Earth Tubes in cold climates (NY)

[ListerD]

Note: This topic was split off from an earlier discussion of a small earth bermed house going up in upstate NY:
http://countryplans.com/smf/index.php?topic=5690

The earth tubes are really just to help moderate incoming temp and keep fresh air.  So many people now believe that they have to make a house air tight which is unhealthy.   In a conventional house where heat is store mostly in the air it's a bitch lol, you almost have to?  The mass here should allow me to swap out air for a better indoor environment without losing my heat.   There are 2 incoming 4" tubes and will be 2 tubes going out the back for exhaust with fans setup on them.   A great resource for earthtubes is the http://www.thenaturalhome.com/earthtube.htm.   He had some good tips on cleaning and maintenance.  I'm not sure about a few of the details but overall it's a great site and where I first found out about drystacking as well.

We're planning on using a lot of the ideas from thenaturalhome.com, I just can't wrap my head around earthtubes in our area of Missouri. We talked about different ways of treating the air (to remove humidity) before it enters the house through the tubes including weep holes below grade. Just can't come up with one that's efficient or effective enough without raising maintenance tasks.

The best we came up with (and I believe it was John who suggested it) was to use the weep holes and then have a rag tied to a string both ways in the tubes to allow for cleaning in the future (like you run string in a dead electrical chase for future expansion).

The other contender was to have the intakes as high as possible in the air and running them into external shed and in there use a whole house dehumidifier and then let the air fall into the underground portion of the system and then into the house.

[ListerD]

I guess I read the cleaning thing on thenaturalhome.com site...  Credit where credit is due... I know John and Glenn both had ideas. Guess I'll read my own post again.

[speedfunk]

Lister:

You pretty much described what we are going to do.  The earth tubes with have an overall downward slope from the house.  Both in the front and the back.   The slope should be pretty substantial ,  maybe 20 degree's in the front and 15 in the back.  We will do the weep holes and the string so we can pull the cloth through just like natural home which seems like a very good idea.   We will also have fans setup to control the air.  Natural convection is supposed to work but it's the one part of the house that I'm making "Active".

There is little to no info on earth tubes that I've found so if you see something send it my way!!   I'm guessing on the amount of tubes also but I think it scales well lol.  we will see. 

One thing I didn't think made sense with natural homes way of running earthtubes is that they ran them right next to each other.   The PAHS book I read on them did not recommend that.   I've separated mine so we will see.  BTW if you do want more info on earthtubes, this is by the far the best book  I've found!   I cannot plug this enough, just a very unbiased, logically way of looking at passive heat storage.
http://www.earthshelters.com/PAHS_Improving_ch_1_intro.html

[glenn kangiser]

I believe the earthtubes should start uphill and fall to the house with drains at the bottom by the house, as cool air is heavier than warm air so as the air cools it will fall pulling in more warm air from the top of the hill.  As it cools it loses it's capacity to carry moisture so the water will run out at the low point at the house along with the cool air.  

Whitlock mentioned a house north of here where the tubes were put in wrong,  high at the house and ran down hill and they worked backward pulling warm air into the house as the heavy cooler air exited down hill.

[bgarrett]

....... and get the pvc earthtubes intakes up to floor level THEN dirt backfill

Jeff

Hi Jeff, I googled for earthtubes and found your thread.
I read the entire thread but this is the first mention of earthtubes.
Will you please describe what you plan and the results you hope for?

I am working on a property in Arkansas near the Missouri border and hope to put the earthtubes in, in about two weeks.
My property is on a slope, and I had the bulldozer guy make me a flat spot.
My plan is a 40 by 40 foot pole barn with a concrete floor, using 4 earthtubes that are 15 inch diameter and about 100 feet long, buried about 6 feet deep, straight runs to daylight.
My son is an engineer so he and another engineer made up a spreadsheet for me and 15", 100" is what I plan,  hoping for 2 tons of cooling per tube.

[bgarrett]

I believe the earthtubes should start uphill and fall to the house with drains at the bottom by the house, as cool air is heavier than warm air so as the air cools it will fall pulling in more warm air from the top of the hill.  As it cools it loses it's capacity to carry moisture so the water will run out at the low point at the house along with the cool air.  

Whitlock mentioned a house north of here where the tubes were put in wrong,  high at the house and ran down hill and they worked backward pulling warm air into the house as the heavy cooler air exited down hill.

