A water-to-water geothermal heat pump is designed to produce hot or cold water. Heated or chilled water is used to convey energy using water as a heat transfer medium. Hot water is often used in a radiant floor heating system, and chilled water is used in conjunction with a fan coil unit. A water-to-water heat pump can also be used to heat water for domestic use.
Related topic: More information on geothermal systems