Wasilla, Alaska instalation

Discussion in 'Geothermal Loops' started by William Wise, Jul 30, 2013.

  1. William Wise

    William Wise New Member

    Hello from Alaska to everyone on the forum and here is what I hope is an easy question. I have a 1,950 square foot home, that is new construction in Wasilla AK. We should have a tight house because we went with spray foam insulation and triple pane windows. Also there is 1/2'' ridgid foam on all exterior wall studs that should supply a thermal break, and a 1/2'' void behind the sheet rock. The walls are 2x6 with 6'' of foam and there are fiberglass exterior doors. We are using radiant in floor heat in the house and garage and we went with the gypcret in the house with the tubing encased in it. The garage is 32'x36' with 14' walls. And we have an Envision series NSW 5 ton heat pump . I installed the 6, 600' long 3/4 HDPE loops laid parallel in a 50' x 75' pit aprox 12'' apart, and we are using 1.25'' home runs aprox 100' each way so 200' total. I only recently found this forum and now I have questions about the install. I have no reason to doudt our heating guy and I am only looking for an arm chair opinion as to weather it sounds like a reasonable instalation. I have never seen any calculations on the heating system and I am wondering if it sounds about the right size. Also the tubes are right at 9' deep.
    Will
     
  2. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Hello and Welcome.

    You are a bit out of our A/O, even for the Geo Gypsies. We have yet to do a job West of the big river.

    I do get water 2 water systems. So here is what I see at your house from Cleveland, OH. Go Browns.

    Often your weather and my weather are the same. Some times you are warmer in winter than here.

    Each home is an individual and therefore what works in one home may not work in the one next door.

    Foam insulation is an amazement to me. What happens vs what is touted makes me think we maybe wrong in looking to "R" factors and infiltration for judgmental projections of cost for comfort.

    From my rolling arm chair I think your new system will serve you well.

    I want my loop field at least 12" below what the JHA wants for a frost line footer pour. You sound that deep or better. Nine feet deep should do the job. You are not in Nome or the North Slope, no perma- frosted ground to worry about. If you brined the loops you will be fine.

    I run 300' to 500' per ton using srd 11 HDPE pipe with a .75" ID. I then manifold the loops and move the fluid to the load in pipe big enough to move the BTUH I need for comfort. The magic of W2W is the buffering tank. Storage if you will. The next trick is keeping the delivery temperatures as low as possible.

    You have not told me much about the delivery end of this system.

    Your guy seems to me to know his stuff.

    You should be fine>
     
  3. William Wise

    William Wise New Member

    I guess I don't know much about the delivery system or what it would be?What type of pump? Or brand of tubing in the floors?
     
  4. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    I'd like to know the heating load calculation, whether a blower door test was done and if so what result. Also what entering water temperature was figured into the design...I would imagine a bit lower than in the contiguous 48.
     

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