small window unit not to work efficiently at that temperature.

[working on it]

• Here's my take on mounting the A/c in front: use stacked aluminum truck underbody storage boxes. Simple to do, and has the benefit of being cheap, with good boxes available on Amazon (or E-bay) for around $100. I wish I had thought of doing it this way, instead of my thrice-rebuilt rear-inside installation,
• I mounted my A/C inside, high up on the rear bulkhead wall, routing my exhaust thru a complicated right-angle ducting system, so I learned the hard way to ensure unrestricted exhaust flow, if you want it to cool properly. Any restriction(s) to the exhaust flow, or even having some of that heated exhaust being wafted over the chassis cooling vents, can cause the A/C to short-cycle, due to "thermal shutdown", as I had experienced. I finally used a larger, straighter, duct hose, with a high flow axial fan inside to get the heat out fast. The exhaust was totally sealed off from the A/C chassis cooling vents, so no intermix was possible, either.
• Alternative A/C install plan

  

  alternative simple squareback trailer plan, with front airconditioner box.png (64.93 KiB) Viewed 443 times

• vs. an overly complicated plan

  

  totally enclosed galley ducting.jpg (296.2 KiB) Viewed 443 times

• In hindsight, I like the alternative better than my set-up, which took untold hours of re-building and re-testing until it became totally reliable. Good luck with your build!