2 existing water wells on property, would It make sense to even consider closed loop?

Discussion in 'Geothermal Loops' started by Raventai, Jan 2, 2019.

  1. Raventai

    Raventai New Member

    Hello I am early in the planning phases of a geothermal install, trying to gather data to see if the added initial expense will make financial sense for my family.

    we have a 2K sq' mobil home on 2.5 acres in north central Florida, the standard 20 year old air sourced 3 ton package heat pump has given up the ghost. we had quite unpleasant $300/month electric bills during the summer and with the death of that unit we have an opportunity to try do something about it.

    I have been aware of geothermal for quite a while and its purported efficiency but I have never dug into the details.

    lacking a basement I am hoping to get some sort of split system with a typical air handler inside and the compressor and water heat exchanger in a small shed or dog house outside, having an AC compressor in my dining room does not sound pleasant.

    my first attraction was to direct exchange, the lack of water pumps with their necessary added power draw and added failure points was attractive. but I have read a lot of FUD (fear uncertainty doubt) copper corrosion, compressor oiling, etc that have made me concerned.

    Next is the typical coolant filled closed horizontal loop, but from what I have heard https://www.geoexchange.org/forum/threads/best-horizontal-loop-for-a-doit-yourselfer.7295/ in my area heavy cooling activity during the summer and little heating in the winter cause heat build up in the already warm soil so the loop must be oversized to compensate,

    but on this property are two wells, the original owners had the second well drilled about 150' away from the first as the original well would get river water (tannins) about a week after the river runs high. the second well did absolutely nothing to fix this and if anything is worse. but bonus I have a open loop source and inject well already in place just waiting for plumbing and a dedicated geo pump, I have read about corrosion issues in some well water.

    I could just bunt and pick up an air sourced. I need to price this anyway as a control to compare to.

    I have until about may to get some air going.

    so what steps to I need to take to evaluate my options?

    I think I need to figure out how to do a load calculation
    soil type is mostly silty (rare in FL) with pockets of clay and sand
    find soild PH and well water PH to evaluate corrosion issues?

    Do the existing wells just make it a no brainer monetarily?
     
  2. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    Hi and welcome!
    2 wells on the property and a river near by? This sounds like a situation that can work for you. A 3 ton geo will take 9 gpm max, and could be as low as 4.5 gpm when tuned tight. My first call to go down this road is to call the local talent, well drilling that is and find out what the aquifer will provide and what it will take. Ideally you would have a larger pump installed in your supply well to accommodate your domestic supply and geo and dump it in the other well.
    Hope this helps
    Eric
     
  3. Raventai

    Raventai New Member

    The Suwanee river is about 5 miles away, it's surrounds us on 3 sides and part of the fourth. Since we get river water in the well so quickly I figure there has to be relatively quickly flowing ground water. (Not uncommon in Florida, the ground is Swiss cheesed limestone) So temp build up in the ground at well level should not be a problem.

    I measured my well output temp at 64F this morning, will probably be in the lower 70's in the summer.

    You would run one pump for domestic and heat pump? Is there much of an effeciency penalty for bringing the heat pump water to that high a pressure?
     
  4. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    The only compromise is the watts to generate the pressure. With a anticipated usage of no more than 9 gpm, I would not worry about it.
    Eric
     
  5. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Not working in the south, but the high cooling load would likely result in much less efficient entering water temps. Open system seems preferable to keep water temps low, high 60s seems perfect. The key will be to watch the pumping power,
     

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