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What is geothermal energy?

Geothermal energy is the heat that comes from the Earth’s subsurface. The energy is carried to the surface in water or vapour. Depending on its characteristics, geothermal energy can be used for heating or cooling, or even to produce clean electricity.
 

How does geothermal energy work?

A geothermal system consists of two main elements:

1. A geothermal heat pump located inside a home (normally where the furnace was); and
2. Underground channels, called underground loops, which are located in the yard under the frost line.

A geothermal heat pump

The technology is based on the fact that the earth (below ground) remains at a relatively constant temperature all year-long, warmer than the air above ground in the winter, and cooler in the summer, a bit like a cave. A geothermal heat pump transfers the underground heat inside in the winter and transfers the heat from the house underground in the summer.

The main difference between a furnace and a geothermal pump is the source of energy used to heat a house. A typical furnace creates heat by burning fuel oil or gas in its combustion chamber, whereas a geothermal pump simply moves the existing heat from underground.
 

What are the pros and cons of geothermal energy?

Types of underground loops:

Horizontal loop

Trenches are dug to a depth of 5 to 6 feet, measuring 300 to 500 feet in length.

• There are several options for pipe configurations, depending on the available space.
• A minimum 0.5 acres is required for a typical residential home.

Vertical loop

• These are drilled down to depths of 50 m to 150 m and more.
• They are appropriate for new constructions and additions to existing residences with small lots.
• These do not require much space.
• Their installation does require specialized equipment and personnel.
• The cost of installation is higher.

Where does geothermal energy come from?

1. The sun’s energy heats the ground.
2. The loop absorbs the heat from the soil and carries it to the building.
3. The geomatics unit transfers the heat to the house.

Exciting project

The Hellisheidi power plant ranks sixth among the world’s biggest geothermal power plants by installed capacity.

LEarn more

Interesting facts

Heat is captured in the ground

The heat captured in the ground can reach upwards of 300 degrees Celsius. That happens at depths of over 1,500 metres, and this type of installation is normally found in volcanic zones.

Residential drilling

For residences, drilling goes no deeper than 100 metres, and the captured heat can reach 30 degrees Celsius.
 

Sources :
¹ https://www.greenwatt.fr/chauffage-geothermique-avantages-inconvenients/