Ground-source heat pump explained

Intro

All heat pumps collect ambient energy and convert it into heat. Ground-source models do this by tapping into the upper layers of soil, which store geothermal energy from solar radiation and rainwater. The relatively stable temperatures of the soil create ideal operating conditions for ground-source heat pumps: Providing more daily comfort and less dependence on fossils and public energy grids, while enabling ample savings on running costs and emissions.

Advantages of ground-source heat pumps

Ground-source heat pumps: a glance at benefits and drawbacks.

Generally, ground-source heat pumps offer several major improvements over conventional heating systems in terms of comfort, efficiency, and sustainability. Yet, to provide a holistic view on the technology, it is necessary to point out the increased effort for excavation or drilling works as well as the importance of ground conditions for the heat pump's efficiency.

Savings costs.
Ground-source heat pumps have the lowest electricity demand of all heat pump types thanks to steady soil temperatures. Using free geothermal energy also generates savings on operating costs.
Enjoy the silence.
Our elaborate Sound Safe System keeps noise emission from heat pump operation at a minimum and thus enables flexible placement of the system. Since it doesn’t operate with an unit outside, there’s no noise emission outside your home.

Operating principle of a ground-source heat pump

How do ground-source heat pumps work?

The ground-source heat pump is connected to a set of pipes with a very cold mix of water and an antifreeze in them – a so-called carrier fluid. This fluid is transported through the pipes to the ground and back to the heat pump. When passing this cycle, thermal energy in the ground heats the carrier fluid until its low boiling point causes it to evaporate.

Back in the heat pump, the resulting vapor is compressed to heat up even more. Ultimately, a heat exchanger transfers this heat to the heating system which then passes it on to your home.

In summer the heating process works vice versa, too: Simply maintain a cool indoor climate by reversing the heat exchanger’s function to cool with your heat pump. Heat from inside your home can be discharged through the circuit into the ground and therefore passively cool your home!

Different ground-source heat pumps

Types of geothermal energy extraction.

There are various types of geothermal energy extraction that we would like to present to you in detail.

Ground collectors
Geothermal heat baskets
Ring trench collectors
Geothermal probes

Horizontal piping system of the ground collectors

Ground collectors consist of a horizontal pipe system that is laid flat in the ground to a depth of around 1.5 m below the frost line. Ground collectors consist of a horizontal pipe system that is laid flat in the ground to a depth of around 1.5 m below the frost line. They require a large area, which makes them less suitable for smaller plots. As a rule of thumb, the area for the installation of ground collectors must be about twice as large as the living space of the house.

In addition, the heating requirement and the nature of the ground also influence the size of the required area. It is important that the area for the ground collectors is not built on or paved over, as otherwise the sun will not be able to heat the entire surface of the ground. However, it is possible to plant bushes, shrubs or trees with shallow roots.

The installation of ground collectors is simpler and cheaper than geothermal probes, geothermal baskets and ring trenches, which is why they are often used in new development areas with sufficient space. Another major advantage of ground collectors is that no permits are required.

Spiral pipe structures of the geothermal baskets

Geothermal baskets are a form of near-surface ground collector and consist of spiral-shaped pipe structures that are sunk vertically into the ground. The prefabricated geothermal baskets with a diameter of around 2 m are installed in pits up to 4 m deep. Installation on a slope is also possible. It is important to ensure that the surface above remains as free as possible so that the ground can absorb the solar heat.

As with ground collectors, it is not possible to build on or pave over the area, as the ground would not be able to fully absorb the solar heat. Planting, on the other hand, is possible without any problems as long as no deep-rooted plants are used.

Geothermal baskets are ideal for smaller properties in particular, as they require less space than ground collectors. This makes them suitable for smaller gardens and easier to install than geothermal probes. Another clear advantage of geothermal baskets is that no permit is required for this type of heat recovery.

Elongated loop shape of the ring collectors

Ring trench collectors are laid horizontally in an elongated loop shape below the frost line at a depth of around 2 m on the property. The length and shape of the trench are individually adapted to the size of the property and the energy requirements of the house. A brine fluid circulates in the pipes laid in the ring trench, which absorbs the heat and transfers it to the geothermal heat pump.

The advantages of the ring trench collector are that no deep boreholes are required as with geothermal probes and that, in contrast to ground collectors, there is no need to lay the pipes over large areas of land. The land can be fully used again after installation, for example as a lawn. However, it is important to note that the area above the ring trench collectors must not be paved or built on in order to ensure heat absorption by the sun. Planting with shallow roots, on the other hand, is not a problem.

The advantage of ring trench collectors is that no approval is required.

Geothermal probes are inserted into layers of earth 40 to over 100 m deep. They consist of vertical pipes that are inserted into deep boreholes. A brine fluid circulates in the pipes, which absorbs the heat at depth and transports it upwards to the heat pump.

The biggest advantage of heat recovery with a geothermal probe is its particularly high energy efficiency. The temperatures in the ground are constant all year round - and rise with increasing depth. How deep the geothermal probe is installed depends on the heat requirement of the house.

In addition, geothermal probes require less space than other types of geothermal heat extraction, which is why they are particularly suitable for properties with limited space.

A disadvantage is the comparatively higher cost of planning and drilling. In addition, you must obtain approval from the lower water authority in advance and, from a depth of 100 m, comply with mining law and other permits.

Suitability check

The right choice for your home?

In properties with large gardens, ground-source heat pumps offer plenty of advantages. To find out whether you can benefit from these, too, just check your home on these required main characteristics:

Sufficient property area.
You don’t need a huge garden to install a ground-source heat pump system. A vertical system doesn’t require more space than is needed to operate the necessary digging machinery in your garden.
Effective insulation.
All heat pumps operate more efficiently at lower flow temperatures and therefore need a sufficient heat distribution in the building. Therefore, a well-insulated building is mandatory to retain sufficient heat.

Please be aware: The more gritty or sandy the soil, the less efficient the heat pump can operate. Therefore, ground conditions play a major role and increased excavation or drilling work for installation are needed. This raises development effort and costs.

Would you like advice on the various heat pump technologies? Our local partner will put together a heating system tailored to your specific needs.

Contact local partner

System expansions

We build the perfect system around your ground-source heat pump.

Solar thermal
Easily meet increases in heat demand via solar thermal energy with heat from solar radiation.
Read more
Ventilation
Reduce heat loss and costs via fresh air by ventilation to support your heating system’s performance.
Read more
System controls
Monitoring and control your heating system to save costs and flexibly set the room temperature.
Read more

Frequently Asked Questions

Still have questions? We have the answers.

Is the financial effort of installing a ground-source heat pump worth it?

How much property area do I need to install a ground-source heat pump?

This depends on the chosen type of collector as well as the size of the living space. Outdoor space requirements of geothermal probes are close to none as long as operating the required drilling machinery is enabled. For surface collectors, on the other hand, significantly more land without any trees or buildings is required for installation. As a rule of thumb: double the amount of square metres to be heated by the heat pump.

Do ground-source heat pumps maintain their efficiency in cold climates?

What’s the general life span of a ground-source heat pump?

What’s the difference between near-surface and deep geothermal energy?

Dive deeper into efficient heating.

All about our ground-source heat pumps.