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Geothermal Facts and Stats #6

Geothermal Heat Pumps

Our 6th Geothermal Fact and Stat looks into Geothermal Heat Pumps (GHPs).  GHPs are the fastest form of geothermal energy (heat) growth worldwide – due to their residential applications and ability to use the easily accessible subsurface temperatures to heat and cool water.

Geothermal Heat Pumps

How do geothermal heat pumps work?
Animals burrow underground for warmth in the winter and to escape the heat of the summer. The same basic principle of constant, moderate temperature in the subsurface is applied to geothermal heat pumps (GHPs), which provide both heating and cooling solutions. The Geothermal Exchange Organization notes that geothermal heat pumps can utilize average ground temperatures between ~40˚and 70˚F (“Spectrum”). GHP heating systems circulate water or other liquids to pull heat from the Earth through pipes in a continuous loop.

Electricity is used to boost or cool the temperature and distribute it through a heat pump and conventional duct system. For cooling, the process is reversed; the system extracts heat from the building and moves it back into the earth loop. The loop system can be used almost everywhere in the world, taking advantage of the Earth’s relatively constant temperature at depths below about 10 ft to 300 ft. and can be buried conveniently on a property such as under a landscaped area, parking lot, or pond, either horizontally or vertically. A GHP system can also direct the heat to a water heater unit for hot water use.

—  Furthermore —
Geothermal (ground-source) heat pumps (GHP) are one of the fastest growing applications of renewable energy in the world, with annual increases of 10% in about 30 countries over the past 10 years.  Most of this growth has occurred in the United States and Europe, though interest is developing in other countries such as Japan and Turkey. The present worldwide installed capacity is estimated at almost 12,000 MWt (thermal) and the annual energy use is about 72,000 TJ (20,000 GWh).

Sources: GEA Geothermal Basics Q and A – 2012
(PDF) Geothermal (ground source) heat pumps—A world overview. Available from: .

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