Heating-Cooling Exchange Well System Regulation

Open-Loop Heating-Cooling Exchange Well means a well system in which groundwater is extracted from a typical water production well and pumped through an above ground heat exchanger inside the heat pump system. Heat is either extracted or added by the primary refrigerant loop, which does not come into contact with the pumped groundwater, and then the groundwater is returned to the same aquifer by injection through the original extraction well or through a separate injection well.

For open-loop systems where groundwater is removed, processed, and re-injected, a non-consumptive use water right approval must be obtained from the state engineer. Approval to re-inject water underground is also required from the Utah Division of Water Quality. Open-loop system wells shall be constructed in accordance with the requirements found in Section R655-4-11. If a separate well or borehole is required for re-injection purposes, it must also comply with these standards and the groundwater must be injected into the same water bearing zones from which it is initially withdrawn. The quality and quantity of groundwater shall not be diminished or degraded upon re-injection.

Most open-loop heat pumps which use groundwater operate by circulating the water from a well into a heat exchanger where heat is transferred out of the water into a refrigerant causing it to vaporize. The gaseous refrigerant is then compressed, raising the temperature. The refrigerant, now a hot gas, passes through a fan coil where heat is transferred out of it and circulated through the building space. As the heat is transferred out of the refrigerant, it is condensed to a liquid. It passes through an expansion device, which lowers the pressure, and, accordingly, the temperature. The refrigerant is now a cold liquid ready to pass through the heat exchanger, pick up heat from the groundwater, and start the cycle again. After the groundwater has passed through the heat exchanger and has given up heat, it is discharged, usually to an injection well.

In accordance with Utah Law, an approved water right is required for all uses of water within the state, including non-consumptive uses such as open-loop heat exchange systems. . Application for a water right for these purposes is made through the standard water right procedure, and should specify the use, amount, location, the consumptive or non-consumptive nature of the proposed use, method of disposal, and other relevant information. If the heat pump is to be connected to an existing well and used under an existing water right, a change application may be filed to include the heat exchange use in the water right. In any case, an approved application stating the specific use must be on file with the Division of Water Rights before the system is put into operation.

A Non-Production Well Construction Request should NOT be used for an open-loop heat exchange well.

Disposal of spent groundwater by reinjection will be required in most cases in order to protect the groundwater resource and to utilize it most efficiently. In some areas of Utah, the groundwater is already seriously depleted; in those areas, no new water rights for consumptive use will be approved, and new applications for open-loop heat exchange systems will not be approved unless the plans include non-consumptive use by disposal by reinjection.

A two-well system is usually used for reinjection; this allows the wells to be alternated for heating and cooling, and this kind of heat storage system can increase the efficiency of the heat pump system.

An approved water right is necessary before a production or injection well may be drilled, and the driller must have a current drilling license from the state. A complete well log must be submitted, and other general regulations for water well drilling must be followed.

Closed-Loop Heating-Cooling Exchange Well means the subsystem of a geothermal heat pump system that consists of the drilled vertical borehole into the earth that is equipped with a heat exchange media conveyance loop tube (typically HDPE tubing), and is grouted from the bottom of the vertical borehole to the earth's surface at the drilling site. Construction of a geothermal heat pump loop well includes, in continuous order, drilling of the vertical borehole, placement of the loop tube to the bottom of the vertical borehole with the grout tremie, and grouting of the vertical borehole from the bottom of the borehole to the earth's surface at the drill site. Closed-loop systems circulate a heat transfer fluid, such as water or a mixture of water and food grade, non-toxic antifreeze, to exchange heat with the subsurface geological environment.

Closed-loop heating-cooling exchange wells which are greater than 30 feet in depth and encounter formations containing groundwater, must be drilled by a licensed driller and the owner or applicant must have an approved application for that specific purpose as outlined in Section R655-4-9. Wells or boreholes installed for heat or thermal exchange process must comply with the minimum construction standards of Section R655-4-11. Direct exchange (DX) systems are allowed on a case by case basis as approved by the state engineer.

Approval to drill and construction regulated non-production wells must be obtained from the Well Drilling Program office in the SLC office or the State Engineer’s regional offices. The request to construct a non-production well can be made by completing the form titled Request for Non-Production WellConstruction and submitting it to the regional office or the Well Drilling Program office in the SLC main office. The Division can take up to 14-days to review and respond to the NPW application. If non-production well authorization to drill is granted, the applicant will be allowed to drill, construct, develop, and test the well only. Water from the test well shall not be put to beneficial use. Non-production wells that are no longer being utilized for their intended purpose should be properly abandoned by a licensed driller, which is the responsibility of the applicant/owner.

This permit may not be the only authorization needed to drill a well. The applicant is responsible for obtaining other permits/authorizations from federal agencies, other state agencies, and/or local jurisdictions as applicable. Moreover, if the applicant is not the landowner, it is the applicant's responsibility to ensure that approvals/permissions have been obtained to trespass and drill a well(s) on the property. This permit does not give authorization to trespass on private property.

A public listing of non-production well applications, including closed-loop heat exchange can is available on the well drilling pages of this website at this link.