- Geothermal heat pump with vertical capture: how does it work?
- Vertical catchment on groundwater
- Geothermal heat pump with vertical capture: more expensive... but more efficient!
Install at home a geothermal heat pump with vertical capture, it is a sacred investment: about 200 € / m²! But the vertical capture is not only bad side: small and very powerful, it is an investment all that is profitable...
Geothermal heat pump with vertical capture: how does it work?
Unsurprisingly, vertical capture is done by digging... vertically! This system is therefore perfect for small lots, because its deployment does not require more than 3m². Beware however: the installation of a geothermal heat pump with vertical capture is rather complex, and requires quite expensive work.
Indeed, to install vertical sensors, it is necessary to dig, and dig deep: the geothermal probes go down to a well, located between 80 and 100m. These probes are installed by drilling, and about 50 € per meter of probe, we understand immediately why the vertical capture is more expensive! Fortunately, 2 probes 70m deep enough to power a house of 150m ².
Regarding the operation, it differs little from that of a horizontal capture: the geothermal probes are connected to 4 tubes in which glycol water circulates in a closed circuit. Except that in a vertical capture, this pipe goes deeper in search of terrestrial heat, which it will transmit to the heat pump in the house. And once connected to the heat pump, the probes are sealed in their well, thanks to a cement-clay mixture that will protect them and make them more conductible.
To note: Drilling requires a authorization from the Regional Directorate for Industry, Research and the Environment (DRIRE).
Vertical catchment on groundwater
This is the recommended solution when a house is just above an accessible water table and not too deep.
Drilling is shallower than for standard vertical capture. And even if drilling costs are higher on groundwater, only 2 wells are drilled, between 10 and 50m. The first well will pump the water to supply the heat pump. The second well is used to reinject the water into the water table.
Geothermal heat pump with vertical capture: more expensive... but more efficient!
It is a fact: a geothermal heat pump with vertical capture, it is more expensive than a heat pump with horizontal capture. But even if the basic investment is higher because of the necessary work, vertical capture has many advantages:
- First of all, it does not require any particular surface. Whether you have a huge field or a smaller area, this is not a problem, since the system deploys in depth. Once installed, the vertical capture does not represent more than 2m ² on the ground!
- And even if it requires little floor space, it is no less efficient. On the contrary: in depth, the heat of the earth is more constant than on the surface. The probes will therefore be less sensitive to changes in temperature.
This is even more the case for vertical catchment on groundwater: the water temperature of a water table always oscillates between 8° and 12° C, no more. This capture system is the one that offers the most important performance, with a coefficient of performance of 5!