Solar Energy and Geothermal - SGT -

The Solar Energy and Geothermal group focuses on solar and near-surface geothermal energy. Their research approach covers topics from the development and optimisation of individual components to the integration of such into complex energy systems. Both, thermal and electrical problems are considered with their interplay being investigated.

The main work focuses are:

  • Integration of solar and near-surface geothermal energy into energy systems
  • Interaction of volatile sources and consumers with power and heat grids
  • Intelligent power grids (smart grids)
  • Development of innovative sensible heat storages
  • Development of solar and PVT collectors
  • Quality assurance for geothermal heat sources
  • Innovative geothermal heat sources and their applications (e.g. CO2 geothermal probes).

Head of Group:
Dipl.-Phys. Lars Staudacher
Walther-Meißner-Str. 6
85748 Garching
Tel.: +49 89 329442-41
Fax: +49 89 329442-12

Deputy Head of Group:
Dipl.-Ing. Hanne Karrer
Walther-Meißner-Str. 6
85748 Garching
Tel.: +49 89 329442-48
Fax: +49 89 329442-12

Services & Equipment


  • Development of thermal energy system components (thermal storages, low-temperature heating systems, solar collectors, PVT collectors, high-temperature thermal insulation)
  • Independent component testing
  • Planning support and metrological monitoring for demonstration projects
  • Non-invasive analysis of PV systems
  • Thermal response testing for geothermal probes
  • Validation of thermal response test devices
  • Dynamic simulation (e.g. with TRNSYS, Dymola, Polysun, ANSYS)
  • Simulation of power grids
  • Forecasting of electrical consumers and sources
  • Modelling of smart grid components (e.g. converters, batteries)
  • Plausibility checking, management, and visualisation of large data volumes and time series
  • Development of energy concepts based on renewable energies and (seasonal) storage of heat and electricity
  • Economic feasibility studies


  • Solar testing rig and tracker
    • Thermal power measurement of collectors up to 160 °C
    • Thermal and electrical power (up to 1000 W short-term) of PVT collectors
    • Biaxial tracking
  • Electrical storages and grids
    • District storage 72 kW and 330 kWh incl. weather station (Epplas/Hof)
    • Electrical load and generation measurement (PV) via first-generation smart meter in about 30 participant households
  • Testing centre Arzberg
    • Battery test site with 20 kW DC power supply and sink
    • Weather station with direct radiation sensor and SkyCam
    • About 50 kWp PV generators using different module technologies
    • Redox flow battery cluster with 90 kW and 390 kWh
  • Thermal response test (TRT)
    • Mobile measuring equipment for the determination of thermal subsurface properties (undisturbed ground temperature, thermal conductivity of the subsurface, thermal borehole resistance)
    • Application: Coaxial probes, single, and double U-probes, each between 30 and 200 m in length
  • Testing device for TRT instruments
  • Climatic chamber with artificial snowmaking
    • Snowing of areas up to 1 m2
    • Conditioning of large parts down to -20 °C
  • Thermal conductivity measurement
  • Thermal imaging camera


QEWSplus - Quality Improvement for Near-Surface Geothermal Systems

ZAE Bayern KopernikusPower2X Projekt

This joint project with a total of eight partners is funded by the Federal Ministry for Economic Affairs and Energy. It deals with improving the quality of near-surface geothermal systems. Building on the knowledge gained in the preceding project QEWS II, important aspects from design and planning to execution and commissioning are being investigated, solutions to problems developed. Four sub-tasks deal with thermal testing methods, TRT testing devices, backfill materials, and modelling, with several project partners contributing their expertise to each.

In its sub-project, ZAE Bayern is developing an in-situ measurement and evaluation procedure that enables the testing and determination of the thermal-energetic properties of connected geothermal source systems during start-up. Moreover, the thermal response test (TRT) procedure is to be made usable for further source systems besides borehole heat exchangers to characterise thermal behaviour in the subsurface and improve design calculations. The already existing testing rig for TRT devices will also be further developed and used to establish certification rules for such devices. Furthermore, the quality of various backfill materials, especially with regard to freeze-thaw cycles, will be further investigated and means of improvement sought.

The project's overall goal is to maintain and increase the quality of near-surface geothermal systems. Risks are to be reduced, energy production costs lowered while efficiency and plant availability as well as awareness and public acceptance of near-surface geothermal systems are to be increased.

Head of Project: Hanne Karrer,
Project Duration: 01/2021-12/2023


HT-VSI - Development of a Vacuum Super Insulation for Highly Efficient Thermal Insulation in Industrial High-Temperature Applications

ZAE Bayern-open_BEA Projekt -  Graphik

A large share of Germany's primary energy consumption is accounted for by processes in energy-intensive industries (e.g. metal, glass) at high temperatures (200 to 1,000 °C). However, despite thermal insulation and heat recovery, high thermal losses are common to occur. To increase industrial energy efficiency, this project addresses the development of a highly efficient high-temperature thermal insulation in the form of vacuum super insulation (VSI). The functional principle of VSI rests on the evacuation of porous powder materials (fumed silica, expanded perlite) to suppress gaseous heat conduction. By compacting the powders into sheets and wrapping them in a vacuum-tight film, flat vacuum insulation panels (VIPs) may be produced in particular. The main application for high-temperature VIPs in this project is containerised mobile solid-state heat storages with storage temperatures of 200 to 600 °C. These are to be equipped with high-temperature VIPs to improve their storage efficiency and make better use of the high waste heat potential of energy-intensive industries, both internally and externally (district heating).

Head of Project: Peter Osgyan,
Project Duration: 12/2018-5/2022

GERDI - Energy Efficient Heating of Surfaces using CO2 Borehole Heat Exchangers

Most critical exterior traffic areas in Germany are heated directly using electricity. Ground-coupled heat pumps, which are also already in use, work much more efficiently. The technology of the directly coupled CO2 geothermal probe, on the other hand, which exclusively uses geothermal energy, does not require any additional power for pumps or a compressor. This saves conventional energy, thus reducing CO2 emissions.

The aim of the planned project is to highly extend the technology's field of application and work out the necessary basic principles. First, questions about heat transfer in a CO2 thermosiphon and in surface heating elements will be dealt with. The findings will serve for developing prototypes, which will then undergo laboratory trials. In parallel, the software needed to design such a system will be developed. Finally, two demonstration units will be equipped with the technology and monitored.

Head of Project: Lars Staudacher,
Project Duration: 06/2019-05/2022

C/sells - The Energy System of the Future in Southern Germany

ZAE Bayern - Csells-Projekt

C/sells is cellular, participative, and diverse - just like distribution networks. But for medium and low voltage, we need to catch up on the availability and handling of metering data as well as the understanding of consumers and distributed resources and future challenges such as charging stations. To prepare distribution networks for a power supply largely or completely based on renewable energy, ZAE is researching the grid-relieving effect of flexibility provided by a community storage system with redox flow batteries in C/sells.

Head of Project: Christoph Stegner,
Project Duration: 01/2017-12/2020

ZAE Bayern

We conduct applied research at the interface between basic science and industrial application. Our methods and systems aim to achieve CO2 neutrality and thereby counteract climate change through the intelligent and efficient use of renewable energies.

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