Standing Column Well - Is it worth the bother?

Discussion in 'Standing Column Well (SCW)' started by DavidCraig, Jun 26, 2012.

  1. DavidCraig

    DavidCraig Member

    Given the simplicity, low maintenance, and reliability of a closed vertical loop system does it actually boost efficiency enough for such an open system?

    Or is it solely to 'share resources' (a vertical hole) with a well?
     
  2. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    Once you move into a litology that requires a down hole hammer, i.e. rock drilling, the cost per foot to loop can easily be in the mid 20's per foot or higher.:eek: So yes it shares resources with a domestic water supply well.
    Eric
     
  3. DavidCraig

    DavidCraig Member

    Thanks for the reply. As long as water production is there and pumping costs can be controlled, it would seem useful.

    The potential of plugging up with debris seems a real concern. So many I speak with have wells with sand and/or mineral issues.


    Current application involves a 6" well. It was abandoned because low water production (1/2 gpm), thick water (980 ppm), and unresolvable bacterial contamination that smells like a dead animal (started after a pump replacement).

    While the water is not corrosive (though pH 9) and there is no mineral build up, there is a slime (common to this area) that isn’t harmful to people but plugs up drains. Am told it is a sulfer eating bacteria. Lift the toilet tank and floating is black and tan algae like substance. There are also methane and hydrogen sulfide gases (in small quantity).

    While the well is very low production, when not in use the water is at the top … overflowing in spring and about 6’ from surface during long summer drought. Thus pumping/circulating cost could be same as a closed system (lift ranging from -1' to +5').

    While the temptation of standing column is there, there is concern about what the slime might do. A filter/screen cannot be used, as it would guarantee plugging up. Whereas the pressure of the circulator might be adequate to eliminate problems.

    The low water production severely limits any bleed options.


    Otherwise, the 520’ depth (vertical loop) and 100’ distance from house (horizontal ‘loop’) seems nicely suited for the home. The soil is hard clay and, after 80’ casing in the clay, the bore is shale. A WF rep thought it ideal for their 40 kBtu unit. Some suggest a working capacity of ~4 tons.

    So, it would seem a closed loop system would be the ‘safest’ approach in this case. The ‘adventurous engineer’ in me wishes to explore standing column but the above issues are concern.

    Naturally, boring cost isn’t an issue this time since an abandoned resource is being utilized.
     
    Last edited: Jul 11, 2012
  4. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    I have prototyped and thrown away a number of wild hair ideas. The curious engineer in you should resist the temptation unless you are willing to amuse yourself with the results, win or lose:D.

    A standing column is a lot more involved than it appears at first blush and I feel that the low production rate limiting a bleed under heavy load would be the death of it.

    An option I would look at is to get a looper involved in your area and take your existing resource and fill it up with loops. Vertical loops in shale perform very well, and you would only be spending the cost of the loop install and the grout. If enough loop can be put in that hole to satisfy your load, I would do it.
    Eric
     
  5. DavidCraig

    DavidCraig Member

    Thank you for your response.

    ...resist the temptation unless you are willing to amuse yourself with the results...

    Yes, I'm getting too old for the aggregation ... $$$ and 'bronze' aren't there :rolleyes:

    ...the low production rate limiting a bleed under heavy load would be the death of it.

    I understand that bleeding is a key point in making it work, otherwise freezing (without the hope of antifreeze) would shut it down. The replacement well is also low production, barely 3 gpm, so injecting from it is out of the question.

    get a looper involved in your area and take your existing resource and fill it up with loops

    I presume that "looper" means someone who install vertical loops with U bend on the bottom?

    Have you had experience yourself putting in a vertical loop? Since buoyancy would require prefilling the pipe, it would seem a nightmare fighting the weight of the whole thing.


    Edit: For what it is worth, this application is north of Albany, NY and ground water is about 52 F
     
    Last edited: Jul 13, 2012
  6. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    Resisting the urge to be snarky:D

    You should click on the web address in my sig line. Yes I have put in a couple of loops. Depending on the water table in the well there a lot of ways to get the loop and tremie package to the bottom, with little or no effort. Consulting some local talent is key to your success.
    Eric
     
  7. DavidCraig

    DavidCraig Member

    Actually thanks. I know a well driller I can fall back on if I can't do it. But the challenge is enticing (definately insane).

    Do you have a YouTube of doing an actual vertical install?

    I've made a wooden reel to hold the pipe. Hope to fill it with water and start it down the hole. I assume that PE is heavier than water, so once the air is out it will want to sink without brute force pushing being required. With the reel over 1000 lbs (the well depth is 520'), it will NOT be easy to handle. Also, being coiled, there will probably be resistance to straighten out just to make the job harder. It would be helpful if it doesn't take 2 weeks the get the thing down, lol.
     