If the tubes are run your way, how would the condensate drain out?
I have been searching the internet for three years hoping to learn about earthtubes and no one else suggests running them downhill to the house.
Most of the websites suggest combining earthtubes with solar chimneys, to create an upward draft.
My engineer suggests a high rate of flow that may not be possible by natural forces, so I am considering solar powered attic fans to assist.

[bgarrett]

We're planning on using a lot of the ideas from thenaturalhome.com, I just can't wrap my head around earthtubes in our area of Missouri. We talked about different ways of treating the air (to remove humidity) before it enters the house through the tubes including weep holes below grade.

Lister, my plan is to put an earthtube in each of my four corners of the building.
Each tube will go down about 5 feet and then run straight to the edge of my plateau which has a dropoff of about 7 feet.
That will give a nice slope to each pipe, allowing condensate to run out of the pipe.
Drawing hot air thru the cooler earth causes dehumidification.
Faster air flow causes more dehumidification.
Because I prefer to pay as I go and do all the work myself,
I will set  the earthtubes, then erect the building.
By the time I get the walls closed in the experiment will be functioning.
I will be able to determine how much natural airflow I am getting with the solar chimney effect and can install one fan to find out how much difference it makes.
If I need more cooling or more dehumidification, I can add more fans.

thenaturalhome website assumes you are on a flat property and takes a rather negative approach to the success of earthtube climate control.
I may be over optimistic...we will see.
several people have suggested that I set up an experiment first to see how it works.
Yep, thats what I am doing. A full scale, full price experiment, but I see no way to experiment on a smaller scale.

[ListerD]

(maybe we need to create an earthtube thread?)

The tubes running "downhill" makes good sense to me. Glenn points to the common sense part of cool air falling that I keep forgetting.

I still can't wrap my head around the weep holes in some ways. I know it's not enough moisture to worry about and I'm sure it would be readily absorbed, but introducing additional moisture under my slab somehow makes me nervous. 

bgarret - where are you located?

speedfunk - I think the idea of placing them together was to get as much as possible absorption out of the ground. I figured a larger pipe made more sense since it provides more surface area.

[Bishopknight]

Just fyi:

I read recently that Rob Roy, author of earth-sheltered houses, does not endorse earthtubes in his book because of Radon concerns.

[ListerD]

OK, I'll bite - IF the tube is open outside *above* ground, *sealed* for the entire underground distance (except for possibly a few small weep holes) and then opens up in the home *above* ground, how does the radon get in?  

Surely Radon can't pass through the tubing?     I know it comes in via unsealed/cracked foundations, bad sumps and etc... I thought it was too dense to pass through most materials.

Maybe I'm dense? 

If the house takes in ventilation from low points besides the tubes, or the flow is high enough from the tubes the ventilation should be high enough to have it eliminated. No?

[speedfunk]

Cool, thoughtful discussion on earth tubes going on. 

bgarrett welcome!

wow ..that seems like a substantial project .  Please keep us posted on how this turns out.   Sometimes as a good friend says " ya can't be scared" go for it!  We need people to try this stuff so we all can learn

I'd like elaborate on the goals of this setup for me.  B/c I think each of us has a different climate and needs for earthtubes.  First off I'm in cold upstate NY so to be honest cooling is not really that big of a deal.  I know the system will cool a bitin summer but I'm really not designing for that goal in y mind.  I'm also not expecting earthtubes to completely heat my house.  The mass around my house will moderate (heat/cool) our house and provide the storage of heat for the earthtubes to use to warm incoming air and retrieve some of that outgoing heat.  The intakes for me are just taking the chill out of the winter air in the most passive way I can, and keeping us happy and healthy, while also trying to recoup as much heat as  possible on way out.

Condensation: something that is usually brought up, but for me personally winter air tends to be dry and warming it up will not add any moisture (I BELIEVE!).  In the summer here in NY which can me humid  The reason to pitch the tubes downward makes sense also.  Why invite water (run off or condensation )to drain into your house.  So this is why I"m doing that.  This will also allow me to clean the tubes using alternative methods.  I could run a hose temporarily to them when I want to clean them and follow that with the rag on a string and a good chemical free cleaning that will dilute and drain any bad stuff that MIGHT grow in the tubes. 

Radon:  Following listers logic on this one.   I can't see how radon would get into the earthtubes except for VERY minor amounts that will be diluted by a massive amount (relative to the intake of drain holes that the radon could get into) of fresh air being brought in.   I think the big thing here is that as long as you constantly have fresh air coming in you will have healthy home.  locking it up tight allows small amounts of bad gases ( ) to linger and pollute your indoor environment.   

