A geothermal system with six separate geothermal probes is being installed for a holiday home on Bartholomäberg in Montafon (Austria). The challenging geology, with its groundwater aquifer, required careful planning and a tailored drilling procedure.
This project demonstrates how collaboration within the separatus partner network works. separatus handled the thermal simulation and design. Our drilling partner, Plankel, carried out the drilling work and installed the geothermal probes. Geser Erdwärme is responsible for the hydraulic connection.
This results in a seamless solution from planning to completion.
Das Ferienhaus liegt am Bartholomäberg im Montafon auf ungefähr 734 Metern Seehöhe. Für die Wärmeversorgung des Gebäudes soll die oberflächennahe Geothermie genutzt werden. In einer ersten Planung waren 6 Erdwärmesonden mit einer Tiefe von jeweils 53 Metern grob kalkuliert.
The separatus system is particularly suitable for geothermal projects with shallow drilling depths. The flow and return lines are integrated within the compact splitpipe. This creates favorable hydraulic conditions, which can be crucial for efficient heat transfer with short probes.
Distributing the required total drilling length across several short boreholes offers a significant advantage in challenging geological conditions. Particularly deep and technically risky drilling sections can be avoided. At the same time, the borehole field can be precisely adapted to local conditions.
Erdwärmesonden sollten sorgfältig auf den Energiebedarf des Gebäudes, die klimatischen Bedingungen, die Eigenschaften des Untergrunds und die hydraulischen Bedingungen abgestimmt werden.
Im Zuge der Detailplanung führte das separatus Planungsteam eine thermische Simulation des Erdwärmesystems durch und überprüfte die projektspezifischen Randbedingungen. Dabei zeigte sich, dass die ursprünglich angesetzte pauschale spezifische Entzugsleistung für diesen Standort eher optimistisch gewählt war. Aufgrund der klimatischen Bedingungen auf dieser Höhe im Montafon sowie der örtlichen Geologie lautete die Empfehlung, die Sondenlänge zu erhöhen, um die Anlageneffizienz langfristig zu optimieren. Die Anlage wurde schließlich mit 6 Erdwärmesonden zu je 60 Metern ausgeführt. Die gesamte Sondenlänge beträgt somit 360 Meter.
Die thermischen Simulationen zeigten ausserdem, dass für dieses Projekt mit dem separatus System höhere Soletemperaturen zu erwarten sind als mit einer herkömmlichen Doppel-U-Sonde. Der wesentliche Grund dafür liegt in den Strömungsverhältnissen: Bei Doppel-U-Sonden wäre aufgrund der projektspezifischen Volumenströme von einer überwiegend laminaren Strömung auszugehen gewesen, was den Wärmeübergang im Sondenrohr verschlechtert. Das separatus System erreicht unter denselben Randbedingungen günstigere hydraulische Verhältnisse und damit eine effizientere Wärmeübertragung.
Six uniformly sized geothermal probes create a clearly arranged drilling field. The chosen configuration combines a limited drilling depth with the required thermal output.
The geological conditions presented particular challenges for the execution. There is a groundwater aquifer underground. The drilling procedure was adapted to the different geological zones.
First, a 160-millimeter diameter casing was installed using the horizontal directional drilling (HDD) method. This casing secures the upper part of the borehole and allows for controlled continuation of the drilling operations. Subsequently, the drilling process was switched to down-the-hole hammer drilling within the casing. Using a drill bit with a diameter of 132 millimeters, the boreholes were then drilled to a depth of 60 meters.
The combination of the two drilling methods enabled a controlled execution adapted to the subsoil.
The drilling work and the installation of the separatus geothermal probes were carried out by our experienced drilling partner Plankel.
The implementation included:
Especially in complex geological conditions, experience, suitable machinery, and the right combination of drilling methods are crucial. Plankel contributed these competencies to the project and professionally implemented the planned solution on the construction site.
After the installation of the geothermal probes, Geser Erdwärme takes over the hydraulic connection of the system.
The individual probes are connected to the distribution system and integrated into the overall system. Careful hydraulic design is essential to ensure that all probes receive a uniform flow and can reliably deliver the planned output.
Early coordination between planning, drilling and connection clearly defines the interfaces between the companies involved.
The project at Bartholomäberg demonstrates the benefits of a coordinated partner network.
Each company takes on the area in which it has the relevant experience. This results in a seamless solution for the client. The individual project phases are not considered in isolation, but are technically coordinated.
This is important for demanding projects. A good simulation alone is not enough if the planned solution is not compatible with the available drilling technology. Likewise, the hydraulic connection must be matched to the design and the actual borehole configuration.
The separatus partner network combines these competencies.
The project demonstrates that geothermal energy can be reliably utilized even with shallow borehole depths and challenging geological conditions. Crucially, the solution must be perfectly coordinated between thermal design, drilling technology, and hydraulic connection.
Six separate geothermal probes, each 60 meters long, create a compact geothermal system with a total probe length of 360 meters. The adapted drilling process, including flush drilling, casing, and subsequent down-the-hole hammer drilling, takes into account the specific conditions of the subsurface.
At the same time, this reference project demonstrates the strength of the separatus partner network. From simulation and drilling to hydraulic connection, specialized companies contribute their expertise to a joint solution.
Are you planning a geothermal energy project in Vorarlberg and looking for a high-quality solution with sound design?
Our network supports you from the initial simulation through drilling to the hydraulic connection.
