I will be building a shipping container domicilie/shop in the next couple weeks and am designing the cooling system for it now.
I'm looking at installing a ground loop pipe (maybe 1' in diamter) about 6 feet below grade, that will bring in air from ground level, pass it through x feet (probably around 80), then bring it into the container at either a high or low point opposite from the heat exhaust.
Does anyone have experience with this method of cooling?
For what it's worth, I'll also be pouring a lightweight slab for the floor of the container and setting in electric radiant heating. I was considering a hydronic system but it seems like it more trouble creating a system of this scale than it's worth.
p.s. Mod - if there is a better place for this thread, by all means, move it to its rightful home
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An important thing to consider with Earth Tubes, is to make sure that they have a way to drain. They will condense water if you live in a climate with any humidity at all, so that water needs to drain effectively, to avoid encouraging mildew and mold. 1' diameter seems like an awfully big pipe for something as small as a shipping container. What sort of CFMs are you wanting or expecting? It is not clear from your description, but are you making a closed loop, or just an intake pipe. I would favor the latter, since you will need some fresh air anyways, and it might as well be conditioned.
If you search here, there are discussions on cooling tubes with good links. I know some that have worked and some that haven't. They cost a lot more than you think they would by the time you pay for the pipe and excavation. Four or six inch pipe is usually the most economical to use. 12 inch pipe doesn't have enough surface area for the volume to transfer the heat unless you are doing a LONG run.
+1 on proper slope for drainage and a sump at the low point if you can't do a daylight drain.
As for the box:
Is it insulated? Are you adding windows or other ventilation or just tubes and doors?
No affiliation with the link, just a place I knew had pictures and prices. You can do it cheaper if you shop around. A misting system will cool it further if you are in a dryish climate (doesn't help much if you are 80%+ humidity).
Set it up to be able to catch breezes. Even if it gets hot in the day, if you set it up to catch the breeze at dusk it will cool down quickly so you can sleep comfortably.
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Location: Midcoast Maine (zone 5b)
posted 5 years ago
Luke Miller Callahan wrote:What CFM would you shoot for?
I would do an energy analysis (But that's what I do, so...) Somewhere below 50 cfm would be a good starting guess, I should think.
What size pipe would you recommend
4 inch would be sufficient, I think.
What material pipe?
I hate PVC, so I would probably use ABS. Cast iron might work, if you could find scrap. Ceramic would be awesome, but I can't imagine there is any of that around still.
How do you drain a pipe like this?
Rule 1: It must slope at least 1/4" per foot, over it entire length (NO RISES!) to daylight.
Rule 2: Figure out, in advance, how to clean it when it is in service.
Rule 3: Screen the end against critters.
Rule 4: If the end might get buried in snow, you can add an up tube with a cap.
You might consider a solar chimney, a tall black pipe to increase stack effect, and draw air out of the container, on the exhaust side.
Drainage - It is on flat ground so it looks like the best bet will be to have it slope 1" per foot into a veritcal pipe that can capture the water and hold the sump pump. The top end of the vertical pipe will act as the intake for the incoming air. I'll put a chimney cap with screen on it to deter critters, and thinking it will extend up 1-2' above grade... ideal tripping height.
Water Trap - Is there any advantage at all in using some sort of water trap to keep debris out of it? It seems like it will probably be more trouble than it's worth, just inquiring if there is any value in it.
Reducing pipe somewhere along the way - to create a venturi effect to help move air along. No idea if this would be beneficial, but you guys might.
I will be putting doors and windows into this. I'm also tentatively thinking about putting a vapor barrier on top and around 3 sides and adding dirt around it. This probably will not happen, but could in the future.
I'll be positioning it so one end receives the prevailing wind which should help.
This will be a 40' high cube (9.5') and it may or may not be insulated (old reefer) depending on what I can find sub $4k.
Thanks for the input guys, I really appreciate it. I'll post some pictures and maybe even a video once I get rolling on it in a couple weeks.
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The reason earth tubes havent taken off is that humid air condenses on the interior walls of the cool pipe, collects dust/pollen and grows mold and mildew. Its the cleaning part thats supposed to solve this serious issue so dont take it lightly. I would love to hear how you plan on cleaning this system where one end is buried. I would think that for proper cleaning you need good access at both ends to pull a pig/plug on a rope or wire.
Its possible your sump pump will burn more energy than the preferred methods of providing fresh outdoor air; an exhaust fan, ERV or HRV.
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My experience with my shipping container is that If you have an exposed south facing wall it will get hot very quickly in the sun, even if it's partially shaded some of the day. on a sunny 60f day this spring it was stifling inside container, closer to 90f. I would suggest screening or insulating at least that wall if you are going to be living inside. Even something like reflectix Mylar bubble wrap would do a great deal of good.
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