Case studies

Zipf Brewery / Austria

Planning / Implementation / Main components

KWN Engineering Gesellschaft mbH


Ammonia (NH3)

System start-up


The Zipf brewery, a Brau Union Österreich AG brand, relies on an ammonia plant with slurry ice as coolant for its refrigeration needs. The retrofit was realised by Austria’s KWN Engineering GmbH.


The new system was to reduce the high energy consumption associated with the old pumping and refrigeration system. The modernisation had to be undertaken without interrupting operations.


The refrigeration experts at the Austrian company KWN Engineering Gesellschaft kept the existing refrigeration system, but replaced the coolant cycle as well as part of the ammonia pump system with slurry ice – a mix of ice, refrigerants and anti-corrosives. Most of the existing pipelines were kept, as were the heat exchangers on the beer tanks and in the refrigeration rooms. New installations included two 230-kilowatt ice generators and air coolers supplied by Güntner. A 110 m³ silo with a refrigeration capacity of 2,800 kW was added to serve as an ice bank.

Technical data:


Type of facility

Central system



Refrigerant volume

500 kg

Secondary refrigerant

Slurry ice

Refrigerating capacity

2 x 230 kW

Main components

Heat exchangers, two ice generators, air coolers, ice bank

Special features / Comments

Retrofitting the refrigeration plant made it possible to reduce the charge to 500 kg of ammonia. At the same time, the required system output was essentially cut in half, from 1,300 kW to 670 kW.



KWN Engineering Gesellschaft mbH
Bernd Kaltenbrunner
Sommerweg 13
A-5201 Seekirchen

Phone: +43 (0)6212 7833
Fax: +43 (0)6212 7833 14
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