Using a computer program, Kaiser can analyze precisely when, where and how much electricity is consumed. Like a cardiologist carefully analyzing the curve of an EKG, Kaiser looks at the trends in energy consumption twice a week.
“You can quickly track down outliers – perhaps due to defects – in this way,” said Kaiser, a certified electrician. The energy monitoring system was set up step-by-step after a basic plant reorganization that added 1,000 square meters of production space.
“This was almost a new construction,” said business unit manager Angelo Acerboni. “We updated nearly the entire electric system, creating the basis for improved energy management.”
As they set up the monitoring system, the staff benefited from the experience that Freudenberg’s plant in Öhringen, Germany, had gained earlier. But Kaiser and his colleagues were not content to merely observe and cut electric power consumption. They wanted to actively control it.
To avoid expensive peak loads, special software forecasts the average output for the current 15-minute interval. If a limit looks as though it is going to be exceeded, certain machines are automatically instructed to take a break – so current manufacturing operations are not impaired.
For example, this can be done with the electric furnaces used to heat up the tools that are needed later. The Oberwihl team has identified about 25 installations that it can use to control levels of operation.
Energy experts call this process “demand-side management.” It is considered a key technology to safeguard energy supplies in a system based on the fluctuating availability of wind and solar power.
Small steps, great effect
But systematic energy management in Oberwihl does not just involve electric power. Over the past few years, all the processes involving cooling and heating were examined.
Sometimes it was easy to find real savings – for example, as Acerboni noted, the cooling unit in one hall during the summer was always working at maximum power – still, the temperature never reached the set level of 18°C due to waste heat from production operations.
Now that the target temperature has been increased to a more realistic 23°C, the company has been saving 50,000 Euros on electricity per year.
Nonetheless, it is cooler in the manufacturing area than before the restructuring. That’s because the waste heat produced at the injection moulding machines is suctioned away with the air and partly used for other processes with the help of heat exchangers.
And with smart heat management, the consumption of heating oil has been reduced by up to two-thirds, depending on the time of year.
The compressed air supply also deserves close attention. The management of the energy-devouring compressors is now based on demand.