Since May 2011, UFA’s poultry feed mill built in 1965 has been one of only a few unmanned feed mills in the world. The mill runs from 9 p.m. until 5 a.m. without any operating personnel.
Mechanical engineer Peter Hofer is a member of management and responsible for the entire production of UFA. Using power as efficiently as possible for UFA’s large production volume is important for him and the company – for reasons of cost and for the sake of principle:
“You can do a lot to efficiently use energy if you analyze the processes accurately," stresses Hofer.
Working with the Bühler Technology Group, UFA has been particularly successful in optimizing processes at its Sursee feed mill. The energy savings mean the investment pays for itself in just a few years.
Until the beginning of 2015, an aspiration ventilator was installed here with a conventional 75 kW induction motor. This ventilator dehumidifies and cools the steamed, pelleted feed before it is packed.
For this, it draws the air through the material to be dried from the tenth floor of the production tower. The ventilation was controlled simply via a flap; the motor directly coupled to the power grid always operates at fixed speed.
This ventilation system, which was state of the art when it was installed in the 1980s, needed to be replaced.
“I read a technical article about a ventilation system at University Hospital in Zürich where, during a renovation, a new, highly efficient synchronous reluctance motor from ABB with a frequency converter was used. I was impressed by the figures that showed how much less energy it used," remembers Hofer.
Peter Hofer sat down with experts from Bühler to explore the potential efficiency improvements that renovating the ventilation system with an ABB drive package could bring. Together, they first thoroughly inspected the process of measuring the power of the motor.
The new plant was finally precisely designed along with specialists from ABB and Bühler.
A 37-kilowatt (kW) ABB synchronous reluctance motor was installed for the drive of the new aspiration ventilator, controlled by an ABB ACS880 frequency converter.
The solution was made possible by excellent collaboration between UFA, Bühler and ABB in Switzerland.
“When three proven specialists contribute equally to the solution and bring their expertise to the table, impressive savings are possible."
The commissioning was carried out together with an ABB engineer and a Bühler process expert in April 2015. The ventilation system has proven itself completely. It runs five to six days a week around the clock, all year round.
The results are convincing: On average, the motor draws an electrical output of 14 kW from the converter.
"It's around 300 megawatt-hours in this system", he continues. "At approximately 120 Swiss francs ($118) per megawatt hour for industrial electricity, that makes 36,000 Swiss francs ($35,400) a year. The drive package pays for itself quickly. And the reduced CO2 emissions are also considerable."
Additional positive side effects, such as a reduced need for cooling in the control cabinet, reduced space requirements, and savings due to the smaller size of the motor, have not yet been considered in this analysis.
Synchronous reluctance motors had already been retrofitted in the UFA plant in St. Margrethen, and two more are installed in the Herzogenbuchsee plant.
“I think these efficient systems are in increasing demand in the market, if the investment costs are offset with the entire life cycle costs. The savings speak for themselves – even the reduced CO2 emissions from an operation."