Building a Micro-Split AC System

You will probably have to have the compressor start at full speed then switch to a slower speed. What about using a soft start that is used in RV and Boat AC systems. It will help in dropping that massive compressor surge everytime it starts up.
 

dreadlocks

Well-known member
would there be any way to just steal the compressor out of one of these and wire it up in parallel with the vehicles existing evap and condenser? or is the vehicles electric radiator fans too much wattage to make this reasonable? I'm wanting to install both shore power and engine powered AirCon into my Westy with its engine swap and since its gonna have to be all custom and I'd rather just have one condenser and evap to install.. I thought about just wiring up an AC motor on a custom bracket to a double clutch belt on the engine compressor but that seems rather rube goldberg.
 

dreadlocks

Well-known member
I'm fine with that as there's no way in hell I can fit enough solar on that lil VW to run it off battery, the radiator I'm looking at is not that big, its a little drag race radiator shrouded w/fan.. it can be powered by genset, and I'll have full control over fan speed.. but for a bigger vehicle to try solar mebe an aux fan that only runs for AC that is more reasonable?
 
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luthj

Engineer In Residence
You will probably have to have the compressor start at full speed then switch to a slower speed. What about using a soft start that is used in RV and Boat AC systems. It will help in dropping that massive compressor surge everytime it starts up.
I don't have any issue with startup surge, as I have a 3kw inverter. I am mostly just thinking of ways to reduce cycling and power consumption when cooling just my bed area. In modest temps, such as a 80F night with 100% humidity, I may want to sleep in comfort. That doesn't need a lot of BTUs.


would there be any way to just steal the compressor out of one of these and wire it up in parallel with the vehicles existing evap and condenser? or is the vehicles electric radiator fans too much wattage to make this reasonable? I'm wanting to install both shore power and engine powered AirCon into my Westy with its engine swap and since its gonna have to be all custom and I'd rather just have one condenser and evap to install.. I thought about just wiring up an AC motor on a custom bracket to a double clutch belt on the engine compressor but that seems rather rube goldberg.
Its possible to plumb two compressors in parallel, however you may need check valves on their outputs. You need to choose a compressor with the correct displacement for your refrigerant. Many automotive systems have mechanical or electrical controlled variable displacement compressors. So there are considerations at play. From a technical standpoint there is no reason you cannot make a dual power system. The issue is making sure your control and air flow mechanisms work with the engine off. On something like a Vanagon Westy that's not an issue, as the system is mechanical with a expansion valve and constant displacement compressor. Just be aware that automotive systems are pretty inefficient with COPs of 1.5-2.5 at best.
 

tanuki.himself

Active member
There would be a marked for such a product :) Please keep us updated - if it works!

Surfy
they do exist


but very low powered, still heavy and expensive. And if the product is as bad as the web site i would avoid it like the plague....
 

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The Artisan

Adventurer
Picked up some 16 and 22 gauge steel sheet and started hacking a bit.





Welding dirty 28 gauge metal is not fun with 0.03" wire, bit it should hold together.

IS there is a reason you welded it. Could it be done with sheet metal, bent sides and screwed. Looking forward to updates
Kevin
 

luthj

Engineer In Residence
IS there is a reason you welded it. Could it be done with sheet metal, bent sides and screwed. Looking forward to updates
Kevin
The process could be performed using just rivets. Sheetmetal screws tend to loosen over time. Small machine bolts could work, but there is limited interior clearance in spots. I chose to weld because I had the machine setup from another project. The evap will require some different assembly, so I am considering 1/8" blind rivets to hold that together. If you plan to brake/bend sheetmetal, there are some small vice breaks which will work fine with 22 gauge. Depending on how you plan to attach the condenser unit, you could use 24-26 gauge, or even galvanized. That material is thin, so its not suited to attaching brackets for suspending a 20-25lb compressor on its own.

The evaporator needs a water tight drain pan, so you need to factor that into the fabrication. Either make a new one (or use a plastic tub?), or return the existing halved pan to water tight status. I still need to source a drain fitting, but some 1/4" steel tubing should work.
 
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The Artisan

Adventurer
The process could be performed using just rivets. Sheetmetal screws tend to loosen over time. Small machine bolts could work, but there is limited interior clearance in spots. I chose to weld because I had the machine setup from another project. The evap will require some different assembly, so I am considering 1/8" blind rivets to hold that together. If you plan to brake/bend sheetmetal, there are some small vice breaks which will work fine with 22 gauge. If you Depending on how you plant to attach the condenser unit, you could use 24-26 gauge, or even galvanized. That material is thin, so its not suited to attaching brackets for suspending a 20-25lb compressor on its own.

The evaporator needs a water tight drain pan, so you need to factor that into the fabrication. Either make a new one (or use a plastic tub?), or return the existing halved pan to water tight status. I still need to source a drain fitting, but some 1/4" steel tubing should work.
Thanks I plan to use a catch tank for the water to reuse for shower and sink
Kevin
 

jmnielsen

Tinkerer
Very cool! I wanted to try something like this for my truck camper, but needed AC quick and didn't have time to mess around with this. I'm surprised there is nothing on the market in this size range for a decent price. I've seen 12v ones but they seem to start around $3k. Maybe I'll pick on up and play with it for a future build.
 

Alloy

Well-known member
Initial work on this subject is over here.





Another issue is sealing the motor on the outside unit. It will be exposed to dust and moisture. Neither end of the shaft has a seal. One side can just be capped, as I will be cutting the unused shaft off. The other side is 8mm, I think there is room to glue a shaft seal to the motor housing, and then seal the wire penetration. That should eliminate issues with dust/moisture.

We've been on trips in the spring when they spray the sufficant on the FS roads and end up with 1/4"-3/8" of mud that dries like plaster to everthing. The sufficant must be alkaline as there is electrolysis on all the aluminum.
 
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