Variable speed compressor cuts energy costs at world’s oldest brewery

The brewery, established by the Benedictine monks of Weihenstephan Abbey in 1040, is believed to be the oldest brewery in the world, and now produces premium wheat beers in Freising near Munich. Gerd Abstreiter, engineering manager, says that, as well as electricity, nearly all this plant's processes require compressed air and steam. He also explains that the brewery's previous compressed air system comprised two CompAir oil-free piston compressors, supplying 7.8m3 and 10m3 of compressed air per minute respectively – one operating at full load and the other at half load. That worked for full capacity operations from Monday to Friday, but not when production was reduced for night shifts and at weekends. "When the brew house and bottling plant are both inactive, we only need around 1.5 m3 of air per minute to maintain the system pressure and operate the pneumatic control elements," says Abstreiter. "As a result, the large compressors were spending a lot of time idling, which was uneconomical." Abstreiter says the plant worked on repairing leaks – reducing the amount of air lost by 50% – while also installing a new control system and compressor in the form of an oil-free, variable speed D22H RS unit, also from CompAir. He explains that, with its PureAir technology, the compressor generates totally oil-free air, making it ideally suited for the brewery's hygiene requirements. Also, water is used to lubricate, seal and cool the equipment, meaning low compression temperatures of just 60°C. Variable-speed drive technology now matches compressor flow to demand, he says, resulting in greater efficiency. He also reports that the new setup has improved production reliability; if one of the two larger compressors fails, there is still enough air to meet requirements. The D22H RS was also integrated into the brewery's compressor control system, so allowing operators to monitor the demand for compressed air and review recent consumption trends. "Together with CompAir we measured the power consumption of the system and found that the combination of the new compressor and the leak repairs has reduced our electricity consumption by around a third," confirms Abstreiter.