ListerD:  Yeah a larger pipe does have more total surface area but smaller pipes have more contact area per volume unit of air.   This make sense, I;d have to do the math? lol    .  The reason that the pipes being separated is good is b/c eventually if you have all the pipes in one area the ground around that area around group of pipes  will equalize  to the pipes temp and losing it's effectiveness.  As in where the pipes are separated by farther distances that earth doesn't have as much stress put on it to heat or cool the air and can maintain it's temp better overr a longer period of time.

Great discussion all. 

[bgarrett]

Lister, there will be no 'weepholes' in my earthtubes.

Therefore no radon entering.

The only thing entering my earthtubes is outside air.



Thank you for the welcome Jeff.

Let me say again, all I have is ideas.

There are no facts yet.

I will document and share my results.



My tubes are going downhill so the condensation will drain out the open intake.

Earthtubes are used in conjunction with a solar chimney so air is drawn in and continuously moves upward til it leaves at the top of the building.



The earthtubes are located at each corner of the building and are far apart.

Placing several tubes in one excavation will defeat the purpose of using the earths normal temperature to temper the air in the tubes.



I have been searching the internet for 3 years for earthtube information and what I find suggests tubes from 6 to 18 inches, about 100 feet long.

Using a 4 inch tube would be like sucking thru a very small straw.

You want easy flow of air but not tubes so big that the air passes thru without being affected by the earths temperature.



I have a flow chart make up by real engineers and will be happy to share it, if I can.

It allow the user to plug in any size pipe and see the results.

My goal is to get as close as I can to room temperature equalling the earths temperature.
This is not achieveable, of course but will decrease my need for additional heat and cooling.

[ListerD]

My tubes are going downhill so the condensation will drain out the open intake.

I'm not sure about this as I can see that as temps fall in the house at night, the cycle is reversed and it allows the cool air to fall out of the home and then drawing air in from the top, reversing the chimney effect. Rather than maintaining the temps via the mass releasing heat into the home.

Guys? Sanity check?

Earthtubes are used in conjunction with a solar chimney so air is drawn in and continuously moves upward til it leaves at the top of the building.

See above.

I have been searching the internet for 3 years for earthtube information and what I find suggests tubes from 6 to 18 inches, about 100 feet long.

Using a 4 inch tube would be like sucking thru a very small straw.

You want easy flow of air but not tubes so big that the air passes thru without being affected by the earths temperature.

Makes sense to me.

I have a flow chart make up by real engineers and will be happy to share it, if I can.

It allow the user to plug in any size pipe and see the results.

Oh PLEASE DO share it! 

[speedfunk]

bgarrett: yeah please share the flow chart, that would be very helpful!!  It sounds like you given this a lot of time.
I'm kind of stuck with 4"s though lol.  I'm ok with that though, it's what I decided on.  My thought is our house is not all that big and wouldn't need that much air exchange.  I never sat down and figured out "real" values though.  So it is what it is.

[bgarrett]

Its a Microsoft Works spreadsheet.
How can I transfer it to this forum?

[glenn kangiser]

I believe the earthtubes should start uphill and fall to the house with drains at the bottom by the house, as cool air is heavier than warm air so as the air cools it will fall pulling in more warm air from the top of the hill.  As it cools it loses it's capacity to carry moisture so the water will run out at the low point at the house along with the cool air. 

Whitlock mentioned a house north of here where the tubes were put in wrong,  high at the house and ran down hill and they worked backward pulling warm air into the house as the heavy cooler air exited down hill.

If the tubes are run your way, how would the condensate drain out?
I have been searching the internet for three years hoping to learn about earthtubes and no one else suggests running them downhill to the house.
Most of the websites suggest combining earthtubes with solar chimneys, to create an upward draft.
My engineer suggests a high rate of flow that may not be possible by natural forces, so I am considering solar powered attic fans to assist.

You would have to make a way to drain it at the bottom but that is the natural way cooling air will want to flow - downhill. 

Cooling air gets heavier so wants to fall - you are right - moisture will be dropped as the air becomes heavier and it will flow downhill toward the house.  A cooling tower could be incorporated as in the middle east to enhance the flow.  Solar chimneys could help to draw the cool air across the house.

This is information I studied in flight school on avoiding CAT (clear air turbulence).

Making the cool air go uphill would have to be power assisted.


