Geothermal Loops?

[powerstroke444e]

I got several bids for a new geo system and all were north of $20,000

So I did some digin and found a dealer that was setting on some units that he would like to move. Here is my problem or questions.
I am putting a 6 ton unit in and putting 600 foot of pipe per ton. Should be complete material cost of under $8K unlesse I have to do it twice. The contractors that bid it were going to put in less pipe and then in and out pipe were going to be in the same trench. When I said what happens if you keep them seperate trenches they said that would cost to much??wtf

So I have bored them for others but I don't have a bore machine anymore. So how deep do I need the lines??? I have a 60" trencher which would be the easiest but don't know if its deep enought to get it to work well. If needed I could get something that will trench 72" or I could dig it all but the thought of that much time on a hoe don't sound fun.

Although anything is better than 2000 gal of propane.

Attached is photo of loop system.

 

[20 20]

I did a lot of research and have decided it is WAY cheaper for me to stay with wood for now then go to pellets. I have nothing against the geo system but for the price I could heat for 40 + years that doesn't include the $$ for electric on the geo system.

 

[Chilly807]

How large is your pipe diameter? Ours is 3/4 inch, we used 1000 feet per ton, each length of pipe coiled up in a "flat slinky" and buried 6-7 feet deep in a separate trench that was approx. 6 feet wide and 100 feet long to accomodate the "slinky".

So, we had three trenches, spread in a fan like a chicken foot, the tails of each slinky fed into a common trench under the footing and into the house.

According to the experts, 6 feet is about the minimum recommended depth, and going deeper doesn't accomplish much in most climates.

I have some pics of the slinkies and the install process, I will post them if you like.

Sean

 

[mfreund]

I used the well drill method for my Geo system. The cost to move that much earth made it cost comparable(4 ton unit). The installer said he preferred the drill method because by 150 ft you are going to hit water here and get better heat transfer vs the ground loop.

Every place is different because of ground water and soil type. What type did the installer recommend? Do you have any energy co rebates? We got back from the electric co. over $6500 on a $19k bill

 

[coolconnection]

I am in ohio and my lines are about 6 feet deep and they dug the width of the bucket for the trenches. My lines were installed slinky style in I believe 3 trenches. All the lines come together in a main trench and one trench dug to the house for the inlet and outlet of the lines. If you do it yourself remember do not use glue to hold the lines together. They need to be plastic welded together otherwise it will not hold up. When they dug up my yard it didn't take that much time for them on the back hoe. A couple hours is all at best. If you can trench a couple thousand feet 6 foot deep go for it but it all depends on soil type for efficiency. I love my geo and not having to cut wood each winter. Good luck,

 

[powerstroke444e]

The 2 bids I got both said hoizonal would work fine but cost more? 6 wells would cost $7,000. @ 60" it would take 8-9hrs to get that much trenched at 6 foot I am going to have to rent a machine and it would take about 12hrs. No rocks and topsoil is about 40" then wet clay.
Frost is line is about 36". I was thinking I would get better transfer going one line in a trench vs a slinky. One bid had system @ 8foot deep but he didn't seem to know what he was talking about.

 

[buffy12590]

While it would be nice to have a geothermal heat pump, the cost your talking it is going to take a lot of years to recover your intital investment. I lived in Waterloo Iowa and had a heat pump on the house with auxillary electric heaters installed. The cost was a lot less than your talking and the payback was a lot shorter. Now I live in New York and also have a heat pump but instead of the auxillary electric heaters I have hot water baseboard. This is because the cost of electric is so high vs gas. Why not look at a standard air transfer heat pump with either alternative vs geothermal? Thats a lot of money, the heat pump installed with all the duct work was less than $6000. The efficency is better and the cut over is set at 39 degrees

 

[powerstroke444e]

I agree it will take some time but with propane @ $2.00 and using 2000 gal and still having a $600 electic bill I should be about 3 year payback but if it takes 10 and the house is warm its worth it to me.

I also knew when we bought this place that heating bill was part of the reason it was so cheap. It was built in 1860 with remodel in 1990's but they didn't use any insulation.

 

[JimRB]

I have a Climatemaster with horizontal ground loops. Three trenches of slinky fed from a common main line. Not sure how they made the connections. I assume they did a manifold in the trench. I saw my pictures of them trenching but I forgot what I did with the pictures. The HVAC installer's brother was used to do our septic tank. He dug those trenches fairly fast with his backhoe.

What size is this house? No insulation at all? What would happen if you insulated the house first which would reduce the tonnage? Some insulation contractors can insulate from the outside siding.

 

[leonz]

The semi open loop drilled well method of
geothermal heating and cooling is the most
cost efficient.


No tubing runs
No grouting multiple holes
No multiple drilled wells three hundred feet deep
no paying for drilled holes that can collapse and also tear into
pipe loops creating leaks before the grouting
No leaking of U bend pipes from bad fusion joints and piping.
(yes it does happen and if they deny it does walk away!!!!)


No fusing multiple pipe runs
No need for sub surface valve controls in a pit box
Much less excavation.
No excessive costs.


If you can drill a deep well and establish a deep water column by surging the well providing that the new well does not have an effect on the drinking water well depth your home free as a deep water column is money in the bank with 48-52 degree cold water always at the bottom.


A two well system:
As long as you have 2 depths of water for a shallow
well and a deeper well you can accomplish the same
thing with less money involved.


They will whine. and stomp their feet, and say I do not know
what I am talking about but you can contact the
National Ground Water Association and get all the
information you need for a semi open loop geothermal well
system.


Oh, and I am a "NYSDEC certified water well driller" but I am unregistered
and what I have told you is true about the semi open loop method of geothermal heat exchange.


What your geo heat installer did not tell you is this;


The so called geothermal grout is still made
of clay and holds heat which is why you need
so many drilled hole "LOOPS" which adds to
the expense. DO NOT LET THEM TELL YOU ANY DIFFERENT!!!!,
as clay is a NET INSULATOR!!!


A drilled water well for geothermal use needs less work
labor and materials The semi open loop method uses a
single very deep well with a tall water column; If I
remember correctly it is 10 feet of water column per ton
of cooling/heating.


A two well drilled well system for geothermal use needs
to have a deeper second well to transfer the water for
winter heating and summer cooling depending upon the
season.