What is a Ground Source Heat pump?
is a mechanical device that extracts heat from a "source" and conducts that heat into another place called a "sink", it is also reversible. Depending on whether you want to heat or cool an object will determine if it is the "source" or the "sink".
Think of heat energy as a fluid. A heat pump is like a ladle. It doesn't create any heat, it simply ladles heat from one source to another. The beauty of the heat pump is that depending on the amount and quality of heat energy that exists from the source, the heat pump may move much more energy than it uses to operate.
Types of heat pumps:
Air source heat pump
Is the most commonly used heat pump system, the unit is located outside and it uses the outside air as the source/sink. The conditioned refrigerant is piped into the house to an air handling furnace that circulates the hot, or cold air. Efficiency drops significantly in extreme hot or cold outside air temperature.
Ground source, or Geothermal heat pump
Is a commonly used high efficiency heat pump system, the unit is located inside, water/antifreeze solution is piped outside to a closed loop field buried in the ground, uses the deep ground as the source or sink. An air handling furnace, may be combined or split from the compressor unit, circulates the hot or cold air. Requires a separate pumping system to circulate the water/antifreeze solution. Efficiency stays high throughout the year, because the ground temperature remains constant.
In a comparison between the Air source and Ground source heat pumps.
Before incentives, air source heat pump systems are about half as expensive as Ground source heat pump systems. Despite the initial cost, ROI for a Ground source heat pump system (before incentives) is about 6 years.
There is little comparison between the two regarding efficiency. Because of the physics involved, the Ground source heat pump has an unfair advantage . Remember the analogy describing heat energy as a fluid, and the heat pump's ability to move heat energy being dependent on the amount and quality of the heat energy of the source. Using the same analogy, if the Air source heat pump moves heat using a ladle, then the Ground source heat pump moves heat using a bucket.