Simulating near-surface geothermal energy systems
Our geothermal tools at a glance:
EWS (simulation of geothermal sources)
While smaller systems can be designed using parameters, larger geothermal systems should be simulated. We use the ‘EWS’ simulation software from Huber Energietechnik AG for this purpose. This programme can be used to simulate geothermal probe systems over a period of up to 200 years. This is necessary to prove that the subsurface does not cool down or heat up too much even after many years of operation. In addition to the parameters for the probe field, brine mixture and subsurface, a monthly or hourly load profile is specified.
- TRNSYS
TRNSYS - the ‘Transient System Simulation Tool’ - is another simulation environment for the dynamic simulation of energy systems, which is mainly used in research. TRNSYS can be used to simulate near-surface geothermal energy sources as well as solar thermal systems, for example. We use TRNSYS for the simulation and design of ground collectors, for example. However, TRNSYS is also suitable for modelling other dynamic systems such as traffic flows or biological processes. TRNSYS has been available on the market for 35 years.
- Polysun
If the interaction of several sources, heat generators and consumers is to be simulated, we use the Polysun simulation software from Vela Solaris. Polysun contains an interface to EWS, allowing complex energy systems with geothermal probes to be simulated holistically. For example, the summer regeneration of geothermal probes can also be simulated using recoolers or PVT. In order to achieve an optimised system in terms of performance and efficiency, this should always be the final step.
- FEFLOW (thermal subsurface simulation with groundwater flow)
In a few projects, the interaction between heat transport and groundwater flow plays a decisive role. FEFLOW enables a detailed simulation of thermal and hydraulic processes in the subsurface in order to optimise the design of geothermal plant sites. - Thermal Response Test (TRT)
As from a certain plant size, a detailed knowledge of the thermodynamic properties of the subsurface is useful. Although the thermal response test is not software, it is a tool that we like to commission from a geologist in connection with larger geothermal plants. The TRT increases planning accuracy and thus reduces the investment risk. A pilot probe is drilled and heated water flows through it. By measuring the temperatures at the probe inlet and outlet, conclusions can be drawn about the soil parameters. A TRT often takes several days.
Why are these geothermal tools so important?
The planning of geothermal systems quickly becomes complex, especially in combination with other sources for regeneration. With the software solutions presented, we can master this complexity and thus increase planning reliability. It is also possible to optimise initial investments in order to efficiently implement sustainable heat supply concepts.
Without these simulation and analysis tools, geothermal projects would be subject to considerable uncertainties. For example, an incorrect assessment of the thermal conductivity of the subsurface can lead to a system not delivering the expected output - i.e. being undersized or oversized. The precise calculations of our software tools ensure that resources are utilised in such a way that they allow for stable systems in the long term.
These tools also facilitate communication with stakeholders, as they provide reliable, visualised data that makes complex geothermal processes understandable. For municipal heating projects in particular, such well-founded decision-making bases are essential in order to communicate economically and ecologically sensible solutions.
In the field of geothermal energy and cold local heating in particular, the simulation of the subsoil is essential. Soil conditions, groundwater flows and long-term thermal effects play a major role here. By using specialised software, we ensure that geothermal systems work efficiently and do not harm the environment.