Our Team

Our Team


Founder and
Senior Advisor

Walter Mittelbach founded SorTech AG, the predecessor of FAHRENHEIT, in 2002. For many years, he built up the company as CEO. Walter Mittelbach holds several patents on adsorption technology and, together with his team, won numerous awards for developing efficient and compact adsorption chillers. He continues to shape our technology and product development as Senior Advisor.

Walter Mittelbach was a researcher at Fraunhofer Institute for Solar Energy Systems (ISE) in Freiburg. He studied physics at Graz University and at Free University Berlin.



Matthias Hoene has been in charge of leading FAHRENHEIT since 2017. He started his career as a software developer with Trilogy Software in Austin/Texas, and went on to become a project manager with BMW in their logistics division. He then joined McKinsey as a consultant to automotive, high-tech, and healthcare clients. In 2010, Matthias Hoene co-founded ZebraMobil GmbH in Munich, the first free-floating car sharing operator in a major city. After selling the car sharing operations of ZebraMobil, he returned to McKinsey to run Horizon360, an internal startup which offers data and standard tools to help with IT and Digital transformations.

Matthias Hoene graduated from ETH Zurich with a degree in Industrial Management and Production Engineering, and holds an undergraduate diploma in Mechanical Engineering.


Head of Sales

Gregor Feig is in charge of sales for adsorption chillers. Mr. Feig, who is originally an architect, first joined our company in 2011 as Sales Manager for Southern Germany. In the meantime, he served a stint as Sales Manager for a maker of digital building models and simulations. Prior to joining FAHRENHEIT, he has worked in various sales functions, including in his own business. He started his career as a planner in engineering companies.

Gregor Feig completed his architectural studies at the University for Applied Sciences in Regensburg.

Dr. Ralph

Head of Research &

Dr. Ralph Herrmann is in charge of research and development at FAHRENHEIT. Trained as a chemist, Dr. Herrmann dedicated a large part of his professional life to researching and evolving zeolite crystals. He holds numerous patents in this field. Since 2004, he has been applying his expertise at FAHRENHEIT.

Prior to joining FAHRENHEIT, Dr. Herrmann obtained his Ph.D. from the University of Halle and spent several years at the University of Erlangen as a researcher and as a lecturer for chemical engineers.

Dr. Ralph Herrmann


Technical Director

Steffen Kühnert is Technical Director at FAHRENHEIT. He joined the company in 2007 as development engineer. From then, he took on responsibility for both product development and manufacturing. Prior to joining FAHRENHEIT, Steffen Kühnert had been working for engineering companies. He started his career by serving seven years in the German armed forces.

Steffen Kühnert completed an apprenticeship as a cutting machine operator and holds a diploma in Mechanical Engineering.

Steffen Kühnert

Dr. Alexander

SVP Business Development

Dr. Alexander Raach is in charge of Business Development at FAHRENHEIT. He began his career as a consultant at McKinsey, where he served clients primarily in high tech industries. Subsequently he served as CTO at motionID technologies AG, where he was responsible for technology, product development, and operations. Prior to FAHRENHEIT, he was Chief of Staff and Head of Program Management at semiconductor manufacturer Globalfoundries in Dresden.

Dr. Raach holds a degree in physics from the Technical University of Munich and a doctorate in statistics from LMU Munich.


FAHRENHEIT derives its strength from a highly skilled and motivated team of technicians, developers, scientists, and business experts in Halle and Munich.