GeoThermal loops, why only underground?

Discussion in 'General Discussions' started by Shaikh Ahmed, Oct 24, 2019.

  1. Shaikh Ahmed

    Shaikh Ahmed New Member

    hi guys, im new to this forum. and trying to understand why the geo thermal loops have to be buried underground or submerged in water.
    if the physics behind geothermal heating is that the fluid with in the loops absorbs the surrounding temperature and brings it back to the heat pump for the heat (or cold) to be extracted, then why do the loops have to be buried at all? why couldn't we leave the loops in our heated basement and renew the heat from already heated fluid in the loops?
    does burying or submerging the loops affect transfer of energy in any way?
  2. SShaw

    SShaw Member

    "Geothermal" heat pumps can be described as "ground source heat pumps (GSHP)" versus conventional "air source heat pumps (ASHP)." One reason GSHPs perform more efficiently is because the temperature underground, or underwater, is more stable year round, and tends to be in a range where heat pumps operate most efficiently (40 degrees and above). Putting the loops in a heated basement wouldn't work. The reason we need heaters is because heat moves from inside our homes to the cooler atmosphere outside. With the loop inside the home, where would the heat come from to heat the basement?
  3. Shaikh Ahmed

    Shaikh Ahmed New Member

    Where does that heat come from when loops are buried?
    Except now in the basement the liquid in the loop is drawing heat from a warmer environment that is being recycled with less rise temperature rise and the heat pump having to work less to extract heat from a warmer loop.
    My understanding is that the heat pump extracts energy (heat) from the liquid in the loop. If there is more heat in the loops because it’s in the basement then the heat pump works less.
  4. SShaw

    SShaw Member

    GSHPs extract heat from the ground. The heat in the ground comes from the sun. The loop is just a mechanism to exchange the heat with the ground. Hundreds of feet of loop must be in contact with the ground to extract sufficient heat to warm your house. Assuming for the sake of discussion that a heat pump could move heat from a basement to the living space in a house, there would not be enough heat in the basement to warm the house. The house would lose heat to the atmosphere, and the basement would get colder and colder until the heat pump stopped working.
    Last edited: Oct 25, 2019
  5. mtrentw

    mtrentw Active Member Industry Professional Forum Leader

    Buried loops are effectively acting as a collector of stored solar energy. The sun continues to heat the ground and store that in the earths crust. As we take heat away from that ground (to move into the house), the earth surrounding the geothermal loop pipes cools down. Heat always frows from higher to lower temperature, so heat from surrounding earth replenishes what we just took away. That is one reason geothermal pipes need adequate spacing, to ensure adequate area for heat recovery.

    Your scenario with pipes in the basement would basically just take heat from the basement space and move it into the heat pump system, but any gains you had would cool your basement further. That is on top of the fact that air is not a great heat transfer medium.

    In the middle of winter, my geothermal loops will usually get down to 30 degrees F. Having ice cold loops in the basement would lead to much condensation and ice also.

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