Shipping Container solar AC

[sunshine_eggo]

Want to thank the OP and @Bluedog225 for the ideas. I had wanted to do something similar, but I never had the bandwidth to give it much thought. Both are great solutions.

 

[SoakedUp]

Others have reported that insulating the outside is far more effective than insulating the inside. Even just shading the outside makes a big difference.

Ideally I would like to panel the outside East and west walls and put some kind of insulation under the paneling. Trying to decide if I should throw insulation under the panels on the roof. I like the gap for air flow to help keep the panels cool.

 

[sunshine_eggo]

Ideally I would like to panel the outside East and west walls and put some kind of insulation under the paneling. Trying to decide if I should throw insulation under the panels on the roof. I like the gap for air flow to help keep the panels cool.

Generally speaking, it's one or the other or both everywhere. If you insulate on the inside in some areas, and the outside in others, you get thermal bridging at the gap, and you don't get the R-value the materials should yield.

I'd keep the gap.

 

[Rednecktek]

I currently have a 12k btu Mr. Cool mini split in the cabin next to this container. It’s awesome. The problem is its start up power is about 1200-1300 watts for about 3-5 min. I’m using a Victron 12/1200 inverter with my solar which will sometimes power that mini split but sometimes it will trip the inverter. I plan to get a bigger inverter but I’m not there yet. Also a mini split is in the $1000-1500 range plus the bigger inverter to run it. The window unit is $400 and can run off my existing inverter. This window unit essentially is a small mini-split. Inverter technology in a small window size package.

A mini-split just needs a place to fish the tubes and wires through, you could mount the exterior unit outsidecand fish everything under and up through the floor.

Either way if you don't get the heat OUT of the container then it's still hot in there.

 

[SoakedUp]

A mini-split just needs a place to fish the tubes and wires through, you could mount the exterior unit outsidecand fish everything under and up through the floor.

Either way if you don't get the heat OUT of the container then it's still hot in there.

Yeah. A mini split would be the best option cost aside.

My OP was asking about just transferring the heat from one side to the other with an insulated wall between two halves. I don’t care how hot the front half gets I just need the back half where the solar equipment is to stay a bit cooler than ambient temps. I would then exhaust the front half with an 4-6” inline vent fan Through the floor.

 

[Rednecktek]

Ok, let me put it out this way.

Your container gets hot in the sun, and any AirCon just moves heat from where you don't want it to where you don't care. So, throwing a 12k BTU aircon in the wall between the 2 sides would remove 12k BTU's from the battery room and put it in the warm side every hour.

Personally I think putting a 12k BTU heater into a shipping container that's already getting cooked will overload the condensor really quick and get the warm side unbearably hot. Aircon units get less and less efficient as the temperature rises on the condenser up until they just shut down all together.

Exausting out the floor makes for a negative pressure system so you'll need to not only get air up in there but also get that fresh air to the aircon unit.

The best thing you can do is the minisplit idea with the condenser unit outside and keep that excess heat out of the container all together.

Next best option is a freestanding portable dual hose aircon in the battery room and duct it right to the floor. There are nice heat pump units with a tube-in-tube design so they don't try to suck fresh air from the space creating a negative pressure issue. Keep the 2 sections completely seperated and insulated.

 

[Bluedog225]

The Costco Mideast [edit Midea] portable is inverter and dual hose.

 

[SoakedUp]

The Costco Mideast portable is inverter and dual hose.

Yeah I’m looking at it. A bit more expensive but it might be the way to go. Wish they had a 10k or 8k btu unit. 12k might be too much for the victron 12/1200 pheonix. Might need to pick up a multiplus 2000 to make all this work. I’m planning on adding a 48v system in the future and was trying to hold out with the existing 12v inverter I have.

 

[Bluedog225]

I’m going to be setting it up in my house first. If I can find the watts meter plug in thing I have, I may be able to find starting watts.

 

[OhYou_]

I was considering this unit here for a bit but I think I will be going a different route. https://www.amazon.com/gp/product/B0B535XW9K
it has some advantages past the obvious being a 12v.
using r134a, you should be able to rent the equipment from your local auto parts store and assemble/charge it yourself. I think mine even offers free rental with a refunded safety deposit.
it is also a mini split design which as stated before is decently efficient. You can even dig a cave under the container and mount the condenser to the bottom assuming you dont have a rain issue.

Actually a bit interested in this as I'm planning to build out a 40ft hc as a field office/temp living quarters, which will be cooled.

like a cool setup. I’d love to see pics of the panel attachments.

I’m in the process of super insulating my conex. Mylar with spacers, 5” polyiso on the roof and 2.5” on the walls, tyvek to keep cool air from leaking to the hot walls, and 5/8 fireguard sheet rock. all on the first 10’. That will be a little air conditioned room for the solar stuff. The rest of the conex will be lightly insulated and a little hotter.

I decided to get the Midea portable unit from Costco. Just got it. Hole in the floor seems like better security. The thing is a beast as well. I’m going to run it here for the summer and see if it is reliable. And costco returns policy gives me a lot of peace of mind. Cheaper than a split and easy install through the floor.

how did this come out? I'm interested in your choice on wall insulation methods.
my plan on mine is to make a foam cutter and fill the convolutions with styro, then drop down 0.5 sheet styro or maybe tyvec or similar foam. from there a moisture barrier, 1.75 deep studs with rockwool smashed in between and capped off with sheet rock.
I understand the air gap but I'm interested what the differences are between that and the low density foam, just effort of cutting it to shape?

 

[PC99]

Sounds like a cool setup. I’d love to see pics of the panel attachments.

I’m in the process of super insulating my conex. Mylar with spacers, 5” polyiso on the roof and 2.5” on the walls, tyvek to keep cool air from leaking to the hot walls, and 5/8 fireguard sheet rock. all on the first 10’. That will be a little air conditioned room for the solar stuff. The rest of the conex will be lightly insulated and a little hotter.

I decided to get the Midea portable unit from Costco. Just got it. Hole in the floor seems like better security. The thing is a beast as well. I’m going to run it here for the summer and see if it is reliable. And costco returns policy gives me a lot of peace of mind. Cheaper than a split and easy install through the floor.

View attachment 146967View attachment 146968

Hi, how did your A/C and insulation turn out, any updated images? Regards

 

[Bluedog225]

Still working on the finish out details. There were some delays and it’s getting to be hot enough that I can’t work out here anymore. I’ll try again this fall.

 

[orangezero]

I’m going to be setting it up in my house first. If I can find the watts meter plug in thing I have, I may be able to find starting watts.

I think you are talking about the portable one, but if anyone wants to know my midea 8k U-shaped window unit is around 400-500w at full blast, and closer to 300w in low fan/ECO mode. I'm sure it uses less if it just has the fan going but I haven't checked that.

In regards to shading, I aways wondered what would happen to my attic temps if I mounted a tarp on the south side of my house (away from the street so no one sees) that had a 6-12in air gap to allow airflow but shaded a huge section of my black roof all day. I have to think that would be a lot easier to do with a container.

 

[SilverbackMP]

Hey there! You have quite the setup in your 20ft HC shipping container in the Southern California Desert, and keeping your solar equipment, especially those batteries, cool in those scorching temperatures is crucial. Your plan to create a separate, cooled space within the container by constructing a wall and installing an 8k BTU window AC unit for the back 8ft is smart. It's an effective way to focus on cooling where it's needed most without worrying too much about the front 12ft of the container. If you ever need additional storage or a different shipping container setup,

Reported for spam. And really? Dropping keyword rich anchor text on a site which will have nofollow links within user generated content? Go back to SEO school.

 

[Bluedog225]

good bot

 

[superchachi]

I have two 20’ containers. We used Tiger closed cell spray foam to seal up the inside after tension fitting 2x4 wall and ceiling framing and wiring. Sealed it up with drywall, etc.

We mounted a window unit into the front (wood framed) wall. We set the front wall back a couple of feet to allow us to close up the original container doors.

Doing it over again, I would put a mini split in instead of the window unit. I have a z-wave plug monitoring energy usage now and it uses 764w during hot days (105-115F). The container is fairly well shaded under oak trees.

We have a 230v 12k mini-split on a 18x12 shed that uses less than half of that.

