The ground water heat pump is an open loop system. It requires a reliable supply of good quality water, and a suitable means of disposing of the thermally altered water after the process.
Lakes, Ponds and Others
The water source must be adequate to provide 1.5 to three gallons of water per minute per ton of heat pump capacity. Adequate disposal must also be available.
The quality of water is a major concern. Bad water can corrode the heat exchanger, and reduce the service life of the equipment.
In deciding whether or not to use available good ground water, the pumping cost must be considered. Should analysis indicate that pumping costs will be 25 percent of more of the space heating and cooling energy costs, an alternative closed loop system should also be investigated.
Water issues, such as reinjection and disposal and legal restrictions on use, are a major concern, and should be carefully examined.