The OTTC and BITZER: Then and now

The Open Trade Training Centre (OTTC) recently had their 25th anniversary. They celebrated 25 years of internationally certified training courses for Commercial and Industrial Refrigeration, Air-Conditioning, Ammonia Refrigeration, Heat-pump Systems, Electrical Engineering, Controls for R & AC and Transport Refrigeration. They also celebrated 25 years of award winning excellent and quality courses that provide and advance technical, practical and theoretical knowledge.

This type of excellence does however not come without a rich history. OTTC’s history stretches back a long way before it was founded by Peter and Isolde Döbelin in 1992. In a recent interview with Isolde Döbelin, she gave us a taste of this history.

“Peter Döbelin worked close together with BITZER Germany in his time working at Ahlborn, Hildesheim from 1962 to 1972 when he started his own company in 1972.

His first contract was to build the refrigeration system for the University in Freiburg/Black Forest. This was probably one of the first Multiplex systems built in 1972. It was his own design.

The first Heat-Pump system was designed and built in 1972 for our own house in Sulzburg, Germany using a spring going through our cellar into the river behind our house as primary energy source cooling it down 30 ⁰C. Of course he was using the BITZER equipment for all the Heat-pumps and other jobs until immigrating to South Africa in 1982.

In 1984 he started again his own company “Combitherm” in South Africa and built Heat-Pump Systems for special applications. His last Heat-Pump build was for an Indoor-Pool in Sandton in 2000 for the OTTC Technical and Air-Conditioning Diploma Project.

Before we started the OTTC Training Centre in 1992, Peter built the first Reclaim Unit for Refrigeration with a BITZER Compressor.

For the development of training material, Peter also used the BITZER Reports and Catalogues.”

At their anniversary event in June 2017, OTTC unveiled a new BITZER CO2 training rack. Training conducted using this new training rack falls within OTTC’s belief in quality training that must be relevant and practical – to prepare learners for various situations encountered in the workplace.

Isolde goes on to explain this new addition: “The OTTC CO2 Plant is a Cascade using 134a and CO2, including special applications and test equipment for training purposes and plant building according to German Standards. The control system was sponsored from Elreha, Germany in 2015 when Christian Richter started with the plant.”

The CO2 training plant was sponsored by the German and South African HVAC&R industry and was designed and built by Christian Richter and Wolfgang Richter. The training rack consists of a CO2 Low Temperature stage in which the lead BITZER compressor is equipped with a BITZER VARIPACK frequency inverter. It also contains an R134a Medium Temperature stage in which the lead BITZER compressor is equipped with a BITZER VARISPEED.


CO2 Training rack compressors

Quantity Compressor
2 4EES-4 1CR2 Compressor c/w CCH
2 2MSL-07K CO2 Compressor c/w CCH


Click here to have a look at some photos of the event: OTTC 25th anniversary details



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