Here is a comparison of how the window unit performed yesterday (high of 90F!) versus Sept 5 (high of 109F). Peaks yesterday for the window unit were 669w...but, the run times were way shorter as you can see.

Hope this helps.

 

[SoakedUp]

Update

So I ended up using 2” closed cell foam panels to insulate the back section of my container. I use magnets to hold the panels in place as well as create a small air gap off the steel walls to hopefully help a bit with thermal bridging when the sun beats down on the container.

I sealed all the seams with tape and spray foam. I then erected a 2x4 wall to seal off the room. Rockwool was used to insulate the wall and 1/2” plywood sheathing.

I got a 2 in 1 exhaust tube portable 10kbtu inverter air conditioner. The tube was a weird shape and I didn’t want to cut the hole to fit it in the floor so I only cut a 6” whole for the exhaust portion. I already had a 4” hole cut in the floor with a 4” inline fan so I directed that intake directly at the intake of the air conditioner. Not the best but it works right now to solve the negative pressure build up.

The room stays 15 degrees cooler than outside temps. I’ve tested in 105 degrees so far and that’s without a door installed in the wall yet. I just had some plastic draped over the door opening.

I also picked up a multiplus 12/2000 to handle the air conditioner load a bit easier.

I’m still considering a mini split as I think it will work much better but want to test this set up through the spring as it warms up again. I’m also in the process of some kind of awning or shading for the sides of the container.

Anyways. Here’s some pictures.

 

[JoeHam]

@SoakedUp , you said “ I used 4x4s on the ends of the container bolted down at the corner iso attachment points. ”

Were those commercial ISO connectors like Domino Clamps or did you DIY something to attach the 4x4’s ?

Here is the Domino stuff for example :

Attach almost anything to shipping containers.

Domino Clamps create versatile fixing points on the corners of shipping containers. You can use them to attach almost anything to a shipping container without the need for welding or drilling.

dominoclamps.com

 

[SilverbackMP]

Update

So I ended up using 2” closed cell foam panels to insulate the back section of my container. I use magnets to hold the panels in place as well as create a small air gap off the steel walls to hopefully help a bit with thermal bridging when the sun beats down on the container.

I sealed all the seams with tape and spray foam. I then erected a 2x4 wall to seal off the room. Rockwool was used to insulate the wall and 1/2” plywood sheathing.

I got a 2 in 1 exhaust tube portable 10kbtu inverter air conditioner. The tube was a weird shape and I didn’t want to cut the hole to fit it in the floor so I only cut a 6” whole for the exhaust portion. I already had a 4” hole cut in the floor with a 4” inline fan so I directed that intake directly at the intake of the air conditioner. Not the best but it works right now to solve the negative pressure build up.

The room stays 15 degrees cooler than outside temps. I’ve tested in 105 degrees so far and that’s without a door installed in the wall yet. I just had some plastic draped over the door opening.

I also picked up a multiplus 12/2000 to handle the air conditioner load a bit easier.

I’m still considering a mini split as I think it will work much better but want to test this set up through the spring as it warms up again. I’m also in the process of some kind of awning or shading for the sides of the container.

Anyways. Here’s some pictures.

View attachment 177640View attachment 177641View attachment 177642View attachment 177643View attachment 177644View attachment 177645

If I get a few of these and insulate them, I’m going take a track saw and cut the foam to completely fill the ribs because of condensation. And then apply another layer to get as much coverage on the metal as possible.

Or have them spray foamed.

Not really pertinent to your location, just more of a PSA to those of us in more humid and colder climates.

 

[Bluedog225]

That looks great. Nice workmanship. Those new conex floors are pristine.

Strangely, my conex is already full of carp. And the floors are muddy. Weird. ?

On shading the outside, any barrier with an air gap will make a big difference for direct sun. Like the old safari land rovers. I was thinking of metal roofing attached with magnets on the sunny side. Should stick and it would take a heck of a wind to get underneath. Or a mixture of magnets and adhesive so you could mount and let it cure.

Also, if I didn’t mention earlier, Henry’s elastomeric cool roof paint is great on areas exposed to sun. The metal goes from too hot to touch to cool enough to lay on.

Anyway, well done.