OTR A/C and house air

[JohnEd]

I recently found a response by Nick Badame in my posts that I did not see when the post was being reviewed by me.  My question was:  Can I use the OTR compressor to run three seperate exchangers in the coach.  One for driver/dash/frontcoach, one for center coach and one for the rear section.  I can intuit that the answer would be yes but I don't know what the considerations might be for getting the lubricant to flow back to the compressor. 

The second part of my "dream" was if I could also integrate a 110 volt compressor into this system and power the A/C with it when parked with shore power or using the gererator.  One set of heat exchangers and two compressors selectable.  The freon would have to be 134.  The thing that stumped me was how to make sure each compressor got its share of oil when it was operated.

I have read numerious posts wher the OTR unit was estimated to need more than 10 HP to run and just where would you get that much power in a shore powered system.  Two roof airs drawing 3,000 btu worth of power do the job and I'm sure they don't add up to 10 hp.

Would an ac powered 134 compressor be efficient?  I don't mean a motor driving an auto compressor....necessarily.  A sort of complicated split system.

Nick, this was long ago and I just accidently ran across you reply.  Year old, I think.

Thanks

John

[belfert]

Dan Hard (www.danhard.com) has a 4 N 1 system that has a 110 volt compressor and works with the engine compressor too.  It says it is 32,000 BTU with engine, but only around 12,000 BTU with 110 volt.

So, it can be done.  This system would be pretty small especially on 110 volt.

[Nick Badame Refrig/ACC]

Hi John,

I'm not sure I remember your question last year.

First, let me inlight you on some figures about tonage and btu's. There are 9,000 btu's in a horse power. And 12,000 btu's in a ton.

If your coach air has a 04G carrier compressor, then it is a 11 ton system or 132,000 btu's, or 15 horse power.

With that said, you can now figure out your needs. The intergration of a 115v compressor is not even in the ballpark. "Maybe 1 1/2 hp."

Multiable evaporators will work as long as you are matching the Btu's of the original system, but all three will have to work at the same time

to not restrict the flow of refrigerant.  Why not just properly duct the original system through out your bus?

Good Luck
Nick-

[kyle4501]

Hey Nick,
I need a little help understanding how the air works in my suburban with a 2nd evaporator for the rear air. The service manual I have is sketchy at best when describing it & you said both evaporators need to be on at the same time. The kids turn the rear off when they get cold & I always have the dash working, so how does that system work. It has a R4 compressor that makes the 'normal' noise most R4s make  .

I was thinking multiple compressors in one system could result in one compressor starved for oil.
Also, the condenser, evaporators, & lines need to be placed such that oil will return to the compressor, not puddle in the coils.

I'm hoping to be able to do this in the bus one day. I've considered using a separate freon system for 110v & stack the otr evap with the 110 evap & use the same fan.
The thought is that when at the power pole, I won't need as much AC capacity as when traveling down the road due to air infiltration & lack of sun shades on the windshields 

Thanks for your help!
kyle

[FloridaCliff]

Kyle,

My GM van has the same setup as yours.

The only thing your doing is shutting off the fan on the rear evaporator.

Note that you can't just use the rear air without the front on also.

I thought there might have been some sort of electric valve on the system, but when I replaced Julies

compressor a year ago I went through my factory shop manuals and NO such thing.

Cliff