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Choosing depth of proposed hot tank for hydronic system

My hot water will be recirculated from an underground insulated potable water reservoir heated by closed . loop on wood heat gasifier. The potable water tank location im considering is at a depth of 50 feet below ground. Should i be concerned with fighting gravity/expense on this proposed depth ? Or does the depth apply on a closed system ? I do have another option to sink a seperate reservoir outside of bunker if depth of water body is too costly.


  • Zman
    Zman Member Posts: 7,572
    That is interesting. Tell us more.

    As a guideline, pulling water up more than one atmosphere (~33') is problematic. In a closed pressurized system, you could make it work once you get it all primed. Careful attention needs to be given the the NPSHR rating of the pump as cavitation will be an issue.

    A submersible pump in the tank eliminates lot's of problems.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • hot_rod
    hot_rod Member Posts: 22,246
    Is the tank pressurized by the well or water system pressure, or an un-pressurized storage?

    You could use the tank as a storage vessel, insert a copper coil for a heat exchanger. A home built reverse indirect tank. The water pressure in the building flows down through the HX to warm, or pre-heat the domestic water.

    A submersible may work also, depending on how hot you plan on running the tank. But you would be pumping water twice, once to fill the tank from the well source, then to pump it back out of an unpressurized underground storage.

    Why so deep?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream