Geothermal with pond

Discussion in 'General Discussions' started by zookpaw, Sep 27, 2009.

  1. zookpaw

    zookpaw New Member

    Hello,

    We are in the midst of construction and want to upgrade to geothermal. Our choices are using trenches or a pond; we are in northeast ohio. If we are to go the pond route this year; what can we expect out of the system if the pond does not fill (we will have to dig a new pond). Can anything happen to the pipes if there is not enough water covering them?

    Also with the system itself, is it worth it to upgrade to a two stage system? Is it that more efficient and will reflect in electricity savings?

    Thank you
     
  2. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    You ask good questions.

    I use ponds first if I can.

    I live in NE Ohio.

    I just poured a 4,000 square foot basement floor that will use radiant/geo in Valley City, Ohio, Wednesday. Want to see it?

    I will use antifreeze or air in the loops while the pond fills. What do you plan on using for the pond loops? Pex or HDPE?

    I can do and do use trenches.

    I can not give you a judgement on one stage vs two stages without more info. What are you thinking water to air or water to water?

    I can help you if you wish. I have various projects I can show you in the NE Ohio area.

    PM me here and I'll give you a phone number.
     
  3. teetech

    teetech Member Forum Leader

    Since your load will vary with the seasons, 2 stage is almost always a good bet. Cost difference is minimal.

    I am curious as to how many people are using pex tubing for geothermal loops. I have never run across one.
     
  4. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    2 stage units are slightly more efficient in the lower stage. I'm not sure the difference will ever pay back in electricity savings.

    They are quieter, better at dehumidification, and more flexible for zoning.
     
  5. teetech

    teetech Member Forum Leader

    WF envision 4 ton single stage EER 19.7 COP 4.0

    WF envision 4 ton two stage (low speed) EER 25.1 COP 4.7

    List price difference less than a Franklin.

    Given the 2 stage should run in low speed a majority of the time, I think there would be a pay back there.
     
  6. GeoXNE

    GeoXNE Guest

    ARI ratings for closed loop are based on a 9*F boost in EWT for 1st stage. I would like someone to confirm what their real world experience is regarding the change in EWT comparing low to high capacity. The numbers have to be applied to the real world.

    I agree 2 stage units have greater design flexability.
     
  7. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    where is

    Zookpaw? He maybe with?
     
  8. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    I thought the price diff was much higher
     
  9. gnick

    gnick New Member

    I've been watching realtime data posted by Bill in Plano (Dallas), TX (http://welserver.com/WEL0043/) since mid-summer and I've never seen his two-stage units run on high speed -- even at 100 deg outdoor temperatures.
     
  10. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    That basically means Bill's equipment is a tad oversized. ideally it runs in 2nd stage during design day or worse conditions.
     
  11. gabby

    gabby Member Industry Professional Forum Leader

    Texas requires a slightly oversized system, or an overkill in insulation to make it bearable on days over 100 degrees. In 1998, Dallas had 44 such days, and Houston with 24 days. It's a wet heat meaning...more like the jungles of the rainforest, than the Mojava Desert...or the 6th ring of Dante's Inferno if you don't appreciate living in a greenhouse with relative humidity of 70%. :D
     
  12. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    I agree that it is miserably hot and humid in most of Texas all summer. My s/w shows Dallas to have a design temperature of 100. In other words, what you describe is the design condition. On really hot days humidity shouldn't matter since systems are running so many hours.

    But if a two stage system never leaves low gear then the system is both oversized and the owner overpaid for two stages. I have no problem with rounding up or adding a half ton, but not much more than that.

    My manual J tasks include asking homeowner typical thermostat settings, whether they often entertain large numbers of people during summer, assessing the kitchen for atypical extra loads such as multiple refrigerators and 6 burner ranges.
     
  13. gabby

    gabby Member Industry Professional Forum Leader

    LOL...also ask if they are a Northern transplant where anything above 73 degrees is hot to them. Up here 55 degrees means its time to break out the shorts.... :D
     
  14. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    Funny, that's almost exactly how I phrase the thermostat setting question - I want to know if homeowner is a northern transplant. Designing for 73 requires a bit more capacity than 78
     
  15. gabby

    gabby Member Industry Professional Forum Leader

    Bill has 8 tons of capacity, thus not a small home.
    The 3 ton unit seems to carry much of the load on light days. I would like to know what load (rooms) each unit handles. It looks very efficient where the 3 ton handles the DHW year round with the option of adding the 5 ton coil to the mix if needed.
     
  16. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    ponda and set points

    elude me.
     

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