True. A well or lake can serve as both the supply and discharge source for an open-loop heat pump system. An open-loop heat pump system is a type of geothermal heat pump that uses groundwater or surface water as a heat source and heat sink. In an open-loop system, water is pumped from a well or a lake and circulated through the heat pump system, where the heat is extracted and used to heat the building. The water is then discharged back into the well or lake.
