Ohio Geo Proposal

Discussion in 'Quotes and Proposals' started by j0sh441, Jul 21, 2016.

  1. j0sh441

    j0sh441 Member

    I've purchased a 4 ton CM Digital 30 with a horizontal 4 pipe loop. I'm just wanting to get it installed for it to do what it's capable of doing. And am here asking for help.
     
  2. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Here is John Manning's "Dumber than Rock" article how detrimental balance valves on loop fields are.
     

    Attached Files:

  3. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    We will be happy to help. But you have to listen. Plus you have to separate the good from the bad from the ugly (in regards to the advise you are getting).
     
  4. j0sh441

    j0sh441 Member

    Believe me I'm listening. Taking in all I can.
     
  5. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    OK. Then lets start working on this.

    Didn't you say you had 6 loops 500ft each?
     
  6. j0sh441

    j0sh441 Member

    Each loop is 500' there is 6 loops. You are correct.
     
  7. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    So each loop sees 2 gpm (12 gpm total for a 4 ton heat pump). With 20% methanol (please confirm that you have methanol in your loops, or is it glycol?) the pressure drop (flow resistance) of SDR 9 versus SDR 11 (which is normally used) is 27.9 % higher due to the lesser internal diameter of the SDR9 pipe.
    You also have 22% lesser heat transfer due to a thicker wall. Not sure what the rationale was to sell you SDR9 pipe.

    But splitting it up between 6 circuits helps, the loops are short and 3000ft of straight pipes in 1500 ft of trench 7 ft deep is a good amount of pipe for 4 tons in your area.
    Let me run some numbers.
    The issue is mainly the pumping and piping.
     
  8. j0sh441

    j0sh441 Member

    Sorry I did not specify. This is not a new home. It is a retrofit for a old home that I'm renovating. Built in 64. Hope that helps. I do not know why he uses sdr9 either, he told me he has 2600 systems out right now and he uses the same sdr9 pipe with every one of them. Also, he said the loops are "pre filled" with methanol as he does not use glycol.
     
  9. j0sh441

    j0sh441 Member

    I have installed all new low e windows through out the house. All new insulated doors coming from outside. I have blown in r38 in the attic, and r19 in the walls. The main living space is 2500 sq ft, the basement is around 1800 sq ft.
     
  10. j0sh441

    j0sh441 Member

    Might I also add that one of the contractors I had here sized a geo unit for this home, but also had an option to install a gas furnace if I chose to go that route. He said I would need a 80,000 btu furnace to heat this place. He also wanted to install a 3 ton central ac unit to go with it.
     
  11. j0sh441

    j0sh441 Member

    If you look at the photo, the 1" used inside the house is also SDR9. Interesting.
     

    Attached Files:

  12. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    The manifolds are for inside. The proposed loops are single circuit.
     
  13. j0sh441

    j0sh441 Member

    This is his reply for the use of the SDR9 pipe My previous statement was the fact that SDR9 did not have as much heat transfer as the SDR11:

    That is not correct, on the contrary it is actually a thiner membrane. It CTS pipe. Which means it is a smaller diameter pipe and the SDR (standard dimension ratio) is the thickness of the pipe wall realitive to the inside diameter of the pipe. So my pipe actullay gets better heat transfer, it does sacrafice gpm. That why we always have at least 1 more loop in the system to make up the flow.

    I hope this makes sense.

    Let me know your thoughts on this.
     
  14. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Are fittings available for that pipe? No it was not clear to me that this was a retro fit. How did you keep warm last winter?
     
  15. j0sh441

    j0sh441 Member

    Yes it is a retro fit. I have a propane furnace in the basement. I also used a wood burner last winter that worked really well but I dont want to cut wood all my life. I own 24 acres. I can't give you any info on the manual j as I've stated before I simply do not have it. My neighbor has geo and he's made up my mind that it's what I want to do.
     
  16. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    This just got easier. We add the wood and the propane and we have a heating load. Did you have a/c too? If so what is the model number of the unit?

    Mark
     
  17. j0sh441

    j0sh441 Member

    Only ever had window ac unit. Never central air.
     
  18. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Well add them up and give me the square footage of the conditioned space.
     
  19. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    The opposite is the case.
    http://www.petersenproducts.com/Specifications/Pipe_SDR.aspx

    nicely explained.


    "With a low SDR ratio the pipe wall is thick compared to the pipe diameter and will have a high pressure rating."

    But that also means that you get lesser heat transfer due to thicker pipe wall in relation the the outside diameter. The lower the SDR number, the thicker the pipe wall is, and the lesser the heat transfer is. So indeed it scarifies GPM, but it also sacrifices heat transfer....That is why I am scratching my head why someone would put it in.

    The only reason why I ever installed SDR9 was the pressure rating in very deep boreholes. But you are 7 ft deep....

    But if the gentleman here got the principle of heat transfer upside down, how good of a designer is he?
     
  20. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    The pipe is not HDPE, and I would not use another material to burry. Many things in a geo install you can fix, the buried pipe you cannot. Not sure what Ohio building code requires, but NY specifies on HDPE pipe. Sorry, but I cannot advise you to use anything else but HDPE pipe, or wether it is easy to break at sub freezing temperatures.
     

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