Design the future

Terra Thech is a new geothermal absorber for heat pumps

Swiss company Terra Thech, part of Waterkotte GmbH, has introduced a new geothermal absorber. A key feature of the new Terra Thech geothermal absorber is the use of the cylindrical geometry of the large area absorber. This geometry enables better and more efficient absorption and accumulation of "renewable energy" stored in the earth.
The main task in the development of the Terra Thech geothermal system was to overcome the geometric mismatch, which is that the volume and thus the need for a coolant (glycol solution) increases in a "square ratio" with the diameter of the cylindrical structure. For this reason, large cylindrical geothermal heat absorbers are hardly used in modern geothermal solutions.

Terra Thech proposed a geothermal absorber based on a large diameter cylindrical absorber that uses water instead of glycol as a working fluid. This solution made it possible to combine direct soil heat extraction and phase transition energy during freezing of water.

The Terra Thech geothermal probe consists of an airtight cylinder made of high density HDPE polyethylene, 315 mm in diameter and 3 meters long, with an HDPE tube spiral inside. The inner space of the cylinder is filled with water, and a glycol solution circulates through the tube coil.
The use of water, which has excellent physical properties, in Terra Thech geothermal systems, provides the most efficient selection of soil energy and provides a number of additional benefits:

  • the water volume in each geothermal module continues to accumulate heat even during heat pump breaks
  • the use of horizontal "heat pipe effect" for thermal compensation along the length of the cylinder, to improve heat extraction
  • using the latent heat of the phase transition of water (eisspecher / ice storage) as a reserve of energy in the case of long periods of extremely low outside temperatures
  • The Terra Thech geothermal energy absorber drive capacity is 2.0 kWh per module. In addition, the absorber provides the use of phase transition energy (eisspecher / ice storage) to the extent of 8.0 kWh per module.
    Each Terra Thech geothermal absorber collects energy from a soil mass of 15 cubic meters, from the highest average annual temperature. The highest possible heat source temperature is achieved by reducing the heat flux density proportional to the radius of the cylinder. 1kW of heat requires less than 12 liters of brine.

    Terra Thech geothermal energy absorbers consist of identical modules that can be installed in series and in parallel. They are shipped as ready-to-connect units and require minimal installation and excavation work.

    Salt is another Terra Thech innovation to reduce the freezing point of water
    If the freezing point is to be lowered, the geothermal absorber is filled with brine. 16 g of salt / liter of water reduce the freezing point by about 1 degree. 40 g of salt / liter of water is brought to a freezing point of –2.5 ° C. 80 g salt / liter of water reduce the freezing point to -5.0 ° C. If the freezing point is to be lowered to -3 ° C, approximately 10 kg of commercially available commercial salt is required for each 3 m module.