So, I ripped apart a "window shaker" to get a good look inside. Immediately I noticed two things. This unit is a sealed system with no service valve and it's using the new eco-friendly R410A refrigerant. My hope is to be able to take a cheap wall unit like this and reconfigure it so that the condensor and evaporator coils are in separate parts of the van, something like the split units mentioned earlier but way more compact and about $1,000 cheaper.
These units are painfully simple in design and the sections can be spaced out by splicing and brazing in new longer lines. The biggest obstacle is the pressure within those lines. R410A is under nearly 500psi of pressure. That is scary stuff for the inexperienced tinkerer. Add to that the lack of a service valve and things could get interesting. A bullet valve would be needed to bolt onto the line and puncture it for pressure relief into either a suitable recovery tank...or...well, the air we breathe. Supposedly R410A is not ozone depleting.
I only use "supco" Bullet valves, I've used them for years and was working on a system with one on it, hit 550psi and no leaks. Two Supco bullet valves, a recovery machine and tank & nitrogen, will get you an empty system thats ready to cut/weld. Please don't let your freon into the atmosphere.
My original idea was to take this unit and convert it so it could run on R134A like the stock AC in the van and be powered using an inverter and house batteries and/or solar. After a little research and a consult with Leeann and her hubby I found that this is not as straight forward as I had hoped. The compressor for R410A is not compatible with R134A. So I began looking into swapping out the compressor for one that is designed to pump R134A. This seems possible as the rest of the system is just tubing and should work fine no matter the refrigerant used. The only problem is that for whatever reason new electronic R134A compressors tend to be priced in the $200 range! That kinda defeats the cheap aspect of this mod.
Yes, keep the R410a and its matching compressor oil, the expansion device in your window shaker is designed for the characteristics of R410a.
It is possible to open the existing system, braze in longer piping and refill with R410A and not have to swap out or replace any of the existing parts. This refrigerant is available for purchase without a license on the internet. I'm not entirely sure yet how much refrigerant would be needed (if any provided you are able to collect the original in a recovery tank) but it costs about $100 for 25lb tank. The filling process is the same as any other AC system, requiring pre-vaccumed lines, a set of gauges and manifold. A weight scale may be needed as well since these systems are best refilled by monitoring the weight of refrigerant added. Add another $200 for those tools. Now we're looking at a $400-$500 system and that doesn't include the extension lines and whatever materials you require to create an enclosure and mounting system. This is getting expensive, but still weighing in about about 100lbs less than a pre-made split system and a hell of a lot more compact.
I would at a minimum add a small liquid line filter drier and weld in two schrader/service ports. Refrigerant weigh in is the accurate way to do it. Too much freon will flood the compressor, bad, not enough freon compressor overheats, really bad. If you like to freeze, maybe look at an 8500 or 10,000 btu window shaker to help with satisfying your cooling load.
Anyway, here are some pix of the 6,000btu unit I surveyed:
There are two separate rooms in this unit. The front part that is made out of a styrofoam enclosure has a fan blade inside that sucks air through the evaporator coil and out through the top vents. The rear portion consists of a fan blade inside a shroud that sucks ambient outside air in from vents in the side of the outer housing (removed for pix) and pushes it through the condensor coils back to the outside world. One motor with dual shafts is used to power both fans. The compressor is the black canister.
Inside the electrical panel:
Even though it will cost me some coin I am half tempted to continue exploring this project. I already have a vacuum pump so the tools and materials would cost me an additional $300 to $400. For me that is way worth it compared to some gigantic and heavy split system made for a house that weighs 150lbs and costs over $1200. It is however way less practical than just mounting the unit through the side of the van or out the back window. I don't have dutch doors so that cool little opening below the hatch isn't a possibility for me. I would have maybe done a permanent install in the drivers side rear door but my tire carrier is in the way. There are probably 100 other ways to mount an un-modded unit but I have a preference for an integrated assembly.
The controls are really simple for an a/c, unlimited possibilities!
Ideally I would want the evaporator coil mounted inside the van someplace and the condensor coil underneath the van. Clearly I will need to add some sort of electric fan onto each coil, the exact same type as used for an e-fan conversion on the radiator. Piping needs to be extended and pass through the floor.
This will work just need to match the cfm of the fan to the original design or add a head pressure controller they're kinda expensive though. At this point its all about airflow, the proper amount though.
Take all this with a grain of salt. I am by no means knowledgeable on AC systems. My only experience is a clean piece by piece install of the R134A system in my van which was surprisingly easy. I have zero experience with R410A based systems. Anyone knowledgeable please feel free to add your suggestions and possible techniques for expanding the piping on this type of system.
Extending the lines is no problem, Nitrogen brazing with 15% silfos rod, stay away from mechanical connections! I've been hvac for 10 plus years now, I've done some pretty inventive stuff. Noting that I usually get to put my equipment in under stairways, closets, attics,crawl spaces, rarely do we get the room we want. It helps with this kind of project though.