DIY Digging trenches for Geothermal

[Diggin It]

Y'all are talking about a whole bunch o' diggin' which could take a lot of surface repair, seed/sod, and so on. And you're only getting down a few feet, barely scratching the surface so to speak where the warm and cool may not be all that different than the surface. Does it really make out better than drilling vertical holes 50' deep or more where the temperature could be significantly different?

 

[LD1]

Y'all are talking about a whole bunch o' diggin' which could take a lot of surface repair, seed/sod, and so on. And you're only getting down a few feet, barely scratching the surface so to speak where the warm and cool may not be all that different than the surface. Does it really make out better than drilling vertical holes 50' deep or more where the temperature could be significantly different?

It's more than a few feet. It's 5-6' deep. That's several feet below frost depth. So when it's 0 outside and my loop is in the ground where it's 40 degrees......is drilling a vertical well really all that different?

And large area to repair is relative. Bout a 80 x 120 area in my case. 1/4 acre out of my 4.5 acre mowable yard. And I have a tractor and equipment to fix.

I'm not trying to sell anyone on horizontal or vertical.

Horizontal is cheaper.

Vertical is an option for those that DONT have the land....still gives them the geothermal option for HVAC.

From a preformance standpoint...properly designed....no difference. You are trying to make a problem where one simply doesn't exist

 

[buckeyefarmer]

X2 for LD1

 

[Gofast]

LD1 I read your other post. Thanks for sharing we did go through a lot of the same thought process and math.

I dug under the foundation and up into the crawl space started a 6 am. All hand digging in very hard clay. That was a pain in the butt I am glad it is done. I then mounted the manifold in the crawl space.
I have the first to loops done and the return lines staked 2’ up the trench. it was a muddy mess. They finished digging the trench so I can now install the next two loops then start back filling.
Water is about a foot deep in places.
I was dark when I finished so I did not get any pictures. I was a wet cold muddy mess but ½ done with the loops.

 

[3Ts]

5 years ago, our well driller charged $17/foot for the hole and was the cheapest in the area. Most were charging $20+. I talked to him and he said that he has geothermal using the wells. However, he also said that if you don't have your own equipment to drill the wells, it is not cost effective. He had to have multiple 300' wells for it to work. So, depends on the geology of your area.

 

[buckeyefarmer]

Y'all are talking about a whole bunch o' diggin' which could take a lot of surface repair, seed/sod, and so on. And you're only getting down a few feet, barely scratching the surface so to speak where the warm and cool may not be all that different than the surface. Does it really make out better than drilling vertical holes 50' deep or more where the temperature could be significantly different?

Your hole would need to be 300' minimum per ton, or drill more than one hole per ton.

 

[Reg]

Around here the frost line can go down to 4 ft., not sure how far you need to go down to get to the "constant" 55 or so degrees, but I suspect that it is WAY below 6 ft.

 

[LD1]

Around here the frost line can go down to 4 ft., not sure how far you need to go down to get to the "constant" 55 or so degrees, but I suspect that it is WAY below 6 ft.

It doesnt need a constant 55 degrees to work. 50 works too, so does 40....

 

[Bremse]

Another option if you don稚 have enough land for horizontal is an open loop system. You need a well and a place to dump the water. If your domestic well produces enough flow you don稚 need to drill a new one. The system takes water out of the well, runs it through the heat exchanger and then dumps it into a ditch or creek or dry well. That痴 what I have and it works great. If you have the well already or need it anyways for domestic water then the cost ist a lot less than a closed loop system.

