alphagamma® technology

When we put the first prototypes of the motors using the alphgamma® process into operation at the beginning of 2018, we knew after a short time that we were on the right path.

The difference between the standard alpha Stirling motors and the new alphagamma® technology can be illustrated graphically as follows:


Standard alpha principle

This schematic representation shows the structure of a Stirling-alpha principle, as can be found in many publications and numerous design implementations.

alphagamma® principle

A stepped piston is used in the alphagamma® process, which divides the compression volume between two cylinder chambers.

Stirling alphagamma Prinzip
The effects of the stepped piston along with the division of the compression volume are essential: Despite the same cycle work, the piston forces are reduced by about a third compared to the standard alpha design. The reason for this lies primarily in the smaller effective piston cross-sections supported by the lower pressure peaks as a result of the larger resulting phase angle. The results are smooth running, low friction losses and a very long service life for the oil-free operated units.

Read more about the thermodynamic analysis, in which we show comparisons with the Standard Alpha, “optimized” Alpha and alphagamma® processes.

Please also take a look at the expert reports:

Expert reports

Dr. Michael Gschwendtner of Auckland University of Technology (AUT) has been dealing with thermodynamic calculation methods, particularly in the area of Stirling technology, for many years.

We have asked Prof. Dr.-Ing. Bernd Thomas of Reutlingen University to analyse the alphagamma® technology and write an expert opinion.

Prof. Thomas has been working with thermodynamic machines, in particular with Stirling engines and refrigeration machines, for over 30 years.