Sizing SCW with low water volumn

Discussion in 'Standing Column Well (SCW)' started by DavidCraig, Feb 11, 2014.

  1. DavidCraig

    DavidCraig Member

    A number of posts have said that designing any Geo system involves knowing water flow through the ground. This was a surprise since it seems almost impossible to know.

    Recently was told that in upstate New York, the ONLY systems that work are SCW and that a closed vertical loop cannot succeed. And SCW don't require toxic antifreeze. SCW don't require water good water production since the water is return from where it is pumped ... it just requires water in the well.

    This raises the question: Would not the designed deep requirement be the same for SCW verses vertical closed loop?

    For example, if a vertical closed loop required 150' / ton to ensure EWT above freezing, would not a SCW require the same? Or wouldn't a SCW require more depth since LWT must be stay above freezing?
     
  2. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    SCW is more based on the thermoconductivity of the rock stratigraphy. Hydroconductivity certainly can be measured, but is often just a small gravel seam in the typical producing well that drives much of the water exchange.
     
  3. DavidCraig

    DavidCraig Member

    Guess what I'm suggesting is that BOTH are based on thermoconductivity of the rock/gravel/clay/sand. And BOTH would benefit EQUALLY with any water flow through the area. Therefore, the sizeing would be the same.

    SCW give advantage of not having a heat exchanger in the ground (i.e. PE pipe). It also give an advantage of being shared with water well IF water production is sufficient.

    Vertical closed loop give the advanage of being sealed and not having a submersable pump. And use of antifreeze.

    But again, if for example, a 3 ton vertical closed loop would need to be 450' or more, so too would not a SCW also need to be 450' or more ... the same?

    How would you protect a coax from freezing with a SCW since there is no antifreeze?
     
  4. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    closed loop don't have to worry about dropping below freezing, SCW does. This alone would dictate the the SCW needs to transfer more heat.
     
  5. Bergy

    Bergy Member Industry Professional Forum Leader

    If a closed loop can work in Northern Minnesota it will work in up-state NY. The anti-freeze is NOT toxic in the 20~25% mix. Perhaps another contractor is in order...

    Bergy
     
  6. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

  7. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    If the above arguments were the sales show from the contractor, go and find another one.
     
  8. Tamar

    Tamar Member Forum Leader

    "And SCW don't require toxic antifreeze."

    Maybe I am wrong, but I think the propylene glycol that must be used in closed vertical loops in Minnesota is food-grade.
     
    Lerronious likes this.
  9. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    .....more geo wives tales......yes the typical methyl mix is not considered hazardous to transport or in the ground in many cases because of the dilution. That however has not stopped government and geo do-gooders from demanding an inferior product that reduces efficiency as well as raises job cost.
    I've mentioned before the political based vs rationale based system of selection.....it sure ain't "natural" selection or glycol would be abandoned.
     
    waterpirate likes this.

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