Well do some research on ground source heat pumps then, in particular
in a cold climate. In a horizontal loop configuration,in the heating
mode the pipes get cold, even making frost below the frost line.
Mositure in the soil will migrate towrds the pipes.
These type of systems extract a lot of latent heat from the ground, and
can you can use less pipe per nominal ton than places in warmer
climates with dryer soils and no snow cover.
In air conditioning mode, the pipes become warm and moisture tends to
migrate away from the pipes.
Perhaps search "moisture migration" & "ground source heat pumps" and
avoid the atricles that deal with buildings having moisture migration
problems through the building envelope. It is a difficult concept to
properly allow for in the calculations, a lot of papers out there
discuss the difficulties in adequately allowing for mositure migration
to the cold pipes.