If you sit on a plot of land and have enough surface area to tap into this wealth of free warm water, you just need to circulate and store the glycol somewhere temporarily. For office buildings the ideal place is on the roof, in the penthouse of a new building. To do this, you need to lay glycol pipes thoroughly connected from the subsurface to the tank on the roof and back again to where the heat is needed.
All of this takes planning and special engineering services that can determine how much of the glycol one can realistically take out of the ground and re-circulate the used cold glycol back down into the ground.
Once this free heat is stored in an insulated tank, this glycol can be used, through a piping system incorporated into the floor layout cast into the concrete formwork, to melt snow and ice in the winter off parking lots and walkways as visible above on the left. This free energy can also heat the basement walls of a parking garage, providing winter time heat to the underground garages as well as to the offices and other spaces inside the building. The only prerequisite to using this new source is area, around ½ or more acres. Thus ground source heat pumps are perfectly suited for new malls and office buildings; occupying large real estate areas in downtown areas.
Just remember that using this free energy is kind to the environment as it uses readily available water from down below to provide heat and allow you to reduce your use of electricity to do that, or use salt to melt ice off your parking lots and walkways and can also be used to obtain LEED points too. One more point to incorporating such methods. Though they cost a slight bit more to incorporate, the rent paid by tenants are somewhat higher than for ordinary buildings. Therefore, the owner can sell the building for more than he paid to put it up.
The balance between the water and the retrieved glycol is not going to go out of kilt; in other words, the system cannot extract too much heat from the warm water region and return warm glycol back. That would entail termination of the ground source heat pump. Putting an excess of warm glycol down 400 feet would cause the temperature at that level to go up. Meaning that the system would be bringing warmer glycol back up; this situation would correspond to the summer season. That is when cooler glycol is brought up to cool the building. In the winter heat is extracted from the warm temperatures and the cool glycol is returned.