Flender uses waste heat from its in-house hardening facility to heat buildings
The scene in the Flender hardening shop is spectacular: flames several meters high leap out of a cooling basin and light up the dark walls of the hall. Just seconds earlier, an employee used a crane to lift several red-hot gears from a hardening furnace into the basin. The gearbox components, heated to 840ºC, are plunged into an oil bath. It is obvious that gearbox specialist Flender needs a lot of energy to operate its 26 hardening furnaces at the Bocholt site. Now, part of this energy is fed back into the process, and heats the site – another step on Flender’s journey towards more sustainable production.
Flender requires around 20 million kilowatt hours of electricity annually to harden 15,000 tons of geared component to ensure their surface quality. This is a significant amount of energy, and yet the gear manufacturer is by no means one of the energy intensive companies such as steel mills or foundries. Only through the hardening process does the surface of the gears achieve the quality needed to ensure that gearboxes in applications, like wind turbines, run reliably and efficiently for decades. Energy to drive the energy transition, so to speak.
For several years, Flender’s building and facility management team has been exploring ways to reuse this energy. For a long time, the technology required was lacking. “With the launch of the new heat pump, we can transfer the waste heat generated when cooling the hardening furnaces to the site’s heating system. This is a unique process in this setup and scale,” explains Project Manager, Robert Iding.