Construction instructions for the Sí-BoFe-1000 geothermal drilling field for air temperature control

The Sí-BoFe-1000 is a design for a vertical ground-source heat pump system for passive air temperature control. The system utilizes the relatively stable ground temperature of approximately 8–12 °C at a depth of a few meters to preheat outside air in winter and precool it in summer.

The design is based on a DN200 borehole with a continuous divider plate . This creates two separate air channels within the same pipe: The supply air flows downwards in the first channel, is redirected at the pipe end, and rises again in the second channel. This results in an air path of approximately 10 m in the ground per borehole.

Several boreholes are combined into a compact borehole field. This allows for stable air temperature control even on small properties – without a heat pump, compressor, or complex technology. Typical applications include supplying fresh air to buildings, greenhouses, animal barns, or utility rooms, as well as pre-heating the intake air for air-source heat pumps.

An integrated condensate management system ensures that any condensate that may form is drained away via a hose at the lowest point of the pipe. This eliminates the need for additional drilling in the pipe and ensures the system remains permanently leak-proof.

The construction plan describes the complete assembly of the system – from the drilling pattern and pipework to the connection to the manifold and air mixer. The system is modularly expandable and suitable for DIY projects, agriculture, greenhouse projects, and energy-efficient ventilation solutions.

Drilling field

Several boreholes form a common drilling field.

Typical sizes:

Drilling distance: approx. 1.5 – 2 m