There is a house near here where the tubes go downhill and warm air is sucked into the house as the cooled air exits downhill.  It will not naturally work that way - it will need power assist.

[bgarrett]

this forum will not accept the spreadsheet
it says "The upload folder is full"

[ListerD]

If you want to email it to me I can share it from my webserver.

[ListerD]

http://cid-3ceb429f78459841.skydrive.live.com/self.aspx/Public/heat%20exchanger.xls

Here's the EarthTube spreadsheet that was mentioned earlier.

Not sure I'm following it, so if you can explain it that would help some.  

[bgarrett]

Rick, I clicked on your link but do not see it
Is it working?

I sent two of the spreadsheet, one with 16 degrees outside air and one with 95 degree air.
This is a working spreadsheet and you can substitute any ground temp and outside air and pipe size.

Column A (misspelled the word 'iteration')   which means repetition or sequence

this column numbers the 100 feet of the pipe with

Column B showing each foot of the pipe

Column C is the same as B but in meters (dont ask me why the engineers did that)

Column D is the diameter of the pipe and you can plug in any size you want and get results

I put in 15" because the plumber has it available

4" would be too restrictive and 36" would be too expensive

Column E is 15" in meters

Column F and G are way beyond my comprehension, I guess you'll have to google

Column H is another where you can substitute your ground temperature or any other

Column I is where you plug in the outside air temperature

I have lived in hot humid Louisiana all my life, so I put 95 degrees here, looking for the amount of cooling I could hope for

I also plugged in 16 degrees because I wanted to know the temperature of the outlet on a cold day

Columns J thru N are  Engineers stuff--I dunno

Column O to T are airflow which will have to have mechanical assist to be reached

Column U and V--ask an engineer

and Finally Column X shows the temperature of the air each foot of the 100 foot pipe and at the outlet



I hope this helps you understand what the spreadsheet shows and my limited understanding of it

[ListerD]

Rick, I clicked on your link but do not see it
Is it working?

Yes, click the big spreadsheet icon.

This should also work as a direct download:
http://yqtynw.blu.livefilestore.com/y1pRoCtS55V4HIrkYrgwbei1exC4eUthRgwMEF6x4SVl9VM31XU7mPmNbK-o5BWEKGynkgifz8ltbwxWkyNDp_jMA/heat%20exchanger.xls?download

[bgarrett]

Thank you for posting it, Rick.
I hope everyone can see it.
I look forward to comments.
I am trusting the engineers, but not sure if what they are  telling me will work.  
I plan to start digging and burying the pipe in just a few days so y'all Speak Up!

[bgarrett]

Some websites say that earthtubes were a fad in the 70s and 80s but nowhere do I find any other information telling whether they succeeded or failed.

Has anyone seen any results?

If mine doesnt work I will say so  and of course if it does work I will tell that too.

[drainl]

July 30 - August 3

It feels like we didn’t get much done in July for various reasons, but I feel a little better when I look through our photos from the month.  Jeff finished up July getting the inside of the house parged so we could bring it up to floor level with dirt.  There’s been a lot of rain this summer, so timing has been tough.  My main job is still stacking blocks, which were getting hard to lift onto the wall, so I’m happy the ground is higher now.

Here’s our supervisor checking out our work from our lovely front stairs.



We got the two sonotubes filled with concrete for the posts.



Photos of the two earth tubes (which I know nothing about so I won't add to that conversation!)





All ready to go!  Jeff had to move a bunch of materials inside and outside the house to make room for Vinny and the excavator.



First he filled in the ditch for the electrical lines.



Then the inside of the house got filled.  I had fears of one of my walls getting knocked down, but I had nothing to worry about!





And then on to the biggest project - Jeff decided it’d be best to put in the two posts (aka trees) while we had the machinery.  They were successful as you can see.  We’ll debark the trees and poly them eventually.  Until we get the roof on we’ll need the extra bracing.  It’ll be interesting to see what our inspector thinks of the trees.  They look impressive when you drive up to the house.  They’re 2-3 feet taller than they need to be, so we’ll trim them when we get to the roof.  You can also see we left area open in the bathroom for a crawlspace.



Total bill for the day was $708.  Now we need to place an order tomorrow for more block (6 pallets were thinking) and a pallet of SBC.  That and installing windows will keep us busy for awhile.  We really want to get the roof on before the first snowfall.  Last year we got 8″ mid October.  Fingers crossed!

[bgarrett]

Looking Good!
I apologize for kinda hijacking your thread