Refrigerant Cycles

  Refrigerant cycles Copyright: © EBC

Our vision is an energy-efficient and sustainable heat supply through systematic development of the refrigeration cycle process - from molecule to operating strategy.

We investigate heat pumps and chillers with focus on increasing energy efficiency and reducing direct emissions. Starting with specific fluid selection, to optimal component design, system aggregation and control, we develop and support the next generation of refrigeration cycles, both on a civil and industrial scale.

Thereby, we combine theoretical analysis with experimental investigations at the hardware-in-the-loop test bench. The development of static and dynamic refrigeration cycle simulations is based on thermodynamic principles using widely available programming languages (Matlab, Python, Modelica). By using experimental data of our test benches, the simulation models can be calibrated and validated, both for entire refrigeration cycles and for individual system components. In this way, generally applicable and at the same demand-oriented design and control strategies are developed, which can be applied to future refrigeration cycles.


Compression chillers and heat pumps are established energy conversion machines with a long history of use in both civil and industrial applications. Simply put, these machines are an integral part of everyday life! Depending on the application and field of use, they provide cold and heat in a wide temperature range (cryogenics / domestic hot water). Due to the advancing climate change and the development towards an electrified total energy system, the heat pump is considered a key technology for the heat supply of the future. Recent discussions also show that heat pumps are becoming increasingly important for innovative process approaches (electricity-heat-electricity-storage systems) in the high-temperature range as well.

In summary, our main research topics are as follows:

  1. Theoretical and experimental analysis and evaluation of refrigerants with a focus on sustainable refrigerants (hydrocarbons, CO2 and refrigerants with a low greenhouse effect).
    • Pure substances
    • Tailor-made refrigerant mixtures oriented to specific applications
    • Safety considerations of flammable refrigerants
  2. Optimization of design and operation of the refrigeration cycle process
    • Dynamic simulations of complex refrigeration cycle schemes
    • Experimental investigation on hardware-in-the-loop test bench
    • Method development with focus on different control strategies (analysis of frost formation and corresponding defrosting strategies)
  3. Analysis and optimization of individual system components
    • Investigation of frosting and defrosting processes of evaporators with air as heat source
    • Theoretical and experimental analysis of different compressor types using a compressor test bench
    • Interactions of oil and working fluid

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