Open Loop Spring Fed System Help

Discussion in 'General Discussions' started by johncomyn, Aug 19, 2008.

  1. johncomyn

    johncomyn New Member

    Heat Loss

    Hi, I new here and am looking at installing a ground loop system.

    The contarctor has quoted me a Climate Master 4 ton unit.

    I tried to do a heat loss on this website and came up with between 60,000btuh to 70,000btuh heat loss.

    Home Heat Loss Calculator

    According to the Climate Master website the full load Btuh is 37500. I'm thinking the unit is too small.

    Or the link I supplied is giving me way incorrect info.

    Maybe I'm not understanding how they decide what size unit to use.

    What size unit do you guys think I'd need at 60,00btuh?

    Thanks for any help.

  2. Ona

    Ona Member


    Did your contractor do a manual J calculation? Did he/she share it with you? This is the first step in sizing a system. It is actually what the website that you referred us to is based on.

    It is not unusual for a geo system to not fully cover the heat loss because over sizing the system will make your home humid in the summertime. I believe that some geo systems recommend undersizing the heat load to an amount equal to ~15% of use. Meaning, during a typical year in your climate, the electric coil backup may run ~15% of the time.

    I am not a contractor, just someone who has done some research and interviewed many contractors before having my system installed (which is still in process).

    Good Luck!
  3. johncomyn

    johncomyn New Member

    Thanks for the reply.

    Not sure what his calculations are. I will try to get the information from him.

    From my estimates on the website I mentioned, I think the 5 ton would be more appropriate. What do you think?

    What I have not calculated for is heat gains due to southern exposure. We have quite a few windows for sun to shine in.


  4. Ona

    Ona Member

    Since I am not a professional, I don't really want to give too much advice. But my gut tells me that you want to go smaller. Maybe someone else from the forum with professional experience will have some better insight than me.
  5. bluesky

    bluesky New Member

    I have a spring about 250 ft from my house. The flow rate varies between 130 and 200 gallons per minute and is probably 10' below the level of the house. I think the water temp stays 50-65 year round. The spring supplies water to the house and stays clear after major rains. The house was built in 1978, is approx 5000 square feet, 2 stories with a full basement apartment. I currently use 2 heat pumps. One for the basement and ground level and one for upstairs. I can't find much information on spring fed systems. I want to know if I can do this and how. This website seems to be one of the few resources I can find and hope some members can help me.

    Thank you
  6. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    What do you want to do?

    Do you want to use the spring as a heat source and change the heat pumps to geo?

    We have designed and are currently building such a system in Massillon, Ohio, with much less flow than you describe. Did you measure the flow?
  7. bluesky

    bluesky New Member

    Mark thanks for the reply, Merry Christmas to you and all forum participants. I would replace the heat pumps and hot water tank if necessary. Both heat pumps work fine one is only about 5 years old the other is about 10. The current Fed incentives are very good, although Virginia had money set aside for solar and geo the money was gone in about 3 weeks, maybe they will have a second round of rebates. I use Appalachian Power and rates have been good over the years but have been rising quickly and will continue to rise. Winter months last year I was getting bills close to $400 a month. I'm using about 2600kwh a month, house is all electric. I usually turn my upstairs heat pump back so far it never comes on unless I have company. spring flow was measured by a engineering company for close too a year. The lowest output was 130gpm and highest was 180 or 200gpm.
  8. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Have tools, will travel.

    That is a lot off low grade heat to let go down the holler with a $400.00 per month electric bill for heating.

    What is the water like? You drink it untreated? Does it turn white cottons orange?

    When do you want to make the change?

    Do you need the tax credit for 2009? It is a little late for that.

    Where are you?

    You may PM me here.
  9. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    That spring is crying out for a water-water heat pump!
  10. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader


    He has air to air. I love water to water. Shhhh. I was sneaking up on him.

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