What is ... Geothermal
Safe Geothermal energy: Renowned drilling companies such as BauGrund Süd vouch for quality and guarantee a certain extraction capacity. (Weishaupt)
Geothermal energy is - as the translation implies - heat from the ground. But what are the types of geothermal energy and how can the ground help us save energy? How is heat extracted and what happens to it once it has been extracted?
The difference in depth
When talking about geothermal energy one distinguishes between "geothermal energy" and so-called "near-surface geothermal energy”. The former is usually used in power stations, which extract heat from the ground at a depth of up to 5000 m to generate electricity or for district heating distribution. The near-surface geothermal draws heat from a depth of 70 to 140 m using one or more probes or with a ground collector spread across an area at a depth of 1 to 2 m.
The ground collector
A frost-proof liquid (brine) in the plastic tubes of a ground collector absorbs the ambient heat. (Picture: Weishaupt)
The term "near-surface geothermal energy” is best applied to ground collectors, which also extract energy from the ground. This energy is not fed by the hot core of the earth, but supplied by the sun and rain to the upper layer of soil, however, the area above the ground collector must not be planted or built on.
The geothermal probe
Brine also circulates in a probe and absorbs the heat from the depth. (Fig: Weishaupt)
Near-surface geothermal energy can be utilised using not only ground collectors but also geothermal probes. Geothermal probes are placed into a deep borehole where they extract heat from the ground generated by the sun, the rain and the Earth's core. Although this type is more expensive to buy, it is much more efficient and space saving than the collector variation.
Harnessing geothermal energy
Even if brine in the probes at a depth of 100 m is warmed up by about 4 degrees Celsius, this is obviously not sufficient to heat a building. Therefore, a heat pump is always used in conjunction with near-surface geothermal energy extraction, which “pumps” the energy to a more useful level.
Advantages of geothermal energy
Fully installed heat pump (Picture: Weishaupt)
The heat from the ground itself is free. The "extraction" of heat and the operation of a heat pump costs approximately 1 / 4 of the energy yielded. Another advantage is that the system operates without emissions, that is to say - the house needs no chimney for a heat pump.
If you are interested in the geothermal energy or other heating systems, please request the Weishaupt guidebook about heat pumps, solar systems and other modern heating systems, which is available free of charge. The Weishaupt Partner Locator will help you find the appropriate local contact.