  8. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader


    PE is lighter than water. You will have to add weight to keep the loop from floating out of the hole. We use rebar.
     
  9. Blake Clark

    Blake Clark Member

    I can't speak to contamination (well, uh, I can - it's bad), but low production isn't necessarily a deal breaker for standing column. My standing column well produces only about 1/2 GPM and other than domestic use, I don't have a bleed. In two years, I've never had a freeze lockout, but I've been close. My reasoning is with enough feet per ton a bleed would be necessary only in extreme conditions, and under those rare conditions electric-resistance is probably the cheapest insurance policy.
     
  10. Calladrilling

    Calladrilling Member Industry Professional Forum Leader

    We made up a loop insertion rod to get the loops and tremie pipe down with no effort at all.
    Once down use a curb stake pin to hold the loop in place from floating back up after loop tooling is removed then grouted into place right away.
    Works perfect every time!
     
  11. DavidCraig

    DavidCraig Member

    How deep is your well? Water table?

    How much heat are you pulling? (ton, etc.)

    With normal use (before contaminated) the water table would drop about 80 giving about 420 feet under water.

    I've heard that an ungrouted well has better heat transfer (presuming the water table is high) ... but it would seem less than a standing column (since there is no PE barrier).
     
    Last edited: Jul 13, 2012
  12. DavidCraig

    DavidCraig Member

    Wow ... thanks.

    Just looked up specific gravity of HDPE as ~0.95.

    So 400 lbs of pipe will need 20 lbs added (minimum)
     
  13. redneck_savant

    redneck_savant New Member

    My geo system uses a 5 to Geocool, I used 3/4 PE pipe down a bored vertical well depth 540 with water contact for the first 380 feet of the well - dropping the pipe down that well required no special tools other than leather gloves. Why? I filled the loop AFTER install. My well did have a 6" PVC pipe tile at the top, I had to work to lift the last 200 feet of my vertical loop off that so it didn't shave off some of the PE pipe - other than that it was an easy 1 man job. (The bouyancy of the pipe in the water made it easier to lower down there than otherwise would have been the case.) If filled with water, that pipe's going to break your back, your rig to lower it, and your pocketbook. Fill it later!

    Oh, one final tip. I share this well with my drinking well as an additional reservoir. Didn't want to use any toxic form of anti-freeze accordingly. What did I use? VODKA! Just the cheap kind. If it leaks into the well, just something else to smile about as I sit in my cozy warm geothermal house!
     
  14. nc73

    nc73 Member Forum Leader

    Is this done a lot in the geo world? I'd like to try it. My well is 371 but the pump is at 187 so I'd like to move the pump down further and put in a closed loop. Course I'd need to buy a new pump to handle the depth. Although my well casing is only 4.5 inches so it'll be tight.

     
  15. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    It is all about the amount of pipe you do the exchange with. Form follows function, or dare I say it??? Pipe allways follows load. What is the load you are trying to deal with? The answer to that question will tell you how much pipe you need to support that load. After that it will be clear if it will fit in your existing well.
    Eric
     
  16. nc73

    nc73 Member Forum Leader

    I'm looking to go down to 250-300'. I realize it's not enough for a 3 ton but I was going to compensate with trenches or have another hole drilled for vertical. The casing from what I can tell is metal but the drilling reports says pvc. Would 300ft net me 1 ton at least? All else fails I'll go open loop but I haven't figured out where to dump the water yet. Standing column won't do since it's mostly clay and shale here.
     
  17. Calladrilling

    Calladrilling Member Industry Professional Forum Leader

    NC73....
    Is this a cased well all the way to the bottom?
    Let me make sure i understand your idea before commenting.
    You want to lower your pump towards the bottom of your well and install a closed loop in the same well?
     
  18. nc73

    nc73 Member Forum Leader

    I think it is cased all the way. I don't remember seeing the info on the well report I got from the health dept though. I'll have to look. Yes I want to lower the pump to make room for the loop. Apparently I don't need to upgrade my pump.

     
  19. nc73

    nc73 Member Forum Leader

    Just checked the report, it's cased 0 to 350ft.
     
  20. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    "Oh, one final tip. I share this well with my drinking well as an additional reservoir. Didn't want to use any toxic form of anti-freeze accordingly. What did I use? VODKA! Just the cheap kind. If it leaks into the well, just something else to smile about as I sit in my cozy warm geothermal house!"

    So if freezing is a concern, what sort of antifreeze do you employ in your drinking water?
     
    waterpirate likes this.

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