The planning of geothermal systems involves three stages: pre-planning, design planning and execution planning. For the pre-planning process, we collate all the information liable to influence implementation of the project:
- Geological/hydrogeological conditions on-site, identified from geological maps or from records of drilling close-by for example
- Official planning constraints, such as a maximum permissible drilling depth or sensitive ground-water horizon
- Physical factors, such as the projected thermal conductivity and temperature of the undisturbed ground as well as hydraulic characteristics of ground-water conductors, which are key variables in terms of system design
- Drilling risks, assessment of the probability of their occurring at the location, and possible measures to control them
- Economic criteria, such as the investment cost of a geothermal system and the saving on operating cost relative to conventional methods of heat and cold generation.
Our expertise enables us to analyse and assess all the relevant facts in their totality, to determine the provisional dimensions of the installation, to calculate a range of probe field variants, and to submit an initial cost estimate. If this preliminary assessment indicates that a geothermal system would make sense, we usually recommend carrying out a test bore to gather more detailed information about the on-site geological conditions. Developed to create a geothermal probe, the test bore is then available for field measurements. The data obtained in this way is incorporated into the design, which specifies the dimensioning and positioning of the optimised installation.
Design planning is carried out on the basis of thermal simulations modelling the heat exchanger system and its life-cycle (Modelling). This data resource then enables us to design systems that will run highly efficiently – not just initially, but over the long term.
Execution planning involves preparing all the drawings covering the entire project ready for execution. In doing this, we also design and dimension the horizontal connection routing and the heat transfer medium distribution system. We carry out calculations of pressure loss in the pipe network in order to ensure that the system hydraulics conform to the parameters of the installed circulating pump, and we supply the data necessary for system configuration.
Block diagram: geothermal probe