Sustainable refrigeration for Nuremberg grilled sausages
The Nuremberg-based company HoWe Wurstwaren has modernised its existing refrigeration system and now cools using the natural refrigerant ammonia (R717). This not only makes it future-proof, but also enables it to achieve significant efficiency gains.
More than 8,000 m2 of production space is now cooled with
- a BITZER Ammonia Compressor Pack (ACP) for an evaporation temperature of –5°C, and
- a rack with three screw compressors from the OS.A74 series by BITZER for an evaporation temperature of –10°C.
The task facing the implementing company, Amberger Kühltechnik, was challenging: the new system, with a total cooling capacity of 2.4 MW, had to be installed alongside the existing, repeatedly expanded cooling system – while operations continued. Work on-site could only take place on non-production days, and all installations had to be planned and installed around the existing components. The new pipes alone are 2,500 m long, 1,300 m of which are made of stainless steel. A new machine room was specially built on the roof of the production hall to centralise as many components as possible. As the entire NH₃ circuit is housed there, a filling quantity of 900 kg is sufficient; further distribution is carried out with 21,000 l of propylene glycol.
Each compressor is equipped with a frequency inverter for precise capacity control. The racks have separate low-pressure sides and a common high-pressure side. The system also includes two condensers for +36°C and +42°C and 26 air coolers with glycol for room temperatures from 0°C to +12°C. The waste heat from the oil cooler and the heat from the compressed gas are used for heating and defrosting. An outlet in the pressure line allows for the subsequent retrofitting of a heat pump.
