Geothermal energy, you know? This technology is based on exploitation of constant ground temperature, ranging from 12 to 15°C, at a depth of a few meters. Thanks to a heat pump and a compressor, it can be increased and supply radiators or a hot water tank. It is therefore an unlimited source of heating, accessible 24 hours a day, and capable of cooling a dwelling in the summer. Where are we in France? Let’s do a check in.
> Read also: How does geothermal heating work?
Geothermal energy, accessible but little exploited
Exploiting geothermal energy to heat buildings in France is not foolish: according to the latest data from the Bureau of Geological and Mining Research (BRGM), 90% of the territory could have access to it. In addition, a recent study indicates that the national underground could cover, in theory, more than half of the hot water and heating needs of the inhabitants of Greater Paris. That is 7 million people, living in 131 municipalities.
The interest of this technology, accessible 24 hours a day whatever the weather conditions, is also ecological. Indeed, Ademe considers that geothermal energy emits on average five times less CO2 than gas heating, and seven times less than fuel-powered appliances. This is to say how full of promise it seems in terms of reducing the carbon footprint.
And yet: France has half as many geothermal heat pumps as Germany. Worse, there are three times less, or almost, than in Sweden… which is nevertheless much less populated!
> To read also: What is the energy source of geothermal energy?
Geothermal heating: which installations?
Concretely, how install a geothermal heating system ? In order to exploit the heat of the ground, it is obligatory to dig. Two options are possible:
- install a coil horizontally, 80 cm deep;
- drill vertical, at a greater depth.
It is then imperative touse a heat pump (PAC). This will “absorb” the energy present in the ground, thanks to sensors buried in the ground. There are four kinds:
- the ground-to-ground heat pump;
- the soil-water heat pump;
- the glycol water-water heat pump (the glycol water ensuring the transport of heat);
- the water-water heat pump (which captures calories from groundwater).
Attention, the installation of a geothermal heat pump modifies the configuration of the ground of a ground: administrative procedures are therefore mandatory. Contact your town hall to find out, in particular, whether you need to obtain authorization from the Regional Department for the Environment, Planning and Housing (DREAL) in your area.
> Read also: What is the lifespan of a geothermal heat pump?