EcoRenovator

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-   -   DIY Earth Tubes? (https://ecorenovator.org/forum/showthread.php?t=2279)

DirtFlinger 06-27-12 04:34 PM

Please ignore the green colored ground. If it's ever green it'll be artificial grass. :D

I haven't used sketchup in months and I can't remember how to change that! Anybody know where the setting for the background images is?

DirtFlinger 06-27-12 05:52 PM

Here's a better view:
http://ecorenovator.org/forum/member...rthtubes-3.jpg

I even added an inline fan, colored weird but easier to see in the model. I think it could run at a very low speed. I didn't have time to add arrows to the screenshot but obviously hot air would get sucked into the upper vents, travel through the earth tubes and exit the lower vents into both rooms.

It seems like each "hole" could lead to an actual adjustable vent like is common in forced air headed homes.

I just have no way to tell what size tubes to actually use; 4", 6" or maybe even 8". But, it's such a small space.

DirtFlinger 06-27-12 05:54 PM

Aw, man I just realized I'd also need some sort of one way valve for at least one of the openings.

OffGridKindaGuy 06-28-12 05:17 AM

I believe that you will need more area for your collector..

Quote.. Home Air Conditioning

"However, if your air conditioning needs are for more than a few hours at a time, this approach will soon lose its effect. Gradually, the soil underneath the basement floor will warm up. Since it is a finite volume of soil (basically the size of the house), once it has all warmed up, the cooling effect would be greatly reduced, until an extended period of non-use occurred so the soil could again cool back down. Anyone who has tried to cool their house in this way has noticed the reduction in cooling effect over time."

DirtFlinger 06-28-12 03:46 PM

Quote:

Originally Posted by OffGridKindaGuy (Post 22656)
I believe that you will need more area for your collector..

Quote.. Home Air Conditioning

"However, if your air conditioning needs are for more than a few hours at a time, this approach will soon lose its effect. Gradually, the soil underneath the basement floor will warm up. Since it is a finite volume of soil (basically the size of the house), once it has all warmed up, the cooling effect would be greatly reduced, until an extended period of non-use occurred so the soil could again cool back down. Anyone who has tried to cool their house in this way has noticed the reduction in cooling effect over time."


Thanks, that was part of my original question(s). Does anyone know the formula or where I can find an online calculator for that?

DirtFlinger 06-28-12 03:47 PM

...for finding the necessary surface area? That would help me figure out what size tubes to use.

OffGridKindaGuy 06-28-12 10:09 PM

The site I linked to is a long read but if you read it fully, it will answer a lot of your questions.

DirtFlinger 06-29-12 01:44 AM

Quote:

Originally Posted by OffGridKindaGuy (Post 22676)
The site I linked to is a long read but if you read it fully, it will answer a lot of your questions.

No, I read it. I saw it. It didn't register right away. You're talking about the area of ground not being able to handle cooling the two rooms.

It's a good point. This little bit of ground might not have enough cool to bother with running tubes through it.

ok. You do know engineers are usually pussies right? I wish I could just get a decent equation for this shiznit.

you guys are pretty useless so far beyond the odd discouragement. wtf? are you all just here to sell sh1t?

DirtFlinger 06-29-12 01:49 AM

Arg, sry just damn wtf? Are all you guys dumb or what? You either know something or you don't. I've never seen a forum with such sleight of hand.

Is everyone dumb or greedy or what? Too realistic? What is this huge block in creativity in energy and homes? Is there some sort of resistence and not awere of ? The builders? Why would they care?

OffGridKindaGuy 06-29-12 05:15 AM

Quote(s)..
"This drawing suggests a very compact arrangement. For example, if a 50 by 50 foot area of yard was involved (about 1/16 acre), nine parallel tubes (six feet apart, or 48 feet across all of them), and each 50 feet in functioning length as shown, a total of around 450 feet of functional tube length would dissipate house heat into the soil. You would probably need around double that amount of the sewer pipe, since they are "bundled" together on their way to and from the building, as the small cross sectional drawing shows. Our drawing does not show the three (or more) identical tubes above the top of the drawing This arrangement would represent a way of installing around 500 lineal feet of heat exchange surfaces in that fairly compact area (counting the bundles). Such a configuration makes sure that one or another of the tubes is within three feet of well over a million pounds of cool soil. (Simple engineering calculations show that that much soil represents over 10,000,000 Btus of cooling available!)"

"In case you're still skeptical, the "heat exchanger" arrangement we are describing has a coefficient U that is around 8 Btu/hr/square foot/F difference. If you look at ONE of our nine tubes, its circumference is around one foot and it is 50 feet long, so its area is around 50 square feet. If the house air begins at 90F and the deep soil temperature is 53F, there is 37F difference. Multiplying these (8 * 50 * 37) gives an effective rating of 14,800 Btu/hr. That's ONE of our tubes, and there are nine of them! This suggests that the total system is capable of about 135,000 Btu/hr cooling, around four times as much as the normal house requires! Well, it could (almost) actually do that for a few minutes, but there are a number of factors that would get it down below 100,000 Btu/hr of cooling in under an hour and within a few hours to the 36,000 Btu/hr that we designed our "standard configuration" for."

"There have been (many) other people who have said they intended to only install four tubes (mostly to save on the cost of digging the trenches) and they figured that was an "improvement". Note again that such an installation would likely only provide around 300 cfm of cooled air to the house. That is certainly enough to nicely cool two or three rooms, but not really enough airflow to give the comfort level that we spoiled Americans expect for a whole house!"

"There are many variables involved, but many installations should be able to use 4" plastic (thinwall) ABS or PVC drain/sewer pipe (called DWV), available at any local 'home' store."

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