Innovative refrigeration technology based on natural refrigerants

With the aim to protect and preserve the environment by reducing the greenhouse effect and in the resulting search for halogen-free alternative solutions for refrigerant in the freeze-drying process, we started in 2005 our cooperation with a renowned pharmaceutical company. An innovative technology based on natural refrigerants has been developed and has already been successfully implemented by our customers at 60 plants over the past years.

We have searched for applicable refrigerants in due consideration of the ODP, GWP and TEWI factors. A two-stage refrigeration system (cascade) is necessary because the low temperature of natural refrigerants can not be achieved in a single stage. The non-halogenated refrigerants R1270 and R170 with a larger energy spectrum (GWP = 3, ODP = 0; Bitzer Kühlmaschinenbau GmbH , Kältemittel-Report , 16. Auflage, page 36 ) can be chosen as a long-term alternative to conventional refrigerants. The global warming potential is considerably reduced compared with the refrigerants such as R507A (GWP = 3850, ODP = 0; Bitzer Kühlmaschinenbau GmbH , Kältemittel-Report , 16. Auflage, page 36).

In addition to the cooling circuit of the chamber, a coolant circuit for the condenser is installed in a modular design. This enables a spatial separation of the freeze drying plant and
the refrigeration system with hydrocarbon. Therefore, vacuum pumps, measurement units, amongst others, don’t have to fill the ATEX requirements (explosion protection). The refrigeration systems are housed separately and are fitted with the appropriate safety concepts according to ATEX Zone 2.

For process safety reasons, a redundant configuration with improved capability can effect the required cooling performance.

The pioneering refrigeration technology can be used for new freeze drying equipment as well as in retrofitting of existing plants.

The advantages at a glance:

1. The encased refrigeration systems can be spatially disposed in a flexible way inside or outside

2. The ATEX requirements only apply within the encased refrigeration systems.

3. Freeze drying equipment with multiple refrigeration systems secure the process. In case of failure at one of the refrigeration systems, the second refrigeration system is sufficient to secure the product.


"Due to the established use of natural refrigerants in the past years, we are facing the challenges of the future with confidence and we are right now able to advance new concepts."

Holger Prinz - Head of Service