Geothermal

On reaching the desired drilling depth during deep geothermics, the hot thermal water is brought to the surface by the air lift method or pumping to enable determination of its properties.  The hot thermal water may only be conveyed to the public sewage system, outfall or infiltration basin following cooling.

Porous limestone strata convey hot thermal water with a temperature of 70-150°C and delivery rate of 50-120l/s at a depth of 900 to 4000m. The thermal energy contained in this can be exploited to generate heat, steam and electric power.  This reservoir is tapped through extended reach drilling. Compressed air is pumped into the borehole using large compressors to convey the water.  Alternatively, a special vertical centrifugal pump is inserted into the narrow borehole. Following determination of the temperature, pH value, conductivity and mineral content, the water is cooled to the required temperature level of between 20-35°C in evaporation cooling towers.  The thermal water is finely atomized in several hundred nozzles and conveyed into a honeycomb structure with a surface the size of a football pitch during this process.  Air is simultaneously forced through the honeycomb in a countercurrent process.  The thermal water is cooled during this.  The cooling capacity is 8MW per cooling tower, depending on the size of the cooling towers.  The water is pumped from a catchment basin into the public sewage system.  The longest pumping distance measures 3500m. Alternatively, if the thermal water is conveyed to an outfall or infiltration basin, the cooled thermal water requires cleaning in activated carbon filters.

We have successfully realised the following geothermal deep drilling operations:

• Garching 2009-2010 3
• Aschheim 2010
• Mehrenbach 2011
• Waldkraiburg 2011
• Taufkirchen 2011-2012