Regulated Geothermal Systems

Single Pass or “Pump and Dump” System

This is a system in which water is withdrawn from a water supply well, passed through a heat pump and then discharged to the ground surface or to a surface water body. If the discharge is to a surface water body, concurrence from a regional DNR office for the location and amount of discharge is required. A standard well construction notification fee must be submitted to the DNR and a notification number obtained by the property owner before the water supply well is constructed.

Closed Loop Geothermal System

A closed loop geothermal system is comprised of several, vertical bore holes into which are placed special geothermal pipe loops. The geothermal loops are connected to a heat pump which provides heating and cooling for a building. Heat transfer fluid in the system is contained, hence the name “closed loop”.

The bore holes in which the geothermal pipe loops are placed, are filled from the bottom to the top with a special sealing material called bentonite to prevent surface water from contaminating the sub-surface aquifers and to allow for the transfer of heat to and from the earth.

A property owner wishing to install a closed loop geothermal system must obtain an approval from the DNR, prior to construction of the system. The Closed Loop Heat Exchange Well application form (Form 3300-255) should be completed by the property owner, well driller or heating and cooling contractor. It must be on an original, clean form and be signed by the property owner. The form and any attachments must be mailed to the address located in the upper left corner of the form. Latitude and longitude values from a Global Positioning System (GPS) must be placed on the form to enable accurate location of the geothermal system.

Typical geothermal system approval conditions can be found here.