Sizing an off-grid Air Conditioning (AC) and fan system

[ReluctantTraveler]

Are you building your own box? If so, have you thought of simply building your own ducts, perhaps with booster fans?

You might dump the cold air into a plenum and then use something like a bilge fan (with a speed control to reduce noise) to force air into your two sleeping areas. Ideally, you want a big fan with low volume for low noise. There are some ideas here: https://www.amazon.com/s?k=6+inch+bilge+fan+12v&crid=26MV1OE8UKCMC&sprefix=6+inch+bilge+fan+12v,aps,517&ref=nb_sb_noss

I am, and I'd be happy to run my own ducts if I could find an energy-efficient system that supports ducted installations. So far, I have not.

 

[1000arms]

Have you read through IdaSHO's thread?

https://expeditionportal.com/forum/...eapo-5kbtu-install-in-the-idacamper2-0.214401

Have you looked at this post in another of IdaSHO's threads?

Idacamper2.0 Color change, please let me know your thoughts.

Thanks guys I've started the reassembly. compartment door hardware installed, water fill port installed, shore power port installed, etc etc... And also very happy to report the fresh taillight buckets, redesigned ;) I was really not excited about the boxy buckets, I had started, so I...

expeditionportal.com

 

[ReluctantTraveler]

Have you read through IdaSHO's thread?

https://expeditionportal.com/forum/...eapo-5kbtu-install-in-the-idacamper2-0.214401

Have you looked at this post in another of IdaSHO's threads?

Idacamper2.0 Color change, please let me know your thoughts.

Thanks guys I've started the reassembly. compartment door hardware installed, water fill port installed, shore power port installed, etc etc... And also very happy to report the fresh taillight buckets, redesigned ;) I was really not excited about the boxy buckets, I had started, so I...

expeditionportal.com

I have. He chose to use a residential in window air conditioner. That comes with its own set of tradeoffs and design challenge is that I don’t think are appropriate for my particular needs or wants at this time.

 

[DiploStrat]

My comments are in the thread. You will note that I recommended a radiator fan with a PWM speed control to assure adequate air flow to the compressor.

Seems that is what he had to do eventually.

 

[Peter_n_Margaret]

This is on our existing MH as part of about 1.2kW of solar. The new build will have about 2.1kW of solar.
Check the efficiency (COP = Coefficient of Performance) of A/C contenders carefully. Everything efficient will have an inverter powered compressor motor that reduces power consumption dramatically as the compressor slows down. I have not seen any such 12V units.

Cheers,
Peter
OKA196 motorhome

 

[1000arms]

I have. He chose to use a residential in window air conditioner. That comes with its own set of tradeoffs and design challenge is that I don’t think are appropriate for my particular needs or wants at this time.

Good, I'm glad you are aware of the thread. If you haven't already considered a through-the-wall AC, you might want to. It would likely eliminate some of the problems IdaSHO had, although it still might not be what you want.

 

[ReluctantTraveler]

This is on our existing MH as part of about 1.2kW of solar. The new build will have about 2.1kW of solar.
Check the efficiency (COP = Coefficient of Performance) of A/C contenders carefully. Everything efficient will have an inverter powered compressor motor that reduces power consumption dramatically as the compressor slows down. I have not seen any such 12V units.

Cheers,
Peter
OKA196 motorhome

thanks for the vid!

looks like the 12v unit I’m leaning heavily towards does have a condensor, unless I’m reading this wrong.

ROOFTOP 12V AIR CONDITIONER 12000 BTU FOR VEHICLES: CAMPERVANS, RV, PR

Click here for the Mabru RV Installation Manual Not Recommended for Self Installation* Maximum Cooling Capacity:12000BTUCondenser fan air volume: 2200m3/hEvaporator blower air volume: 600m3/hRefrigerant / Weight: HFC-134a/650gRefrigerant Oil: RH68Unit Size: 970x858x150mmMin Hole size...

mabrustore.com

 

[Peter_n_Margaret]

looks like the 12v unit I’m leaning heavily towards does have a condensor,

Every a/c ever built has a condenser (and an evaporator). The major efficiency increase of the latest ac models is the use of inverter motors which are able to maintain high efficiencies at low motor speeds (where they spend most of their time) as well as high speeds.
Cheers,
Peter
OKA196 motorhome

 

[ReluctantTraveler]

Every a/c ever built has a condenser (and an evaporator). The major efficiency increase of the latest ac models is the use of inverter motors which are able to maintain high efficiencies at low motor speeds (where they spend most of their time) as well as high speeds.
Cheers,
Peter
OKA196 motorhome

Doh, you DID say an inverter motor. Sorry about that!

Looks like the Mabru does also include an inverter. Van Life Outfitters did some tests on both electrical draw and db levels in operation, independent of what the manufacturer states in their literature.

Mabru 12,000 BTU 12 Volt Rooftop Air Conditioner

Affordable, energy-efficient, 12 volt rooftop air conditioner for overland vehicles and camper vans. Best prices, fast shipping!

www.vanlifeoutfitters.com