Thermal Installations

The interaction of a heat exchanger with its environment is a complex process that is determined by a number of physical and technical factors. For geothermal installations such as surface collectors, borehole heat exchangers (BHE) andthermal-active building systems, in addition the local geological and hydrogeological conditions have to be taken into consideration. Numerical models help to understand e.g. what thermal power a heat exchanger can sustainably achieve or whether and how much a BHE field affects groundwater temperatures.

A special challenge in the simulation of such systems is the robust linkage of the small-scale physics of the heat exchanger with the large-scale processes of the geological environment. The goal here is to create numerically stable models that can reproduce long-term processes with the shortest possible calculation times.

Our in-house software SHEMAT or SHEMAT-Suite for which we have developed various additional modules for the calculation of heat exchangers, has proven itself here. These modules are so-called model-in-model solutions in which the processes within the heat exchanger are solved by analytical functions, while the processes in the geological environment are calculated numerically. This approach allows a significantly faster calculation than a purely numerical approach and at the same time offers the possibility to flexibly adapt the environment of the heat exchange to the local geological conditions.


Our range of services includes points such as

• Short- and long-term simulation of the performance of geothermal heat exchangers

• Performance forecasts for different operating and storage scenarios

• Forecasts taking into account changing flow rates, temperatures and varying heating cycles

• Assessment of geothermal effects of heat exchangers on the underground or groundwater

• Determination of the influence of groundwater flow on the performance

Model-in-Model modules exist for coaxial and double U-shaped BHEs, whereby probe parameters such as tube geometries, wall thickness, borehole diameter, thermal resistances etc. can be freely configured. Additional modules have been developed that can be used to predict the performance of thermal active construction elements such as sealing walls and sheet pile walls. These, as well as a module for the simulation of freezing processes in the subsurface have been developed in cooperation with the Institute for Geotechnical Engineering at RWTH Aachen University.



Geothermal effects of heat exchangers on the underground (1Jear and 20 Jears).