Mini Split AC - Locating the outside unit

[aernan]

We are in our early design for a LMTV M1078 conversion.

For those of you who have a mini split unit. Where did you locate the outside portion on your build? Can you offer any guidance on why you chose that location?

 

[Darwin]

It needs to be mounted so that it meets the airflow requirments of the unit. You can find those online. Generally there needs to be a foot or more behind the unit and free flow of air out the front.

 

[aernan]

Between the cab and the box there will be the air cleaner and spare tire. I could also add the mini-split outddor unit there. Alternatively I could mount it under the vehicle somehow. I wonder if you can mount them horizontally.

 

[Darwin]

I don't think they can go horizontally and it doesn't sound there will be enough airflow on either side to mount it between the cab and camper box. It needs at least a foot or more behind where it sucks in air and free unrestricted flow out the other.

 

[aernan]

Thanks werkstad. Looking at some other threads everyone agrees. Don't lay it down.

what are folks doing for AC units. I am reading that mini split AC units can have very high SEER and EER numbers that really beat everything mobile home AC units have to offer but I'm not finding anything that fits the bill. I'm looking for 15k btu but maybe 12k would do or if it's more efficient a pair of 8k units.

 

[dwh]

Fujitsu.

Their North American 230v 9k BTU units (models 9RLS3 and 9RLS3H (high heat)) have a SEER rating of 33 and EER of 18.

The 12k models are 29.3 SEER and 15.2 EER.
The 15k models are 25.3 and 13.8.

Their 115v units are somewhat less.

http://www.fujitsugeneral.com/us/re...alcyon-mini-split-2016-full-line-brochure.pdf

 

[aernan]

Thanks that's amazing efficiency. Now to figure out where to mount the unit on my build.

 

[Grenadiers]

I've installed a pair of these in a restaurant we used to own. Pretty straight-forward, save for the refrigerant lines, had to call in our HVAC guy. Our Saurer 6dm cabin is 15.5x6.5 in size, and we thought mounting a 32 inch wide evaporator on the front bulkhead would be too intrusive. That section is new, as we added 27" of interior space to the existing aluminum Swiss cargo box. We have a Splendide washer/dryer on one side, and a Thetford cassette toilet on the other, so, an evap unit on the wall would have been a head-banger~! We opted for a Rollicool unit, 7.53 seer rating, not efficient, but, portable. Our big batteries and the solar do just fine with it. 479 bucks on Amazon, and not very good reviews. So far, keeps our cabin nice and cool. Just not sure for how long~! Here's a couple pics of our test-stage setup.

 

[Rebuilder]

Thanks that's amazing efficiency. Now to figure out where to mount the unit on my build.

You had mentioned in my build thread that you were going with a telescoping box. If you do end up going that route you could do what I did and mount it on the front between the air box and spare because when the top is up you'll have plenty of airflow. I just went with a window AC unit but I don't see why a split unit wouldn't work.

 

[aernan]

Rebuilder I love what you have done. I might copy it exactly. I like how your cabin does not stick above the cab. Are you able to put the spare tire in at the same time as the AC unit?

 

[aernan]

Grenadiers: I like how the unit you have is so small and low cost. It looks like the power draw would be low enough to run off battery easily.

 

[Rebuilder]

Rebuilder I love what you have done. I might copy it exactly. I like how your cabin does not stick above the cab. Are you able to put the spare tire in at the same time as the AC unit?

Yep. Plenty of room.

 

[Deshet]

I am thinking about mounting a split unit where the tire is now on the LMTV. Thinking about a dual zone unit. One zone in the cab and one zone in the box.

What did you end up doing?

Thanks

 

[aernan]

I looked into having dual zone. It is possible but does add a little bit of compexity. I spoke with some HVAC techs and a HVAC North America Rep and learned a lot let me try to summarize a bit.

I am planning on taking a conventional mini split unit and running direct 48 v DC into the unit to avoid the AC inverter losses. I will buy the smallest unit with the highest efficiency. It is possible to have a dual zone unit and cool the cab for certain. At this point I'm working on designing the structure of the box and getting that built so I can register the vehicle as an RV. So I won't be visiting the AC install until I get that done. Also before that I need to design and install the solar + BMS + batteries to make it possible to run the AC unit.