Biotechnology Roche

One important process in the research and production of biotechnological products is freezing and defrosting substances for transport and storage. For the pharmaceuticals company Roche the contractor Peter Huber Kältemaschinenbau developed a chiller run on propene using a reciprocating compressor by Bitzer.

Requirements

For the (de-)frosting processes Roche uses tanks with a volume of 300 l which are cooled down to -40°C in a clean room atmosphere. Here the company wanted an efficient refrigeration system to cope with fast changes in temperature between -50 and 130°C with an accuracy of +/- 1 K, with automatic drainage and refilling of the tank's cooling jacket. Furthermore, compliance with the Roche Environment Protection Guidelines restricted the choice of refrigerants to substances that protect the ozone layer and the climate.

Solution

To meet these requirements, the contractor implemented a chiller that works with a small charge of 1.8 kg propene. The core element of the system is a two-stage semi-hermetic reciprocating Bitzer compressor, which is designed for use with propene. After being brought down to a temperature of -60 to -30°C, the propene then cools the silicone oil circulating in the cooling jacket. The output is 12 kW at a secondary refrigerant outlet temperature of 0°C, and 6.5 kW at -40°C.