Ground probe (definition)

Ground probe — is an element of a geothermal heating system, which is a vertical or horizontal pipe immersed in the ground to a certain depth. The main function of a ground probe is to heat collection from the ground and transferring it to the coolant, which circulates inside the probe.

Ground probe: application features

Ground probes are typically used in conjunction with heat pumps to heat and cool buildings, providing a stable and efficient source of energy because the temperature of the ground at a certain depth remains relatively constant year-round.

Ground probe and heat pump form the main part of a geothermal heating system. In this system, the ground probe acts as a heat exchanger, which takes heat from the ground and transfers it to the coolant circulating through the system.

Equipment set:

1. Ground probe:
   • Vertical probes: Installed in deep wells (up to 100-200 meters). This type of installation requires drilling and is used when the area of the site is limited.
   • Horizontal probes: They are laid at a shallow depth (1.5-2 meters) and require a larger land area for placement. They are usually mounted in the form of spirals or serpentines.
   • Materials: Probes are made of polymer pipes (e.g. high-density polyethylene) that are resistant to corrosion and chemicals.
2. Heat pump:
   • Compressor: The heart of the heat pump, which compresses the coolant (for example, freon), increasing its temperature.
   • Evaporator: Here the coolant absorbs the heat coming from the ground probe.
   • Capacitor: Transfers the collected heat to the heating or hot water supply system.
   • Circulation pump: Ensures the movement of the coolant between the ground probe and the heat pump.
   • Expansion tank: Stabilizes the pressure in the system.

System operation:

1. Heat absorption: A heat carrier circulates in the ground probe, which takes heat from the ground. The temperature of the ground at a certain depth remains stable all year round (about 10-15°C).
2. Heat exchange: The heated coolant enters the evaporator of the heat pump. In the evaporator, it transfers heat to the refrigerant, which evaporates.
3. Compression: The refrigerant in its gaseous state is compressed by the compressor, which significantly increases its temperature.
4. Heat dissipation: The heated refrigerant enters the condenser, where it gives off heat to the heating or hot water supply system.
5. The cycle repeats itself: The refrigerant, having given up its heat, enters the evaporator again, and the process is repeated.

Advantages:

• High efficiency: The ground provides a stable heat source, allowing the heat pump to operate with a high coefficient of performance (COP).
• Environmental friendliness: Using renewable energy reduces CO₂ emissions.
• Autonomy: The system requires virtually no external energy sources, except for power supply to operate the pumps and compressor.

Ground probe and heat pump represent an environmentally friendly and cost-effective heating solution, especially in regions with cold winters where traditional heating methods may be less efficient.