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Geothermal for Radiant

we set our radiant geo systems up with a buffer tank with pump zones pulling off of it. heatpump control is via a Tekmar 256 boiler control w/outdoor reset. heatpump is triggered by a drop in storage temperature setpoint that is based on outdoor temperature. there is no direct zone thermostat heat demand to heatpump, which would lead to short cycling.

this is a basic setup, we have many like this and all run without a hitch.

i like vertical boreholes, although "they" say that ground temperature is the same at 5ft. as it is at 200ft. "they" are quite frankly full of it. it's been my experience that vertical loops run on average at least 5deg. warmer.


  • AKO
    AKO Member Posts: 34
    Geothermal for Radiant

    Working with a friend to design radiant for his new house, and I'm thinking that we could consider using a water-to-water heat pump for his heat source, since you can generate up to 120'F water with this, which is more than enough.

    Anyone out there with experience (good or bad) with this?

    If we end up going this way, I would likely recommend a vertical-bore, closed loop geothermal system.
  • Josh_10
    Josh_10 Member Posts: 787

    You know I was a big fan of ground source heat pumps until I became aware of the Simple Comfor Chiller by York. It is an air source heat pump that is arguably more efficeint than a ground source. It definatly pays for itself because the cost of installation is dramatically lower.

    Basically it is a self contained unit and instead of running line-sets you run your hot water supply and return to a buffer tank. The buffer tank allows for long cycles which is where you can get your efficiency. Ask Prfessor Siberstein about the ins and outs. I am sure he is aware.
  • J Matthers_2
    J Matthers_2 Member Posts: 140

    I've got water to water geo with 5,000 SF of Warmboard radiant. Works great. Make sure you size properly. I use the Geo for cooling as well, hydrocoil. I compromised the heating capacity so as not to oversize for cooling. If I were to do it again, I would have put in two staged units. As it is, I suppliment and backup with a Knight 80.
  • Craig Bergman
    Craig Bergman Member Posts: 84
    Define \"Arguably\"

    What are the COP's and EER's? You can't argue without facts. I would have to see those numbers to believe that an Air Source Heat Pump can out perform a Ground Source Heat Pump.

  • Josh_10
    Josh_10 Member Posts: 787

    Ya that is why I say arguably. After a lengthly conversation with the manufacturer I understand the how... However the testing is being done right now. The company was bought by York in the not so distant past. They couldn't afford testing prior to that.

    Not trying to stir up controversy at all. Just an alternative thats all. I will see if I can get the manufacturer to post... He can explain it a heck of alot better than I can...
This discussion has been closed.