Under Chassis Air Conditioner

[Nomad32]

I was reading through RT Campskunk's blog posts on his Roadtrek test model and he briefly hinted that the air conditioning unit was located underneath the chassis in the rear.

Is this type of unit something that currently exists as an aftermarket add-on or is this a "proprietary" Roadtrek innovation?

[markopolo]

Dometic offers products like that: Choices - Dometic

Either self contained under bunk units or split systems. Maybe they're using something like that.

[Nomad32]

Originally Posted by markopolo

Dometic offers products like that: Choices - Dometic

Either self contained under bunk units or split systems. Maybe they're using something like that.

I assume most Class B manufacturers don't use units like that because of limited cargo space.

[gerrym51]

roadtrek uses a product from Proair

some people besides campskunk and mike have it.

it is going to be an option in the future

ProAir

[avanti]

I think the industry uses noisy rooftop systems rather than quiet split systems for the same reason they do most things: Because that's the way they've always done it. I am seriously considering a retrofit. Could end up with a very nice skylight over our bed.

A company called Big Rig Products in OK City sells new and "like new" systems for what are reputed to be a very good price:

Dometic Truck AC Units

I haven't called yet, but word on the Net is that you can buy a complete system for less than $1K. Installation looks straightforward. Tempting...

[gerrym51]

Originally Posted by avanti

I think the industry uses noisy rooftop systems rather than quiet split systems for the same reason they do most things: Because that's the way they've always done it. I am seriously considering a retrofit. Could end up with a very nice skylight over our bed.

A company called Big Rig Products in OK City sells new and "like new" systems for what are reputed to be a very good price:

Dometic Truck AC Units

I haven't called yet, but word on the Net is that you can buy a complete system for less than $1K. Installation looks straightforward. Tempting...

it says it's 120 volts. i would think the DC models would be better

[avanti]

Originally Posted by gerrym51

it says it's 120 volts. i would think the DC models would be better

I go back and forth on that. We have a large inverter, so it doesn't make a huge difference--a little efficiency lost. OTOH, a DC system would need pretty big cables. I wonder if there are performance or reliability differences? I know that the old Airstream Westys came with DC units that proved to be very troublesome--a lot of owners ended up converting to AC. Don't know if that generalizes, though.

[Nomad32]

Originally Posted by avanti

I think the industry uses noisy rooftop systems rather than quiet split systems for the same reason they do most things: Because that's the way they've always done it. I am seriously considering a retrofit. Could end up with a very nice skylight over our bed.

A company called Big Rig Products in OK City sells new and "like new" systems for what are reputed to be a very good price:

Dometic Truck AC Units

I haven't called yet, but word on the Net is that you can buy a complete system for less than $1K. Installation looks straightforward. Tempting...

My thoughts exactly! Moving the air conditioner underneath leaves room for a skylight or more solar panels.

[Jostalli]

The goal for my conversion is DC for as many components as possible. That includes A/C. I have an Autoclima Ugo, which is 12V, Danfoss compressor, compact stand alone unit that will go in a closet. Highest amp draw is 44. Autoclima and IndelB have rooftop, double capacity, and split units as well.

[avanti]

I just went out and measured. The compressor/air-handler of the Dometic unit would easily fit in the far back corner of the upper rear cabinet of our Legend:

AC_loc.jpg

The space is more or less wasted back there anyway. We could duct vents downward on both sides. I would run the plumbing down the rear corner behind the upholstered wall. This would be sweet.

Only complication would be that I would probably need longer-than-normal hoses, since the place I would mount it underneath the vehicle is pretty far forward. Looks like a piece of cake otherwise. Hmmm...

[gerrym51]

Originally Posted by avanti

I just went out and measured. The compressor/air-handler of the Dometic unit would easily fit in the far back corner of the upper rear cabinet of our Legend:

Attachment 2687

The space is more or less wasted back there anyway. We could duct vents downward on both sides. I would run the plumbing down the rear corner behind the upholstered wall. This would be sweet.

Only complication would be that I would probably need longer-than-normal hoses, since the place I would mount it underneath the vehicle is pretty far forward. Looks like a piece of cake otherwise. Hmmm...

'piece of cake' famous last words-lol

[booster]

Wouldn't they normally want the compressor and condenser outside the van with good airflow? The compressor on our AC gets hotter than anything else, same on our compressor frig. Inside would only have the evaporator and a fan.

[obgraham]

Everyone has their preferences. But I'd want to be sure that the underneath compressor is not annoyingly noisy. On my previous Winnie pusher, the "basement air" lived right under my bed, and sounded like a jet takeoff.

[gerrym51]

Originally Posted by obgraham

Everyone has their preferences. But I'd want to be sure that the underneath compressor is not annoyingly noisy. On my previous Winnie pusher, the "basement air" lived right under my bed, and sounded like a jet takeoff.

i've read sportsmobiles underfloor AC is extremely loud. another thing is service.

i would not get an underfloor AC unles i knew where and how close a servicer was

[avanti]

Originally Posted by booster

Wouldn't they normally want the compressor and condenser outside the van with good airflow? The compressor on our AC gets hotter than anything else, same on our compressor frig. Inside would only have the evaporator and a fan.

Here is brochure containing a description of this system:

https://www.google.com/url?sa=t&rct=...98197061,d.eXY

Only the condenser and its fan are outside. It is quite small and only weighs 10 pounds. I don't think that a properly-designed compressor needs to get overly hot--the heat is released at the condenser. Here's what the brochure says;

The system consists of separate inside (evaporator) and outside (condenser) sections connected by flexible refrigerant lines. Designed for the harsh trucking environment, the units are vibration and corrosion resistant, and are backed by more than 40 years of mobile air conditioning experience. A digital thermostat controls the system and is ordered separately. Government-approved environmentally friendly R-417A refrigerant (HFC) is used.
The ACC condenser section has a highly efficient, lightweight, compact all-aluminum condenser and a 24VDC cooling fan within a powder-coated aluminum housing. To save space and reduce noise, it is mounted outside, typically under the cab.
The EHC
inside evaporator unit consists of a compressor, evaporator coil, electric
heat strip and a blower in an aluminum enclosure with a deep condensate
drain pan. A cooling only unit (no heat
strip) is also available. This compact unit is designed to be installed under a bunk, or in the bottom of a closet or cabinet. An efficient rotary compressor was selected for its
quiet operation, and the enclosure further minimizes noise in the sleeper. A built-in electric heat strip provides heat during cold weather. The strong squirrel-cage blower moves the cooled or heated air to one or more discharge grilles through insulated flexible or fixed ducts.

Quiet operation is my main motivation for considering this, so I would certainly want to do further research on this before committing on a particular system.