Thermal Energy Storage - TES -

The Thermal Energy Storage group researches heat and cold storage based on phase change materials (PCMs) and sorption materials. Their research approach ranges from the development and optimisation of individual materials and components to the integration of thermal energy storages into complex energy systems. Storage materials and units for heating/cooling systems, for efficient household appliances, for industrial waste heat utilisation, and for automotive applications are being investigated.

The main work focuses are:

  • Development of highly performing, efficient, and cost-effective heat and cold storages
  • Construction of storage components, design, construction, and monitoring of demonstration setups and solutions for system integration
  • Measurement, modelling, and development of PCMs
  • Characterisation and modelling of sorption materials for open systems (at atmospheric pressure) to be used in heat storages and heat pumps as well as air dehumidification
  • Research on fundamental issues, e.g. the theoretical limits of storage capacity or the cycling stability of storage materials
  • Simulation of fixed beds and mass transfer surfaces for solid and liquid sorbents

Head of Group:
Dr. Stefan Hiebler
Walther-Meißner-Str. 6
85748 Garching
Tel.: +49 89 329442-35
Fax: +49 89 329442-12

Deputy Head of Group:
Dipl.-Phys. Christoph Rathgeber
Walther-Meißner-Str. 6
85748 Garching
Tel.: +49 89 329442-88
Fax: +49 89 329442-12

Services & Equipment


  • Calorimetric determination of the heat storage capacity of PCMs for temperatures ranging from 80 to 1,500 °C
  • Investigation of the thermal cycling stability of PCMs for temperatures ranging from 40 to 200 °C
  • Measurement of latent heat storage systems and heat exchangers for such
  • Investigation of crystal structures and determination of crystallisation rates
  • Determination of the water adsorption capacity of solid sorbents for temperatures ranging from 20 to 350 °C at -15 to 80 °C dew point temperature
  • Determination of temperature and dew point breakthrough curves for fixed beds of solid sorbents
  • Investigation of thermal and hydrothermal cycling stability of solid sorbents


  • Calorimetry: DSC, STA, Calvet and T-History calorimeters
    • Temperature range from -80 to 1,500 °C
    • Sample sizes from about 5 mg to 30 g
    • Measurements according to the guidelines of RAL-PCM Guetegemeinschaft PCM e. V.
  • Cycling apparatus for solid-liquid PCM
    • Temperature range from -40 to 200 °C
    • Sample size of about 60 ml
    • 2 to 3 thermal cycles per day
  • Testing rigs for characterisation of heat exchangers and latent heat storages
    • Temperature range from -10 to 95 °C
    • Volume flow up to 3 m3/h
    • Thermal power up to 25 kW heating/cooling
  • Polarisation microscope
    • Programmable heating and cooling stage for measurements from -190 to 400 °C
  • Microbalance for determination of the water absorption capacity of solid sorbents
    • Temperature range from 20 to 350 °C with -15 to 80 °C dew point temperature
    • Sample size: several grams
  • Self-developed testing rigs for determination of the water absorption capacity of solid sorbents
    • Dew point temperatures from 5 to 70 °C
    • Ambient air temperature up to 300 °C
    • Sample size in kilogram range
  • Testing rig for mass transfer surfaces for liquid sorbents
  • Cycling apparatus for solid sorbents
    • Dew point temperatures from 5 to 70 °C
    • Ambient air temperature up to 300 °C
    • Sample size of several hundred grams
    • Adaptations to real process conditions possible

ZAE Bayern

We work at the interface between knowledge-based basic research and applied industrial research. Under the motto "Excellent Energy Research - Excellent Implementation", we realize complete innovation packages that build on synergies between generation, storage and efficiency measures.

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