 

[Budweiser John]

Geothermal loops out of sight, out of mind, until???
Our system has been in the ground eleven years and performing beautifully. At the time it was laid the contractor furnished a hand drawn map with coordinates allegedly locating the location of the layout and having no reason to doubt it’s accuracy I simply filed the map with other essential household information.
Fast forward to three weeks ago. My wife and I retrieved the map to flag the location the buried grid in preparation for the erection of our new solar arrays.
With flags in the ground and the solar system located, drilling for the supports commenced and to our absolute horr we discovered the original geo map was over 20’ out of sink with reality thus breaching three out of the five loops with one of the solar piers.
Since the solar company was working from information we furnished and the information we received from the original (now deceased and business closed) geo installer was inaccurate we took a big bite in the bank account for the repair bill.
The moral of the story, check, double check, take pictures, or better yet use global positioning and know where your buried stuff is.
One never knows what the future brings

B. John

 

[Code54]

I try and map everything but we always lay survey tape and often some wire above anything we bury that we care about. The wire is close to the surface for the metal detector to pick up and the survey tape about ½ down so if your digging and a piece of plastic tape comes up it is time to STOP.

 

[Bremse]

I would definitely run tracer wire in the trench to help locate the loops in the future. Pictures with reference points are a good idea as well

 

[ovrszd]

Geothermal loops out of sight, out of mind, until???
Our system has been in the ground eleven years and performing beautifully. At the time it was laid the contractor furnished a hand drawn map with coordinates allegedly locating the location of the layout and having no reason to doubt it痴 accuracy I simply filed the map with other essential household information.
Fast forward to three weeks ago. My wife and I retrieved the map to flag the location the buried grid in preparation for the erection of our new solar arrays.
With flags in the ground and the solar system located, drilling for the supports commenced and to our absolute horr we discovered the original geo map was over 20 out of sink with reality thus breaching three out of the five loops with one of the solar piers.
Since the solar company was working from information we furnished and the information we received from the original (now deceased and business closed) geo installer was inaccurate we took a big bite in the bank account for the repair bill.
The moral of the story, check, double check, take pictures, or better yet use global positioning and know where your buried stuff is.
One never knows what the future brings

B. John

Yep. A drone is also a useful tool.

 

[buckeyefarmer]

I would definitely run tracer wire in the trench to help locate the loops in the future. Pictures with reference points are a good idea as well

I put a 2" pvc pipe with a cap at ground level at each end of my loops. And lots of pictures...

 

[buckeyefarmer]

Another option if you don稚 have enough land for horizontal is an open loop system. You need a well and a place to dump the water. If your domestic well produces enough flow you don稚 need to drill a new one. The system takes water out of the well, runs it through the heat exchanger and then dumps it into a ditch or creek or dry well. That痴 what I have and it works great. If you have the well already or need it anyways for domestic water then the cost ist a lot less than a closed loop system.

This works very "well" if you are over a good aquifer. I know one guy who did this. Very few will have this good of water supply.

 

[Gofast]

I have all my loops run. I have about 200 foot covered back up 2' - 3' My 1710 FEL is doing a good job. It has many hours of work ahead of it.
It needs to move 400 cubic yards of soil. Not sure I could do this without my new BXpanded Piranha toothbar. Red clay is not soft.

The mini Ex went home today.
https://www.tractorbynet.com/forums...gging-trenches-geothermal-20181206_173644-jpg

 

[irvingj]

Bremse, we used to call that a "pump & dump" system... I just couldn't bring myself to do that. Used a manifolded double 3/4" loop down the well, right along with my pump & supply line. That has worked fine, installed about 30 years ago when we built. My personal feeling, for the past 40 years or so, is that water is going to be the new oil -- we're gradually poisoning our supplies of fresh, clean water.

 

[Gofast]

I was amazed how well my tractor is doing back filling the trenches. I was able to spend 5 hours back filling using the dirt between the two trenches.
I got a lot done. Very impressed with the tractor. I have 440 cubic yards to fill the trenches in both were dug a little long.
Here are the trenches partly filling in it is going to rain for the next 3 days so it will be a while before I can finish.

 

[ovrszd]

Lookin good. Remember, patience is a virtue.

 

[edgarrian]

I need answer to an odd question

Here we go

My buddy and I were discussing the cost associated with Geo thermal. I told him that I think part of the reason for them to be as expensive as they are is bc of the federal tax credit. Is that a good assumption b/c seems to think its not and i don't understand his thinking.

Thanks