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S&B Geothermal

How Ground Source Heat Pumps Heat

Fluid (water and antifreeze) is circulated from the heat pump, through a loop buried below the frost line in your yard which returns to the heat pump. During this trip, the water enters the loop field cold and is warmed by the earth. Back at the heat pump, the fluid is run through a heat exchanger where the cold refrigerant is warmed by the fluid. The water leaves the heat exchanger colder than it entered and is rewarmed by the earth.

The refrigerant entered the heat exchanger cold and exits it warmer. Due to the low refrigerant boiling temperature, the refrigerant enters the heat exchanger as a liquid and is boiled by the loop fluid. The refrigerant travels to the compressor where the compressor compresses the refrigerant causing its temperature to rise to about 160 degrees. This hot refrigerant is then sent to an air coil where the heat pumps blower blows air from the home over the coil. As it passes over the coil it is warmed and is sent to the home to warm the occupants. The refrigerant condensed to a cold liquid and is sent back to be warmed by the earth loop fluid.

This process continues constantly moving warmth from the earth, compressing it to a usable temperature and moving the warmth into the home. As the winter progresses, the earth's temperature will drop. A properly designed and installed system will never drop to the point where the fluid cannot extract enough heat to heat the home. Once summer starts, this cold earth becomes the source of cooling for the home.

On open systems, water is pumped from the well, cooled in the heat pump and returned to the earth. No water is consumed or contaminated in this process and it becomes available for reuse as it returns to the earth.

On systems that are operating at 3.5 Coefficient of Performance (COP), 2.5 units of heat are moved from the earth and 1 unit of heat is generated by the heat pump moving the heat. The warmer the earth is above 32 degrees, the more units of heat that are moved for every 1 unit that is generated.

Click here to learn how ground source heat pumps cool.