Open Loop System
For the open loop system, we drill until an adequate supply of water is reached. This supply is usually 10 gallons per minute or greater depending on the size of the heat pump needed. A second well or return well is then drilled. The return well can receive water from the first well without overflowing. Both wells should be drilled with 100 feet of separation between them.
After the wells are drilled, we place a pump in the supply well and plumb it into the house to the heat exchanger. A second water line exits the unit and returns the water into the ground with the return well thus forming an open loop.
Closed Loop System
A closed loop system uses 1 to 3 wells depending on the size of your home. First, a plastic line leaves your home’s heat exchanger, goes to the bottom of the first well, and then comes back to the top of the well using a U-bend. Using the same setup as the first well the flow moves to the second well, then the third, and so on. When the line exits the last well, it returns to the heat exchanger. These lines are filled with a glycol solution that is circulated through the wells in a closed loop.
The wells for the closed loop system also have to be grouted from the bottom to the top to ensure that the lines always have contact with the bedrock for maximum heat exchange.